CUBANGBANG, JEFFERSON S.

2162462

A STATE OF THE ART REVIEW ON REINFORCED CONCRETE VOIDED SLABS

The excess concrete from the insignificant or unnecessary parts of the structure are removed by the voided slabs to
reduce the weight of the structure. About 27 years ago it was invented in Denmark and is now gaining wide popularity in the
world. This study is subjected primarily to make reviews on the many studies that were accomplished on voided slab system. In
this review is incorporated the tabulated specialized parameters of the voided slab system systematically. This review includes
the theoretical investigation and documentation action of the works done by the creators on the voided section ideas.

Voided slab systems are being used as an alternative to the traditional concrete slab used way before until now in
construction. Voided slabs can pretty be much lighter than the conventional concrete slabs while it tries to maintain long spans.
This review of the voided slab system also explains how the voided slabs are being constructed and how long spans and reduced
weights influence the building design. Usually in the design of structures, the common limitation is that the span of the slabs
between columns are restricted or are so limited to the expense of having so much redundant of columns for a voided slab
perspective. In the design of long spans between those columns often times require the utilization of support beams and/or large
depth slabs therefore increasing the structure’s weight requiring more volume of concrete and in the sense also makes cost.
Lightweight structures are always better and preferred because of the smaller dead load for structures decreases the magnitude of
inertia forces. Heavy dead load usually contributes to a higher seismic weight and lastly, incorporating support beams can also
add to a higher floor-to-floor height which normally would increase the costs especially for cladding and finish materials.

In the voided slab construction, voided slabs are being utilized to remove the concrete in areas of the sections where the
slab is expected to less resist the applied loads of the slab. Between the voided slab and the conventional slab, the voided slab
tends to act with the same section modulus and stiffness, but the thing is that the self-weight of the structure is greatly reduced to
a significant figure.

BACKGROUND AND THEORIES

It was in the middle of 19th century that a new system for the voided slab system was invented. This was pioneered by
the inventor Jordan-Breuning which is the Bubbledeck System. He then found out that the bubbledeck system reduced the weight
for more than 30% with comparison to the conventional slab system and it allows a longer span between the supports. In this kind
of technology, it locks a sort of ellipsoidal shapes from the top to the bottom reinforcement’s mesh, thus making a natural cell
structure which act like a conventional solid slab.

The same principles were applied in the concrete slabs in a find to make a way of making the slabs lighter in South
Africa and is called the Cobiax System during 1997. The cross section of the Cobiax system is actually more complex than that
of the bubbledeck system but the significant thing is that the flexural design has no significant problems. There were entirely no
design codes of practices has a design specific recommendation for Cobiax system. Shear resistance of the Cobiax system were
further researched in Germany. In this type of system, decks from the lower layer of reinforcing steel and the deck at the bottom
of the slab must also be placed. Steel wire meshes covers the voids in the system which can still be altered to fit some parti cular
kind of applications. This type of method may require a more number of formworks specifically and of course the labor costs, but
what makes it cheaper is that it requires a less transportation of materials.

Elliot et al. (1982) introduced the plate bending stiffness of circular hollow slabs. Results had comparison with the
previous results that had been made which obtained from test on a voided elastic plates. The tests were made ion 4 epoxy resin
model plates with variable sizes. In their methods and designs, charts were use and presented which helped any designer of a
concrete slab, with poisson ratio of 0.2, determine the plate bending stiffness that are required for an analysis of thin plates such
as slabs.

Abdel Rahman and Hinton (1986) made present the nonlinear and the linear finite element analysis of reinforced
concrete voided slabs where it is based on a slab-beam model. This layer approach allows the difference in the state of materials
across its thickness. It was then found out that the slab-beam formulation was it was adequate in describing the structural
behaviors of composite slab beams.

Stanton (1992) introduced program supported by results, and it was conducted to determine if the response distribution
in voided slab floors subjected to loads. They used an extensive computer generated parametric study to even precisely and
accurately analyze all the responses on the elements of the slab. They found out that the proposed analysis rules behave more
closely with the rules presented in the PCI Manual for the Design of Hollow-Core Slabs and it showed that the PCI Manual was
too liberal for others and conservative in some cases.
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Yang (1994), presented how to find the required capacity of shear on the webs of typical voided core slabs. Pre-stress
forces of strands which caused an increase in the shear stresses were also taken into consideration in this procedure. Model slabs
and test specimens were where the proposed procedure was applied.

DESIGN and METHOD

In areas where openings do exist, Ghadiali and Johnson (1972) investigated the distribution of loads on a hollow core
slabs that are precast. The panels had a total of 4 precast units where shear keys are being connected with a 40x40cm opening
panel-centered. The type of test that was made in the field test was made in a pre-stressed concrete plant using equipment and
materials that are normally available to them, however the test procedure can’t really make comparisons with the techniques of
the laboratory testing which are rigidly controlled. Moreover, they said that the type of field testing that was made can be coupled
with types of analysis which may prove and provide a relevant information and useful data.

RESULTS and FINDINGS

Based on the reviews of the previous investigations, the mode of behavior of hollow or voided slabs were primarily
simulated with numerical analysis and laboratory experiments were carried out with differing void shapes, reinforcements and a
numbers of geometry.

Basically, it was found out that most reviews do prefer the use of a voided slabs since it is of convenient use in flooring
and roofing since it accounts to much lesser self-weight of slabs, they find ease in the construction of the voided system and a
lighter system for supporting.

The previous studies showed that: the deflection of the slab decreases as the diameters of the void decreases also,
between the waffle slabs and the conventional solid slabs, waffle slabs were found to have higher flexural rigidity than that of the
solid slabs, the decreasing in the ratio of void to depth improves the load distribution cross the entire voided slab, test results were
found out that the reduction in percentage of cross sectional areas of the voided slab ranges from 30 percent to 40 percent, the test
results also indicated that the utilization of rectangular or square solids instead of the circular reduces the ultimate capacity by
2.8% and 14.7% relative to the voids in circular shape respectively for the hollow core slabs, the test also proved that the full load
distribution is capable of achieving until the ultimate flexural capacity of the system, the weight reduction in percentage yields in
the range of 19-35%, when utilizing the minimum shear reinforcement it usually increases the shear capacity of the voided slabs
significantly., it is found out that the decreasing of shear spans to an effective depth ratios for a aggregates that are lightweight
results to an increase in the cracking strength and ultimate strength so the mode of failure varies from flexural to a shear flexural.

LIST OF REFERENCES

Adel, A., & Omar, A.A. (2018). A State of the Art Review on Reinforced Concrete Voided Slabs. Journal of Engineering and
Applied Science, 13(5). Retrieved from http://www.arpnjournals.org/jeas/research_papers/rp_2018/jeas_0318_6852.pdf.
CUBANGBANG, JEFFERSON S.
2162462

DYNAMIC COMPRESSIVE STRENGTH AND CRUSHING PROPERTIES OF EXPANDED POLYSTYRENE FOAM

FOR DIFFERENT STRAIN RATES AND DIFFERENT TEMPERATURES

In this study, the crushing tests and the dynamic and static compression tests were conducted on an expanded
polystyrene (EPS) foam, which is one of the two kinds of polystyrene, for characterization of materials at high rates of strain.
This is accomplished to obtain the stress-strain curves for varying densities and temperatures. On the experimental data, an
influence of the strain rate is shown. Through tests with the high speed drop tower, curves for modelling had been extracted from
the experimental data. Also, the methodologies for the experimental data processing for the finite element (FE) is also presented
in this study. LS-Dyna was the foam material model that was used to simulate the process of dynamic compression. The model is
dedicated in modelling foam of crushable structure with strain rate effects, tension cut-off and an optional damping.

There are many variations or types of polystyrene, but EPS foam is the choice for many materials because of it having a
high energy absorbing efficiency. Efficient properties had been observed with the EPS such as light weight, moisture resistance,
acoustic absorption, low thermal conductivity, good thermal insulation and durability, excellent in energy dissipation properties
and reduction of cost materials.

EPS may undergo a large deformation in compression and absorb energy. Through cell bending and fracture or
buckling, energy is dissipated throughout the material. This just explains how efficient the Styrofoam with high energy. In
addition, for a similar amount of dissipated energy, the specimen would give a max force lower than as solid material of same
material and of equal volume. Wit comparison to other types of foams, EPS remains to be insensitive to temperature changes, it
keeps its capacity in absorbing in both cold and hot conditions.

The density of the foam, has also an influence in the microstructure and also in the properties of the foam. Therefore,
the foam has to be studied with many parameters such as the microstructure, the density, and importantly the strain rate imposed
during the dynamic loadings. The compressive stress-strain behavior of such foams had been investigated over a wide range of
strain rates of engineering from 0.0.1 to 1500 s -1, this is to demonstrate the foam effects on the strain and density strain rate on
the initial hardening modulus and initial collapse stress in the post-yield plateau region. But unfortunately, no studies were made
on the EPS foam. The data that resulted and that were collected can be f help to validate or construct the predictive models, but,
since the materials is in multi-scale.

Wensu Chen et al. presents the paper with the results of a very extensive experimental investigations into the dynamic
and static mechanical properties of EPS foam. Their study can be seen the results of the dynamic and the static compressive and
tensile test data of EPS with a density of 13.5 kg/m3 and 28 kg/m3 with a variable strain rates. However, authors did not explain
how to utilize the data from the resulted experiments. The maximum observed compressive strain rate in their experiments
yielded to an approximate of 280 1/s, not 533 1/s it has been expected. Results from the dynamic and the static compressive
strengths were also reported in their reviews of literature. Their study was utilized to investigate a foam, and this shows that the
rate of strain effects become more pronounced at rates above 1000/s. however, this study did not present a numerical method and
models which can be used to predict the properties of the EPS in simulations of the dynamic responses up to the impact loads.

There are only little articles about the EPS foam modelling, especially topics regarding the study of high dynamic strain
rate. Moreover, analysis about the finite element (FEA) of the EPS foams presented a multiple compressive unloading and
loading of foams of EPS. LS-DYNA and ABAQUS were utilized as comparison to compression test results and diagram for
crushing for multiple types of loadings. A material model was utilized for this type of simulation, which in sense didn’t made
include the influence of the strain rate foams. Masso-Moreu and Mills had presented the works about the dynamic compression of
polystyrene foams that are pyramids in shapes.

Gerhard Slik et al. made an experiments and analysis of finite elements for materials model validations of a very high
energy absorbing foam efficiency, but these were strain-rate is independent in both works.

This article or study rather, presents a detailed comparison between the experimental data and numerical models for the
crushing properties, and the dynamic compressive strength of the EPS foam at varying temperature and varying strain rates.

DYNAMIC COMPRESSION TEST: Foams like EPS can be definitely utilized for energy absorption. Therefore, the
ability and performance of such foams should be studied as a function parameter such as microstructure, density and also the
strain rate that has been imposed during loading it dynamically. 25 mm side length of EPS foam were used in the conduction of
the dynamic compression experiments. These were cut from plate of foams. The size of these specimens, has been chosen to be
able to obtain a reasonable compromise between the maximum quantities of compression of the specimens. In the process of
experimentation, four types of EPS foam had been used.
CUBANGBANG, JEFFERSON S.
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The specimen was weighed and accurately measured before the testing were made, and the density that is apparent was
computed for each type of cubed foams. EPS mostly depends on the material and on the topology. The density of EPS is found to
be 1.0x0-4. During the processes of static tests, the poisson ratio and young’s modulus were extracted. The relative density, mass,
volume, density, Poisson’s Ratio and Young’s modulus of the foam materials are listed and reviewed in the study.

With the objective to make a characterization of the foam materials, experiments on impacts were made and carried out
by means of a Drop tower test machine with a flat impactor. Several temperatures and heights were tested to obtain a varying
combination of strain, stress and strain rate. Velocity, acceleration and displacements had been measured during the tests in the
use of Oscilloscope and a grating method 2D line. The dynamic compression properties of the EPS foam used a flat anvil and
each configuration was repeated for 3 times. In entirety, there were 72 experiments that were done throughout the process. In the
process of experimentations, three temperatures were used, 18o C as the room temperature, -20oC as low temperature and +50oC
as high temperature, then after a day, these specimens were used in the experiments with the Drop Tower Test Machine.

In the examination of the results, it was found out that there was no lateral expansion, this just proves that the poisson
ratio of the material was close to zero. There was no conservation in the volume of the material during the compression, but more
often the density increased while the materials were being compressed.
The results of the research concluded that the density was found to be an important parameter affecting the characterization of
the EPS foam during the dynamic compression. The temperatures that were also tested resulted an influence too in the material.
The strength of the foam decreased, as the temperature increased and increased in strength when temperature decreased to -20oC/

LIST OF REFERENCES

Bruyne, G., Gagliardi, F., Krundaeva, A., & Papepegem, W. (2000). Dynamic Compressive Strength And Crushing
Properties Of Expanded Polystyrene Foam For Different Strain Rates And Different Temperatures. Materials
Science and Engineering. Retrieved from https://www.researchgate.net/publication/306021749_Dynamic_
compressive_strength_and_crushing_properties_of_ex_panded_polysterene_foam_for_different_
strain_rates_and_different_temperature.
CUBANGBANG, JEFFERSON S.
2162462

FLAT PLATE VOIDED SLABS: A LIGHTWEIGHT CONCRETE FLOOR SYSTEM ALTERNATIVE

Flat Plate Voided Slabs are a kind of effective alternative to standard flat plate concrete slab since it accounts enough
reduction of the concrete’s total volume relative to its weight reduction, in addition, the reuse of recycled materials as plastic void
formers in the inside of the slab also accounts in the reduction.

This research mainly focuses on the comparison between the voided flat plate slabs with the conventional solid flat
plate slabs used for the concrete floor system. Furthermore, elaboration of which were extended with pertinent facts and data
about voided flat plate slab advantages and disadvantages. This study is necessary because most structural members fail due to
overloading and with the increase in use of the voided slabs, emissions of Carbon Dioxide is reduced from cement productions.

BACKGROUND AND THEORIES

From concepts of reinforced concrete design and perspective, voided slab eliminates concrete in part of sections where
a volume of concrete is not considered (Mota, 2013). The loads, more specifically, gravity loads that are being undertaken by the
columns and foundations through reducing of slab self-weight results to a smaller column and foundation dimensions. Therefore,
the whole structure volume of building material will be reduced, which makes owner save cost or money. The reduction of
concrete’s volume also reduces the cement production needed for building constructions and since production of cement is a
major cause of carbon dioxide emissions, carbon dioxide is significantly reduced. The reduction of dead loads of the whole
structure also significantly decrease the seismic loads in structures and thus reduce the size of members in lateral force resisting
system. In regions where high seismic is observed, cost is most often considered as a controlling factor over systems like gravity
systems. Therefore, the significant decrease of dead load will also decrease the base shear under seismic, which will also
minimize the forces into the lateral force resisting system into which reduces the lateral members cost.

The ideas of introducing voids in the slabs were dated back to the ancient times. Construction workers found hard in
lengthening the spans because of the high dead loads of the existing structural members. After decades of years, building
materials had undergone far and wide evolutions. However, there are still some innovations in the concepts of voided slab to
significantly decrease the volume and dead load of the structural members.

THE PANTHEON: Coffered ceiling dome of Pantheon in Rome can be dated back in 125 AD and is the very first
known example of a voided slab system and is also known for being the world’s largest unreinforced concrete dome before the
building of the Florence Cathedral in 1436. The dome can span up to a length of 140 feet. The concrete that are not necessary in
certain locations in the slab were removed by constructors and engineers, since it primarily has no help in resisting gravity loads.
Using external void formworks which adds a decorative element are formed making a unique shape.

It is not allowed that unreinforced concrete domes or any structures be built to this day since there are already code
restrictions in the design of such structures, however we still can see the Pantheon still standing up to this day near 2000 years
later.

CONTEMPORARY VOIDED SLAB: 1950’s was the turning point in the world of structural engineering, more
specifically in the structural floor systems. Due to the modular removable forms, the one way pan-joist increased in popularity,
but the cost of labor and construction were modified as a the result of close spacing of joists that needed modification, so in
1960’s the wide-module “skip” joist system was introduced wherein the spacing of the joists were increased resulting in a faster
construction and thicker slabs that met the standards of fire codes. However, the “joists” in the system is already considered as
beams in modern concrete codes because this requires shear reinforcements.
Deep girders are often required in the joints of Pan-joist systems for greater spans to reduce the effect of defection.
The floor-to-floor height of buildings increase for these deep members which causes increase in costs due to materials that are
needed. The idea of post-tensioning the girders is used to create an efficient structural system by decreasing the depth of the
members to the same height as pan joints to form a simpler type of formworks and lower floor to floor heights (CRSI 2014). In
the Midwest, pan-joist systems are still popular but not as once were change in innovations and evolutions in concrete floor
systems.

MODERN VOIDED SLABS: As early as 1990’s types of voided slabs was created in Europe. High-density
polyethylene (HDPE) plastics are the main resource for a flat plate voided slabs which spans at about 50 feet (15 meters) with the
conventional reinforcements and a post-tensioning of 60 feet. Cobiax and Bubble deck were primarily the pioneering companies
for this innovation. From 1990 to 2000’s, voided slabs has been used all over South America and Europe and in the late of
2000’s, concrete voided slabs found its way to North America. The very first project ever made in North America was the
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popular Perez Art Museum located in Miami which was completed in the year 2011 which they found that it has reduced costs
and materials in construction.

DESIGN AND METHODS

The design process of a two-way voided concrete slab is just the same with how a solid two-way concrete slab is made
but somehow has additional requirements or steps to design due to some irregularities. The design followed the CRSI Design
Guide for a Voided Concrete Slabs and ACI 318-14 Building Code Requirements for all the Structural Concrete. Common
parameters such as slab thickness, choice of void formers, self-weight, moments at critical sections, flexural design, two-way
shear and deflections were observed just like with the analysis and design of a conventional solid two-way concrete slab.

The main objective of the study was to determine the effectiveness between a conventional solid concrete slab with an
innovated voided concrete slab over various spans of 35, 30, and 25 feet and is tested through a 5x5 bays which is 4 stories tall.
The study was consistent with column sizes, loadings, steel strengths and concrete strengths significantly. The live load was 60
psf and the dead load is superimposed with a weight of 20 psf. The chosen strengths of steel and concrete were 60 and 4 ksi
respectively. An area of 18in2 for columns were chosen for consistency to not cause any varying result in the latter.

RESULTS AND FINDINGS

The results found that there was a substantially reduction in the volume of the concrete, the structure’s weight and
emission of carbon dioxide. The study proved that the design of a voided concrete slab is much more effective for long span
structures due to the substantial self-weight reduction of concrete, for spans shorter than 25 feet, it may still be effective but the
savings for these concrete sans may not outweigh the costs associated with flat plate concrete slabs. There are projects where the
concrete voided slab are found significant, as such may include projects which require a very limited ceiling to ceiling heights
and projects which require large spans but somehow may also found voided concrete slabs to be insignificant, but still, owners
tend to choose the system of introducing voided concrete slab to their structures to have eco-friendlier building. A more
innovative construction method must be analyzed to somehow make reductions in the schedule of construction and more
significantly the labor cost to make a substantial improvement on the viability of the structural system.

The results of the project were considerably viable and I strongly agree that the voided concrete slab is more effective
than that of the conventional solid concrete slab because of the tests described to have a significant reduction of the weight of the
structure, reduction in costs in construction more specifically for larger projects and the less emission of Carbon dioxide to the
environment. Follow-up or further researches are still needed for this project because most constructors and engineers don’t have
a clear grasp of what may be the effects of a voided concrete slab to the structures, they definitely don’t have ideas on the
effectiveness of the voided slab than that of the conventional concrete slab.
I find the author’s research to be useful because the bulk of our study is also about the effectiveness of the voided slab, we’ll not
only be incorporating the processes in the research but also add some innovations to the research of this study.

LIST OF REFERENCES

Wheeler, H. (2018). Flat Plate Voided Slabs: A Lightweight Concrete Floor System Alternative. Department of Architectural
Engineering. Kansas State University. Retrieved from https://krex.k state.edu/dspace/bitsream/handle/2097/39263/
HunterWheeler2018.pdf?sequence=1&isAllowed=y.
CUBANGBANG, JEFFERSON S.
2162462

ASSESSMENT OF CARBON DIOXIDE EMISSIONS BY REPLACING AN ORDINARY REINFORCED CONCRETE

SLAB SYSTEM IN A HIGH-RISE COMMERCIAL RESIDENTIAL COMPLEX BUILDING IN SOUTH KOREA

High-storey buildings nowadays are preferred for both commercial and residential cases to make use effective of land
resources considering that most cities now are significantly urbanized. In the sense of global warming as a worldwide topic, there
are so many factors or concerns regarding the applications of high story buildings. In engineering, architecture and most
specifically construction industry, they have been modified to be the main contributor to global warming and to the consumption
of mass energy considering that it makes 38 percent Carbon Dioxide emission annually, 40% consumption of natural resources
annually and 39% of the energy consumption annually.

So many studies had already been observed and they have established that the widely use of concrete in construction
does not just consume a very large quantity of energy and natural resources but also considerably emits CO 2 to the environment
during transportation and manufacturing. Suggestions and approaches had been made to significantly reduce the environmental
impact of concrete, this includes, using a high-performance and recycled materials and replacing the use of high carbon content
materials with low carbon content materials.

BACKGROUND AND THEORIES

Tae et al. say that an effective solution to at least minimize the emission of CO 2 is the use of high strength concrete as it
helps in size reduction and quantity of rebar significantly to the vertical members cross sectional areas. Also, another study by
Kim et al. proved the reduction of Carbon dioxide emission by using high concrete strengths in buildings despite that same floor
area were utilized. Aside fom using high concrete strength, selection of materials and optimum design are also considered to be
significant factors for reducing Carbon dioxide emissions, Gonzalez and Navarro emphasized that selection of material is
appropriate in the early stage of design which they found that through test, carbon dioxide emission reduced by 28 percent. Same
study with Chau et al. affirmed that a designer could have an important role in the reduction of carbon dioxide by selecting
materials of low carbon footprint. Use of steel structure as replacement for the concrete is also considered to have low effect on
the emission of carbon dioxide as studied.

This system which is a new development which improves the performance of conventional slabs through increasing its
stiffness and reduction of its weight. This method increases and develops the slab strength in load supports through effective use
of its moment of inertia. It is also considered that environmental impacts especially on the emission of carbon dioxide and energy
consumption be reduced to a significant amount by using lightweight formers in the middle of this slab.

Introduction
However, there had already been a number of studies about the environmental impacts of the voided slab system
compared to its performance, void formers shape and optimum void ratios. Some previous studies made increase the
reinforcements to anchor the voids tightly in the slab but they found out that the installation methods for voided slab system ws
slightly complicated with that of the conventional slab, the mode of speed and accuracy of its installation merely depends n the
skill of the construction workers. Further studies were made and found out that the use of reinforcements for anchoring the
formers to its place causes more environmental problems compared to the conventional reinforced concrete slabs.

This study focuses on the use of voided deck slab made up of expanded polystyrene (EPS) which decreases the use of
steel materials and incorporating some techniques for anchoring the formers into the slab.

DESIGN and METHOD

The objective of the study was to make comparison between the conventional concrete slab and the voided slab system
in a high-story commercial building in Seoul, South Korea. This adopted the Life Cycle Assessment technique for the assessment
of the impact to the environment for the two selected slabs. The Life Cycle Assessment Techniques (LCA) deals with the
utilization of carbon dioxide emission and energy consumption in all the stages of the building’s life cycle

To optimize the performance of the building during the development stage, the value-for-money analysis had been used
for a lesser cost and that the materials be at optimum. In the design, the voided concrete slab system was the chosen alternative
for the reason of reducing both the construction materials and the construction costs. In addition, making use of the voided slab
system will enable the bearing walls to oppose the loads that are to be removed from the structure. By introducing the voided
concrete slab system rather than that of the conventional concrete slab, the span or the length between columns can be extended
to a much more distance of 9 meters. By utilizing the structural design processes and the analysis for “value for money”, the
system for voided slab was accepted as an alternative for the conventional reinforced concrete slab due to the satisfied economic
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aspects and structural requirements. The study was designed with ACI 318-05, ASCE/SE17-05 and the Korean Building Code.
The compressive strength of concrete that was used was 25 MPa and a 400 MPa reinforcing steel bar.

Previous researches showed that the void former be tightly fixed at the bottom reinforcement by using devices of
anchorage but these materials usually increases the amount of materials for construction. So the study incorporated a technique
by integrating an anchoring materials to the void formers which has the same property with that of the void formers to reduce
cost. The method of anchoring for this technique would substantially decrease the need for steel materials and reinforcing bars

RESULTS AND FINDINGS

The carbon dioxide emission for the voided slab systems was 151,754.75 kg and that of the conventional concrete slab
was 204,433.06 kg CO2-equivalent. In comparison, the voided slab system basically emitted 34 percent less carbon dioxide than
that of the conventional solid concrete slab. The carbon dioxide emission for the voided slab system mostly accounts for the
concrete which makes a percentage of 50. The formers that are used for the voids in the system definitely decreased the self-
weight of concrete as well as the volume of concrete. Therefore, the use of voided slab system as an alternative for the
conventional type of slab would prominently help in the reduction of the weight of the slab and the entirety of the structure,
lastly, it also will enhance the environmental impacts which makes it eco-friendly.

For the conventional concrete slab, the highest source of carbon dioxide emission which has accounted for 62.9 % was
the moulds that are used in the curing of the concrete, and by which is followed by the ready-mixed concrete which accounts for
a percentage of 34.3 %, and the lowest among the materials that were used was the rebars and the steel materials that accounts for
just 2.8%. From the transportation process, the carbon dioxide emission only accounted for a percentage of only 1 % which is
very low to have an impact for assessments. In the construction stage, carbon dioxide emissions primarily made use of the
consumption of an amounts of petrol, diesel, and electricity as parameters for assessment of carbon dioxide.

The emission of carbon dioxide of the voided slab system was also considered and they found out that that the total
emitted carbon dioxide was 151,754.75 kg Carbon dioxide-eq. the highest source or carbon dioxide for this system is the ready-
mixed concrete which has an amount of 49.7% then followed by the moulds with 75,381.60 kg Carbon dioxide-eq which makes
27.2% of the totality. The utilization of deck plates was 19.4%, while for the transportation is just similar with the conventional
concrete slab that has 1% less. Therefore the total emission for the voided slab system turned out to be 33.9% lesser than the
conventional concrete slab.

The modern construction nowadays doesn’t care already for the environment, what they care all about is the profit they
get from the projects and the comfort they can give to their clients, they don’t consider the massive effect and impact of what
they do to the environment, they are blinded by the downside of their activities. The use of voided slab system in the construction
would be of great help to at least minimize carbon dioxide emissions. From the data that had been gathered, they have proved that
the use of voided slab really is of great help in lessening the risk of carbon dioxide emissions which is 33.9% lesser than that of
the conventional concrete slabs.

I think that there is still a need for further verification because the method done were just of small scale, they don’t
consider the whole structure itself in estimating for the total emissions of carbon dioxide. There is still a need for further research
to at least give a very sufficient and effective results. This study is very useful for our research since it defines the impact to the
environment once used in the construction industry.

REFERENCES

Na, S., Paik, I., & Yoon, S. (2018). Assessment Of Carbon Dioxide Emissions By Replacing An Ordinary
Reinforced Concrete Slab System In a High-Rise Commercial Residential Complex Building In South Korea.
Sustainability, 11(82). doi: 10.3390/su11010082 www.mdpi.com/journal/sustainability.
CURA, Eirwell V. (2162474)

A COMPARATIVE ANALYSIS OF COBIAX - BUBBLE DECK SYSTEM OVER OTHER CONVENTIONAL SLAB
SYSTEMS
Construction industry has been revolutionized through innovations and technologies. As we all know, tall or high-rise
structures are highly susceptible to seismic loads, thus, this yields to high weight of the building. According to this article, of all
the structural members in a building, slab was considered to be the highest member which occupies most of the area of the
building. The higher the area, the higher its weight; hence, it will affect the sizes of the columns and also the foundations, making
the structure uneconomical. Therefore, the weight of the building is mainly constituted by the slab. Moreover, there was an
innovation back in 90’s which is its main concern is to reduce the area occupied by the slab and to achieve a much lesser self-
weight of the reinforced concrete slab. A biaxial floor system is to be incorporated within the entire structural building. This
biaxial floor system is known as Bubble Deck slab. By the use of this system, this would reduce the area occupied by the
concrete within the slab, which does not perform any structural standing. This almost-blooming biaxial concrete floor system was
first developed in Europe in 1990s by Jorgen Breuning. This new innovation by Breuning, involves the direct way of linking steel
and air at the same time.

Different concepts which was undiscovered regarding this topic has led keen interest for various scientists to dig in
deeper. In which this has led engineering-concerned people to decipher and fathom the mechanism of load transfer, bending
moment, shear force, deflection, casting, and reaction to various loads regarding the bubble deck system.

European scientists found out that the reduction of concrete in the slab can only be achieved by reducing the concrete in
the tension zone of the stress diagram, where concrete is mostly irrelevant. This customary system consists of hollow plastic
spheres cast inside the concrete slab, in which its main objective is to create voids in it and to eliminate irrelevant concrete in the
tension portion. Hollow plastic spheres are designed to be High Density Polyethylene (HDPE) which does not chemically react
with concrete. Through the spherical HDPE, voids were cast inside the tension portion of the slab which in turn lessen the weight
of the slab itself. Through the use of this system, it incorporates air (voids) inside the slab, which in turn eliminates 30% to 50%
of materials to be used in the slab. Thus, it reduces the load on columns, walls, and will eventually yield a result of smaller
foundations. Being incorporated in the floor (slab), these hollow plastic spheres may be viewed in a two-dimensional manner and
cast in a factory. This type of slab optimizes the size of the columns and of the foundation itself – the building in general. The
conventional analyzation of slab, deflection is the utmost importance. The longer the length or span, the more it deflects. Thus, in
order to minimize the deflection, the thickness of the slab is to be increased; and increasing the slab’s thickness, the heavier it
gets, which further leads to increased sizes of columns and footings. Furthermore, this will yield for an overall increased weight
of the building – in which engineers have given more attention into. Moreover, Bubble Deck Slab suits the remedy of the
foreseen problem, this is because this system may be used if the span of the floor is quite long.

In accordance to this article, there are certain pros upon adopting this kind of system. Bubble deck slab is not just cost-
efficient, but it is also environmental-friendly. Environmentally friendly to the sense that it limits the use of concrete, thereby
reducing the bags or weight of the Portland cement in the concrete mixture – wherein exhaust gases from the production of such
product would yield to emission of carbon dioxide (CO2) in the atmosphere. One of the advantages of this system is the
consumption of less energy in either production (or materials needed) and transportation. In addition to that, this system is pre-
fabricated upon arrival at the site. Contractors may order a customized span and height of the slab in accordance with their
desired design. Thus, this would be of quite a helping hand for the workers to ease their respective jobs. Also, through the
utilization of this slab system, it reduces construction time – to the fact that the construction of slabs (i.e. formworks, top and
bottom bars, tie wires, spacers, and installation of reinforced steel bars) were the ones that causes the delay of construction, due
to various installation of construction materials.

Researchers have tested three different structural systems, namely: Bubble Deck System, Conventional System and Flat
Slab System. These structural systems were applied in a commercial building in which it is analyzed for gravity, wind,
earthquake and various internal forces (bending moment, shear force, axial force of the members) at various levels, joint
displacements etc. – in all cases the building has to be studied and compared to. The structural analysis was carried out through
the use of a software program, SAP2000. In comparison with the three systems stated above, base shear is usually the expected
maximum lateral force that will occur due to seismic ground movement at the footing. Tests further initiated that in comparison
of a bubble deck slab system with flat slab system, the shear in the bubble deck slab is reduced by 46.53%; and with the
conventional two-way slab, the shear is reduced to 76%. It is blatantly clear that due to the reduction of weight from the slabs,
base shear was reduced through the use of a bubble deck system to the building.

Further results with respect to the moment force in the columns; in line with this, this is also one of the solutions to
reduce the sizes of the structural members and to fathom the behavior of the building during earthquake.

Not only bending moment was tested through the said three systems, but also the shear force of the columns. According
to this article, shear force is used to understand on how to increase the shear reinforcement in any member of the building.
Researchers have said that bubble deck slab is not supported by any beams or girders, hence, in this aspect, the bubble deck slab
CURA, Eirwell V. (2162474)
system has increased shear force as compared to the conventional ones. Conventional slabs have beams or girders to act as
supports in order to reduce the shear force.

Moreover, researchers were able to cover the bags of cement needed for every type of structural system used. The
number of cements that the researchers was able to compute is only for an 8 x 8.5m sample. For the conventional system
weighing 2 Tons, a number of 41 cement bags needed for the concrete mix. While for the bubble deck system, having a weight of
0.62 Tons, wherein computations have shown that there is to be 12 cement bags which needs to be utilized. Meanwhile, for the
flat slab system with a weight of 0.728 Tons, it was found out that it needs to have 14 cement bags in order to have the desired
concrete mix.
Upon reading the whole paper, I may have to agree with the results of the experiment. In fact, the researcher’s
conclusions are of fair judgements. They were able to attain their agenda through the experiment. Results were not bias and they
have balanced their perception in the use of the bubble deck slab and the conventional slab. Moreover, they achieved to compare
the two system’s behavior with each other.

Listed below are the references of the researchers:

J.H. Chang, B.H. Kim, H.K. Choi, S.C Lee and C.S. Choi: Flexural capacities of hollow slab with material properties.
Proceedings of the Korea Concrete Institute. Vol.22 No.1 (2010).

J.H. Chang, N.K. Ahn, H.K. Choi. And C.S. Choi: An analytical study of optimal hollow sphere shapes in hollow slab. Journal of
the Korea Institute for structural maintenance. (2009).

J.H. Chang, H.K. CHOI, S.C. LEE, J.K. Oh. And C.S. Choi: An Analytical Study of the Impact of Hollow Sphere on Biaxial
Hollow slab. Proceeding of the annual conference of the architectural institute of Korea. (2009).

Dr. Ing. A.C. Fuchs Deputy Director. Bubble Deck Floor System - An Innovative Sustainable Floor System Bubble Deck
Netherlands B.V., AD Leiden, the Netherlands, (2009).

Schellenbach -Held, Stefan Ehmann, Karsten Pfeear. Bubble Deck - New Ways in Concrete Building. Technical University
Darmstadts, Germany, (1998).

ANSYS, "ANSYS Help", Release 12.0, Copyright (2009).

Desayi, P. And Krishnan, S., Equation for the Stress-Strain Curve of Concrete, Journal of the American Concrete Institute, 61,
pp. 345-350, March (1964).

Gere, J. M. And Timoshenko, S. P., Mechanics of Materials, PWS Publishing Company, Boston, Massachusetts (1997).

Wolanski A. J., Flexural Behavior of Reinforced and Pre-stressed Concrete Beams using Finite Element Analysis, M.Sc. Thesis,
University of Marquette, May (2004).

REFERENCE:

Yadav, M.S., Srinath, G. and Dongre, A. (2018). A Comparative Analysis of Cobiax – Bubble Deck System over other
Conventional Slab Stystems. Vidya Jyothi Institute of Technology. Aziz Nagar, Hyderabad. Retrieved from,
https://www.ijsr.in/upload/434287057Chapter_57.pdf
CURA, Eirwell V. (2162474)

ANALYSIS OF BUBBLE DECK SLAB DESIGN BY FINITE ELEMENT METHOD

Engineers utilizes variety of tools, techniques and even methodologies to the assurance that the designs that they create
are structurally safe for its occupants. Also, engineers should ensure that their designs or products would serve its intended
purpose efficiently, and as much as possible to avoid to reach a maximum failure under any circumstances. Thus, once of the
tools used widely in the engineering era is the finite element method.

In this paper, the researchers analyzed the design of the bubble deck slab system through the utilization of the finite
element method. Finite element method is utterly one of the most used technique in solving for differential and integral equations
of initial and boundary-value problem in a geometrically complicated portion. It may be concluded that this method is indeed
popular due to its process to design analysis. Furthermore, finite element method may be used to deal with one, two and three-
dimensional problems. This method simply divides the whole element into a finite number of small elements, and the advantage
of which is that the small element has a simpler shape in the sense that it would yield a good approximation for its analysis.

Furthermore, the researchers made use of the finite element method in analyzing the bubble deck slab system, in which
they also considered the shear force and deflection based from a moving load, and having the same condition, then now be
compared to a conventional slab. The finite element analysis software, was used to obtain an approximate solution for boundary
problems. Boundary problems are value problems and those what engineers called field problems. A 3-dimensional solid slab and
bubble deck slab were constructed using the ANSYS 2000 software, in which the two samples have approximately 8,100
elements. The bubble deck slab was generated as a layered shell, while the conventional slab was designed as a thick shell of pure
concrete. In this manner, having a rectangular layer of high-density polyethylene (HDPE), which was incorporated in between the
two layers of concrete on top and bottom portion, is basically the design of a simple bubble deck slab system. Its concrete cover
for upper and lower portion has a thickness of 3.75cm, while its total depth and with are 14cm and 30cm, also having a spherical
HDPE diameter of 6.5cm. Moreover, the model samples were applied to have a 100kN moving load in addition to their
respective self-weight for the dynamic design and static design.

Under this paper, in the laboratory, Static Method was used in the analysis of the behavior of the two samples. Static
analysis simply determines the displacements, stresses, strain and forces in the structure under the effect of a steady load, while
ignoring the effects of inertia loads and damping, such as those caused by time-varying loads. Aside from the moving load
condition, the two slab samples were also subjected to a 50kN point load, wherein maximum stresses and maximum deformations
were obtained from the two slab system samples, and to which they are compared upon. Same procedure was done for the 100kN
moving load, maximum stress and maximum deformations were obtained from the two samples, and after which compared
between the two.

Upon deciphering and understanding the results shown by the two different applied loads (50kN point load and 100kN
moving load), it was shown in the analysis that the behavior of the bubble deck model slab has exceeded the maximum internal
stresses and forces than that of the conventional solid slab. According to the computations, the maximum moment and internal
stress of the bubble deck slab model was 64% higher as compared to the conventional solid deck.

Making use of the ANSYS2000, various load parameters were subjected to the two deck models. Shear forces in the x-
z, y-z direction, and the maximum stresses as well as the deflection was taken into consideration. Based from the results of the
software, it was observed that the bubble deck slab system’s maximum moment, shear force and stress is 10% to 25% less than
that of the conventional solid slab. This is due to the decreased self-weight of the deck. Thus, load reduction for a deck reduces
the overall stress and it’s then beneficial for the long-term response of the deck system.

Furthermore, researchers concluded that in the construction industry, whether bridge deck slab or building industry,
they mainly consist of concrete floors, hollow core slab floors, prefabricated filigree slab floors; and this kind of situation did not
change for a couple of years now – even up to present. Not until an innovative slab construction was proven to be efficient than
the conventional slabs used. This no other than a Bubble Deck Slab system. According to the results, its deflection is 18% more
than the traditional slab due to the reduced stiffness because of the follow portion. Also, a 15% reduction of self-weight as
compared to the conventional deck. Moreover, bubble deck slab system is not only cost-effective, but it also enhances structural
possibilities which in turn contributes to sustainable development. And at the same time, with the considerable reduction of self-
weight, it saves construction materials (i.e. aggregates) which leads to one of its advantages.

I may have to agree with the results of the analysis, because the researcher’s main objective is to determine the
deflection and to how much reduction of weight did the bubble deck had. Also, from the other articles and journals that I have
had read, results from their experiment and analysis is somehow the same with the results done by the researchers.

These are the references used by the authors:

Wang, K., Jansen, D.C., and Shah, S. Permeability study of cracked concrete, Cement and Concrete Research, Vol.27, No.3,
1997, pp. 381-393.
CURA, Eirwell V. (2162474)
Sergiu Cal in, Ciprian Asavoaie and N. Florea, "Issues for achieving an experimental model" Bul. Inst. Polit. lai, t. LV (LIX), f.
3, 2009.

Martina Schnellen bach-Held and Karsten Pfeffer,"Punching behavior of biaxial hollow slabs" Cement and Concrete Composites,
Volume 24, Issue 6, Pages 551-556, December 2002

Sergiu Calin and Ciprian Asavoaie, "Method for Bubble deck slab concrete slab with gaps", The Buletinul Institutului Politehnic
din lai,LV (LTX), f. 2,2009.

Sergiu Cal in, C.Mugurel, G.Dascalu, C.Asavoaie, "Computational simulation for concrete slab with spherical gaps", Proceedings
of The 8-th International Symposium, Concepts in Civil Engineering, Ed.SocietatiiAcademice "Matei-TeiuBotez",
2010, pp. 154-161.

Kim, Y. Y., Fischer, G., and Li, V. (2004). “Performance of bridge deck link slab designed with ductile engineered cementations
composite.”ACI Structure Journal. 101(6), 792–801.
Gastal F.P.S.L. (1987). “Instantaneous and time-dependent response and strength of joint less bridge beams.”Ph.D. dissertation,
North Carolina State Univ., Dept. of Civil Eng., Raleigh, NC.

Caner, A. and Zia, P., “Behavior and Design of Link Slab for Joint less Bridge Decks,” PCI J., May-June, 1998, pp.68-80.

Gilani, A., and Juntunen, D., Link Slabs for Simply Supported Bridges: Incorporating Engineered Cementations Composites,
Report No. MDOT SPR-54181, Michigan Department of Transportation, July, 2001.

Kim, Y.Y., Fischer, G. and Li, V.C., "Performance of Bridge Deck Link Slabs Designed with Ductile ECC," Submitted, ACI
Journal, 2003.

Oesterle, R.G. et al., Joint less and Integral Abutment Bridges – Summary Report, Final Report to Federal Highway
Administration, Washington D.C., 1999.

REFERENCE:
Pandey, M. and Srivastava, M. (2016). Analysis of Bubble Deck Slab System by Finite Element Method, Vol. 2, Issue 11.
International Journal of Science Technology and Engineering. Gorakhpur. Retrieved from,
https://pdfs.semanticscholar.org/b96f/15994c8b4675c694ed8ecc5f2efbd42e2893.pdf
CURA, Eirwell V. (2162474)

ANALYTICAL STUDY OF SOLID SLAB WITH DIFFERENT TYPES OF CAVITY

Inevitably speaking, population growth is indeed fluctuating as days pass by. Thus, having a house to live in is one of
humanity’s basic essential. People nowadays would opt to have low-cost houses, and through the construction of these houses, it
would require an amount of concrete. In which, the production of concrete emits a greenhouse gas, carbon dioxide (CO2) in
particular. Through the production of concrete, researchers found out that it approximately covers 40% emission on earth, from
the industries. Wherein carbon dioxide, one of the most emitted greenhouse gasses, severely leads to the depletion of our ozone
layer. For a 1TON of concrete, is has a total emission of 410kg/m 3 of carbon dioxide. In addition to that, the production of
concrete increases with a rate of 2.5% per year. Moreover, the researcher’s aim is to reduce the use of concrete through
constructing low cost residential houses, thus, would utterly compensate the wants of the humans – a low-cost house. By then,
enable for the researchers to meet the demand of humanity, the slab should have a light weight. In order to overcome this
problem, a bubble deck slab system must be induced.
A laboratory model of 100 × 100 × 150mm was used to analyze a voided deck having different kind of recycled
plastic cavities. These cavities are basically in the shape of a sphere, egg and elliptical. A load of 15000 Pa was applied on the
different slab models, and was analyzed using ANSYS WORKBENCH 14.0.

Cobiax is an elliptical plastic ball made from recycled plastics and was first manufactured in Switzerland before it was
rampantly manufactured in many factories of other countries. Along with this, countries such as Singapore, France, Germany,
Iran, Greece, etc., held a partnership with Switzerland to have cobiax cavity manufactured with steel reinforcement, to serve as a
medium in holding them together. Moreover, for the model used in this analysis, the researchers used a 300-gram elliptical cavity
having an external diameter of 80mm, 40mm and 80 mm in the x, y, z direction. In line with this, the egg cavity has a diameter in
x, y, z direction, 61mm, 80mm and 61mm, weighing 60 grams.

U-boot is basically used on roof shuttering wherein this type of cavity tends to lessen the problem on transportation in
which carbon dioxide comes (from machines). Moreover, this was invented by an Italian engineer back in 2001 wherein this type
of cavity effectively reduces concrete a bit more than the cobiax and bubble deck slab system.

Back in the 90’s, Jorgan Breuning invented the bubble deck slab system. This system reduces the weight of the deck by
approximately 30% and it further supports longer spans as compared to the conventional slab. The name itself generally explicate
the shape of the cavity – spherical. Basically, it the cavity is installed in between the top and bottom layers of the reinforcements.
The sphere is technically made of a recycled plastic, which in turn produced an output to be a high-density polyethylene (HDPE).
In addition, in this specific experiment, the researchers made use of an 80-mm (external) diameter HDPE having a weight of 62
grams.

In this case, four models were analyzed using ANSYS 14.0, however, prior to the analysis, these models were generally
made or prepared using AutoCAD, and eventually imported in the Ansys14.0 in an .iegs file format. The four models are
basically, a conventional solid slab, sphere cavity slab (or bubble deck slab), elliptical cavity slab. Three materials were only
utilized, concrete, reinforcement and recycled plastic. Each having a density of 2400, 7850, 1100 respectively (units in kg/m 3).
Four properties were obtained from the analysis, the total deformation, Von-Misses stress, Von-Misses strain, Shear strain and
lastly, Shear stress. Von-Misses stress is basically a value used for determining whether a certain material will rupture or yield,
and it is usually used on a ductile material (i.e. Metal). Meanwhile, Von-Misses strain value would technically give an analysis to
predict the yielding of a material from a uniaxial tensile stress.

Upon pondering about the results yielded by the four different models, researchers found out that out of the four
parameters done in the analysis, cavity slabs have exceeded the behavior than that of the solid slab. Moreover, there were only
few discrepancies among the cavity slabs and the solid slab when it comes to total deformation, thus, the researchers concluded
that the total deformation of the solid slab is approximately the same to those of the cavity slabs. Results further showed t hat in
the case of Von-Misses Strain behavior, the egg and elliptical shaped cavity is then the same with the solid slab. In addition to
that, they also found out that out of the four models, the sphere cavity (bubble deck slab) yielded efficient results. In terms of
shear stress, the results further imply that elliptical cavity behaves better as compared among the three other models. Lastly,
economically speaking, sphere cavity slab (bubble deck slab) actually saves 6% of concrete, while egg cavity saves 4% of
concrete and for the elliptical cavity, it saves 15% of concrete.

There were some vague points on this journal. Researchers did not specify what type of cavity would they prefer to a
voided slab. Each cavity has different capabilities or strengths, therefore, there were no conclusion on what would be the better or
best cavity to be incorporated into the slab to act as voids. Nevertheless, I do agree with the results of the comparison among the
behavior of the three cavities, because the researchers have made strong points on the different strengths of the said cavities.

Listed below are the references of the researchers:

Shetkar, A., & Hanche, N. (2015). An experimental study on Bubble Deck slab system with elliptical balls. Proceeding of
NCRIET-2015 and Indian J. Sci, Volume 12, Issue 1, Page 021-027.
CURA, Eirwell V. (2162474)
Churakov, A. (2014). “Biaxial hollow slab with innovative types of voids”. Saint-Petersburg University. Volume 6, Issue 21,
Page 70.

A. K. Dwivedi, Prof. H. J Joshi, R. Raj, et. All (2016). “Voided Slab Design: Review” 3rd International Conference on
Multidisciplinary Research & Practice, Volume 4, Issue 1, Page 220-226

Jamal, J., & Jolly, J. (2017). “A study on structural behavior of bubble deck slab using spherical and elliptical balls”.
International Research Journal of Engineering and Technology, Volume-4, Issue-5, Page 2090-2095.

Harding P. (2004). BubbleDeck – “Advanced Structure Engineering. BubbleDeck” article. 2004. Pp. 4-7.

Calin, S., Gîntu, R., & Dascalu, G. (2009). “Sumary of Tests and Studies Done Abroad on the Bubble Deck System”. Buletinul
university of polytechnic for construction and architecture, volume 55, Issue 3, Page 75.

Lai, T. (2010). “Structural behavior of Bubble Deck slabs and their application to lightweight bridge decks” (Doctoral
Dissertation, Massachusetts Institute of Technology).

Calin, S., Asavoaie, C., & Florea, N. (2010). “Issues for achieving an experimental model concerning bubble deck concrete slab
with spherical gaps”. Buletinul university of polytechnic for construction and architecture, volume 56 Issue 2, Page 19.

Prakash, A. N. (2011). “The revolutionary concept in voided slabs”. Dimensions-A Journal of AN Prakash CPMC Pvt. Ltd.,
Issue, (10).

Teja, P. P., Kumar, P. V., Anusha, S., Mounika, C. H., & Saha, P. (2012, March). “Structural behavior of bubble deck slab”. In
Advances in Engineering, Science and Management (ICAESM), 2012 International Conference on (pp. 383-388).
IEEE.

Ibrahim, A. M., Ali, N. K., & Salman, W. D. (2013). “Flexural capacities of reinforced concrete two-way bubble deck slabs of
plastic spherical voids”. Diyala Journal of Engineering Sciences, volume 6, Issue 2, Page 9-20.

Hai, L. V., Hung, V. D., Thi, T. M., Nguyen-Thoi, T., & Phuoc, N. T. (2013, September). “The experimental analysis of bubble
deck slab using modified elliptical balls”. In Proceedings of the Thirteenth East Asia-Pacific Conference on Structural
Engineering and Construction (EASEC-13) (pp. G-6). The Thirteenth East Asia-Pacific Conference on Structural
Engineering an Construction (EASEC-13).

Bindea, M., Zagon, R., & Kiss, Z. (2013). “Flat slabs with spherical voids. Part II: Experimental tests concerning shear strength”.
Acta Technica Napocensis: Civil Engineering and Architecture, Volume 56, Issue 1, Page 74-81.

Ibrahim, A. M., Ali, N. K., & Salman, W. D. (2013). “Flexural capacities of reinforced concrete two-way bubble deck slabs of
plastic spherical voids”. Diyala Journal of Engineering Sciences, Volume 6, Issue02, Page 9-20.

REFERENCE:

Golghate, K. and Awasthi, P. (2018). Analytical Study of Solid Slab with Different Types of Cavity, Vol. 5, Issue 03.
International Journal of Science Technology and Engineering. Madhya Pradech,India. Retrieved from,
https://www.irjet.net/archives/V5/i3/IRJET-V5I3114.pdf
CURA, Eirwell V. (2162474)

A REVIEW STUDY ON BUBBLE DECK SLAB

In a building structure, concrete slab is indeed the most important aspect because it provides flooring and roofing.
However, there is a downside upon utilizing concrete slab, due to more than 5% emission of carbon dioxide (CO 2) during the
manufacture of cement. Researchers studied that in order to produce a lightweight member, reduction of concrete in the slab is
proper solution; and may be considered to be an effective concrete deck through the utilization of spherical (hollow) high-density
polyethylene (HDPE). The purpose of this hollow spheres is to rule out the concrete which does not structurally perform any
function; hence, this would eventually increase the slab’s efficiency and reduce the dead weight of the beam. This would induce a
30% to 50 % lighter load carried by the other members of the structure (i.e. beams, columns and foundations).
Generally speaking, slab is defined as a structural member wherein its intended purpose is to transfer loads (i.e. dead
load and live load) to other structural members such as beams and columns. In the construction industry, slabs have two types,
one way and two way, each has different purpose in accordance to their deflection. For a slab having a bending in two directions,
it is technically called a two-way slab or as slab spanning in two directions. Meanwhile, for a one-way slab, the bending only
occurs in one direction. This new innovation was developed in the 90’s by Jorgen Bruenig in Denmark. Bubble deck slab system
also known as voided slab, is a time-saving system due to the fact that this is a pre-cast system, thereby it makes up a faster
construction to approximately 20%. Although, other researchers attempted to make use of other light-weight materials to produce
a light-weight concrete. Such as polystyrene induced in the middle of the slab as an alternative for concrete. Moreover, the
primary goal of this system is to reduce the self-weight of the beam, thus, researchers found out that there is a 35% reduced
weight of the slab and thereby a reduced load carried by the other structural members up to 20%. One may not notice that bubble
deck slab is indeed environmentally friendly, and these are some aspects that makes it to be one: low energy consumption,
utilization of recycled plastic materials, reducing the emission of carbon dioxide (CO2, upon the manufacture of cement),
reducing the overall construction materials (i.e. aggregates), and less use of transportation devices. Through the use of the
spherical HDPE, upon elimination of 35% self-weight, as compared to a conventional slab, having the same thickness, their
behavior is not affected in terms of bending strength and deflection.

Voided slab has three types - filigree elements, reinforcement modules and finished plank. With these three types, there
are no difference when it comes to their capacity upon connected on site. Filigree elements is a type of bubble deck slab wherein
it is primarily a combination of unconstructed and constructed elements. In this case, there is a precast concrete layer (the bottom
part of the slab) to be brought on site having a thickness of 60mm, along with the unconcreted (unattached) spherical HDPE and
steel reinforcement. In order to prevent the movement of the bubbles upon transportation, an interconnected steel mesh is
installed. Furthermore, additional installment of reinforcement may be inserted in reference to the design requirement. Thereaft er,
after casting the system and some additional reinforcements (if there are) into the site, the full depth of the deck is accomplished
by the common concrete pouring technique. Reinforcement modules is primarily a pre-assembled spherical HDPE cast in
between steel mesh. This type of bubble deck slab is used or recommended for those construction sites having narrow areas to
move in. In other words, these is like the traditional way of casting a slab. The materials are cast into the formwork, connecting
the reinforcement and after which the spherical HDPE, then to be concreted upon finishing the installment of such. Finished
plank is a type of bubble deck slab (precast) wherein the materials were installed and already have already been concreted prior
to the delivery on site. In short, slab is on its finished state – fully concreted with the reinforcement and HDPE installed - upon
casting into the site.

Moreover, researchers have listed the advantages of the bubble deck slab. For the structural advantages, primarily,
through the use of this system, it attains the goal of the researchers, to have a less weight of deck, thereby resulting to a less depth
of foundation. Bubble deck slab supports long spans and just like flat slab, it does not require any supporting beams, thus, only
few columns are required to support the slab. Moving on to the construction advantages, bubble deck slab induced a less
requirement of manpower – less work for the workers. Also, this system provides the ease of incorporating pipes and ducts into
the deck. On the engineering side, the role of slabs and columns would act primarily as an elastic membrane that transfers the
shear forces to vertical members of the structure; and would be of use for the design of resisting of such lateral loads. Further,
bubble deck system helps both the environment and the economy. A 40kg/m 2 reduction of emitted carbon dioxide into the
atmosphere that comes from the production of concrete and transportation of materials. It saves construction materials and have a
faster time for construction, thus, would yield to an easy installation of materials. And for every 1kg of plastic (HDPE), it
replaces an approximately 100kg of concrete.

For the compressive strength and flexural capabilities, although upon removing the un-stressed concreted portion of a
solid slab and replacing it with a spherical hollow HDPE, there were no significant difference between a bubble deck slab and a
conventional solid slab. And in terms of flexural strength, the resisting moments of the two slabs are the same. When it comes
with the durability, having a standard grade of concrete and a suitable design for reinforcements this would give the bubble deck
slab system of equal normal durability standards in comparison with the solid slab. In addition, for a joint of a bubble deck slab,
chamfer is present on the inside to assure that the reinforcement will not have contact with air to have it surrounded with
concrete. Speaking in terms of durability, filigree slabs are manufactured to have the spherical hollow HDPE and reinforcements
vibrated enabling concrete would penetrate within voids so that the density of the concrete’s surface produced is at least as
CURA, Eirwell V. (2162474)
permeable and durable. Fire resistance of a slab is a complex matter to take on, however, fire resistivity depends on the steel’s
ability to retain strength during a fire – because steel would lose strength due to a rise in temperature. If a bubble deck slab starts
burning, the products of burning is indeed harmless. In a case of a prolonged intense fire, the HDPE would eventually melt
without having any significant or detectable effect. Furthermore, fire resistivity depends on the cover of concrete, and it would
nearly have a 60 to 180 minutes of resistance to high temperature. Moreover, bubble deck slab is not designed to be resistive on
high temperatures due to an incorporated spherical hollow HDPE in the middle of the slab. Researchers found out that bubble
deck slab system has approximately 17% to 39% higher thermal resistance as compared to a conventional slab, having the same
thickness, hence, this system may contribute towards thermal insulation on the overall construction.

The researchers discussed about the experimental study and analysis of M.Surendar, et al. They analyzed it using finite
element analysis using ANSYS software. Taking into consideration the ultimate load capacity, stresses, and deformation, results
have shown that conventional slab carried a stress of 30.98Mpa through a uniform dead load of 340kN which caused a deflection
of 12.822mm. While to that of the bubble deck slab, it carried a stress of 30.8MPa, from a subjected uniform dead load of 320kN
and having a deflection of 14.303mm. This led the researchers to a conclusion that bubble deck slab can withstand 80% of stress
as compared to a conventional slab, and that bubble deck slab yielded a better performance than the conventional solid slab.

For the research of Shetkar and Hanche, they have experimented a bubble deck slab wherein they induced forces at the
top and bottom of the slab until rupture would occur, and modes of failure were recorded. Results have shown upon the reduction
of self-weight up to 50%, the behavior of the slab was greatly influenced by the diameter of hollow HPDE and thickness of the
slab. Spherical hollow HDPE diameters varies from 180mm to450mm and the depth of the slab varies from 230mm to 600mm –
depending on the design.

Further studies were conducted by Amer Ibrahim, et al, wherein they conducted and experimental analysis to determine
the flexural strength of a two-way bubble deck slab. The results implied that the bubble deck slab system with a ratio of spherical
hollow diameter to a slab thickness of 0.01 to 0.64, has the same load capacity with that of the conventional solid slabs.

Shrinkage strains of bubble deck slab and conventional solid slab were studied by Teja and Kumar. Wherein they
prepared a samples of bubble deck slab and conventional solid slab having the same grade of concrete. Having equal dimensions,
results have shown that the shrinkage of the bubble deck slab is negligible than a solid slab under same exposure to
environmental conditions. Due to a small portion of concrete is exposed onto the environment, the influence of shrinkage may be
neglected in designing a structure with the use of bubble deck system.
I may somehow agree and disagree with the results done with the researchers. Disagreeing to the fact that the applied
load on the conventional slab and the bubble deck slab is not the same, it has a difference of 20kN load on the bubble deck slab.
Therefore, this may be biased on the results of the deflection of the bubble deck slab as compared to the conventional slab.
Nonetheless, I agree with the results that the bubble deck slab has the same behavior as a conventional slab, however having a bit
of discrepancy with the values.

Listed below are the references of the researchers:

Amer M. Ibrahim, Nazar K. Ali, Wissam D. Salman. (June 2013). “Flexural capacities of reinforced concrete two-way bubble
deck slabs of plastic spherical voids”, Diyala Journal of Engineering Sciences, ISSN 1999-8716, Vol. 06, No. 02, June
2013.

M.Surendar M.Ranjitham (2016). Numerical and Experimental Study on Bubble Deck Slab Research Article Volume 6 Issue No.
5 DOI 10.4010/2016.1445ISSN 2321 3361 © 2016 IJESC.

Arati Shetkar and Nagesh Hanche. (2015). “An experimental study on bubble deck slab system with elliptical balls”. ISSN: 0976-
2876.

Chung J.H., Choi H.K., Lee S.C, “Shear Capacity of Biaxial Hollow Slab with Donut Type Hollow Sphere”, Procedia
Engineering, Vol. 14, Pp. 2219 -2222, 2011.

A. Churakov, “Biaxial hollow slab with innovative types of voids”, Construction of Unique Buildings ad structures, Vol. 6(21),
Pp. 70-88, 2014.

Neeraj Tiwari Sana Zafar, (2016). Structural Behaviour of Bubble Deck Slabs and Its Application: Main Paper IJSRD -
International Journal for Scientific Research & Development| Vol. 4, Issue 02, 2016 | ISSN (online): 2321-0613.

REFERENCE:

Varshney, H. Jauhari, N. and Bhatt, H. (2017). “A Review Study on Bubble Deck Slab”, Vol. 5, Issue 10. International Journal for
Research in Applied Science and Engineering Technology. Bareilly. Retrieved from,
https://www.ijraset.com/fileserve.php?FID=10875
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PUNCHING SHEAR IN VOIDED SLABS

BACKGROUND AND THEORIES OF THE STUDY

One of the most important parts of the structure that is considered during design and construction is the slab since it
consumes a lot of space and concrete. Over the years, many solutions have been incorporated into reducing the thickness of the
slab for structures that are longer in the span since it affects the thickness of the column as well as the foundation, thus affecting
its cost.

One of the proposed solutions that have been developed over time is by reducing the weight of the slabs as well as the
concrete used through biaxial slabs with hollow cavities. This paves the way to the use of polystyrene as a laying block between
the top and bottom reinforcements as well as waffle slabs or grid slabs. But the use of these methods is quite limited due to the
reduced resistance in terms of shear and punching shear.

A new method that utilizes the use of Polyethylene to create air voids while providing adequate strength through the arch
action was developed by Jorgen Breuig in 1990’s called BubbleDeck technology. The hollow slab will act like two-way spanning
concrete slab that decreases 35% of the dead load at the same time increasing the capacity by 100%. The Bubble deck, through
tests, models, and analysis, was proven to be superior to the conventional concrete slabs. This solved the problem in terms of
reducing the weight of the slab, however, the resistance on shear and punching shear of the concrete slab is significantly
decreased since both factors have a direct relation to the depth of the concrete.

To solve for the occurrence of greater shear and punching shear in the Bubble deck slab, design reduction factors have been
introduced to compensate for it. The study mainly focuses on the effects of a 1% and 0.8% steel fibers at the strengthening zone
of the bubble deck slab.

DESIGN AND METHODS USED FOR THE ANALYSIS

The study comprises of designing and testing a model of the bubble deck slab embedded with two different steel fibers.
This study is trying to eliminate the possible factor that affects the use and implementation of such technique. It also incl udes a
possible recommended type of steel fiber to reduce the punching shear directed by the columns on a building.

The study consisted of five slab trials consisting of four SCC (Self- consolidating concrete) and one NSC (Normal strength
concrete) with different parameters. The dimension of the three SCC voided slab is 1000 mm by 10000 mm by 80 mm in which
three of the slabs had plastic spheres of 40 mm diameter with 169 balls in each slab and two were embedded with two different
steel fibers of 1% and 0.8% by volume friction from a distance to the face of column. A flexural reinforcement of 6mm diameter
wire at 100 mm c/c spacing was placed on the tension face of the slab and a wire mesh to stabilize the balls in their places.

Glenium 51, a superplasticizer based on polycarboxylic ether is utilized for the production of the self-compacting concrete
and high strength conventional concrete. Glenium 51, an effective superplasticizer, is free of chlorides and complies with ASTM
C494, which is compatible with all Portland cements. For the load simulation of the void slabs the universal testing machine
(MFL system) was used to guarantee a monotonic loading and achieve the ultimate states. The slabs were carefully situated in the
machine and loaded with a single-point load ensuring a curing of the standard 28 days.
Data and observations were based on the deflections and values that were measured and seen during the test of each trial,
where the load applied was incremented at an equal interval until mid- span deflections and crack development were visible. The
data and computations regarding the deflection and loads were placed on a diagram to establish a relation between the two
parameters and is limited the three stages. The first linear zone of the load-deflection diagram showed a linear relationship
between the load and deflection up to the appearance of the first crack at the tension phase of each trial. The second linear zone,
which can be seen after the appearance of the first crack, where small increments in loads were applied a rapid increase in
deflection was seen. And lastly the failure phase showed a rapid increase in deflections without any load increment applied.

DATA AND OBSERVATIONS

Upon observation there is a clear difference between the self-consolidating concrete and normal concrete slab regarding the
stiffness and deflection values during the application of the monotonic loading. The results showed a favourable advantage on the
self- compacted concrete which seems stiffer than the normal concrete. This is due to the fact that the slab displayed a good bond
characteristics between the concrete and steel making the two components act as a homogeneous mass as compared to the normal
strength slab which showed a weaker bond.

The succeeding report showed a comparison between the voided slab and to that of a self-compacted concrete slab in which
it showed the same results for the first stages of the loading application. During the point where the yielding of the steel
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reinforcement is reached the deflection of the solid slab seems more that the voided deck since the there is a direct relation of the
deflection and stiffness of a slab and the solid slab is stiffer compared to the voided one.

Lastly, a test between a self-compacting concrete slabs SST without steel fiber, an SST with added 0.8% steel fiber by
volume fraction at the zone of 250 by 250 mm in the middle of the slab and another SST reinforced with a steel fiber of 1% by
volume fraction of the same zone. The results showed that during the initial load application the three curves of the load-
deflection diagram have similar behaviors and little discrepancies appeared at the final stage between the three. The punching
strength of the voided self-compacting concrete (SCC) slab with added steel fiber of 1% increased by 7.7% and the voided SCC
with added steel fiber of 8% increased by 2.56% when compared to that of the voided SCC slab without steel fiber.

In terms of deflections, the voided SCC slab with 1% steel fiber has increased by 15.243% and the voided SCC slab with
.8% fiber has increased by 3.153% as compared to the voided SCC without steel fiber. These percentage differences has occurred
due to the adding of the steel fiber by volume fraction to the two sample slabs. The punching stress is dependent to the grade of
steel reinforcement and the concrete compressive strength in which the steel fiber has more effect on the tensile strength and little
effect in terms of compressive strength.Failure on load tests that has been observed by comparing the slabs with self-compacting
concrete to that of a normal concrete showed that the SCC has greater punching strength capacity, and this is due to the fact that
the compressive strength is more control parameter effect in terms of punching shear.

On the other hand, the difference in ultimate strength of the solid and voided slab is very little since the voids are placed at
the center of the section. This process is a way of decreasing the weight of the slab while retaining its ultimate strength.

Another parameter that was observed during the tests is the cracking of the slabs, where in it was seen at the tension zone in the
corners of the column stub. This cracks where defined as tension cracks since they occurred parallel to the line of tension
reinforcement. After the initial cracks there were cracks that appeared parallel to the diagonal axis and it extended towards the
edge of the slab. The load initiated at the first flexural crack was 40 kN in normal and self-compacted concrete slabs and at this
same point the modulus of rupture value for the concrete is reached and the cracking started at the area of maximum tensile
stress. As for the reinforced steel fiber SCC slabs, it was able to withstand a load of 80 kN at 1% and 70 kN at .8% steel fiber
ratio. There is an increase in resistance since the steel fibers acts as a bridge that connects the two sides of crack in which in turn
delays the opening of cracks on the upper fiber of the slab.

It was also noted that the critical zone of the SCC slab and the voided SCC slab has decreased as compared to the normal
concrete slab. For the voided SCC slab with steel fibers, there is an increase in terms of critical crack in the critical zone
especially for the SCC slab with 1% volume fraction of steel ratio.

CONCLUSIONS MADE BASED ON THE STUDY

In general, the study showed that voided slabs reduces the weight of concrete allowing for a longer deck between
columns without beams and could save money due to reduction in steel and concrete for the columns, footings and floors of a
structure as well as allowing for a lighter foundation and total building weight.

It was also concluded that by adding the steel fibers at the critical zones, the punching shear strength is increased and
the angle of punching failure is decreased, but the crack pattern for punching shear has increased specially the voided SCC slab
with 1% volume fraction steel fiber. In terms of mid span deflection, the voided SCC slab without the reinforced steel fibers
showed a decreased value and its punching shear strength is also increased.

PERSONAL VIEWS ON THE STUDY

Personally, I agree with the results and findings of the study since the parameters used like that of a superplasticizers,
reinforcing steel fibers and the use of self-consolidating concretes performed the expected behaviors when used in structures.
But I think it would be better if the critical zone is constructed with pure concrete since it is stronger in shear and punching shear,
and although this method will prove to be hard to create due to inconsistency during the construction works; it would eliminate
the use of reinforcing steel fibers.

The study is very useful in our proposed research since we can anticipate the possible behaviors and effects of the
punching shear in our polystyrene voided slab, we could also base our design of voided slab in this study since it gave us insight
on the advantages and disadvantages of using steel fibers to that of non- reinforced slabs. This study allowed us to consider one
of the critical or weakest points of our proposal and make a possible solution into solving it.

REFERENCE
Sakin, T. S. (2014). Puncing Shear in Voided Slab. Civil and Environmental Research, Vol.6 (10). Retrieved from
https://pdfs.semanticscholar.org/8562/09455a7f5e8b87694acb28a474441e5d691d.pdf
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NUMERICAL ANALYSIS OF FLAT SLABS WITH SPHERICAL VOIDS SUBJECTED TO SHEAR FORCE

BACKGROUND AND THEORIES OF THE STUDY

An alternative by elimination of the concrete in the middle strip of a full flat slab which does not contribute to its structural
performance by the use of spherical balls to obtain a biaxial voided flat slab (Albrecht, 2102). This method has many advantages
as for economic savings, longer spans between supports, faster construction time and environmentally friendly. However some
uncertainties concerning the shear strength are to be expected due to the presence of hollows between the concrete slabs. One of
the questions that may arise is to what degree of influence the spherical voided cores affects the shear bearing capacity of the slab
as compared to the typical solutions of flat slabs or as to what loading level does the shear force generally affects the behavior of
the voided slab. And there is still an issue in regards to the elimination of plastic balls from the areas around the columns unto
establishing the dimension for the perimeter of the solid slab.
The first control perimeter ul=2d as the perimeter of the solid slab as considered in punching shear provisions by Kiss and
Onet at 2008 in order to check of the relation to the shear strength of the hollow flat slab. As for the load bearing behavior of the
biaxial hollow slab, there have been numerical and experimental studies but all the loading conditions was not considered.

DESIGN AND METHODS USED FOR THE ANALYSIS

The experimental test conducted on the study was made with the design and supervision of the behavior of flat slabs with
the spherical voids and the low steel ratio under the shear force which also explored a wide range of influence of the studied
parameters on the program analysis.

The Advanced Tool for Engineering Nonlinear Analysis (ATENA 3D) nonlinear design software which was developed by
Cervenka Consulting Company was used in the study in order to achieve numerical analysis. Cervenka (2011) stated that the
program was used with success especially for the simulation of the reinforced concrete structures. Papanikolaou & Kappos
(2007) added that the concrete modeling in ATENA 3D is based on a tension cracking model with a compression plastic range
which can also handle the increased deformation capacity of concrete under the triaxial compressions.

By the use of the component model for the concrete, it allowed the researchers to use the material curves determined by lab
experiments. And in order to be able to define the compression concrete, a sigma was initiated - epsilon variation diagram which
was traced by 20 points from the experimental curve.

For the concrete tensile behavior, a linear sigma was introduced- epsiolon diagram which was define by 3 points
determined accordingly to the values of the tensile strength and the elastic compression modulus of the concrete. The values were
obtained on 150 mm cubes and compression test on a 100 x 100-300 mm prisms in the laboratory by split tests. To avoid any
errors due to plasticity in higher steel areas the steel sections used for loading and support of the elements were considered as an
ideal elastic material.

The concrete and steel section discretization was made in CCIso Tetra (Tetraedic Volumetric Finite Elements) to display
the capabilities of nonlinear behavior and count no more than 10 integration nodes and the reinforcements was modeled as
independent truss bars. There were a number of several similar analyses like the varied dimension of 6cm and 10 cm in order to
assign a finite element and it was established that the finite element mesh is 8 cm.

The numerical model considered a perfect liability between the longitudinal reinforcement and to that of the concrete since
the bubble deck reinforcement models were made with steel mesh at both sides.

The mechanical characteristics for the theoretical model has taken into account the elasticity modulus of concrete to be
36800 MPa, compression strength of concrete to be 46.86 MPa, tensile strength of concrete to be 3.62 MPa, Poisson’s coefficient
of concrete to be 0.2, the elastic modulus of steel reinforcement to be 200000 MPa and the yield strength for the reinforcement to
be 462 MPa.

DATA AND OBSERVATIONS

The theoretical model was adjusted regarding the material properties of both the slabs with voids and solid slabs with the
same thickness. The data showed the displacement curves of both the MG3 slab having reinforcing percentage of 0.52% and the
MG4 with the reinforcing percentage of 0.31% in terms of the shear load which showed the inequality of stiffness between the
specimen with voids and a gradual decrease in the curve was seen for the slab without voids with decrease of a/d ratio. This is
due to the fact that, the inclined cracks become more present between bearings while increasing the a/d ratio.
Gumpad, Guiller M.
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In terms of the maximum shear force of the voided and normal slabs, there is no high differences seen. The worst case is for
the flat slab with the longitudinal reinforcement ratio of 0.52% and a/d of 2.6. The models with a 0.52% of reinforcement ratio
has failed in terms of shear force and all models with 0.31% of reinforcement ratio failed at bending moment.
All the models without voids failed at bending moment and the inclined cracks had lower values as compared to the
perpendicular ones in the central area of the slab from the shear force applied.

The differences in stiffness and maximal load grow in value as the reinforcing ratio is increased as seen in the force-
deflection diagram. For the slabs with steel ratio of 0.52%, the presence of voids does not negatively affect the maximum shear
value but as the reinforcing steel increases over 0.52% the value of shear force decreases when compared to the corresponding
solid slabs. The decreases was seen to be more profound (14%) when the steel reinforcement reaches a ratio of 0.81%.
The failure occurred after yielding point for the specimen with voids, even those that failed at shear but the crack openings
associated to that of serviceability limit state SLS (width=0.3) was achieved before the elements begins to yield.

CONCLUSIONS MADE BASED ON THE STUDY

In the parametric study that was performed, it was seen that there was a variation of the shear arm and reinforcing
percentage of each voided slabs and slabs without voids. It showed that the differences between the failure forces values were
below 10% from the initial stiffness to failure mode.

The stiffness reduction for bending for the flat slabs with voids to that of slabs without voids was justified in the study
along with the increase of reinforcing percentage and a/d ratio (shear-span ratio). During shear force, all the shear-span ratios for
flat slabs with spherical voids failed at 0.52% while the 0.31% a/d ratio voided slabs the failure occurred at the bending moment.

The ultimate shear force of the voided slabs decreases as compared to that a solid slab when the reinforcing steel percentage
arises.

In the comparison of the ultimate values of shear force for voided flat slabs to that of a normal flat slab with both
reinforced at 0.52%, there is no remarkable differences (+5% or -5%). In line with this it was concluded that voided slabs don’t
display a different behavior for shear force as compared to a solid slab.

PERSONAL VIEWS ON THE STUDY

Although the study provides a detailed data for the computation and analysis of a voided slab and a solid slab with different
reinforcing percentage, the study is not quite reliable in terms of the actual construction since it was purely a numerical analysis
and no prototype was created for actual testing.

The study is quite accurate since it used different types of percentage and ratio of reinforcements but a more solid output
would have a greater impact on providing a solid evidence for the implementation and recommendation of a solution to the
problem.
The study could help us into the design of our proposed polystyrene voided slab in terms of what steel reinforcement would
best suit a residential home for a replacement for a 2 way slab. It also gave us insights as to what parameters to consider in
designing our proposed research. The numerical values and graphs given could also prove to be a supporting evidence for us in
conceptualizing ideas or theory in our study.

REFERENCE
Bindea, M., Chezan, C.M., & Puskas, A. (2015). Numerical Analysis of Flat Slabs With Spherical Voids Subjected to Shear
Force. Journal of Applied Engineering Sciences, 5(18), 7-13. doi: 10.1515/jaes-2015-0001.
Gumpad, Guiller M.
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EVALUATION OF THE FLEXURAL PERFORMANCE AND CO2 EMISSIONS OF THE VOIDED SLAB

BACKGROUND AND THEORIES OF THE STUDY

Reinforced concrete is a composite structure in which it comprises of concrete with a high compressive strength and
reinforcing bars with high tensile strength. The reinforced concrete can make a highly durable structure as well as it can be
formed in a way that the architect designed. Concrete is also relatively inexpensive as compared to steel and other construct ion
materials so the reinforced concrete has been chosen as a suitable material combined with steel since it provides low corrosion
rate, high fire resistance and high water resistance.

The downside is that many studies have shown that the concrete consumes large volume of energy and it also emits large
quantity of carbon dioxide. In order to reduce such environmental burden, many studies have been conducted and such approach
tested. One study by Kim et al. (7) suggested the use of I-slab system, in which it incorporates polystyrene forms into a precast
concrete panels for the reduction of the amount of concrete used.

Many proposal and studies have also been done to solve such problems like the replacement of low-strength materials to
that of a high strength materials, using by products and recycled materials, and the design of optimal structural system to
minimize the construction materials. As for the environmental performance of concrete, one suggestion is that of using added by-
products such as silica fume or other by-products.

On a study conducted by Han and Kim (8), it was seen that the emission of carbon dioxide for a reinforced concrete
structure has emitted a relatively bigger amount as compared to that of a steel structure. Moreover, Molina- Moreno et al. (7)
suggested a voided slab as a new method to reduce environmental burdens since this type of slab section would use a lesser
concrete material and it was also an example of a low-carbon design for three aspects, such as the structural performance,
economic costs, and environmental impacts.

Although many suggests that the use of a voided slab would reduce the environmental burden, it is sparse that such studies
had evaluated the CO2 emissions and environmental performance of such method. While many of the studies has focused on the
micro-perspective such as selection of alternative materials and optimization of the design, there is also a macro-perspective
approach which considers the entire building system rather than the individual parts of it. A research about the different structural
systems and CO2 emissions has been conducted by Nadoushani and Akbarnezhad (14) which they indicated the the significance
of compressive assessment of the embodied carbon and the operating carbon for choosing the structural material during the
structural design.

The purpose of the study was to evaluate the structure performance of a voided slab through testing of the flexural
experiment and empirically validate their environmental influence.

DESIGN AND METHODS USED FOR THE ANALYSIS

In the flexural performance test, the main variable were the depth of slab, the hollowness ratio used, and the presence of
void former materials. The details and dimensions of the specimen tested were 4230 mm in length, 700 mm in width and the
depths were varied at 169 to 210 mm.

A four point bending test was conducted to a simply supported specimen so as to evaluate its flexural performance. The
applied load was a monotonic loading which used an actuator with the capacity of 100 kN resisted by a steel frame with the
capacity of 200kN. For the accurate examination of of the initial flexural behavior, the applied load was at a relatively low
deflection rate of 2.0mm/min. A linear variable differential transformer (LVDT) was installed on the specimens in order to
receive accurately the displacements of the slab. A reinforcement by 10mm and 13mm deformed was used for the specimens and
a 6 mm diameter wires were used as a means to anchor the void former to the upper and lower reinforcing bars. The concrete had
been designed with a compressive strength of 27 MPa and comprised of 333 kg/m3 ordinary Portland cement, a fine aggregate of
821 kg/m3 a coarse aggregate of 1086 kg/m3 and a water of 108 kg/m3. The compressive strength which was tested after 28 days
curing in water bath was 35.16 MPa and slump was 80mm.

The reinforcing bars that was used were D10 and D13 diameters and their nominal yield strength was fy= 400 MPa.
Through the direct tension test in KS B 0802 (29) the ultimate tensile strength was found to be 630-651 MPa for the reinforcing
bars. The void former material is a sphere shape having a diameter 100mm, an oblate shape of 170mm and a height of 110mm.

The sum of the quantity of individual components which were concrete, reinforcing bars, and void formers were calculated
and referred to as the carbon dioxide emissions from the raw materials: CO2M = ⅀M(i) × (CO2emission factor M). In which the
CO2 M is the quantity of carbon dioxide emission during the raw materials stage.
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As for the carbon dioxide emission during the transportation, it was the individual components of the voided slabs as it was
delivered to the site. The number of vehicles, distances from the origin to the manufacturing plant, and fuel efficiency of each
vehicles were also considered for the emission of the carbon dioxide. And for the manufacturing stage, the carbon dioxide
emission of the voided slabs was the sum of the consumed energy and unloading of raw materials and manufacturing of
reinforcing bars.

DATA AND OBSERVATIONS

In the study, the flexural stress result that was indicated on the graph indicated that after the initial flexural cracking
occured in the test specimen there was a gradual cracking expanded to both ends as the loads increased. The strength of the
specimens increased approximately 10 to 30% when the yielding occurred as compared to the reference specimen.
The study was able to compare the data between the expected value of cracking strength and yield strength in accordance
with the structural concrete design code and commentary in South Korea. The results showed that the experimental value was
higher than the load anticipated. The experimental ultimate strength was about 115-139% of the yield strength of each specimen.
A likely reason was that the wires that anchored the void formers compromised the strength of the voided slab which made the
ultimate strength observed in the experiment higher than what was anticipated.

The CO2 emission of each component of the voided slabs were surmised and the data was compared as to which of the
percentage amounts the highest. It was found that the amount of CO 2 emitted by the concrete was 69.59 kg-CO2, which accounted
for 69.94% of the total CO2 emissions.

The second specimen voided slab of approximately 16%hollowness ratio and consists of 64 spherical void formers of 100
mm diameter were used to fill the hollow section of the slab. The volume of the concrete used in this specimen was 0.17 m 3
which is 0.04 m3 lesser than what was used for the first slab. Reinforcing bars and wires were also used which in turn made the
value for the CO2 emission to increase as compared to the first experiment 129.44 kg-CO2/FU.

The third specimen was a voided slab with hollowness ratio of 22% with a 25 oblate shape void formers. The volume of
concrete that was used was 0.16 m3 and the CO2 emitted from the concrete was 53.36 kg-CO2.

The results from the data and graphs that was used validated the structural performance of the voided slab which was
similar or slightly better than the normal reinforced concrete slab. As for the yield strength, it was increased approximately 10-
30% over the anticipated yield strength.

CONCLUSIONS MADE BASED ON THE STUDY

The results upon the CO2 emissions showed that the voided slabs have emitted more carbon dioxide when compared to the
normal reinforced concrete slab, regardless of the hollowness ratio and types of void forms. Additionally, the voided slab would
require additional materials for the anchorage of the void formers to the reinforcing bars in order to prevent buoyancy of the
formers during the curing of concrete and its placing.
The results of the study negated the common notion of voided slabs as being environmentally beneficial due to the
additional steel reinforcements and wires for anchorage. A recommendation was also stated that in order for the voided slabs to
be more eco-friendly methods such as use of recycled materials, new void forms without anchorage and other eco-friendly
materials must be used.

PERSONAL VIEWS ON THE STUDY

I do agree with the study since the parameters used included the transportation of the materials as well as the
fabrication of it. The gathered data also proved to be a solid evidence since formulas and graphs were made as to compare
different trials and specimen that was made.

But on the basis of cast-in place structural analysis of voided slabs it would result to a more eco-friendly performance
since it would then eliminate the use of vehicles for transportation. A manual labor of fabrication can also be done as to reduce
the use of machines and fuel for each steel anchors.

REFERENCE
Cho, S., & Na, S.(2018). Evaluation of the Flexural Performance and CO2 Emissions of the Voided Slab. Advances in
Material Science and Engineering, 1(13). Retrieved from https://doi.org/10.1155/2018/3817580.
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EXPERIMENTAL AND NUMERICAL INVESTIGATION ON STRUCTURAL BEHAVIOR OF BUBBLE DECK

SLAB WITH CONVENTIONAL SLAB

BACKGROUND AND THEORIES OF THE STUDY

Bubble deck was first proposed and made in Denmark as a hollow core slab since it was determined that concrete
contributes 10% of the world’s CO2 emission. A study in USA that was conducted proved that using a prefabricated deck slab
contributes to lesser formwork and faster construction by 20%. The plastic recycled hollow balls which is made of a non-porous
material contributes to the concrete’s high strength and stronger resistance to corrosion. The weight of the concrete decreases
since a part of the slab uses lesser concrete due to the hollowed section.

The use of high density polyethylene hollow spheres increases the efficiency of the floor by replacing the ineffective
middle part of the concrete slab. The introduction of voids also leads to 35 to 55% lighter slab which in turn minimizes the loads
on the column, foundations and walls. The hollow spheres of the slab generally regulates in order to allow the deflection during
service loads applications.

These members are readily brought to site to be placed on a formwork then technical methods are used for the
concreting of the hollow slab. One of the advantages of this method is that the slabs can be precast at sites so as to reduce the
construction time. The curing time would also be lesser since there is a decrease in the volume of concrete.

As the time of construction becomes lesser, the cost relatively decreases since there is a reduction in time and materials
used; same through can also be observed with the design and construction of the columns and beams since the dimensions are
becoming lesser.

The downside of using such method is that its shear resistance will be reduced due to lesser concrete volume. Studies
have found that the shear resistance of a bubble deck slab decreases by 0.6 times the shear resistance of a solid slab with the same
thickness. In terms of bending stress, the bubble deck slab was found to be 7% lower as compared to the solid deck slab.

DESIGN AND METHODS USED FOR THE ANALYSIS

The test used a 100mm diameter size recycled polyethylene hollow spheres and reinforced with a high grade steel of
fy = 500 Mpa. The 10 mm diameter reinforcement steel was both placed on the top and bottom part of the slab. An 8 mm diameter
steel bar was used for the distribution bars. The aggregates that was used was 12 mm diameter and the minimum grade of
concrete M30 and M40 was used. The depth of the slab is about 200 mm and the test was carried out accordingly to the IS 456-
2000 standard.

The project utilized the use of finite element software ANSYS for the structural behavior and strength of both the
bubble deck and the conventional concrete slab. The finite element method is extensively used for the study of the behavior of a
structure such as the equivalent strength, shear strength, crack pattern, ultimate load, and the deflection at the mid-span of a slab.

The connected finite number on the tests are called the nodes in which they are interconnected having different sizes
and shapes. In line with this, all the gathered data were coded to the ANSYS and were based on the parameters such as the
diameter of the ball, slab thickness, and the width of the slab.

DATA AND OBSERVATIONS

For the numerical modelling of the data both the bubble deck slab and the conventional slab are plotted using a tetra
hedral element type which has 4 nodes and each of the nodes has a 6 degree of freedom for the concrete, steel reinforcement and
for the balls. The above mentioned process were both initiated to the hollow deck slabs and the solid concrete slab. The support
conditions established for both specimen was a simple supported structure which contains a hinge on the other end and a roller
for the opposing side.

An area of 500 mm x 500 mm was subjected to a uniformly distributed load over the top portion of the slab. This load
was considered to be axially transmitted over the top portion of the slab with displacement control. The size of the slab is 750
mm x 750 mm x 200mm and the details was drawn using the AUTO CAD software to be able to visualize completely the concept
and to make the data gathered during testing of the specimen systematic.

The design was then explored using the ANSYS Workbench 14.5 as 3D solid objects with identical geometry. The
capacity of the maximum loading of the hydraulic jack was 500 kN. And the deflections were measured at mid span of the both
the hollow deck slab and the conventional deck slab. The strain was also measured using the strain gauge in order plot the
relations of each parameters. The loads were increased at an increment of 10 kN to record the deflections until failure.
Gumpad, Guiller M.
2161508

CONCLUSIONS MADE BASED ON THE STUDY

The study was able to identify 25% reduction when the voided slab was compared to that of a solid slab and it was also
stated that the method of bubble deck slab was environmentally friendly since the cement production has been reduced due to
lesser cement consumption.

The study was able to validate that the elasticity property of slab has improved. It was also concluded that load,
deflection and weight parameters of the bubble deck slab gave better results than that of a conventional slab. The experimental
and numerical results of the bubble slab also showed a high load bearing capacity.

PERSONAL VIEWS ON THE STUDY

The study conducted pointed out many of the advantages of the bubble deck slab and used advance tools for the
analysis and data gathering but the results was not thoroughly explained. The proposed study was generalized and there is no in
depth analysis about other properties of the hollowed deck slab. With the availability of their materials, a more profound analysis
should have been made instead of just comparison of the voided slab to a conventional solid slab.

Although I agree with the results found since the same results have also been concluded by other studies which I have
read, the data still does not give a solution to the weaknesses of the bubble deck slab such as the weak shear resistance and weak
punching shear resistance.

This study may help us into having a solid validation on the properties of a hollow deck slab and into the analysis of
our proposal which utilizes the use of polystyrene instead of a polyethylene. The deflection and strain which was also found on
the study could help us to anticipate the possible behavior of our designed slab.

REFERENCE
Ranjitham, M. & Manjunath, N.V. (2018). Experimental and Numerical Investigation on Structural Behavior of Bubble
Deck Slab with Conventional Slab. International Journal of Trend in Scientific Research and Development, 2(3).
Retrieved from ijtsrd.com/papers/ijtsrd11532.pdf.
STA.CRUZ, John Jeric S. (2157374)

EXPERIMENTAL STUDY ON BUBBLE DECK SLAB USING POLYPROPYLENE BALLS

This research is about Bubble deck slab using polypropylene balls for experimental study. The aim of this research is to
determine the distance and the size of the ball to achieve the maximum strength. As we all know that slab is one of the largest
structural member in building constructions. In the 1990’s Jorgen Bruenig was the first person to invent the biaxial hollow slab
known as bubble deck slab in Denmark. Bubble deck offers a lot of help especially to the atmosphere because it less contributes
CO2 in the manufacturing process and its more sustainable construction option by using less concrete than typical concrete floor
system. The phenomenon being observe in this study is find the right proportioning of the spacing and the diameter of the ball
and also to determine the location of crack pattern of bubble deck slab.

However, the bubble deck slab is a new floor system of reinforced concrete that have spherical hollows as substitute
material for solid concrete slab. It is other technique for eliminating the concrete in the middle potion of a floor slab. Its dead load
is lesser because of its spherical hollows in the center of the slab. While the voids in the middle of the slab can resist the thermal
insulation and the weight of the slab is 30% to 50% is lighter than the typical concrete system. Using hollow elliptical balls as a
replacement in concrete is the best alternative to use to obtain better load-bearing ability in the bubble deck.

Bubble Deck slabs ' behavior is influenced by the slab thickness-to-bubble diameter ratio. It is also having advantage to
conventional slab like: it can lower the total cost, use of material can maximize, it enhanced the structural strength, and the
working/construction is decreased and is a green technology.

Bubble Deck consists of three primary materials, steel, plastic and concrete spheres. The steel is manufactured in two
forms-meshed layers for side support and diagonal girders for vertical bubble support. In this experiment (2) two trial are
committed: first trial using the 60mm diameter of balls, the spacing is 20mm and the slab thickness 100mm. The second trial
using the 75mm diameter of balls, spacing is 30mm and the slab thickness 125mm. Using Universal Testing Machine (UTM) we
will know the exact location of crack and the maximum strength of materials. And before we know the result the hollow sphere
here is just made up from recycled high-density polypropylene. The flexure crack is located in 125mm slab thickness and the
shear crack is located in100mm slab thickness.

PERSONAL VIEWS ON THE STUDY

Yes, I agree to the result. I understood that the spacing and diameter of ball have impact to the strength of the concrete.
If the distance of balls increases, its flexural strength of slab also increases. It also observed that 60mm ball diameter and 20mm
spacing is higher the flexural strength than the flexural strength of 75mm ball diameter and 30mm spacing. Compare to the
typical slab (pure concrete) there is a 35% - 50% save in using of concrete which leads to lesser the dead load of slab with the
same flexural strength of the slab. The ratio of weight of the bubble deck and the recycled plastic is 100kg (concrete) replaced by
1kg (recycled plastic).

I find it useful because of the combination of material proposed in the study that could be useful in our research, since
they already provided the information that we could incorporate in our study. As we can improve our results since the experiment
provided informative conclusion and helpful outcome.

Although the research focuses the usefulness and advantages of the voided slab. I think I would be better if they
incorporated some of weaknesses of using such method like its effect on the shear and punching shear on the area of the column.

REFERENCE OF THE AUTHOR

Hai.L.V, Hung.V.D, Thi.T.M, Nguyen-thoi.T and Phuoc.N.T, “The experimental analysis of bubble deck slab using modified
elliptical balls”, Hokkaido University.

Sergiu Calin, Roxana Gintu and Gabriela Dascalu, “The summary of tests and studies done abroad on the bubble deck system”.

Prabhu Teja. P, Vijay Kumar. P, Anusha. S, Mounika. C.H, Purna chandra Saha, “Structural behavior of bubble deck slab”,
IEEE-International Conference On Advances In Engineering, Science And Management (ICAESM -2012) March 30,
31, 2012.

Terec.I.R, Terec.M.A, “The bubble deck floor system”

Vaignan.B, Dr.Prasad.B.S.R.K, “Analysis of voided deck slab and cellular deck slab using midas civ

Harishma.K.R, Reshmi.K.N, ‘A study on bubble deck slab”, International Journal of Advanced Research Trends in Engineering
and Technology (IJARTET) Vol. II, Special Issue X, March 2015.
STA.CRUZ, John Jeric S. (2157374)
Subramanian. K and Bhuvaneshwari. P, “Finite Element Analysis of Voided Formers”, International Journal of ChemTech
Research Vol.8, No.2, pp 746-753.

Amer M. Ibrahim, Nazark Ali , Wissam D. salman, “Flexural capacities of Reinforced Concrete Two-way Bubble deck slabs of
Plastic Spherical Voids”, Vol. 06, No. 02, pp. 9-20.

Aratishetkar and Nageshhan cheb, “An experimental study on bubble deck slab system with elliptical balls”

Rinku John, Jobil Varghese, “A study on behavior of bubble deck slab using ansys, International Journal of Innovative Science,
Engineering & Technology’, Volume 2 Issue 11.

REFERENCE
Dheepan, K.R., Saranya, S., & Aswini, S. (2017). Experimental Study on Bubble Deck Slab using Polypropylene Balls.
International Journal of Engineering Development and Research, 5(4).716-721. Retrieved from,
https://www.ijedr.org/papers/IJEDR1704116.pdf
STA.CRUZ, John Jeric S. (2157374)

EXPERIMENTAL STUDY ON BUBBLE DECK SLAB

This research about study on bubble deck slab. The aim of this research is to determine the capabilities of a bubble deck
slab and to compare it to conventional slab with different types of base and height ratio. Together with estimating how much
concrete will save using spherical balls into the core of the slab. Bubble deck is also known as slab which its core is embedded in
spherical balls that can be a different shapes and sizes, is a technology that presently has an enormous beneficial effect on the
worldwide knowledge result in its positive impacts on the whole structure.

This research work is concentrated on the use of bubble deck in construction includes its weight, cost-effectiveness and
slab span flexibility. The slab with bubbles, (1) has 90mm size of spherical ball which have 164kg of concrete and (2) has
120mm size of spherical ball also have 151.54kg of concrete. While in the conventional slab (without bubbles) casted with
183.35kg of concrete, the base and height ratios are 0.60 & 0.35 having 16 and 35 spherical balls respectively.
The result of the experimental test shows that after a load of 164KN with crack, conventional slab carried out a load of 424.95KN
had a deflection of 12.1 mm. The bubble deck slab with B / H ratio 0.6 carried 350KN load causing a 12.64 mm deflection with
crack after 168KN load While the last Bubble Deck slab with base and height ratio of 0.8, carrying a load of 398.2KN and caused
a deflection of 13.3mm with crack after 300KN load. The first Bubble Deck slab save a total of 10.55% of concrete and the
second saved 17% of the concrete. This means that the carrying capacity of the bubble deck slab is smaller than that of the typical
slab, it referred to one-way slab. Usually referred to as two-way slabs when slab is supported by columns generally arrange in
rows to deflect slabs in two directions. In the 1990s, Jorgen Bruenig (who developed Denmark's first biaxial hollow slab) built
the slab with void formers, producing only the voids commonly known as the bubbles and the slab. This fresh bubble deck
building scheme uses recycled spherical balls in slab to reduce the self-weight of the structure by replacing bubble concrete as
part of concrete.

The economic value of South Africa's internal spherical void formers (SVF) slabs was studied, comparing the instant
construction expense to those of two other big span structure slabs, namely coffer and post-tensioned slabs. They discovered that
the rigidity of the SVF slab fields should be reduced by approximately 10 percent compared to that of the same strong slab
thickness.

Using of recycled industrial spheres to produce air void in traditional way of bubble deck while offering strength
through arch action. The results indicate a drastic decrease of up to 50 percent in dead weight, enabling a considerably longer
length and less structural support than traditional alternatives. Bubble Deck therefore has many benefits over traditional cement
plating like: lower overall costs, reduced use of materials, improved structural effectiveness, reduced building time and green
technologies. Engineers and researchers from around the world pay much attention to it.

Bubble Deck was researched based on the technology of patented inclusion. The direct way of connecting air to steel
The Bubble Deck is an optimized concrete construction with an optimum concrete construction with simultaneous maximum
utilization, both moment and shear zones, for the purpose of the removing g-concrete without carrying effect. The results showed
the bubble's fundamental impact in reducing the weight of the deck. The results also indicate a 1/3 lower dead load than a strong
deck with same density–without affecting the deck's bending power and deflection behavior.

PERSONAL VIEWS IN THE STUDY

The research was clearly showed the correlation between the maximum strength of concrete using one-way slab and the
maximum strength of concrete using two-way slab. This means that the load carrying capacity of the bubble deck slab is lower
than the conventional slab.

The study is useful in terms of improving the strength of the concrete. Since this research contributed information
regarding on the enhancement of the strength and durability of the slab.

REFERENCE OF THE AUTHOR

A.N Prakash (2011), “ The revolutionary concept in voided slabs”, Dimensions - A Journal of A N Prakash CPMC Pvt. Ltd.,
Issue No.10, March 2011.

Amer M. Ibrahim, Nazar K. Ali, Wissam D. Salman. (June 2013). “Flexural capacities of reinforced concrete two-way bubble
deck slabs of plastic spherical voids”, Diyala Journal of Engineering Sciences, ISSN 1999-8716, Vol. 06, No. 02, June
2013.

Arati Shetkar and Nagesh Hanche. (2015). “An experimental study on bubble deck slab system with elliptical balls”. ISSN: 0976-
2876
STA.CRUZ, John Jeric S. (2157374)
Bhagyashri G. Bhade and S.M Barelikar AN EXPERIMENTAL STUDY ON TWO WAY BUBBL E DECK SLAB WITH
SPHERICAL HOLLOW BALLS International Journal of Recent Scientific Researc h Vol. 7, Issue, 6, pp. 11621-
11626, 2016

Vaignan.B, Dr.Prasad.B.S.R.K, “Analysis of voided deck slab and cellular deck slab using midas civil”.

Harishma.K.R, Reshmi.K.N, ‘A study on bubble deck slab”, International Journal of Advanced Research Trends in
Engineering and Technology (IJARTET) Vol. II, Special Issue X, March 2015.

Subramanian. K and Bhuvaneshwari. P, “Finite Element Analysis of Voided Slab with High Density Polypropylene Void
Formers”, International Journal of ChemTech Research Vol.8, No.2, pp 746-753

REFERENCE

Mushfiq, M.S., Saini, S., & Rajoria, N. (2017). EXPERIMENTAL STUDY ON BUBBLE DECK SLAB. International Research
Journal of Engineering and Technology, 4(5). 1000-1004. Retrieved from,
https://www.irjet.net/archives/V4/i5/IRJET-V4I5339.pdf
STA.CRUZ, John Jeric S. (2157374)

SPHERICAL VOID FORMERS IN CONCRETE SLABS

This research is about the form of void in concrete slabs. Large-scale concrete flat slab systems with internal spherical
void formers (SVF) have been used in Europe for more than a century. They are bi-axially strengthened flat-slab concrete
systems with an inner spherical void former grid.
The applicability of such a slab scheme has been explored in South Africa. South Africa has its own loading and
concrete design code (at the point of this research). Obviously, the price structure for concrete building differs from that of
European nations. Research at the Technical University of Darmstadt (TUD) in Germany has shown that a shear strength
reduction factor of 0.55 (Schellenbach-Held & Pfeffer 1999) is conservative, whereas study at the University of Pretoria indicates
a higher factor of 0.85 when taking into consideration the shear ability of the continuous steel cages holding the spheres in some
SVF plates. In addition, the TUD laboratory experiments (Schellenbach-
Held & Pfeffer 1999), backed by theoretical calculations, showed decreased deflections for SVF plates Stiffness is not lowered as
much as self-weight leading to lower general short-
term deflections for SVF plates compared to strong plates of the same density.This article will investigate the economic
importance of SVF slabs in South Africa by comparing direct building expenses with those of two other big span slab
technologies, namely coffer and post-tensioned slabs.

SVF slabs shear behavior: Introduction to shear behavior SVF slab shear behavior will differ from solid concrete flat
slab due to the existence of inner spherical voids in SVF slab. The loss of aggregate interlock owing to the reality that a diagonal
shear crack will find voids in the central portion of the beam and the existence of steel reinforcement cages that hold the spheres
in place and act as partial shear reinforcement are two primary criteria to be regarded. Therefore, before debating the distinctive
behavior of SVF slabs, it is essential to first briefly explore the overall shear behavior of concrete slabs.

In comparison with the force-controlled SVF experiments in the University of Pretoria's (Marais, 2008) concrete
laboratory in 2007, theoretical calculations for shear strength in SVF plates were carried out. In comparison with a concrete slab
with the same thickness, stress enhancements and concrete characteristics, a comparison had to be made for the shear resistance
factor for SVF slab. Earlier TUD study showed that a lower SVF shear strength decrease factor of 0.55 times the shear strength of
a solid concrete slab of the same size and without shear reinforcement approximated the shear strength of SVF structures
(Schellenbach-Held & Pfeffer 1999). In accordance with Eurocode 2 (1992) specifications, the shear strength of the solid slabs
was calculated. The UP (Marais 2008) experimental work consisted of testing 12 beam samples of equal length and width, but
with differing thicknesses and voltage reinforcement amounts, some with SVF spheres, and some solid. All beams, simulating
strips of 600 mm broad flat plates, were designed to fail in shear before failing in flexure in accordance with the job mentioned
above by Park and Paulay (1975), in order to draw conclusions about their shear capacity.

PERSONAL VIEWS IN THE STUDY

The result of this research suggest that they would withstand even the extreme weather conditions. By implementing
some extra design considerations, large-scale concrete flat slab structure with internal spherical void formers (SVF) can be
effectively built in accordance with SANS 10100-1 (SABS 2000). Different design specifications have been examined. It is
possible to take the shear strength of the voided areas as 55% of that of a solid slab of the same density (Schellenbach-Held &
Pfeffer 1999). Shear test findings at the University of Pretoria (Marais 2008) on SVF plates with metal cages suggest that this
proportion could be improved to 85%. In order to validate this factor, further tests are needed.

REFERENCE OF THE AUTHOR

Schellenbach-Held, M & Pfeffer, K 1999. Transverse force capability of the BubbleDeck, Technical University Darmstadt’s
Institute for Solid Construction (in German), Germany. rand7 2006. Strand7 finite element analysis software. Strand7
Pty Ltd, Australia.

Marais, C C 2008. Design adjustment factors and the economical application of concrete flat-slabs with internal spherical voids
in South Africa. MEng Dissertation, University of Pretoria.

Park, R & Gamble, W L 2000. Reinforced concrete slabs, 2nd ed. Canada: Wiley.

Park, R & Paulay, T 1975. Reinforced concrete structure, New York: Wiley

South African Bureau of Standards (SABS) 1994. SABS 0160 (1989). Code of practice for the general procedures and loadings
to be adopted in the design of buildings (as amended 1990, 1991 and 1993). Pretoria: SABS.
South African Bureau of Standards (SABS) 2000. SANS 10100-1 2000. South African National Standards 200. Code
of practice for the structural use of concrete. Part 1. Pretoria: SABS.
STA.CRUZ, John Jeric S. (2157374)
Schellenbach-Held, M & Pfeffer, K 1999. Transverse force capability of the BubbleDeck, Technical University Darmstadt’s
Institute for Solid Construction (in German), Germany.

Committee of State Road Authorities (CSRA) 1989. Code of practice for the design of highway bridges and culverts in South
Africa. Pretoria: National Department of Transport.

REFERENCE

Marais, C.C., Robberts J.M., & Rensburg, J.V. (2010). Spherical void formers
in concrete slabs. Journal of the South African Institution of Civil Engineering, 52(2). 2-11. Retrieved from,
http://www.scielo.org.za/scielo.php?pid=S1021-20192010000200001&script=sci_arttext
STA.CRUZ, John Jeric S. (2157374)

BEHAVIORAL ANALYSIS OF CONVENTIONAL SLAB AND BUBBLE DECK SLAB UNDER VARIOUS SUPPORT
AND LOADING CONDITIONS USING ANSYS WORKBENCH
This research is about conducting analysis of conventional slab and bubble deck slab using ANSYS Workbench under
various support and loading conditions. The finite element method is a numerical technique designed to fix differential and
integral equation of original and distinct limit value issues under very complex geometric circumstances. Some factors cannot be
ignored by the finited element method when analyzing an element. This information is intended to identify the domain, border
and initial condition, as well as the specimen's physical characteristics. If the analysis is performed closely after understanding
this information, it will yield the satisfactory outcome. It can also be said that it is very methodical to evaluate finite elements and
that is why it is so prevalent because it makes the implementation easier. The question of evaluating finite elements is
systematically divided into a set of logical steps that can be implemented on a digital computer and can be used to tackle a wide
range of problems simply by changing the software's input of data.
Analysis of finite elements is used for one, two and three-dimensional issues. Sometimes the simpler problem includes
issues of one and two sizes, and if they are treated carefully, a precise outcome can be obtained without software. But if the
assessment needs three-dimensional instruments, it would be much more complex, as it involves a bunch of equations that are
very hard to fix without mistakes. Because this software has been created that makes it simpler to conduct these analyzes by
computer. With a very excellent precision, this software can analyze one, two- and three-dimensional problems.

A fundamental aspect of finite element works is that the whole element is divided into a finite number of tiny
components. The problem domain is regarded as a set of easy sub-domains that are not intersecting, called the finite element. The
subdivision of a domain into components is called the discretization of finite elements. The element collection is called the
domain's finite element mesh. The advantage of separating a large element into tiny ones is that it enables each tiny element to
have a simpler shape, leading to a good analytical approximation. At the turn of the 20 th and 21st centuries, the invention of
bubble deck slab was a break through. Many studies on the feasibility of using bubble deck technology were conducted during
the first century. Slabs are the primarily used for berthing purposes in any structure and are also used to convey the stacking and
loading to other fundamental structural members. According to the reviews, the concrete in the center of the chapter is not fully
used. Unused concrete can deliver up to 80% of the total concrete volume. This unused concrete cannot be expelled completely
as it decreases the capacity of the load carrying at the conveying limit and also increases the deflection.

Slab is one of the largest devouring concrete. We understand that the rise in span length also improves the slab
thickness. Increasing slab thickness makes slabs heavier and finishes in enhanced size of the column and base. It therefore makes
the structure more concrete and steel consumption. Now, owing to restricted understanding, this innovative technology was
implemented to just a few residential or high-rise structures, and industrial floor slab. In order to understand this method and
compare it with the present slab scheme, the structural behavior of Bubble Deck will be analyzed for this inquiry under different
loading circumstances. Bubble deck slab is produced on standard slab design over the prefabricated bubble matrix. In this slab
scheme, a pre-cast concrete layer is given at the bottom of the slab. Bubble Deck is designed to be a column-supported flat slab,
two-way spanning slab. It consists of plastic spheres sandwiched between the upper and lower steel meshes.

PERSONAL VIEWS ON THE STUDY

This research suggests that using finite element method computer software can easily to solve even one, two or three
dimensional problem. But sometimes you can solve problems including one or two dimensional problems and can be solve
without using software, you can have achieved the correct answer but you will be careful about the solution with step by step
process. This detailed investigation has shown that the concept of the Bubble Deck is more efficient in all aspects than a
conventional concrete slab.

REFERENCE OF THE AUTHOR

M.Surendar et. al.“Numerical and Experimental Study on Bubble Deck Slab” Department of Civil Engineering,Dr. Mahalingam
College of Engineering and technology, Coimbatore, India (2016)

L. V. HAI et. al. “The experimental analysis of bubble deck slab using Modified elliptical balls” Department of Civil and
Environmental Engineering, National University of Singapore, Singapor (2012)

Neeraj Tiwari et. al. “Behaviour of Bubble Deck Slabs and Its Application” Madan Mohan Malviya University of Technology,
Gorakhpur (2000)

Mrinank Pandey et. al. “Analysis of Bubble Deck Slab Design by Finite Element Method” Department of Civil Engineering
Madan Mohan Malaviya University of Technology, Gorakhpur (2014
STA.CRUZ, John Jeric S. (2157374)
Rinku John et. al. “A study on behaviour of bubble deck slab” IJISET - International Journal of Innovative Science, Engineering
& Technology, Vol. 2 Issue 11, November 2015

Reshma Mathew et.al. “Shear Strength Development of Bubble deck Slab Using GFRP Stirrups” IOSR Journal of Mechanical
and Civil Engineering (IOSR-JMCE) eISSN: 2278-1684,p-ISSN: 2320-334X, PP 01-06) (2006)

Bhagyashri G. Bhade et.al. “An Experimental Study On Two Way Bubble Deck Slab With Spherical Hollow Balls” International
Journal of Recent Scientific Research Vol. 7, Issue, 6, pp. 11621-11626, June, 2016

REFERENCE

Ali, S., & Kumar, M. (2017). Behavioral Analysis of Conventional Slab and Bubble Deck Slab under
various Support and Loading Conditions using ANSYS Workbench. International Journal for Scientific Research &
Development. 5(300. 1357-1362. Retrieved from, http://www.ijsrd.com/articles/IJSRDV5I30938.pdf?fbclid=
IwAR0HKsD8n5ZRKwDuGAiJNoncwGvQlHSKlmxtmqyJdT8wtDHoOC8674qORz8
TULAGAN, John Lloyd P.
2162521

MIX DESIGN OF STYROFOAM CONCRETE

This publication tried to produce lightweight concrete for structural applications. Authors choose the recycled Styrofoam as a
substitute for coarse aggregate in the mixture of concrete. Additional to that is the environmental limitations imposed on mining
on natural aggregates. To be able to use their mix design as structural concrete, they must achieve a compressive strength of not
less than 17 MPa according to BS8110 used in Malaysia. Using recycled Styrofoam as substitute for coarse aggregate can lessen
the waste in the country.

The authors added a pulverized fly ash to contribute additional strength to their mix design. They compared the 28-day strength of
pure Styrofoam as a substitute for coarse aggregate versus few substitutions of Styrofoam in coarse aggregate. The guidelines of
their design is the grade M40 design. They produced five different mixture as a sample for testing. Achieving more than 30 MPa
as compressive strength for lightweight makes the authors labored. The compressive strength of concrete is dependent on the
stiffness and dense of the aggregates.

Using trial-and-error in differentiating the strength of their mix design helps the author to decide and asses if the Styrofoam is
suitable as a substitute for natural crushed gravel in the mixture of structural concrete. The strength of five specimen conducted in
tests was carefully observed incorporating the pulverized fly ash compared with 100 percent ordinary Portland cement concrete. In
the mix design of this concrete, they added a small amount of super-plasticizers and confidently put cement to act as paste depending
on water-cement ratio. Adding pulverized fly ash provides more production of calcium silicate-hydrate that contributes to the
density, durable and strength of the concrete. Recycled Styrofoam of 10mm to 20mm square in size as replacement for crushed
gravel is used but during mixing, Styrofoam cubed reduced about 30% of its size. Close spacing cell type of Styrofoam having 0.56
specific gravity was used. After mixing, the specimen is placed in barrel of curing purposes.

The result of the concrete mixture is below expectations. Expecting to produce a structural concrete that is lightweight can lessen
the self-weight of the structure. Self-weight of concrete structure is the main contributor of dead load imposed in building. Due to
reduction of self-weight, small section of structural members is adequate to support the building. Lightweight concrete also helps
to enhance the fire resistivity and provides good thermal and sound insulation. The natural aggregates require more water because
of their water absorption. The increase in water will increase also the water-cement ratio, hence, more amount of cement is needed.
One of the goals of the author is to substitute porous aggregates with Styrofoam which is hydrophobic but without compensating
the structural strength of the concrete. The author disregarded the water content and water absorption of the substitute coarse
aggregate due to its characteristic which is hydrophobic.

The use of super-plasticizers is recommended by the author to provide high strength concrete. The first thing they did before mixing
the cement is to add a little amount of water with super-plasticizer to the prepared cubed Styrofoam in order to make the dry
Styrofoam a wet aggregates. After mixing thoroughly the water with super-plasticizer and dry Styrofoam, river sand and ordinary
Portland cement is added with pulverized fly ash. After the leftover water is added to the mixture, slump test is conducted to ensure
the workability and consistency of the mixture. When the mix design is ready, they placed the freshly mixed concrete into mold to
form 100mm by 100mm by 100mm in size. The author used BS1881: Part 108 as a reference for his method for making test cubes
from fresh concrete. After 12 hours being covered by gunnysacks and stripped after 24 hours, the sample mix design is placed in a
water tank for curing purposes. By the used of Universal Testing Machine in Universiti Tun Hussein Onn Malaysia, the test is
successfully and safely conducted prior to BS1881: Part 115 of 1986.

Using pulverized fly ash it enhances the strength and durability of the concrete. Pulverized fly ash is produced in coal-fired electric
power plant. Fly ash changes the practice in construction industry and also the standard code of practice worldwide. Portland
cement with the combination of fly ash typically in the range 80% to 60% Portland cement and 20% to 40% fly ash. Fly ash is
used as a supplementary cementitious material in the production of Portland cement concrete. A supplementary cementitious
material, when used in conjunction with portland cement, contributes to the properties of the hardened concrete through hydraulic
activity.

The compressive strength of the lightweight concrete ranges to 3.1 to 6.9 MPa as a result of the conducted compressive test. This
mix design concrete focuses to produce structural lightweight concrete. The target design and the reference design used is the
strength of 40 Newton per square millimeter. To be able to use the lightweight concrete in structural application, it must have not
less than 17 MPa of compressive strength according to the BS8110. BS 8110 is an outdated British Standard for the design and
construction of reinforced and pre-stressed concrete structures. It is based on limit state design principles. Although used for most
civil engineering and building structures, bridges and water-retaining structures are covered by separate standards (BS 5400 and
BS 8007). The density of Styrofoam concrete produced is 1297 to 1387 kilograms per cubic meter. Resulting in 45 % reduced in
total dead load.
TULAGAN, John Lloyd P.
2162521

The compressive strength of the Styrofoam concrete still too far from the target strength of 40 Mpa at 28-days. Due to the low
modulus of Styrofoam aggregates, the compressive strength of the mixture is compensated. Concrete compressive strength is very
dependent on strength stiffness and density of its aggregates which the Styrofoam is reluctant. The author concluded that the failure
is due to bond between Styrofoam and concrete.

Proportioning of concrete mixes can he regarded as procedure set to proportion the most economical concrete mix for specified
durability and grade for required site conditions. As a guarantor of the quality of concrete in the construction the constructor should
carry out mix proportioning and the engineer-in-charge should approve the mix so proportioned. The method given in this standard
is to be regarded as the guidelines only to arrive at an acceptable product, which satisfies the requirements of placement re quired
with development of strength with age and ensures the requirements of durability.

The target strength of 40 MPa in lightweight concrete is too far and difficult to achieve due to the characteristic of the St yrofoam.
The compressive strength of the mix design is compensated due to the change of stiffness and strength of substitute coarse
aggregate. The mix design concrete result may be used as walls but not for structural purposes. The mix concrete design may b e
used as a structural element if they use M30 design according to what I read in other articles specifically wrote by Divya Patel,
Uresh Kachhadia, Mehul Shah and Rahul Shah.

This research is very useful in the construction industry, especially in the preliminary design. It can be used as an advantage if the
project is a renovation or extension of an existing structure. Using its characteristic of being a lightweight, the designer can use it
to reduce the total loads of the structure to build or construct. But this research may be used only in architectural or part ition
members only not for structural application. The result of the test concluded that it cannot be used in structural applications. In the
Structural Code of the Philippines, it also provides the use of lightweight concrete in the floor fill in the dead loads of chapter 2:
Minimum Design Loads.

Three mix design of lightweight Styrofoam concrete incorporating pulverized fly ash replacement level; namely 0%, 5%, 10%, and
15% were used. According to many researchers, this range is normally used in cement replacement. The aims of their research is
to produce lightweight concrete for structural application; mix design was developed with less water-binders ratio for producing
higher strength purposes. During the compression strength cube test, all the Styrofoam mix-design shows that the failures were due
to the bonding between the lightweight Styrofoam aggregates used and cement paste. Since no mix design that can produce
compressive strength even closer to 17 MPa, authors should look into the physical properties for the Styrofoam that been employed
or to enhanced the bond with cement paste, the Styrofoam used have to be treated in certain way. For untreated Styrofoam, the
concrete produced is only suitable for general purposes and not for structural applications.

Technically, the denser the concrete, the higher is the density and therefore gave higher compressive strength. The Styrofoam is
not that dense compared with the natural coarse aggregate. One of the author's objectives is to produce lightweight concrete but at
the same time it has good workability and strength. Therefore the more density will directly give the higher compressive strength.
The strength of the cement past also contributes to the compressive strength of the mixture which the author concluded that the
failure is due to the bond between Styrofoam and concrete. Styrofoam should be bond with rough surfaces to make it stronger bond
with cement paste. There is no single mix design can produce compressive strength more than 17 MPa to be used in structural
application. Styrofoam needs to be treated before it might be suitable for structural purposes.

Refecrence

Ahmad, M. H. et al. (2018). Mix Design of Styrofoam Concrete. International conference on construction and building
techmology, 26, 285 – 296. Retrieved from https://www.researchgate.net/publication/259936673
TULAGAN, John Lloyd P.
2162521

EXPERIMENTAL STUDY ON LIGHTWEIGHT CONCRETE WITH STYROFOAM

AS A REPLACEMENT FOR COARSE AGGREGATE

The aim of this research is to reduce the heavy loads or self-weight of tall buildings; to replace the percentage of conventional
coarse aggregate with Styrofoam. Concrete of substantially lower unit weight that hat of conventionally made of gravel or crushed
stone is may be defined as lightweight concrete. Conventional concrete is heavy. Due to the concrete industry like concrete
construction, natural resources are heavily exploited.

Many researchers studies if they can use artificial coarse aggregates as substitute and as a replacement for conventional gra vel or
crushed stone in the concrete. One of the potential artificial coarse aggregate and a lightweight aggregate is the Styrofoam.
Styrofoam not only serves as thermal insulation but also it can reduce the total self-weight of the structure. Due to this reduction
of load follows the reduction of the section of each member, therefore, reduces the total cost of the project.

The objective of this study is to study the basics of lightweight concrete; to find a potential replacement for coarse aggregates; to
cast M30 grade concrete consisting different proportions of replacement material; to compare the compressive strength and dry
density of the concrete; to comment on probability of replacement of coarse aggregates with replacement material.

The author cited the use of pumice stone as a partial replacement to natural coarse aggregates by L.K Minapu, Ratnam and U.
Rangaraju in different proportions along with the use of pulverized fly ash and silica fumes in varying proportion cast adopting
M30 design mix proportions; use of lightweight cinder aggregates by as a replacement for natural coarse aggregates by V. B. Desai
and A. Sathyam cast adopting the M20 design mix; use of volcanic pumice lightweight aggregate as a replacement for conventional
natural coarse aggregates by T. Parhizkar, M. Najimi and R. Pourkhorshidi. The use of pumice stone as partial replacement to
natural coarse aggregates result was failed but the use of lightweight cinder aggregates and volcanic pumice as a replacement for
natural coarse aggregates results concluded that volcanic pumice and cinder can be used as a replacement for natural coarse
aggregates.

Based on IS 10262, concrete has become a main material in construction industry and concrete has overpassed the stage of mere
four-component system, that is, cement, water, gravel, and sand. It is a mixture of way more variety of ingredients, for instance, an
even handed combination of ingredients from as several as ten materials. within the recent past, excluding the main ingredients
mentioned higher than, fly ash, ground coarse furnace dross, silicon dioxide fume, rice husk ash, metakaolin and superplasticizer
are six a lot of ingredients that are typically utilized in concrete created in apply because the state of affairs demands. Hence, it's
all the lot of essential at this juncture to possess general tips on proportioning concrete mixes.

The authors used the Styrofoam as a replacement material for coarse aggregates. It serves as an insulation material to the concrete
and making a concrete mix a lightweight. The dry density of Styrofoam used was approximately to be 33.2 kg/m3 and adopting the
IS 10262: 2009 method for M30 grade design of concrete. Total of six specimens with different percentages of replacement of
aggregate of Styrofoam having a dimension of 150 x 150 x 150 mm. After preparing the cured samples, Non-destructive test was
performed specifically the Rebound Hammer test at the interval of 7, 21 and 28 days.

Portland cement of grade 53, sand that passed through IS 4.75 mm sieve having a specific gravity of 2.634 and water absorption of
0.72%, natural aggregate having a specific gravity of 2.841 and water absorption of 0.81% and Styrofoam having a specific gravity
of 0.033 and water absorption of 23.33% was used as a materials in the mix design of the concrete.

The guidelines used by the author in the process of proportioning the cement, sand, and coarse aggregate are the IS:10262-2009 to
obtained M30 grade concrete. Proportions used are 1:1.35:2.48 with a water-cement ratio of 0.5. In National Structural Code of the
Philippines stated that the maximum water-cement ratio is -.5 but it is advisable and recommended that use 0.45 as water-cement
ratio.

The results of the Rebound hammer test in the cubical specimen at the end of 7, 21 and 28 days were tabulated by the author. It is
easy to evaluate data if tabulated. Results concluded that the target strength of 30 MPa was successfully achieved even if 100%
replacement for natural aggregates is used. To be specific in the result, conventional average compressive strength of the concrete
is 22.5 MPa, 32.06 MPa, and 39.81 MPa in 7, 21 and 28 days respectively. For 20% replacement for coarse aggregates, the average
compressive strength of the concrete is 20.3 MPa, 31.68 MPa and 38.25 MPa in 7, 21 and 28 days respectively. For 100%
replacement for coarse aggregates, the average compressive strength of the concrete is 16.4 MPa, 23.52 MPa and 30.5 MPa in 7,
21 and 28 days respectively. The average dry density and specific gravity of the mix design with different percentages of
replacement indicate also the same relationship with the compressive strength of the mix design.
TULAGAN, John Lloyd P.
2162521

The aim of designing the proportion of concrete mix is to achieve the same performance requirements under specified conditions
of USC of concrete at the most efficient, economical and practical combinations of different admixtures. The essential part of
designing the proportions of concrete mix is to achieve a balanced requirement between workability and strength, concomitantly
satisfying durability by preparing trial mix design and effect adjustments to such trials.

Concrete needs to be of comply and achieve the quality for both fresh and hardened states. The use of certain established
relationships of different boundaries and by analysis of data already generated thereby providing a basis for judicious combination
of all the ingredients involved is the objective of this accomplished trial mix design.

The specific compressive strength is needed to ensure that fresh concrete of the mix proportioned is able to achieve adequate
workability for placement without segregation and bleeding while attaining its purpose is technically the objective of this mix
proportion design. In line with this, the method has an objective to consider the combination of wider spectrum of cement and
mineral aggregates admixture subjected to be used to achieve the requirements of strength for the type of exposure conditions in
environment anticipated in the part of application.

Technically, the solution solved in mix proportions shall be adequate and feasible by means of trial batches. Workability of the mix
design I shall be test and measured. The design of mix proportion shall be technically observed in terms of bleeding, segre gation
and its final properties. If the result workability of mix design I is different from the expected value, the water or admixture content
shall be calculated adequately and suitably. In this calculated design adjustment, the mix design proportion should be redesign
carefully which will result to mix design II. In line with this, two more mix design III and mix design IV should be made with the
water content same as mix design II with different variety of the free water-cement ratio by ±10 percent of the initial selected value.

Sometimes when placement is requiring by pump or when the mix design concrete is needed to be worked around congested
reinforcing deformed bars, it may be desirable to reduce the estimated natural gravel content by designing the concrete mixture to
be more workable. The slump, water content and dosage of admixture shall be test in adjusted mix design for achieving the needed
slump referring on trial if needed. The design mix proportions should be recomputed for the actual water content and verified for
durability requirements.

The results concluded that the compressive strength is inversely proportional to the proportion of Styrofoam in the mix concrete
design. Therefore, the decreased in concrete mass by 42.85% by full replacement for gravels or coarse aggregates. Also after
completely replacing the gravels in the mixtures, the compressive strength is higher than the expected and calculated strengt h,
therefore Styrofoam can be used as a replacement for natural gravels in the mixture of concrete adopting the M30 grade of concrete.

The design proportion of concrete mixes can be anticipated as procedure to set the proportion to be most efficient and economical
concrete mix design for specified durability and grade for needed conditions in site. As a provider of the quality of concrete in the
construction the constructor shall carry out mix design proportions and the engineer-in-charge shall approve the proportion of mix
design. The method provided in this standard is to be regarded as the guidelines specifically to arrive at an adequate product, which
provides the requirements of placement needed with development of strength with age and ensures the target durability.

Refecrence

Patel, D., Kachhadia, U., Shah, M., & Shah, R. (2017). Experimental Study on Lightweight Concrete with Styrofoam as a
Replacement for Coarse Aggregate. International Conference on Research and Innovations in Science, Engineering &
Technology, 1, 103 – 108. Kalpa Publications in Civil Engineering
TULAGAN, John Lloyd P.
2162521

STUDY AND MODEL MAKING OF SLAB USING BUBBLE DECK TECHNOLOGY

The Bubble Deck technology is used to overcome the increase of the self-weight of the slab in the structure. It replaces less amount
of concrete volume using the recycled balls. One of the objectives of this paper is to impart the innovation in construction industry
and to use the new construction method using high-density polyethylene hollow spheres in the construction industry considering
the total cost, efficiency and structural behavior of the concrete structure.

The total concrete volume of the flat slab is not totally utilized, instead it contributes to the dead load of the structure and only in
the portion of the column is the transfer of loads. This paper reduces the volume of concrete of the flat slab using a high-density
polyethylene hollow sphere as a replacement for the certain volume of the concrete except in the portion of the column. We all
know that the punching shear is relatively high in the portion of column that is why the author did not reduce the concrete volume
of slab in the portion of column. Therefore, the dead load is inversely proportional to the efficiency of the floor.

The bubble deck slab is a lightweight and a biaxial concrete slab is generally designed using the conventional design method. This
innovation generally decreasing all concrete from the center of a floor slab that is not contributing to structural function. Due to the
elimination of certain concrete, it reduces the structural dead load and produces a thinner section. Using HDPE hollow sphere as a
replacement in ineffective concrete in the center of the slab results in a lightweight but efficient floor slab system.

The results of using the bubble deck method for slab is a reduced quantity of concrete and cement by 30 to 50% compared with
the conventional slab and also gives an important factor that it reduced the quantity of emitted carbon dioxide. The method used in
the construction and laying out the high-density polyethylene hollow sphere is with the use of interlocked connection so they will
not scatter and to reduce the potential hazard during construction. Using bubble deck also can increase the span length of the slab
with a lower cost and reduced material.

This paper also studied the influence of the cavities due to the employment of plastic balls on the punching behavior of self-
compacted concrete since the punching shear capacity is one of the most important properties of a flat slab. With the use of high-
density polyethylene for recycled balls can reduce the volume of plastic waste, thus, the bubble deck slab is also recyclable except
for the concrete and steel used. It can be recovered and recycled in the demolition of building with bubble deck.

The properties of high-density polyethylene ball used has a specific gravity of 0.96, water absorption is zero, elongated at yield by
900%, Rockwell hardness of R30-60, maximum service temperature of 160 ℉. High-grade steel is generally used. Also same grade
of steel is used in both bottom and top steel reinforcement. The steel reinforcement shall be placed and secured in position that it
will not have a large displacement during pouring of concrete.

Diagonal bars are used to fix the bubbles between the top and bottom reinforcement and also acts as a support of the ball. The
girders or diagonal bars may also act as shear force reinforcement provided that the center-to-center-distance of the girder should
be maximum of twice thickness of the floor; the center-to-center-distance of two down running or up running diagonals should be
a maximum of 2/3 of the floor thickness; Every pair of two diagonals, existing of one up running and one down running bar, should
be welded with 2 welding points to both the lower and the upper longitudinal bar; the welding points with which the diagonals are
attached to the lower and upper longitudinal bar should have a resistance per welding point of at least 25% of the flow strength of
the diagonal; the distance between the edge of the floor support and the connection of the first diagonal from the floor support with
upper longitudinal bar of the girder should be maximal times the height of the girder.

In the construction methodology, the initial step is laying the bottom reinforcement and tied with galvanized iron wire or welded
to ensure that the bars will not disperse. After laying out the bottom bars, initial concrete is poured to act as a bonding material.
The high-density polyethylene hollow spheres are now placed with its cage and then the top reinforcement is provided on the top
of the sphere. After proper inspection, concrete is poured to fill the gaps between the balls followed and proper curing is required.
While pouring the concrete, vibration is provided to remove air content from the slab. Self-compacting concrete may also be used
to allow air to escape and avoid segregation of aggregates. Other construction methodology used precast bubble deck slab.

Conventional slab and bubble deck slab was compared in terms of cost. The volume of the slab is 8.505 cubic meter and the amount
of concrete replaced by bubbles is 2.6 cubic meters having amount of concrete of 5.905 cubic meters. The concrete volume of the
conventional slab is 8.07 cubic meters. Therefore 27% of concrete replaced, that is 20 pcs bags of Portland cement saved if you
used class A concrete. Using bubble deck system can lower the costs and reduced the carbon monoxide emitted during the
construction period.
TULAGAN, John Lloyd P.
2162521

Some references used in this paper were the Bubble Deck Voided Flat Slab Solution, Technical Manual, and Documents by Bubble
Deck UK; Flat slabs with spherical voids. Part I: Prescriptions for flexural and shear design by M. Bindea, Z. Kiss and D. Moldovan;
BubbleSlab. Abstract of test results. Comparative analysis Bubble slab –solid slab by Schmidt C., Neumeier B., Christoffersen J.

To allow longer spans between column supports and a whole range of other design, cost and construction benefits, reduced the
dead load or the self-weight of the concrete slab by using bubble deck as structural voided flat slab. In this system reduces all other
supporting structures such as beams or walls, the completed floor slab spans in two directions directly onto reinforced concrete
columns.

Within the perimeter so defined, the Bubble deck is left solid without bubbles and the shear resistance is calculated on the basis of
a solid slab in the code dependent customary way. Shear reinforcement may be added, exactly as in a solid slab. Given equival ent
spans, bubble deck has the capacity to produce lighter column loads and alleviate shear stresses. However, the advantages of bubble
deck are usually employed to maximize spans well beyond what can be achieved with a solid slab.

One of the greatest advantages of bubble deck is that it removes the need for much, often poorly controlled, site operations by
fabricating a large proportion of the slab off-site in a factory under controlled conditions and using production techniques that are,
through organized process, far more productive than site work. This leads to large units that are simply transported to site, lifted
into position and the concrete poured.

The forces is distributed in a better way than any other hollow floor structures using bubble deck system. The hollow areas will not
contribute any effect in the strength of concrete slab due to the gentle graduated force flow. Bubbles are omitted around the columns
in an area, rectangular circular or oval as convenient, which is defined by the punching shear perimeter where the applied shear
stress is exceeded by the capacity of the bubble deck voided slab.

The engineering design should be very familiar with the principals of slab design and particularly flat slabs as well as havi ng a
good grounding in general structural engineering. All design work should be checked or reviewed by a competent person. It is not
recommended to rely on Local Authority as some checking engineers lack the specialized knowledge and experience to properly
check the advanced reinforced concrete designs.

Refecrence

Lakshmipriya, N., & Pandi, M. K. (2018). Study and Model Making of Slab using Bubble Deck Technology. International
Research Journal of Engineering and Technology, 5(2). 501 – 506. Retrieved from
https://www.irjet.net/archives/V5/i2/IRJET-V5I2116.pdf
TULAGAN, John Lloyd P.
2162521

SPECIFICATION COMPARATIVE ANALYSIS BETWEEN CONVENTIONAL AND BUBBLE DECK

Prefabricated building is the new trend in the construction industry. Several construction firms use bubble deck slab as an alternative
for conventional slab and implementing new innovations. This paper will differentiate theoretical specification of flat slabs and
bubble deck slabs.

Slabs are always part of the structures which should be technically designed to be effective and efficient. Flat slab requires more
amount of concrete, especially when having a long span. As the span increases, the depth also increases. Also when large load is
acting in the slab, the thickness also increases. The increase of depth of slab contributes amount of concrete resulting in inefficient
sections of slab and a large transfer of load due to its self-weight.

Construction industries contribute about 5% of the world’s carbon dioxide during the fabrication of cement and mobilization.
Additional to that is the environmental limitations imposed on mining on natural aggregates. But in actual, not all the volume of
concrete in the slab is utilized. Generally, the load on slabs is vertical load but recently the users want to use vibration and noise.

Heavier structures are less desirable than lighter structures in seismically active regions because a larger dead load for a building
increases the magnitude of inertia forces which the structure must resist, as large dead load contributes to higher seismic weight.
Bubble deck can be designed exactly like a solid slab with very few differences. The bubble deck is a lightweight, thus the defection
is less compared to the solid slab. The flexural stiffness is approximately 90% of a similar thickness solid slab but thus us
overwhelmingly compensated by the weight reduction in terms of deflection. It is recommended that a crack moment of 80% of a
similar thickness solid slab is used. Shear resistance of the solid zone is conservatively taken as 60% of a similar thickness solid
slab.

Many researcher shows the results of their literature analysis of bubble deck slab. The various classes of inquiry that has been
performed up to now provide associate degree estimate of the doable things on that intensive analysis study is administrated since
it tend to do have problems until nowadays within the sort of concrete slabs tend to use additional concrete than a necessity, so it
delivers to be optimized. Literature review shows that variety of papers are published on the analysis work done on victimization
void formers, during this case spherical or elliptical formed, hollow plastic balls.

Some references used in this paper were; Shetkar A, Hanche N (2015) “An Experimental Study On bubble deck slab system with
elliptical balls”. NCRIET- 2015 & Indian Journal science of research 12(1):021- 027; Harishma KR, Reshmi KN (2015) “A study
on Bubble Deck slab”. International Journal of Advanced Research Trends in Engineering and Technology (IJARTET) Vol. II,
Special Issue X; Subramanian K, Bhuvaneshwari P (2015) “Finite Element Analysis of Voided Slab with High Density
Polypropylene Void Formers”. International Journal of Chem Tech Research, CODEN (USA): IJCRGG ISSN: 0974- 4290, Vol.8,
No.2, pp. 746-753; Bhagat S, Parikh KB (2014) “Comparative Study of Voided Flat Plate Slab and Solid Flat Plate Slab”. ISSN
2278 – 0211, Vol. 3 Issue 3

The methodology used in this paper is through investigation and experimentation. References used are the conventional slab is a
slab specified and developed with M30 grade of concrete by IS 456:2000 and IS 10262:2009; the bubble deck slab used is specified
and developed for experiment purposes with concrete grade of M30 by DIN 1045 (1998) or DIN 1045 (2001). Conventional slab
size of 1.0m x 1.0m x 0.125m is cast. The bubble deck slab also same size of conventional slab of 1.0m x 1.0m x 0.125m.

To arrive in the result, they prepare and analyzed the conventional slab with M30 grade of concrete and design the reinforcement
according to IS Code 456-2000 and IS 10626:2009. After casting the said slab, curing is made in curing tank within 28 days and
conducted a test after 28 days on conventional slab and bubble deck slab. According to the results of the text, the conventional slab
having a load of 260 KN, a deflection of 8.70mm and a weight of 321 Kg comparing it to bubble deck slab having a load of 320KN,
deflection of 9.20 mm and a weight of 242 Kg.

Results conclude that the load-carrying capability of the continuous bubble deck slab is high as compare to different slab. It is
mentioned that three cases of bubble deck slabs carry additional freight than the traditional block. The continual bubble deck block
is twenty-third additional load carrying capability than the conventional slab. Although the deflection of continuous bubble deck
is relatively high than the conventional slab. The conventional slab having a relatively heavier than the continuous bubble deck.

To be specific, the continuous bubble deck slab is 6% more deflection behavior than the conventional slab and the continuous
bubble deck slab is 33% less weight than the conventional slab. Analytical and theoretical work can be done to study and anal yse
the bubble deck slab with respect to different loads like earthquake loading by using suitable software. Prior to that, the designer
should check the design theoretically.
TULAGAN, John Lloyd P.
2162521

Bubble deck joints have a cut a furrow on the inside to ensure that concrete surrounds each bar and does not allow a direct route to
air from the reinforcing bar surface. This is generally a function of the fire resistivity but is also relevant to durability. The cracking
in bubble deck slabs is not typically happened, and technically better, than solid slabs analysed and designed to work at the same
amount of stress

Within the perimeter so defined, the Bubble deck is left solid without bubbles and the shear resistance is calculated on the basis of
a solid slab in the code dependent customary way. Shear reinforcement may be added, exactly as in a solid slab. Given equivalent
spans, bubble deck has the capacity to produce lighter column loads and alleviate shear stresses. However, the advantages of bubble
deck are usually employed to maximize spans well beyond what can be achieved with a solid slab.

Distribution of forces is improved using bubble deck slab than any other hollow flow structures. Due to the gentle graduated force
flow, the hollow spheres will have no significant effect in terms of strength and durability of the concrete slab. It also behaves like
a spatial structure, as the only known hollow concrete floor structure. The results concludes that the shear strength is even higher
than the target strength. This result concludes a positive effect of the balls. Moreover, the typical experience shows a positive effect
on the process of concrete.

The designer should be very familiar with the principles of slab design and particularly flat slabs as well as having a good grounding
in general structural engineering. All design work should be checked or reviewed by a competent person. It is not recommended to
rely on Local Authority as some checking engineers lack the specialized knowledge and experience to properly check the advanced
reinforced concrete designs.

Creep is defined as the elastic and long-term deformation of concrete under continuous load. In this case, no significant variation
in this comparison between bubble deck and solid deck was observed. The factors that vary in this situation can be due to the fact
that the tests were only considered in a one-way-span.

The analysis and calculation of resistances for bubble deck is much the same as for ordinary slabs except for some additional
criteria. It is essential that the engineering designer has an understanding of analytical manual methods, particularly yield line
theory, and an understanding of the principals and application of finite element analysis. In the latter case, an understanding of
linear elastic and non-linear methods is necessary.

Refecrence

Fatma, N., & Chandraka, V. (2018). Specification Comparative Analysis Between Conventional and Bubble Deck.
International Research Journal of Engineering and Technology, 5(2). 605 – 609. Retrieved from
https://www.irjet.net/archives/V5/i2/IRJET-V5I2137.pdf
CUNANAN, Jeremi J. 2162881

ANALYSIS OF LIGHT WEIGHT FORMERS IN CONCRETE SLABS USING VOIDS

Having one of the largest volumes of concrete in the structural member is the slab. The higher the loads that are acting
on the slab, the higher its thickness becomes, making the loads are directly proportional to the thickness. And when its thickness
is increasing it causes more materials making its weight heavier. To avoid this problem a voided flat plate slab system to
eliminate some weight of the slab is proposed. This research presents the most suitable hollow slab in a voided slab. A two-way
reinforced concrete slab is compared to a plastic voided slabs by using a design comparison.

The design for the slab is only for resisting vertical loads, however, due to some factors, the slab’s deflection and
vibration are recently considered. Additionally, the thickness of the slab will increase when the span is too long, causing t he
columns and beams to increase its dimension. When this happens the cost for the whole structural framing of the building will be
more expensive. Moreover, when the weight of the building increase it is a disadvantage when an earthquake occurs. So, the void
slab is introduced to avoid this disadvantage. Using this type of slab the self-weight lightens making it more economical.
Using the Finite Element Method the researchers were able to imitate the behavior of the reinforced concrete with the different
voids from the hollow slab that undergoes a five-point load. These Finite models allowed the researchers to eliminate limitations
for the study.

For the concrete, the researchers use the Solid65 model, because it is effectual of plastic deformation and cracking in
integration point for three different directions.. The cracking is monitored by three different trials by adjusting the material
properties through changing its element stiffness matrices. When the concrete fails in the integration point the concrete is
concluded that it is crushed at that point. Crushing is reducing the strength of the concrete. The Solid 65 model can crack in
tension and crush in compression.

For steel reinforcement, the 3-D spar element LINK8 is used for modeling trusses, spring, sag cables, and links. It is a
uniaxial tension-compression element having three degrees namely nodal x, y, and z.

Their Modeling of Material Properties Parameters includes concrete properties and steel properties. In concrete
properties, it is known that in compression, 30 percent of the maximum compressive strength from the stress-strain curve is
linearly elastic after this point the stress gradually increases up until the maximum compressive strength. After reaching the
maximum compressive strength the curve gradually decreases and eventually the crushing failure will occur to the ultimate strain.

While in tension, the stress-strain curve is approximately linearly elastic until the maximum tensile strength. After this
point, the curve gradually decreases to zero and having concrete cracks. The researchers assumed that the concrete is
homogeneous and originally isotropic.

In the steel properties, they stated that the steel in RC slab is a grade of Fy=550. For the finite element method, they
assumed that the steel is to be an elastic-perfectly plastic material and supposed to be identical in tension and compression. The
researchers also used the Poisson’s ratio of ℽ= 0.3 for steel. They used the Elastic Modulus Es = 200,000 Mpa and Poisson’s ratio
of 0.3 for all the steel bars in this study. For more even stress distribution in all the support and loading areas, they provided a
steel plate in all supports and loading areas in the finite element model. The Es = 200,000 Mpa and Poisson’s ratio of 0.3 were
also used in the steel plates.

For the Test Specimens and Modeling includes the Loading and Boundary Condition. The finite element method used
with approximate alternatives to a wide variety of engineering issues is used for numerical analysis. While the ANSYS is a
technique of multi-purpose finite elements to solve wide issues including issues in nonlinear static structural analysis.

The two way solid slabs are analyzed and tested in a non-linear way using the finite element method having both
compression and tension steel reinforcements (top and bottom bars) assumed that there is a total connection between the concrete
and the steel reinforcements.

The test specimens were designed into seven types of slab, two of them were designed as usual two-way RC slab and
the remaining are designed as two-way voided slabs. The test specimens are then tested using a five hydraulic jack and a five
loading plate under the five-point load system to satisfy the actual loading conditions. The reasons for using the special loading
systems having the five-point bearing load are: the loading condition of the usual two-way slab is UDL in general, the deflections
are measured in mid-span under the lower face of the tested slabs, the load was gradually increased to record the deflection until
the failure, and slabs with different thickness having 100mm and 125mm.

It is necessary to have a proper solution for the static structural for the Loading and Boundary Condition because the
entire model slab is used in the internal faces for planes of symmetry and model. First, the boundary symmetric condition is
established.
CUNANAN, Jeremi J. 2162881
The part model used is symmetric on the plane X and Z around two poles. Using the symmetry of the plate and
loadings, a complete slab was used for modeling Balance planes were needed on the inward faces. The deformation in the
direction perpendicular to the plane was kept at zero on a plane of symmetry. The deformation was held at zero on a line of
symmetry in the direction perpendicular to the plane.

It is a type of slab where the ends are simply supported and the other has a roller. In that slab parameters are fixed to six
sides to allow boundary conditions to give assistance and roller support is one movement in a direction. A simply supported slab
has resistance for both vertical and horizontal forces but does not resist a moment. Free to rotate and translate roller supports
along the ground on which the roller rests. The surface at any angle can be horizontal, vertical or sloping. The resulting force of
response is always a single force perpendicular to the ground and away from it.

For the Load-Deformation curves, deformation is measured in the middle of the slab's bottom face at the mid-span. In
particular, the curves of load deformation of the finite element analyzes for the plates. In the finite element models, there are
several effects that can trigger the greater stiffness. On the other hand, micro-cracks are not included in the finite element models.
Next, the finite element analyzes assume a perfect bond between concrete and steel reinforcement, but the assumption for the
experimental slabs would not be true.

The void sphere hole acts as avoiding a slab deflection. And since the hole diameter of the voided sphere was lower,
the plate deflection was larger. Finite element assessment (FEA) was performed using the ANSYS to study the slab's structural
behavior. The strong and voided slab slab was subject to load distributed evenly.

In conclusion, the deflections of voided samples under service load were a little greater than those of a strong slab.
Better than a strong specimen, the concrete compressive stress of void samples. As the corner rise of the voided slab is used for
bottle voided and the voided sphere was lower crack, crack induced by focused stress was previously created. Vacuum bottle acts
as stopping slab deflection. And since the voided slab's bottle diameter was lower, the slab deflection was larger.

PERSONAL VIEWS ON STUDY

I agree that this kind of slab is economical because this lessen the construction time and also cheaper than solid slab
because this uses lesser amount of concrete. This study will surely help us in our study because the failures of the voided slab are
presented well. The grey area in this study is that the plastic bottles were not securely placed which may cause difference in the
results.

REFERENCES OF THE AUTHOR

C. C. Marais, “Design adjustment factors and the economical application of concrete flat slabs with internal spherical voids in
South Africa”, M.E Dissertation, University of Pretoria.

C. C. Marais, J. M. Robberts and B. W. J. van Rensburg, “Spherical void formers in concrete slabs”, Journal of the South African
Institution of Civil Engineering, Vol 52 No 2, pp. 2 – 11, October 2010.
Mike Mota, “Voided slabs then and now”, Concrete Industry Board Bulletin, summer 2010

Neil M. Hawkins, S. K. Ghosh, "Shear Strength of Hollow-Core Slabs, " PCI Journal, 2, 2006.

Y.G. Park, H.S. Kim, H. Ko, H.J Park and D.G. Lee, , "Evaluation of The Nonlinear Seismic Behavior of a Biaxial Hollow Slab,"
Journal of ESK, Vol. 15, No.1, pp.1-10, 2011.

J. H. Chung & J. H. Park, H. K. Choi, S. C. LEE and C. S. CHOI, “An analytical study on the impact of hollow spheres in bi-
axial hollow slabs”, Fracture Mechanics of Concrete and Concrete Structure, pp. 1729 – 1736, 2010.

REFERENCE
Hirapara, A. and Patel, D. (2017). Analysis of Light Weight Forers in Concrete Slabs Using Voids. International Journal of
Advance Engineering and Research Development, Vol. (04), Issue 04. Retrieved, from,https://l.facebook.com/l.php?u=
http%3A%2F%2Fwww.ijaerd.com%2Fpapers%2Ffinished_papers%2FANALYSIS%520OF%2520LIGHT%
2520WEIGHT%2520FORMERS%2520IN%2520CONCRETE%2520SLABS%2520USING2520V
OIDS-IJAERDV04I0473264.pdf%3Ffbclid%3DIwAR0iaPPZurQlBKvjdXsO-Gs3lBD
YEh5AjkKyrqFpoTmZimZdIia8cU68geM&h=AT3Ycdn8Xwi8jvE1w0P25XHL2I1QjmdpnOl5O3pkY5exlv
EOsWmeFA86PpulgV1gF68xM5hh64MxUfcbhGgmwtEhAlCfs1rGale2nWA
CUNANAN, Jeremi J. (2162881)

AN EXPERIMENTAL STUDY ON SPHERICAL VOIDED SLAB

Most structures are constructed in RCC in India. With the fast development of construction sectors, the use of concrete
rises day by day. The slab is a very significant structural component in building structures to create a room and also one of the
biggest concrete-consuming members. In the event of horizontal slabs, the primary barrier with concrete structures is the
heavyweight, which limits the span. As a result, an effort was produced to decrease the slab's weight by offering spherical plastic
voids in RC Slab in two ways without compromising strength and safety.

There is a two-dimensional array of voids in a spherical voided slab in the plates to decrease self-weight. In the middle
of the plate, plastic hollow sphere balls are introduced. The conduct of voided plates is affected by the slab thickness ratio of
bubble diameter. A special charging frame was used to test two-dimensional flexural tests. Three sample samples are used, one
was a standard strong slab, and two plates with a 37 mm and 45 mm void diameter were voided. Test ball diameter to slab
thickness ratios of voided slab (0.47 and 0.57) and the same under the five-point charging system. The comparison was made in
the form of ultimate load capability, deflection, concrete compressive strain and stiffness decrease factor with ordinary strong
slab to check the flexural conduct of voided slab.

The slab is a very significant structural component for making a room in construction structures. And the slab is one of
concrete consumption's biggest members. In the event of horizontal slabs, the primary barrier with concrete structures is the
heavyweight, which limits the span. Because of this, significant innovations in reinforced concrete have concentrated on
improving the weight reduction span or overcoming the natural tension weakness of concrete. As the span increases; the slab
deflection increases as well.

The thickness of the slab should, therefore, be increased. Increasing the thickness of the slab heavens the slabs and
increases the size of the column and foundations. It, therefore, makes Structure consume more materials such as reinforcement of
concrete and steel. The slab's self-weight can be reduced by replacing the center height of the slab's cross-section with the
previous void. The slab's self-weight can be reduced by incorporating void former into the slab and this leads to a decrease in the
slab's general price. The spherical balls placed in the center of the slabs are made of recycled plastic that does not respond with
concrete or steel chemically.

These are the main materials used by the researchers; steel, concrete, and a recycled plastic ball. First is the concrete,
Standard Portland cement is used for the concrete mix. For present and concrete layout as per the EFFNARC guideline, Self
Compacted Concrete is used. The structure of the specimen's compressive strength after 28 days is 25 N / mm2 and casting was
used for the strength identification of the concrete cubes and average strain of 3 cubes. For steel reinforcement, specimens are
used to reinforce bars of 6 mm diameter of Fe415 HYSD bars. Reinforcement is given both longitudinal and transverse at the
bottom and in both directions. For the recycled plastic ball, the recycled plastic ball used to reduce plastic waste instead of
dumping it and also helps reduce pollution from the environment. Compare the concrete material to the low cost of plastic ball. In
this research work, plastic spheres of 37 mm and 45 mm diameter were used. The spheres are intended to reduce the concrete and
dead load of specimens.

Three test samples are constructed, one is a standard two-way R.C slab and the other two are two-way voided spherical
plates. The test parameters included the bubble diameter ratio (B) to slab thickness (H), (B / H). Four steel beams, which had a
hinge in the bottom layer to minimize fixed end-moment and other supporting condition errors, merely backed the slab at all
corners. Therefore, the punching impact was produced under the hydraulic jack on the plate specimen owing to a single point
load. With the assistance of the dial gage, the deflection of the samples was evaluated at their mid-span under the reduced face of
the tested plates.

The compressive side strain of the specimens was measured using 350 ohm strain of 20 mm at six points, two on the
horizontal axis and two on the vertical axis at a distance of 150 mm and 300 mm respectively, and two on the border of the
sample at the same distance from the center of the stack. At increments of (2.5kN) the load was gradually risen to record the
deflection to failure.

The researchers’ results for Ultimate load capacity, compared to the ordinary strong slab, the spherical voided slab with
the plastic sphere showed excellent ultimate load ability. The ultimate load of the normal solid slab was 51.3KN, with voids of 37
mm and 45 mm diameter respectively for spherical void slab 50kN and 41.5kN. The deflection of the normal solid slab and the
spherical void slab was 22.9 mm, 25.3 mm and 22.1 mm for the same ultimate load.
For the load-deflection relationship, the load-deformation curve is known as a curve displaying the connection between
the load on the structure and the deformation. It is distinctive for each material and can be discovered by recording the quantity of
deformation at separate tensile or compressive loading intervals.
CUNANAN, Jeremi J. (2162881)
For the concrete compressive strain, the spherical vacuum specimens offer the concrete compressive strain above that
of the strong reference specimen a rise. Due to plastic spheres in spherically voided samples, this is owing to reduced concrete
quantity in the compression area.

For stiffness reduction factor, the main variable when performing slab structural analysis is the second moment of
inertia. The untracked moment of inertia relies on the slab's density and width, and the contribution made by steel can be ignored
as steel is not involved before cracking. From the calculation of voided slab inertia and powerful slab inertia, the stiffness
decrease factor can be achieved. In order to derive the stiffness reduction factor Iv can be subtracted from Is and then the
response can be split by Is (Is-moment of strong section inertia, Iv-moment of void section inertia).

In conclusion, spherical voided slab's stiffness values were slightly distinct from strong slab. Based on the outcomes
obtained so far, two-way spherical voided plates function as general solid R.C plates basically The use of plastic spheres in
strengthened concrete plates (B / H=0.47, 0.57), had a outcome compared to reference solid slabs (without plastic spheres),
voided plates had (100%) the ultimate load of a comparable reference solid slab but only (84%, 69%) of the con.
The deflections of voided samples under service load were slightly greater than those of an equivalent strong slab.
The concrete compressive strain of vacuum samples is higher than that of a strong specimen equivalent.

PERSONAL VIEWS ON STUDY

Yes I agree with the result of the study, because the studies that I have read has almost the same results. Also, it
obvious that the voided slab will have a higher deflection than the solid slab. The researchers’ study is helpful in my part because
they conducted a research with the dimensions of the slab that will help us in the future.

REFERENCES OF THE AUTHOR

Bhagat, S., & Parikh, K. B. (2014). COMPARATIVE STUDY OF VOIDED FLAT PLATE SLAB AND SOLID FLAT PLATE
SLAB. International Journal of Innovative Research and Development|| ISSN 2278–0211

Mota, M. (2013). VOIDED "TWO-WAY" FLAT SLABS. In ASCE Structures Congress (pp. 1640-1649).

Ibrahim, A. M., Ali, N. K., & Salman, W. D. (2013). FLEXURAL CAPACITIES OF REINFORCED CONCRETE TWO-WAY
BUBBLEDECK SLABS OF PLASTIC SPHERICAL VOIDS. Diyala Journal of Engineering Sciences,6(02), 9-20.

Marais C.C., Robberts, J.M., & Van Rensburg, B. W. (2010). SPHERICAL VOID FORMERS IN CONCRETE SLABS. Journal
of the South African institution of civil engineering, 52(2), 2-11.

Bindea, M., Moldovan, D., & Kiss, Z. (2013). FLAT SLABS WITH SPHERICAL VOIDS. PART I: PRESCRIPTIONS FOR
FLEXURAL AND SHEAR DESIGN. Acta Technica Napocensis: Civil Engineering & Architecture, 56(1), 67-73.

Lai, T. (2010). STRUCTURAL BEHAVIOR OF BUBBLEDECK® SLABS AND THEIR APPLICATION TO LIGHTWEIGHT
BRIDGE DECKS (Doctoral dissertation, Massachusetts Institute of Technology.

REFERENCE

Sarvaiya, D. M. and Jivani, D.K. (2017). An Experimental Study on Spherical Voided Slab. Journal of Emerging Technologies
and Innovative Research. Vol. (04), Issue 04. Retrived from, http://www.jetir.org/papers/JETIR1704056.pdf
CUNANAN, Jeremi J. (2162881)

STUDIES ON STRUCTURAL BEHAVIOR AND FEAIBILITY OF CONSTRUCTION METHODOLOGY OF

BUBBLE DECK SLAB
As a biaxial hollow core slab, Bubble Deck Slab was created in Denmark. It is a technique of almost eliminating all
concrete from the center of a floor slab that has no structural function, thereby dramatically decreasing structural dead wei ght.
Bubble deck slab is based on a fresh patented method involving the direct connection between air and steel Using plastic spheres,
empty shapes in the center of a flat slab eliminate 35 percent of a slab's self-weight, removing limitations of elevated dead loads
and brief spans. Its flexible design adapts readily to irregular and curved settings of the plan.

The system for storage floors, roof floors and ground floor plates can be used with the bubble deck slab floor. The ratio
of the diameter of the plastic spheres to the thickness of the floor is such that, compared to a solid concrete floor of the same
thickness, a 35 percent saving is achieved on the material or concrete consumption of the floor. The weight savings thus acquired
outcome in a Bubble deck slab floor being able to provide the necessary load-bearing ability at a lower density, leading in a
further benefit, leading in a savings of 40 to 50 percent of the material consumption in the floor building.

This is not the last advantage of the Bubble deck slab floor scheme: it may also be less heavy to support structures such
as columns and foundations owing to the decreased weight of the ground scheme itself. This can eventually lead to a complete
weight or material savings of up to 50 percent in building construction. This sort of structure may be helpful to decrease
earthquake harm as the weight of the structure decreases.

Only the outside shell of concrete on the compression side and the steel on the tension side are the only components
that work. As far as flexural strength is concerned, the resistance moments are the same as for strong plates, as long as this
compression depth is checked during construction so that it does not substantially impact the ball.

Design shear resistance is typically critical near columns in any flat slab. The shear stress remote from the columns
decreases rapidly and is shown to be within the capacity of the bubble deck slab system outside the column zones by testing and
calculating the transverse and longitudinal shear stress. Bubbles are left out near the columns, so a Bubble deck plate is intended
precisely like a strong plate in these areas. If the shear applied exceeds this, we leave out the balls in a column, for instance, and
use the complete strong shear values.

If the shear applied exceeds the hollow slab's strength, we omit balls and make them solid and then inspect the strong
portion. Two ratios a / d (distance from applied force to support separated by deck density) measure the shear ability. If the
strength is still greater than the powerful slab resistance and less than the maximum allowed, the scientists provide shear
reinforcement.
For these purposes, it is shown that the design can be executed in any manner that treats the slab as a strong slab, with
the above provisions, all of which are taken into consideration in the design phase. Punching shear measure an average shear
ability of 91 percent relative to a strong deck's calculated values.

Bubble deck slab durability is not essentially distinct from normal strong slabs. The reinforcement module and balls are
vibrated into the concrete when the filigree slabs are produced, and the compaction standard and uniformity is such that a surface
concrete density is produced that is at least as impermeable and durable as that normally produced on site.

Compared to steel framed and light weight skeletal structures, RC slab structures are usually less prone to vibration
issues, particularly using thin slabs. Bubble deck slab, however, is light and in all instances is not resistant to vibration, so this
must be verified just as it should be in suitable strong slab apps The fire resistance of the slab is a complex problem, but it mainly
depends on the ability of the steel to maintain adequate strength when heated during a fire and loses significant energy as the
temperature rises. The steel temperature is governed by the flame and steel isolation from the fire.

The span depth ratio calculations for deflections are very approximate and are not appropriate for irregularly designed
flat plates except in the easiest or most insignificant cases FE modeling, including non-linear cracked section assessment, is used
to calculate deflection using normal structural concrete with a Young's Modulus (secant) Ecm multiplied by 0.9 and a fctm-
multiplied tensile strength enhanced by 0.8 (to reduce the crack moment as mentioned above).

There was a comparison between BubbleDeck and comparable height one-way prefabricated hollow deck. The primary
criterion for noise reduction is the weight of the deck and therefore BubbleDeck will not behave with equal weight other than
other types of deck. The building of the Bubble deck slab follows every usual criterion and can be calculated as normal.
CUNANAN, Jeremi J. (2162881)
There are also some disadvantages in this project, since the fitting of hollow plastic bodies between the lower steel
mesh and the upper steel mesh is always carried out in a high position where a bubble deck is cast, thereby reducing the
productivity of engineers and workers much at the same time as traveling up and down or casting a concrete deck covering a
thousand meters square. Costing a lot of cash to build the system of formwork. To connect reduced and upper steel mesh requires
dedicated welding machines and plenty of time to weld spacers. In addition, structure with too many welding joints can alter the
steel characteristics and decrease the deck structure's durability because spherical plastic bodies are hollow, these plastic bodies
will float to the floor, causing thrust and unstable structure to pour concrete. Costing big quantities of money to construct
factories or workshops to create deck parts. Costing a great deal of cash to transport these constructions to building sites. In
addition, during transportation, the thin concrete layer may be broken.

PERSONAL VIEWS ON STUDY

This study will be helpful in our study because there are a lot of factors stated in this study. Also the disadvantages
stated in the study will help us verify it I also agree that this kind of slab is economical because this lessen the construction time
and also cheaper than solid slab because this uses lesser amount of concrete.

REFERENCES OF THE AUTHOR

Tina Lai ”Structural behavior of bubble deck slab and their applications to lightweight bridge decks” ,M.Tech thesis, MIT, 2009.

Sergiu Calin, Ciprian Asavoaie and N. Florea, “Issues for achieving an experimental model” Bul. Inst. Polit. Iaşi, t. LV (LIX), f.
, 2009.

Martina Schnellenbach-Held and Karste Pfeffer,”Punching behavior of biaxial hollow slabs” Cement and Concrete Composites,
Volume 24, Issue 6, Pages 551-556, December 2002.

Sergiu Calin, Roxana Ginţu and Gabriela Dascalu, ”Summary of tests and studies done abroad on the Bubble deck slab system”,
The Buletinul Institutului Politehnic din Iaşi, t. LV (LIX), f. 3, 2009.

Sergiu Calin and Ciprian Asavoaie, “Method for Bubble deck slab concrete slab with gaps”, The Buletinul Institutului Politehnic
din Iasi, LV (LIX), f. 2,2009.

Sergiu Calin, C. Mugurel, G. Dascalu, C Asavoaie, “Computational simulation for concrete slab with spherical gaps”,
Proceedings of The 8-th International Symposium, Concepts in Civil Engineering, Ed. Societatii Academice "Matei-
Teiu Botez", 2010, pp. 154-161.

BubbleDeck voided Flat Slab Solutions- Technical Manual and Documents,Version:5, Issue 1, BubbleDeck UK, White Lodge,
welington Road, St Saviour, JERSEY, C.I.,2008,Available: www.BubbleDeck-UK.com.

REFERENCE
Radha, S., and Andal N. M. (2018). Studies on Structural Behavior and Feasibility of Construction Methodology of Bubble Deck
Slab. International Journal of Innovative Research in Science, Engineering and Technology, Vol. (07), Issue 05.
Retrieved from, http://www.ijirset.com/upload/2018/icricem/50_ID%20-%2062.pdf
CUNANAN, Jeremi J. (2162881)

COMPARATIVE STUDY OF BUBBLE DECK SLAB AND SOLID DECK SLAB – A REVIEW
The function of bubble deck is to minimize the concrete in the middle of the sab without reducing the strength of the
structure. High density hollow spheres of polyethylene (HDPE) is the substitute to the volume of concrete in the middle of the
slab, and decreasing its self-weight. This results in a lighter slab of 30 to 50% by incorporating the gaps that reduce the loads on
the columns, walls and foundations and, of course, the entire building, thus having different advantages over the traditional slab
scheme. The purpose of this paper is to discuss the Bubble deck plate's various features based on separate studies and research
performed relative to the standard deck slab.

Many efforts have been produced over the past few centuries to decrease the dead weight of the slab. Most of the
efforts consisted of laying blocks of less heavy material such as expanded polystyrene between top and bottom reinforcement,
while other types included waffle plates and grid plates. The focus was on biaxial slabs and weight reduction methods due to the
constraints of hollow-core slabs, mainly lack of structural integrity, inflexibility and decreased architectural opportunities. During
the last decades, several techniques have been implemented, but with very restricted achievement owing to significant issues with
shear ability and fire resistance and impractical implementation.

Only waffle plates can be considered to have some use in the industry of these kinds. However, owing to decreased
resistance to shear, local punching and fire, the use will always be very limited. The concept of placing large blocks of light
material in the plate has the same faults, which is why these schemes have never been approved and are only being used in a
restricted number of projects.

Up to 35% of structural concrete is eliminated by bubble deck technology. In combination with the decreased floor
thickness and façade, lower foundations and columns, building expenses can be reduced by up to 10%. Using Bubble Deck
implies up to 20 percent quicker floor cycles than traditional techniques of building. Regardless of the project's size, shape or
complexity; just for quick concrete decks assembly shore, location, and pour. The Bubble deck scheme provides a broad variety
of benefits in the design and construction of buildings. There are a number of green features, including: decrease of total building
materials, use of recycled materials, lower power consumption and decreased CO2 emissions, lower transport and crane lifts,
making Bubble deck more environmentally friendly than other concrete construction techniques. Without the need for post-
tensioning orpre-stressedparts, bubble deck can attain bigger spans compared to a site cast concrete framework.
Steel, plastic spheres and concrete are the materials in this project. The concrete is produced of conventional Portland
cement with a maximum aggregate size of 20 mm for concrete. There is no need for concrete mixture plasticizers. Tests have
shown that bubble deck slabs achieve the characteristic compressive strength of concrete in the same way as solid slabs.

For steel, the strength of the steel is Fe500 grade or higher. The mesh of Reinforced Steel is created over the ball and
under the ball so that the ball can be placed out of any movement. Only by placing them in reinforcements is it possible to
properly lock bubbles. When required, additional bars and shear bars are provided. Close to the columns, most shear bars are
given.

The hollow spheres are produced of recycled high density polyethylene or HDPE for plastic hollow spheres. Based on
the structure size, plastic hollow spheres are accessible in distinct dimensions. These balls can be reused or recycled again. This
adds to the bubble deck slab's green characteristics.
The advantages observed by the researchers are, the bubble deck slab's dominant benefit is that it utilizes less concrete
30-50 percent than ordinary strong slabs. The HDPE bubbles in the center of the section replace the inefficient concrete, thereby
reducing the dead load of the structure by removing unused heavy material. As the need for reinforcement decreases, decreased
concrete material and weight also lead to less structural steel. Overall, the beams, columns, footing and foundation can be
intended for reduced loads owing to the lighter floor plates, thereby decreasing the generally structure's weight.
Because of the slab's decreased self-weight and its two-way spanning action, the load-bearing walls become useless.
The bubble deck, also designed as a flat plate, it removes the need for supports. As a consequence, some of the structural
demands for the columns and foundations are reduced by these characteristics. Bubble deck panels can also be built and analyzed
based on its strength and ductility studies as a standard concrete flat slab.

Bubble deck can also be manufactured entirely for assembly and transferred on site. Installation on-site requires leeser
time because it does not have beams so that the formwork is just a plane and the mesh for the reinforcement bars will be easily
placedhaving less diameer and time savings can also be accomplished by quicker erection of walls, columns and MEPs owing to
the absence of support beams and load bearing walls for this creative flat slab. As there is less concrete in the slab, additional
time can be saved from the faster healing moment.

There is an exponential increase in the amount of owners, developers and technicians who want green options. Bubble
deck is a suitable option in new structures to lower the embodied carbon. 1 kg of recycled plastic replaces 100 kg of concrete,
according to the Bubble Deck business. By using less concrete, developers can save up to 40% on embodied carbon in the slab,
CUNANAN, Jeremi J. (2162881)
leading to important downstream savings in other structural components design. With the use of fewer products, carbon
emissions from transport and machinery use will also reduce. In addition, it is possible to save and reuse the HDPE bubbles for
other projects or recycle them.

These are some of the factors for comparison of bubble deck slab and solid deck slab. A number of practical test
outcomes verify that the shear strength depends on the concrete's efficient mass. The shear capacity is assessed at 72-91 percent
of a strong deck's shear ability. A factor of 0,6 is used in calculations on the shear capacity for a solid deck of the same height.
This ensures a big margin of safety. Therefore, areas with elevated shear loads, e.g. around columns, need unique attention. This
is solved by omitting a couple of balls around the columns in the critical area, thus providing complete shear ability.
BubbleDeck where both practically and theoretically contrasted with a strong deck. The findings in the table below
show that the bending power for BubbleDeck and a strong deck is the same for the same deck thickness and that the
BubbleDeck's stiffness is slightly smaller. But Denmark's technical university also tested the rigidity of the bubble deck plate.
They tested the outcome and figured out that, owing to HDPE spheres, the bubble deck has 87% of bending stiffness of
comparable strong slab but only 66% concrete quantity.

In conclusion, the Bubble Deck Slab is one the technology which helps us to achieve the economy, easy to construct
and environment friendly. Bubble deck Technology is the innovative system that eliminates Concrete in the mid section,
secondary supporting structure such as beams reinforced concrete columns or structural walls.

BubbleDeck eliminates the structural concrete by up to 35 percent. In combination with the decreased floor thickness
and façade, lower foundations and columns, building expenses can be reduced by up to 10%. Bubble Deck Slab is heavier than
the Solid Deck Slab compared to the structure's weight. The BubbleDeck system provides a broad variety of building and
construction benefits. There are a number of green characteristics, including: decrease of total building materials, use of recycled
materials, lower energy consumption and decreased CO2 emissions, lower transport and crane lifts, making BubbleDeck more
environmentally friendly than other concrete building methods. BubbleDeck Slab is particularly appropriate for use in open floor
models such as commercial, educational, hospitals and other institutional buildings in all kinds of buildings. Ultimately, we can
say that the future of building is BubbleDeck Slab and that more research, research and tests are needed for the different
dimensions of the HDPE Hollow ball and the thickness of the slab to gain popularity and use of this technology.

PERSONAL VIEWS ON THE STUDY

I partially disagree in the limitation of carbon dioxide because in some articles that I’ve read the voided slab produces
more carbon dioxide indirectly. For example, when travelling the materials, the fabrication and more other factors. I just wanted
more explanation in the elimination of the carbon dioxide for me to understand it better. But this study will also be helpful for I
will have more limitations.

REFERENCES OF THE AUTHOR

Tina Lai ”Structural behavior of bubble deck slab and their applications to lightweight bridge decks” M.Tech thesis, MIT, 2009.

P. Prabhu Teja, P. Vijay Kumar, S. Anusha, CH. Mounika- March-2012-“Structural behavior of bubble deck slab”, JISBN:
IEEE,Vol:81-pages:383-388 ISBN: 978-81-909042-2-3.

Sergiu Călin, Roxana Ginţu and Gabriela Dascălu, ”Summary of tests and studies done abroad on the Bubble deck slab system”,
The Buletinul Institutului Politehnic din Iaşi, t. LV (LIX), f. 3, 2009.

Saifee Bhagat and Dr. K. B. Parikh Parametric Study of R.C.C Voided and Solid Flat Plate Slab using SAP 2000, IOSR Journal
of Mechanical and Civil Engineering (IOSR-JMCE), e-ISSN: 2278-1684,p- ISSN: 2320-334X, Volume 11, Issue 2
Ver. VI (Mar- Apr. 2014), PP 12-16.

Bubble deck design and detailing,BubbleDeck Voided Flat Slab Solutions- Technical Manual and Documents (2007).

BubbleDeck Slab properties " Bubble Deck Voided Flat Slab Solutions- Technical Manual and Documents (2006).

BubbleDeck International. "The Light weight Biaxial Slab." Bubble Deck(n.d):1-4.

BubbleDeck Tests and Reports summary. " BubbleDeck Voided Flat Slab Solutions- Technical Manual and Documents!(2006)

REFERENCE
Vakil, R. R. and Nilesh, M. M. (2017). Comparative Study of Bubble Deck Slab and Solid Deck Slab – A Review. International
Journal of Advance Research in Science and Engineering. Vol. (06), Issue 10. Retrieved from,
https://www.ijarse.com/images/fullpdf/1507204839_IETEBanglore_239.pdf
FLORENTINO, Luisa Beatrice C. (2164250)

AN EXPERIMENTAL STUDY ON BUBBLE DECK SLAB SYSTEM WITH ELLIPTICAL BALLS

The research study mainly focuses on the advantages and properties of a hollow slab system.

Bubble deck slab is a method that has a two-dimensional arrangement of voids in the slab thereby reducing its structural dead
weight and helps reduce the concrete part in the middle of the traditional slab which does not help in the structural function.
Bubble deck is an innovatory method that can be composed of a hollow spherical or an elliptical ball that is made by recycled
plastic. Whenever a building is demolished or renovated, the spheres used can still be can be recycled. The slab thickness of the
bubble deck is directly proportional to the bubble diameter as this influences its behavior. Bubble decks slab has already been
applied in many industrial projects worldwide that show the design-effectiveness and workability of the study in the construction.
Voids eliminate up to 35% of the self-weight of the slab, therefore, removing restrictions of high dead loads and short spans.
Longer spans between columns without the use of beams can be 50% permitted just by using recycled plastic bubbles that
provide a wide range of cost and construction benefits.

Jorgen Bruenig developed the first biaxial hollow slab also known as the "Bubble Deck" in Denmark late 1990's. In Denmark and
Holland, the two-way concrete slab system was developed. Bubble deck became an integral part of the Millennium Tower and
this became significant from engineers and researchers worldwide. [Amer M 2013].

30% up to 50% loads in the columns, walls, foundation, or the entire building are reduced because of a lighter slab. Bubble deck
uses less concrete as compared to the traditional slab. Bubble deck can also reduce carbon dioxide to the atmosphere in the
process of manufacturing and offers more sustainability in construction options. Bubble deck has many advantages compared to
conventional concrete slab such as cost-efficient, materials used are reduced, time construction decreases, environment-friendly,
and improves structural efficiency.

A slab is an important structural element that consumes the largest concrete. Reinforcement is placed one mesh is placed at the
bottom part and another on the upper part that can be tied or even welded. The distance between the bars is depended on the
dimensions of the bubble being used and the quantity of the reinforcement from the slab.

MATERIALS AND PROPERTIES

Hallow Bubbles
The bubbles used can be spherical or elliptical which contains enough stiffness and strength to handle loads safely before and
during the pouring of concrete. Bubbles are made of high polypropylene materials and are usually non-porous.

For the specimen, a diameter of 180mm up to 450mm and a slab depth of 230mm to 600mm was used.

The nominal diameter of the spacing of the bubbles may be 180mm, 225mm, 270mm, 315mm, or 360mm.

Concrete
When casting of prefabricated filigree slab, or for joint filling on the site self-compacting concrete is used. Self-compacting
concrete can be used to fill voided sections which allows air to escape and resist segregation.
The concrete used for bubble deck must be M30 and above but not lower that class 20/25.

Reinforcement bars
There are two forms of steel reinforcement namely the wire mesh and diagonal girders which were fabricated for the Bubble deck
in supporting both the lateral and vertical parts of the slab.

The depth between the bars of the slab is dependent to the diameter of the spherical balls that are to be used and to that of the
number of all the reinforcement used in the ribs of the slabs.

EXPERIMENTAL PROGRAM
The experimental program was achieved through a Laboratory of Full-Scale Structural Testing to investigate the behavior of the
bubble deck slab by using spherical balls.
Bubble deck composed of a hollow flat slab using a recycled plastic ball or the "void formers" are incorporated to reduce
concrete that does not contribute to the structural function of the slab. Plastic balls used have dimensions and shapes of hallow
elliptical balls with a diameter of 240mm (front view) and height of 180mm (side view).
There are five (5) samples of Bubble deck named A.BD.2, A.BD.3, A.BD.4, B.BD.2, and B.BD.3. having the same dimensions
of 1900x800x230mm. the notation A denotes for concrete strength B25 while B denotes B35.

A.BD4 sample has been provided with the links while the other samples do not have links.
FLORENTINO, Luisa Beatrice C. (2164250)

There are 24 pieces of 8 diameter reinforcing rebars that was use for the top and bottom bars. As for one bubble deck slab, there
were 18 elliptical balls that was embedded to each sample. The dimension of the concrete cover used is 25mm.

Each bubble deck sample having dimensions of 1200 x 200 x 10 was simple supported by two simple span beams along its short
span.

Hydraulic jack produces the force made at the center of the slab with having the maximum loading of 1000KN. The force applied
should be the same as the self-weight of the slab.

To counteract gravity, the force applied is provided from the bottom to the top of the slab so that it would be easier to record and
observe the strain and deformation of the concrete and the rebars from the top side of the slab. A wire strain gauge was used to
measure its strain and deformation.

The loads were applied incrementally until the first cracks appear in the surface of the slab fobserved crack patterns at failure for
slab B.BD.2 and B.BD.3 are shear and bending modes, respectively while the Bubble Deck using hollow spherical balls A.BD.2
and B.BD.2 has the shear failure modes. On the other hand, a bending failure was seen on the hollow deck slab using the
modified elliptical balls for specimen A.BD.3, A.BD.4 and B.BD.3.

In conclusion, modified elliptical balls have greater ultimate loading with having the same dimension and concrete grade
compared with using other plastic balls.

I agree with the results made in the experiment that using Bubble deck slab using hallow elliptical balls can be cost-efficient
because of the possibility of removing restrictions of high dead loads and short spans, therefore, longer spans between columns
without the use of beams can be 50% permitted. Also, having a ratio of 1kg of recycled plastic replaces 100kg of concrete being
eliminated. With having reduced dead weight for up to 50%, smaller foundation sizes can be achieved.

The use of bubble deck slab helps decrease time construction because of reduced materials and it has a better load-bearing
capacity.

By using the same amount of concrete and with the same dimensions increases the configuration that Bubble slab gives improved
flexural capacity, stiffness, and shear of at least 70% and 30 to 50% of the concrete economy as compared to a solid slab.

Reference

Hanche, N., & Shetkar, A. (2015). An Experimental Study on Bubble Deck Slab System with Elliptical Balls. Bheemanna
Khandrre Institute of Technology, 12(1). Retrieved from, https://www.ijsr.in/upload/1360526075NCRIET-209.pdf
FLORENTINO, Luisa Beatrice C. (2164250)

STUDY ON A COMPARATIVE STUDY OF BUBBLE DECK SLAB AND CONVENTIONAL DECK SLAB

In Denmark, Bubble Deck methodology for the 2-way reinforced composite concrete slab with gaps was fabricated. Bubble deck
type slab is composed of a spherical gap, poured in place on a 2-way direction and it is a way of saving concrete in building
construction.

There can be up to 30 to 50% lighter slab that can reduce the loads on the building itself by introducing the gaps. One of the
advantages of a Bubble Deck slab is that it can be manufactured as a precast cast concrete with a hollowed midspan section or a
reinforced concrete. A mesh wire was placed both at the lower section of the slab and at the upper section which would be tied or
welded. The bottom and the upper part of the hollowed slab is made up of concrete that were connected to the vertical ribs that
are embedded around the gaps.

The distances between the bars are dependent on the size of the bubbles and the amount of the reinforcement from the
longitudinal and the transversal ribs of the slab. When placing the hollow HPDE balls, the two meshes are connected to form a
sturdy shell.

The bubbles are made to be non-porous and place in between the meshes. The materials made will not be chemically reacting to
the concrete or the reinforcement used. The bubbles have enough strength and rigidity to withstand the loads.

The method used in the design and analysis of the bubble deck bridge slab are Design and Analysis in Laboratory and Design and
Analysis using Software.

Bubble deck makes use of PVC balls and reinforced concrete. INDIAN STANDARD is used in the mixer of sand and aggregate
(concrete mix proportioning) 10262:2009.

The main material used for the design of bubble deck slab are cement and aggregate, and for better results, they used a different
type of materials in testing. The use of concrete, HDPE Balls, and Reinforcement mesh.

HDPE Balls are also known as High-density-polyethylene that can withstand higher temperatures. It has somewhat a higher
chemical resistance than LDPE (low-density polyethylene) and a more closely packed structure with higher density with the
absence of branching.

The size of the steel bar used in the vertical direction is 62cm while in the horizontal direction is 24 cm with having a spacing
between 6.5cm. A 6.5 mm diameter rebar was used for the high- density polyethylene and an 8 mm diameter was used for the
hollow deck slab.

Design and Analysis in software by using the Finite Element Method. "Finite Method is the most powerful numerical technique
for solving the differential equation of initial and boundary-value problem in the geometrically complicated region." And "The
finite element analysis of a problem is so systematic that it can be divided into a set of logical steps that can be implemented on a
digital computer and can be utilized to solve a wide range of problems by merely changing the data input to the computer
program" according to (Reddy,1998).

Once the analysis is complete, there are crucial information that are important not to neglect since it could affect the results of the
data. The data gathered were used to outline the boundary, the domain and the initial condition of the physical properties. Upon
knowing this information, if the analysis is finished fastidiously, it'll offer a satisfactory result.

The Finite Analysis can solve problems for a one, two, and three-dimensional problems which are dependent on the input. Easier
problems include one and two-dimensions, and those that can be solved without the use of a computer, but if the analysis requires
three-dimensional tools making it more complicated and involves a lot of equations that are difficult to solve.

Finite element divides the whole element into a finite number of small elements with the advantage of one, allowing every small
element has a simpler shape that leads to a good approximation for the analysis and two, the intersection of boundaries arises an
interplant polynomial which allows an accurate result at a specific point. "The domain of the problem is viewed as a collection of
nonintersecting simple subdomains, called finite element. The subdivision of a domain into elements is termed finite element
discretization. The collection of the elements is called the finite element mesh of the domain." (Reddy, 1988).

Engineers and Physicians used the Finite Difference Method before that involves the use of differential equations.
FLORENTINO, Luisa Beatrice C. (2164250)

The purpose of Finite Element Method is the stress analysis for trusses and other simple structures are carried out based on
dramatic simplification and idealization, mass concentrated at the center of gravity and lastly, beam simplified as a line segment,
the design is based on calculation results of idealized structure and a large safety factor given by experience.

Through the static and dynamic analysis of the solid slab and the bubble deck slab of the finite element analysis software, the
bridge deck model was then designed on the basis of the gathered information.

A comparison between the conventional slab and the new kind of slab was conducted to analyze and perceive the differences and
similarities that can be related to the previous study regarding the bubble deck slab. A 3-dimensional model of a solid slab and
the bubble deck slab was created with complete dimension through the use of the ANYSIS 2000 to be used for laboratory testing.
The solid slab finite element model has approximately 8100 elements and was generated as a thick shell of pure concrete while
on the bubble deck model, The ANYSIS 2000 consist the approximately 7500 elements, and a rectangular layer of HDPE was
placed in between two layers of standard concrete placed on top and at the bottom. In addition to their self-weight for static and
dynamic design, both models were subjected to a 100 kilonewton load. The material properties used in the testing were standard
concrete and HDPE in India.

I agree with the methods used in this article since results are based on experiments made. The study found that the internal stress
as well as the maximum moment of the bubble deck slab was 64% greater than that of the solid slab. The observations under the
bubble deck slab with having slab dimensions of 660mm, 330mm, 14cm of the length, width and depth respectively, that the
maximum shear loading was 157.6 kilonewton and plates cracks appeared at the load of 60 kilonewtons.

The shear strength of the bubble deck voided slab was determined to be 60 to 80% of the conventional slab with having the same
depth in accordance with the theoretical models. Therefore, a reduction factor of a value of 0.6 is to beconsidered in computing
for the shear capacity of the bubble deck slab due to the fact that this is one of the many concerns during the design of a slab.

Due to the addition of HDPE bubbles, the bubble deck slab greatly reduced its shear resistance in comparison to the solid deck
slab as shown in the results of the graph. The shear strength of the slab is directly proportional to the effective mass of concrete.

Reference

Gupta, N., & Jain, D. (2017). Study on a Comparative Study of Bubble Deck Slab and Conventional Deck Slab.
International Journal of Advanced Technology in Engineering and Science, 5 (03), Retrieved from,
https://www.ijates.com/images/short_pdf/1490212005_P572-578.pdf
FLORENTINO, Luisa Beatrice C. (2164250)

STRUCTURAL BEHAVIOR OF BUBBLE DECK SLAB

In Denmark, a biaxial hollow core slab was invented named as a Bubble deck slab. Bubble deck slab is a self-supporting
innovative and sustainable floor. It has the methodology of eliminating concrete that is non-performing structural function and
reducing the structural dead loads therefore, removing constraints of high dead loads and short spans. Almost 35% can be
eliminated by using plastic spheres in the middle of the slab were void forms.

Bubble deck flat slab allows the possibility of having longer spans and elimination of down-stand beams and column heads
which make it more cost-efficient with having 3% of the project cost can be reduced by the manufacturer and making it more
rapid.

The application and use of the Bubble deck floor system was first studied and initiated in Netherlands. Precast slab floors are to
be supplied to the construction site in factory-made units with a maximum depth of 3m and are installed on-site and assembled by
installing connecting rods and by the gushing of concrete. The floors can then be used after the pouring of the concrete unto the
formworks. The hollow plastic spheres are clamped in a factory-made reinforcement structure that is incorporated in the floor.

There is up to 35% saving of concrete consumption for floors in comparison to solid slab floor of the same thickness with the
ratio of the diameter of the plastic spheres to the thickness of the floor. Bubble deck slab floor can provide the required load-
bearing capacity at smaller thickness as to the advantage of saving weight and can result in 40 to 50% saving of the material
consumption in the floor construction. Another advantage of a bubble deck is that the supporting constructions such as columns
and foundations can be less heavy and with the floor system itself, which eventually results in a 50% saving on the building
construction. A bubble deck can also be useful in reducing earthquake damage.

Bubble deck slab is composed of three main materials: Steel with a yield stress of grade 60 or higher and can be fabricated as
meshed layers for lateral support and diagonal girders for vertical supports of the bubbles, Plastic hollow spheres that is made up
of recycled HDPE or also known as High density polyethylene and Concrete made from standard Portland cement with
maximum aggregate size of 20 mm. The use of plasticizers is not necessary for the concrete mix.

The properties of the Bubble deck slab:

For flexure strength, the Bubble deck slab is conceived to reduce a big volume of concrete on the central core where the slab is
principally unstressed in flexure as compared to a solid slab. There is no smart distinction between the behavior of a solid slab
and Bubble Deck since the depth of compressed concrete is usually a small portion of the slab depth. On the compression side,
the outer "shell" of concrete is only working, while on the tension side is the steel. For the hollowed slab, its moment of
resistance is of the same value to that of the solid slab considering that the depth of the compression area is constant all
throughout the design so as to not affect the area of the ball that was embedded.

For shear strength, shear resistance on a flat slab is always critical near the columns where bubbles are left out so, in these zones,
they are designed exactly like the solid slab. The bubble deck slab has a lower shear resistance of having a value of 0.6 to that of
the shear resistance of a solid slab considering that the two have the same thickness. For a column in an example, we leave out
the balls and use full solid shear values when exceeded by the applied shear. No further check is required if the applied shear is
less than the un-reinforced hollow slab resistance while if the applied shear is greater than the hollow slab resistance, we make it
solid and reduce the balls. The distance from the imposed force to support divided by the deck thickness will give us the shear
capacity measured for two ratios. The calculation and testing of the traverse and longitudinal shear stresses were applied only
within the area of the bubble deck slab so as to limit the parameters for data analysis. If the shear resistance is lower as well as
the maximum allowable shear when compared to a solid slab, then the bubble deck slab would need reinforcement for the
reduction of such failure. As compared to the calculated values of a solid deck, the average shear capacity measured is 91% for
the bubble deck slab.

For durability, the durability of the bubble deck is not different with the durability of a conventional slab. Bubble deck slab joints
were enclosed with a chamfer on the inside and the bars were surrounded by concrete to ensure that there is no air route that may
compromise the strength of the slab. Having the same design stress levels, the cracking of the bubble deck is probably better than
the solid slab since it possesses a continuous mesh at the top and at the bottom that ensures the shrinkage restraint. Cracking is
minimized whether intrinsic or extrinsic.

The deflection of both the bubble deck and the solid slab is relative to its thickness. The span depth ratio for deflections does not
apply to the flat slab.

For Sound insulation, the reduction of weight is the main criterion for reducing noise, therefore, making bubble deck not react
than other decks with equal weight. Through comparison between the bubble deck and that of a one-way prefabricated hollow
deck of the same height, the results showed that there was a noise reduction of 1 decibel for the bubble deck as compared top that
of a one -war prefabricated hollow deck.
FLORENTINO, Luisa Beatrice C. (2164250)
Due to the property of the bubble slab having a lighter weight, it can withstand higher frequencies of vibration as compared to the
solid slab. Upon comparison of the solid deck and to that of the bubble slab, it was found that the bubble deck could give up to 2
times the stiffness to that of the solid slab.

The fire resistance is very dependent to the duration of the concrete cover for up to 60 -180 minutes. During the use of a high-
density polyethylene, studies have found that it is harmless and unreactive to the other materials of the slab. In a prolonged fire,
the balls would melt and they simply carbonize. There are no toxic gasses released.

During the assembly of the bubble deck slab, the balls does not fit accurately between the reinforcing bars due to the slight
movements. The inside area of the bubble deck slab is dry and protected whenever the steel reinforcement or the ball contracts.

There is an 87% to 93% approximate of flexural stiffness of the same thickness of solid slab carried out in Denmark, Holland,
and Germany. They used an average of 90% in the design and also, as recommended in Dutch research, the cracking moment is
factored 80%. One-third weight reduction overwhelmingly more than compensates for the very small reduction in stiffness,
therefore reducing the deflections for a given span is beneficial for the system.
Finite Element Analysis was performed to compare the response of this new type of floor with a typical flat, solid concrete slab
in order to understand the response of the system. In SAP2000, A 3D solid slab and a Bubble Deck slab were modeled with
having the same dimensions and as two-way spanning floor systems. There are 12963 approximate elements for each office slab
finite element model. The solid slab uses pure concrete while the bubble deck uses the method of layering. In addition to their
self- weight for the static analysis, both models were subjected to an l0 kilo-newton live load. The material properties used are
standard concrete M30 and High-density polypropylene or HDPE.
The Bubble Deck system is a new innovation which utilizes the use of lesser concrete, lesser materials and lesser dimensions for
columns and foundations. This new innovation paved way to the enhancement of a structural prospects with a more improved
cost- effectiveness.

Prior to analysis and experiment results, I can agree that the bubble deck is more efficient and can be an alternative to the
conventional slab. The Bubble Deck was justified to be more efficient than the conventional 2-way concrete slab through the
analysis and studies done when it was used on a floor system. The results found that the bending stresses of the hollowed slab has
a decrease of 6.43% as compared to that of a solid slab. But the deflection of the hollowed slab was found to be 5.88% more
since it would have a longer span. In terms of the shear resistance of a hollowed slab, it was seen that it was 0.6 times to that of a
solid slab and there was a weight reduction of 35%.

Reference
Anusha, S., Kumar, V., Mounika, C., Saha, P., & Teja, P. (2012). Structural Behavior of Bubble Deck Slab. International
Conference on Advances in Engineering, Science and Management. Retrieved from, https://www.researchgate.
net/publication/254038055_Structural_behavior_of_bubble_deck_slab
FLORENTINO, Luisa Beatrice C. (2164250)

SITE ERECTION AND INSTALLATION MANUAL TYPE B – REINFORCEMENT MODULES

A Bubble Deck flab slab helps in eliminating other supporting structures such as beams or walls. The deadweight of the floor slab
is also reduced to 33% longer spans between column supports and other range of design. The floor slab can be completed by pre-
cast or in-situ reinforced concrete columns.

Site erection and installation is a process where any qualified concrete contractor or sub-contractor can do the job because it is
easy and quick. From the previous projects, over 800 square meters of bubble deck has been erected and completed inside 4
operating days

It is important to take note that RC columns and walls should not be overpoured so as to avoid reducing the slab effective depth
at support locations. Only use enough to bring RC columns and walls to the underside of the bubble deck flat slab level following
British standards.

Formal drawing approval prior to manufacture, Materials and modules manufactured can be implemented and delivered within 4
weeks once they have received the production and installation drawings. Due to several factors and other events beyond control,
the progress of construction on-site may be interrupted. To meet the expected progress in constructing a bubble deck, deliveries
can be advanced.

Combining the erection operation of RC columns and walls with the bubble deck makes it an efficient method that saves time and
the overhead in construction. Combining the erection method, advantages are a) Condensing a two-stage sequence (erecting and
casting columns and walls first followed by the bubble deck slab) into a one-stage sequence; b) Stable and firm platform for
casting walls and columns are provided; c) Separate concrete deliveries for columns and slab are eliminated; lastly, d) Gold bond
between column and wall and bubble deck slab site concrete are ensured.
It is also important to note that the removal of temporary formworks is not allowed before each slab is cured sufficiently to
support its weight and temporary construction loads.

Back-propping, when consecutive floor slabs with the block are to be constructed above each other either; One option prior to
erecting formwork for constructing the next, the formwork of the completed slab is removed from below and erect back-props at
1.8 meters intervals without parallel beams at either midspan or third span, that is dependent on the length of spans involved. The
second option before erecting formwork for constructing the next, slab above loosen the props supporting formwork below the
completed slab so to allow the floor to reach its maximum deflection and then props are tightened again.

Site Delivery, flatbed trailers typically between 12 meters to 13.6 meters long are used to deliver the modules. Reinforcement
modules are stacked on top of each to a height of 2.5 meters while a maximum of 10 layers high on-site.

It is very important to note that upon the arrival of the delivery trailers on-site, drivers will require to let you sign the delivery and
loading control form to confirm that you already received the modules which will be retained by him for recording. The wooden
transport packing beams or blocks must be returned immediately after removing the reinforcement modules for return in the
factory and reuse. Modules should be placed straight in their respective positions onto temporary formworks and modules are to
be lifted off trailers. The modules must be transversely supported on timber packers laid between the bubble rows at a maximum
of 2.4 meters centers resting on flat, level ground and protected from soiling.

Lifting and placing the reinforcement module, modules can be lifted using slings passed around and underneath the cages, or
lifting hooks clipped around the lattice beam girder reinforcement. Safety should also be considered when lifting off modules
making sure that the lifting hook should not be attached to the upper reinforcement mesh. Lifting equipment should be tested and
should be capable of carrying at least 2 tons.
The positioning of placing reinforcement modules on formwork, modules should be lifted into its right position. Take note that in
the final positioning of modules, make sure that the bubble pattern between adjacent elements is aligned as shown in the
installation drawing.

Fixing loose reinforcement, site installation drawings are provided for reinforcement fixed at the bottom of the slab directly on
top of the bottom mesh reinforcement and reinforcement fixed at the top of the slab directly on top of the top reinforcement
together with the bending schedules.

Constructing perimeter shuttering, Erecting perimeter shuttering can start once the perimeter loose reinforcement has been
installed.

Preparation for concreting, prior to pouring site concrete take away all debris or foreign matter. Before pouring there is a need to
power wash the top of the precast concrete formwork to remove retained dirt and formed concrete.
FLORENTINO, Luisa Beatrice C. (2164250)
Preparation for concreting, prior to pouring site concrete take away all debris or foreign matter. Before pouring there is a need to
power wash the top of the precast concrete formwork to remove retained dirt and formed concrete.

Bubble deck site inspection, for the work that need to be undertaken, a technical representative will issue you with an inspection
record listing and confirms you when installation is ready for pouring. It is important to ensure that the inspection team is notified
at least 2 working days to provide quick and efficient service.

The volume of concrete can be estimated depending on the slab of the depth. The concrete volume is not arrived at by taking the
pour area multiplied by the finished slab depth. The concrete must be laid in two stages: first, concrete pouring using self-leveling
concrete to approximately 70 to 100mm depth and by following the initial set of the first, pour the temporary loading weights.
Secondly, pour remaining sections that are not yet poured so to complete the process.

When pouring concrete, make use of a thin vibrating poker to compact the concrete and to ensure a good flow around the bubbles
due to limited space between the bubbles. Heaps must be avoided when pouring concrete evenly. After poring, power float is
then used to level the surface.
Removing temporary formwork, it takes 3 to 5 days from pouring to remove formworks for as long as early concrete test results
have confirmed the site concrete has reached 60% of its final design strength but varies depending on factors like ambient
temperature, floor slab design, or strength of site concrete.

When attaching light-weight and medium-weight, normal methods can be used to provide adequate fixing.

To determine wherever fixings can occur directly below or near to the edge of a bubble, bubble layout drawings are inspected.
Sturdy fixings are needed to resist downward forces from heavy loads to be suspended on the soffit.

Holes should not be place near columns since the loads in the slab are transferred here and it is where the highest shear occurs.
Technical department takes over for holes larger than 250mm diameter, or having multiple holes with a close proximity.
Diamond drilling can be use through the completed slab. The sole limitations are to avoid pruning an excessive amount of
support once holes are shaped close to supporting columns /walls, or a series of holes in a row in certain situations, however,
these can be allowed for throughout the design stage.

I agree with the article that bubble slab should be used because it is quicker and easier in site erection and installation making a
lot of advantage on the construction operations. It is also very important that manuals are used that methods are systematic and
right. Following this article can help prevent conflicts in the operation and can even prevent failure.

Reference

Anonymous. (2008). Site Erection and Installation Manual Type B – Reinforcement Modules. Bubble Structure Solutions.
St. Saviour, Jersey. Retrieved from, http://www.bubbledeck-uk.com/pdf/4-BDSiteManual-Bv6.pdf
SANTIAGO, KATE NICOLE D. (2151007)

BIAXIAL HOLLOW SLAB WITH INNOVATIVE TYPES OF VOIDS

This research is about the innovation of biaxial hollow slab and new types of voids which were presented over the last 15 years
and a review on the advantages of it. During the 20 th and 21st centuries, a new type of hollow core slabs was invented and it
became a breakthrough. Many studies were conducted on the feasibility of this new technology. Examples of this technology
were also presented in this study.

Biaxial voided slabs are reinforced concrete slabs in which the amount of concrete is reduced because of the voids. Considering
the disadvantages of concrete constructions, mostly it comes from the high weight that gives the span a limit. This is one reason
why many types of research focused on improving the span by simply eliminating some weight or overcoming the natural
weakness in the tension of concrete. One of the most well-known examples in ancient history was The Pantheon in Rome. To
reduce the weight of the dome, they put coffers which were not reinforced. The use of hollow slabs begun in the 1950s. These
were prefabricated so it is inexpensive, and it reduces construction time. Although it has advantages, one disadvantage of hollow
slab is that, it can only be used one one-way spans and it must be supported by beams and/or fixed walls. Precast concrete is most
popular to constructions that consider the effect of lateral loads and the economic value because it takes less time in building
assembly and it uses less materials which lessens the self-weight of a slab.

The purpose of this study was to determine the feasibility of new technologies involving hollow biaxial slabs. Another thing is to
consider the various companies that produces this kind of slabs and to review the important differences between them. Several
types of hollow slab systems were mentioned in this study and these are: (1) Airdeck, which was introduced in 2003 and it is
made up of inverted plastic injection molded element. In using this kind of system, there is no need to use retaining mesh during
the pouring of the second layer of the slab.; (2) Cobiax, which is a system that has the same principle of creating voids within the
concrete slabs to lessen the self-weight of a structure. It uses hollow formers that are held in place using metal mesh at the top
and bottom reinforcement of the concrete slab.; (3) U-Boot, is a system in which elements are made up of recycled plastic to
build lighter structures in reinforced concrete. The advantage of using this is that it is stackable. It can also be used along with
other technologies such as pre-fabricated slabs and post-tensioned steel.; (4) Bubble Deck, this is another system that was
invented by Jorgen Bruenig which has the same capabilities as a solid slab but with less weight.
In this research, the parameters for the Bubble Deck slab are the geometry of size and the distance of the hollow balls
from each other. The modulus in steps and effective heights in steps were 25mm and 50 mm respectively. The reinforcement
meshes reduces the use of unnecessary materials. In principle, the installation of ellipsoids can be done in various ways, but only
reinforcing bars reduce the consumption of unnecessary materials and ensure an optimal geometric ratio between concrete,
reinforcement, and holes. The voids are located in the middle of the cross-section where concrete has a limited effect, while still
maintaining the solid parts of the top and bottom, where high pressure may exist. Thus, the plates are fully functional concerning
positive and negative bending. In principle, the Bubble Deck plate acts as a solid slab. The design, as a result, can be obtained as
a solid plate, only with a smaller load, according to the reduced amount of concrete. Extensive studies according to Eurocodes
were carried out at universities in Germany, the Netherlands, and Denmark, concluding that deck plates behaved like solid plates.
[8-16] It is important to emphasize differences in static calculations between different perforated plates. While a true biaxial slab
as a Bubble Deck system must be counted as a solid slab, a ribbed slab system, like the Uboot system, which consists of
orthogonal "I" beam lattice, must be counted as a beam. Bubble Deck technology is directly incorporated into national standards,
such as CUR [17] in the Netherlands.

A solid plate can only carry about one-third of its weight and has problems with long spans because of its high weight.
Bubble Deck's biaxial deck investigation makes it possible to resolve this problem by eliminating 35% of concrete while
maintaining strength. Tests have shown that for the Bubble Deck slab with the same load-carrying capacity can only be used 50%
of the concrete needed for solid plates, or of the same thickness from the Bubble Deck plate, the load-carrying capacity can be
doubled by using 65% concrete. For Bubble Deck plates, the sliding resistance is proportional to the amount of concrete, because
the special geometry formed by the ellipsoidal vacuum works like the famous Roman arch, allowing all concrete to be effective.
Note that this is only valid when considering Bubble Deck technology. Other types of hollow biaxial plates have reduced
resistance to shear, local boxing, and fire.

The references used by the author are:

Lancaster L. C. (2005). Concrete Vaulted Construction in Imperial Rome: Innovations in Context // Cambridge University Press.
2005. Pp. 6-10.

AirDeck [web source] URL: http://www.airdeck.be (date of reference: 18.09.2013).

EN 1992 Eurocode 2 [web source] URL: http://eurocodes.jrc.ec.europa.eu/showpage.php?id=132 (date of reference:

22.09.2013).
SANTIAGO, KATE NICOLE D. (2151007)
Bond A. J., Brooker O., Harris A. J. et. al. (2006). How to Design Concrete Structures using Eurocode 2. 2006. 104 p.

BubbleDeck [web source] URL: http://www.BubbleDeck.com (date of reference: 28.09.2013).

Cobiax [web source] URL: http://www.cobiax.com/en (date of reference: 28.09.2013).

U-boot [web source] URL: http://www.daliform.info/USB/download/referenze/Uboot_reference.pdf (date of reference:

28.09.2013).
Schnellenbach-Held M., Ehmann S., Pfeffer K. (1998). BubbleDeck - New Ways in Concrete Building. Technische Universität
Darmstadt, DACON. 1998. Vol. 13. Pp. 93-100.

Schnellenbach-Held M., Ehmann S., Pfeffer K. (1999). BubbleDeck Design of Biaxial Hollow Slabs. Technische Universität
Darmstadt, DACON. 1999. Vol. 14. Pp. 145-152.

Prof. Kleinman. (1999). BubbleDeck Report from A+U Research Institute. Eindhoven University of Technology. 1999. Pp. 14-
15.
Koning B. (1998). BubbleDeck Test Report. The Netherlands. 1998. Pp. 3-9.

Report of BubbleDeck from Technische Universitaet in Cottbus. 1999. Pp. 10-12.

Report from the Eindhoven University of Technology. Broad comparison of concrete floor systems. 1997. Pp. 13- 14.

Bubble Deck Report from Technical University of Denmark. 2003. Pp. 9-11.

Report from Adviesbureau Peutz & Associes bv Comparison of Bubble Deck vs. Hollow core. Netherlands. 1997. Pp. 5-11.

Optimising of Concrete Constructions. The Engineering School in Horsens / Denmark. 2000. Pp. 18-19

Centre for Civil Engineering Research and Codes (CUR), Recommendation 86. Pp. 4-12.
Schnellenbach-Held M., Denk H. (1999). BubbleDeck Time-Dependent Behaviour, Local Punching Additional Experimental
Tests. Technische Universität Darmstadt, DACON. 1999. Vol. 14. Pp. 137-144.

Schnellenbach-Held M., Pfeffer K. (2001). Tragverhalten zweiachsiger Hohlkörperdecken. Beton- und Stahlbetonbau. 2001. Vol.
96. Issue 9. Pp. 573-578.

According to this study, such conclusions can be drawn: (1) Due to the fact that the structural behavior of this new type of
monolithic flat slab is the same as for solid slab, excluding slab-edge column connections, we can certainly talk about the
suitability of use and the advantages of new technology. (2) Reduced concrete use 1 kg of recycled plastic that replaces 100 kg of
concrete. (3) Reducing ingredients consumption makes it possible to make construction time faster, to reduce overall costs. Apart
from that, it has led to reduced deadweight by up to 50%, which makes it possible to make the foundation size smaller. This
technology is environmentally friendly and sustainable. (4) Avoiding cement production is possible to reduce global CO2
emissions. Use of the Bubble Deck system qualifies for LEED points in North America. This technology is very prospective in
modern construction and may be the future of civil engineering belongs to this new type of hollow slab.

This study was helpful in a way that it gave us a clear explanation about the significance of the study on hollow slabs and the
different technologies that were created for this. It clearly showed the difference among them especially the Bubble Deck whi ch
is the topic that we are focusing. We can use the given information as a basis to our study.

REFERENCE
Churakov, A. (2014). Biaxial hollow slab with innovative types of voids. Construction of Unique Buildings and Structures.
Saint-Petersburg Polytechnical University, 29 Polytechnicheskaya st., St.Petersburg, 195251, Russia. Retrieved from:
http://unistroy.spbstu.ru/index_2014_21/5_churakov_21.pdf
SANTIAGO, KATE NICOLE D. (2151007

TO STUDY COMPARISON BETWEEN CONVENTIONAL SLAB AND BUBBLE DECK SLAB

This research focuses on the comparison between Conventional Slab and Bubble Deck Slab. According to different studies,
Bubble Deck Slab is a process of removing the concrete from the middle of a slab to reduce the structure’s dead weight. The use
of HDPE or High-Density Polyethylene hollow spheres was observed replacing all of the concrete which does not perform any
structural function in the slab. This process helps to decrease the dead weight and increase the floor’s efficiency. Based on the
research, the advantages of using Bubble Deck Slab include, less energy consumption, less emission of exhaust gases, especially,
CO2 and it lessens the cost in construction. In the method of Bubble Deck Slab, this reduces the concrete volume by replacing
concrete with what you call spherical bubbles. The experiment was done by casting continuous conventional slab and bubble
deck slab having different bubbles arrangement. This also tries to enhance the strength of the slab. The determination of the load
carrying capacity of the slab, deflection, cracking and failing characteristics depends in the realization of monolithic slab element.
All the results and conclusion will be used to define the advantages and disadvantages of Bubble Deck slab.

The slab was designed to resist only vertical loads but, over time, people wanted residential structures that can also resist
vibration and noise. The main goal was to focus on developing the span by eliminating some of the concrete in the slab to reduce
its dead weight and overcoming concrete’s natural weakness in tension. There were many attempts made to produce biaxial slabs
that have hollow cavities just to reduce the weight. The research was made by preparing blocks that have light-weight materials
such as, polystyrene placed on top and bottom of the reinforcement concrete. Grid and waffle slabs were also introduced to
people, but of all these types, waffle slabs are the ones used in the market. However, the use of the waffle slab has limitations due
to its low resistance to shear, fire and local punching. Researchers found out that the use of these kinds of slabs has some flaws
that’s why it has not gained any acceptance and they are only used to some projects.

The objective of this study was to create a Bubble Deck Slab which has hollow spheres with specific sizes and placing
it in a reinforcement grid with a certain thickness. Since the Bubble Deck slab has limited formwork, it produces floors 20%
faster that minimize the construction costs and of course, minimizes the use of concrete. Bubble deck helps in designing larger
cantilevers and allows stronger and thicker slabs of concrete having larger areas. The research states that Bubble Deck was
designed to be an effective solution in decreasing the amount of concrete used in building construction, to optimize the weight of
concrete and to strengthen the overall frame.

The test was conducted by using the technology of Bubble Deck producing a lighter weight deck for a bridge. The
researchers used the knowledge collected during behavioral analysis to design a modular deck component for pedestrian bridges
that is lighter but has the strength that is similar to the typical reinforced concrete designs. The behavior of the Bubble deck slab
was studied considering different conditions. This gave the researchers further understanding concerning new techniques and
comparisons between the Bubble deck and the current slab systems. The researchers aimed to produce a slab with decreased
concrete volume and shear resistance. They used the standard measurement of shear capacity which ranges from 72-91% for
solid deck.

In this test, they have considered the three types of Bubble Deck slab which are, (1) Continuous Bubble Deck slab, (2)
Alternative Bubble Deck slab (type I) and (3) Alternative Bubble Deck slab (type III). Bubbles were arranged in vertical and
horizontal directions alternatively throughout the slab of an Alternative Bubble deck (type I). The reinforcement for alternative
and continuous bubble deck slabs is the same. When concrete and bubbles are put together, they will affect slab strength. They
cast both Conventional Slab and Bubble Deck slab of the same size and studied different aspects and structural considerations.
Several parameters were considered including design constant, test data for materials, target mean strength, selection of water-
cement ratio, selection of water content, selection of cement content and the proportion of the volume of both coarse and fine
aggregate content.

The references used by the author are:

Shetkar A, Hanche N (2015) “An Experimental Study On bubble deck slab system with elliptical balls”. NCRIET-2015 & Indian
Journal science of research 12(1):021-027.

Harishma KR, Reshmi KN (2015) “A study on Bubble Deck slab”. International Journal of Advanced Research Trends in
Engineering and Technology (IJARTET) Vol. II, Special Issue X.
Subramanian K, Bhuvaneshwari P (2015) “Finite Element Analysis of Voided Slab with High Density Polypropylene Void
Formers”. International Journal of Chem Tech Research, CODEN (USA): IJCRGG ISSN: 0974-4290, Vol.8, No.2, pp. 746-753.

Bhagat S, Parikh KB (2014) “Comparative Study of Voided Flat Plate Slab and Solid Flat Plate Slab”. ISSN 2278 – 0211, Vol. 3
Issue 3.

Shaimaa TS (2014) “Punching Shear in Voided Slab”. ISSN 2224-5790 , ISSN 2225-0514 , Vol.6, No.10.
SANTIAGO, KATE NICOLE D. (2151007)
Bhagat S, Parikh KB (2014) “Parametric Study of R.C.C Voided and Solid Flat Plate Slab using SAP 2000”. IOSR Journal of
Mechanical and Civil Engineering (IOSR-JMCE), e-ISSN: 2278-1684, p-ISSN: 2320-334X, Volume 11, Issue 2 Ver. VI, PP 12-
16.

Churakov A. (2014) “Biaxial hollow slab with innovative types of voids”. ISSN 2304-6295.6 (21). 70-88.

Ibrahim AM, Nazar KA, Wissam DS (2013) “Flexural capacities of reinforced concrete two-way bubble deck slabs of plastic
spherical voids”. Diyala Journal of Engineering Sciences, ISSN 1999-8716, Vol. 06, No. 02.

Terec LR, Terec MA (2013) “The bubbledeck floor system: a brief presentation”. CS I, INCD URBAN-INCERC Branch of Cluj-
Napoca, CONSTRUCŢII – No. 2.

Wesley NM (2013) “Viscoelastic Analysis of Biaxial Hollow Deck Balls”. International Journal of Computer Aided Engineering,
ISSN: 1071- 2317, Vol.23, Issue.1.

Mihai B, Raul Z, Zoltan K (2013) “Flat slabs with spherical voids. Part II: Experimental tests concerning shear strength”.
ActaTechnicaNapocensis: Civil Engineering & Architecture Vol. 56, No. 1.

Larus HL, Fischer G, Jonsson J (2013) “Prefabricated floor panels composed of fiber reinforced concrete and a steel
substructure”. Elsevier Science engineering. Structures 46, 104-115.

Calin S, Asavoaie C (2010) “Experimental program regarding “Bubble Deck” concrete slab with spherical gaps”. ISSN 1582-
3024, Article No.4, Intersections, Vol.7, No.1.

Lai T. (2010) “Structural Behavior of Bubble Deck Slabs and their application to Lightweight Bridge Decks”. Massachusetts
Institute of Technology.

Bubble Deck-UK (2008). “Bubble Deck structure solutions – Product introduction”. Part 1, Bubble Deck UK Ltd.

Martina SH, Karsten P (2002) “Punching behaviour of biaxial hollow slabs”. Elsevier Science cement concrete composites 24
(2002) 551- 556

The researchers have concluded that a continuous bubble deck reduces the volume of concrete to ultimately decrease the self-
weight of the slab. The arrangement of the hollow balls also affects the load-carrying capacity of the slab. On the other hand,
Bubble Deck also improves the elastic property of slab when compared to Conventional slab which is 6% lesser. Using bubble
deck slab is both cost-efficient and time-efficient and most importantly it helps in the development of the structure by reducing its
dead loads. Thus, they have concluded that the Bubble Deck slab gives better results when it comes to deflection and weight
parameters.

This study clearly showed the comparison between Conventional Slab and Bubble deck slab and I find it useful because it gives
us an idea and background of using Bubble Deck as an alternative in the construction. They have mentioned several advantages
which have a positive effect in the field of construction and can be adopted. On the other hand, it was not mentioned if they used
a spherical or elliptical hollow ball. Nevertheless, a different study can be conducted considering this factor. Another factor to be
considered is the use of Bubble Deck depending on the type of construction, whether it be a residential or commercial type.

REFERENCE
Fatma, N., Chandrakar, V. (2018). To study Comparison between Conventional Slab and Bubble Deck Slab. International
Advance Research Journal in Science, Engineering and Technology. Vol. 05, Issue 01. Retrieved from:
https://iarjset.com/upload/2018/january-18/IARJSET%2011.pdf?fbclid=IwAR01zCj-
Bd5TLkG23Hgb7sDCchdYsfqNuA6HkU_hk9bfMWlUuL2W3sGiEfA.
SANTIAGO, KATE NICOLE D. (2151007)

A STUDY ON STRUCTURAL BEHAVIOR OF BUBBLE DECK SLAB USING SPHERICAL AND ELLIPTICAL
BALLS
Concrete is very important in the construction field because this composes the construction slab which is one of the most
important structural members that uses concrete. More often than not, the slab uses more concrete than the requirement hence it
has the need to be improved and make something as good as possible. According to research, reducing the use of concrete in the
center of the slab and replacing it with hollow recycled plastic balls is one way of optimizing it. They discovered the high-density
polyethylene (HDPE) hollow balls that replaces the concrete in the center of the slab, thus decreasing the dead weight and
increasing the effectiveness of the floor. These gaps make the slab lighter and it reduces the loads on the columns, walls,
foundations, and the building as a whole. The researchers listed some of the advantages of using bubble deck slab and these are,
the minimization of energy consumption (both in production and transport), and it also lessens the emission of exhaust gases,
especially CO2.

Finite element method was used by the researchers to study the structural behavior of the bubble deck slab with spherical and
elliptical balls that were subjected to uniformly distributed load with boundary conditions. This is a faster way of developing a
product and engineers use this to reduce the number of prototypes and experiments thus making their design better. The analysis
was performed by using both M25 and M30 grade of concrete on a bubble deck slab. The study aimed to determine the total
deformation, directional deformation, and equivalent stress. Then the obtained results of bubble deck with spherical and elliptical
balls were set side by side.

The discovery of hollow core slabs became a breakthrough during the 20th and 21st centuries. The concept of a bubble deck slab
was to virtually remove or eliminate all concrete from the middle of a floor slab. Jorgen Bruenig invented the bubble deck slab in
1990, and he was the one who developed the first biaxial hollow core slab (bubble deck slab) in Denmark. The main concern with
concrete constructions when it comes to horizontal slabs is the heavy weight. The development of reinforced concrete has
focused on improving the span eliminating some weights or overcoming the concrete's natural weakness in tension. The slab was
only designed to resist the vertical load. However, based on the researchers’ study people realized that noise and vibration were
also important because as the span increases, the deflection of the slab also increases. They felt the need to increase the slab
thickness. The slab thickness causes the slabs to be heavier and the increase of column and foundation size. These factors make
buildings consume more materials, such as concrete and steel reinforcements. That is why there were so many studies conducted
to lessen the disadvantages caused by the concrete’s self-weight.

There were several attempts made to create biaxial slabs with hollow cavities to reduce self-weight but it turns out that there is a
chance of stress concentration in the corner of hollow cavities. Severe crack generation in slabs was led by stress concentration in
hollow cavities. Some trials were consisted of laying blocks of a lighter material like expanded polystyrene between the top and
bottom reinforcements, while other types include waffle and grid slabs. Out of all those types that have been considered, only the
waffle slab can be taken into consideration to have a particular use in the market. But there will also be limitations in the waffle
slab caused by the reduced resistances towards shear, local punching, and fire. A lot of studies were conducted to minimize self-
weight in concrete slabs. The researchers have chosen a lot of materials for the study related to this, but polypropylene and
polyethylene were found ideal, because of reduced weight and it acts as a good crack arrester. These two were then used to create
hollow plastic balls. These hollow plastic balls were placed in the middle portion of the slab between the top and bottom
reinforcements, thus, reducing the slab’s self-weight. The bubble deck slab technology was introduced to prevent the
disadvantages which were caused by increasing the self-weight of the slabs.

According to them the behavior of the bubble deck slab is determined by the ratio of bubble diameter to slab thickness.
Reinforcement can be either tied or welded. They are placed as two meshes, one at the top part and the other one at the bottom
part. The distance between all of the bars was kept, making sure that the dimensions of the bubbles that were provided between
the top and bottom meshes correspond to it. Through this technology, the ellipsoids between the top and bottom reinforcement
meshes can be locked. It creates a natural cell structure that acts like a solid slab. By replacing the ineffective concrete in the
center of the slab with High-Density Polyethylene (HDPE), it decreases the dead weight and increases the efficiency of the floor.

The bubble deck slab is made up of three main materials which are, steel, hollow plastic balls, and concrete:

Concrete is made up of standard Portland cement having a maximum aggregate size of 20 mm. Concrete mixtures don’t need
plasticizers. It has been proven by the researchers that the compressive strength of concrete is achieved by a bubble deck slab
same as through with solid slabs. A thin layer of concrete at the bottom of a certain type of bubble deck was precast at the
manufacturing plant. This was done so that the bubbles can be placed as per the specifications. This can only be achieved by
putting concrete in platforms and the bubbles in the concrete should be lowered. A platform vibrator or formwork vibrator is then
used to compact concrete. The remaining concreting can be done at site and concrete can be compacted using needles vibrators
and surface vibrators. Usually, M25, M30 and above grades are used for bubble deck construction.
SANTIAGO, KATE NICOLE D. (2151007)
The references used by the author are:

Nizamud Doulah and Md. Ahsanul Kabir, “Non-linear finite element analysis of reinforced concrete rectangular and skew slabs,”
Journal of Civil Engineering, 29(1). Pp1-1, 2001.

Martina Schnellenbach Held, “Punching behaviour of biaxial hollow slab, Journal of Cement and Concrete Composites,” Vol. 24,
Pp 551-556, 2002.

Sergiu Calin and Sergiu Baetu, “Nonlinear finite element modeling of spherical voided biaxial concrete floor slabs”, International
Symposium Computational Civil Engineering, Vol. 08, Pp 81-92, 2011.

P. PrabhuTeja, S. Anusha and C.H Mounika, “Structural behavior of bubble deck slab,” IEEE- International Conference on
Advances in Engineering, Science and Management (ICAESM), Vol. 20, Pp 21-41, 2012.

Amer M Ibrahim, Nazar K Ali and Wissam D Salman, “Flexural capacities of reinforced concrete two-way bubble deck slabs
plastic spherical voids,” Diyala Journal of Engineering Sciences, Vol. 06, Pp 9-20, 2013.
Mustafa Basheer Mahmoud and Agarwal V.C, “Non-linear finite element analysis of RC slabs strengthened with CFRP
laminates,” Int. J. of Eng. Trends and Tech, Vol. 5, Pp 140-143, 2013.

GeethaKumari. T, Ashwin Kumar and M.P Puttappa, “Finite element analysis of flexural characteristics of SFRNC and SFRSCC
one way restrained slabs using ANSYS,” Journal of Civil Engineering Technology and Research, Vol. 2, Pp 267-276, 2014.

Ahmed Sabry, “Experimental and analytical study on punching strength of two-way slabs strengthened externally with CFRP
sheets,” International Journal of Research in Engineering and Technoloy, Vol. 03, Pp 113-120, 2014.

The reinforcement of steel is Fy= 60 ksi or higher. The steel can be constructed in two forms- meshed layers for lateral support
and diagonal girders for vertical support of the bubbles. As soon as the bubbles are prepared, steel reinforcement is arranged. The
only possible way of properly locking the bubbles is by placing them in reinforcements. The reason why it is shaped like a sphere
is that it makes it non-stackable. The bubble is then placed in a framework by proper steel reinforcement. After the top and
bottom reinforcements were held together through welding, then the steel reinforcement is designed. Extra bars and shear
reinforcements should be provided if necessary, for the design procedures.

Generally, recycled plastic balls are used for concrete to reduce waste usage of plastics and to reduce environmental pollution.
Plastic balls are cheap and don’t react chemically with concrete or reinforcement. Plastic balls composed of high-density
polyethylene are commonly used.

The researchers used tetra mesh which is a four noded mesh to create a model for the bubble deck slab with spherical and
elliptical balls. Tetra mesh was used due to the irregular geometry of the slab. A hinged support at one end and a roller support on
the other end was provided in the bubble deck slab with spherical and elliptical balls.
The analysis was done by using M25 and M30 grade of concrete. The researchers were able to study about the total deformation,
directional deformation, and equivalent stress. According to the deflection values obtained by the researchers the load-deflection
graph was plotted. Lastly, the researchers compared the results they obtained from the graph.

The researchers’ goal was to find an alternative to concrete slabs to lessen the use of concrete and to reduce self-weight. This
will increase the efficiency of the floor because of the use of recycled hollow plastic balls. According to them, the use of bubble
deck slab was recently applied in many industrial projects in the world. They have concluded that the bubble deck slab with
elliptical balls has better loading capacity compared to spherical balls. The results also showed that M30 grade concrete has better
performance than M25 grade concrete. It also suggests that for one bubble deck slab with spherical shape, it saves weight up to
33.15% and 34.90% for one elliptical ball.

I find this study relevant to our research because this helped us to decide what shape of plastic hollow balls we are focusing. It
also gave us an overview of what we are studying for and why are we studying an alternative solution to pure concrete slab to
reduce weight and help the environment.

REFERENCE
Jamal, J., Jolly J., (2017). A study on structural behavior of bubble deck slab using spherical and elliptical balls.
International Research of Engineering and Technology (IRJET). Vol. 04, Issue 05. Retrieved from: /33550060/A_study
_on_structural_behaviour_of_bubble_deck_slab_using_spheric https://www.academia.edu/ al_and_elliptical_
balls?fbclid=IwAR1XXJ_01bfqXoyHpBO9gNAQpbCjT8l3MrHSvpS6BpE8yIo7EzeNmnerYl0
SANTIAGO, KATE NICOLE D. (2151007)

REVIEW ON BUBBLE DECK WITH SPHERICAL HOLLOW BALLS

This research is an overview of spherical hollow balls on the bubble deck slab. It aims to discuss the many importance
of Bubble Deck Slab when compared to Conventional Slab. We all know that reinforced concrete slabs are one of the most
common components in building structures and it consumes most of the concrete. Due to the amount of concrete required to
produce slabs, the dead load of them becomes very large. Heavier structures become less desirable considering those seismically
active regions because a larger dead weight for a building increases the inertia forces, which the structure must resist. Bubble
deck slab which was developed in Europe gained popularity and acceptance worldwide. According to the research, this method
virtually eliminates concrete from the middle of the slab, thus reducing the weight of structure. This study gives a wide range of
cost and construction benefits because voids in the middle of a flat slab has been eliminated up to 35% of its self-weight
removing constraints of high dead loads and short spans.

A slab is an essential part of the structure and has to be designed properly and effectively. The researchers’ purpose of
the study on Bubble Deck Slab was to optimize the use of concrete than the required. In Bubble Deck Slab, some amount of
concrete is replaced by the plastic hollow bubbles that are made by waste plastic materials. According to this research, the main
effect of the plastic sphere was to lessen the dead weight of the slab by 1/3, compared to a solid slab with the same thickness but
it has nothing to do with the deflection behavior and bending strength. The slab is formed with the same capabilities as a solid
slab but having a lesser weight due to the removal of excess concrete. Even after the building is demolished or renovated, the
spheres could be recycled. The dead air in the hollow spheres can have additional energy efficiency by adding foam and also
increases its resistance to fire and sound insulation.

The Bubble Deck slab used in this research has spheres having a certain size, which are then placed in a modular grid
for a certain deck thickness, depending upon the diameter of the balls being used. Bubble deck produces floors 20% faster
because of having less framework and beams. It also reduces construction costs by 10% and reduces the use of concrete by 35%.

The references used by the author are:

Tina Lai “Structural behavior of bubble deck slab and their applications to lightweight bridge decks”, M.Tech thesis, MIT, 2009.

Bhagyashri G. Bhade and S.M Barelikar.2016, AN Experimental Study on Two Way Bubble Deck SLAB With Spherical Hollow
Balls. Int J Recent Sci Res. 7(6), pp. 11621- 11626.

Sergiu Călin, Roxana Gînţu and Gabriela Dascălu, ”Summary of tests and studies done abroad on the Bubble deck slab system”,
The Buletinul Institutului Politehnic din Iaşi, t. LV (LIX), f. 3, 2009.

Martina Schnellenbach-Held and Karsten Pfeffer,”Punching behavior of biaxial hollow slabs” Cement and Concrete Composites,
Volume 24, Issue 6, Pages 551-556, December 2002.

Sergiu Călin, Ciprian Asăvoaie and N. Florea, “Issues for achieving an experimental model” Bul. Inst. Polit. Iaşi, t. LV (LIX), f.
3, 2009.
Bubble Deck Acoustic Tests and Reports, Issue:4,BubbleDeckUK,WhiteLodge,Wellington Road, St Saviour, JERSEY,
C.I.,2006,Available: www.BubbleDeck-UK.com.

Bubble Deck Fire resistance Tests and Reports, Test Report D3,BubbleDecak UK, White Lodge, Wellington Road, St Saviour,
JERSEY, C.I.,2002,Available : www.BubbleDeckUK.com.

Bubble Deck voided Flat Slab Solutions- Technical Manual and Documents,Version:5, Issue 1, Bubble Deck UK, White Lodge,
Wellington Road, St Saviour, JERSEY, C.I.,2008,Available: www.BubbleDeck-UK.com.

Bubble Deck Engineering Design & Properties Overview – Technical Manual and Documents, Issue 3, Bubble Deck UK, White
Lodge, Wellington Road, St Saviour, JERSEY,C.I.,2007,Available: www.BubbleDeck-UK.com.

Reshma Mathew, Binu.P “Punching Shear Strength Development of Bubble deck Slab Using GFRP Stirrups” , SNGCE
kadayirippu, India, 2016.

Akshay Garg, Adhiraj Madhav Dar and Simon Jayasingh, Visuvasam J, Analysis of Composite Sandwich Slabs with Patterned
web Reinforcement. International Journal of Civil Engineering and Technology, 8(6) 2017, pp. 664–674.

Kamal Padhiar, Dr. C.D. Modhera and Dr. A. K. Desai, Comparative Parametric Study for Post-Tension Flat Slab and Flat Slab
with Drop System. International Journal of Civil Engineering and Technology, 8(5), 2017, pp. 33-41.
SANTIAGO, KATE NICOLE D. (2151007)
The main objective of the study is to know the practicality of using hollow spherical plastic balls in slabs. Another one is to have
a comparison of all the parameters between solid conventional slab and bubble deck slab to know the behavior of the two slabs.
Lastly, they want to know the effects of hollow plastic ball (HDPE- High density of polyethylene) in the reinforced concrete slab.

The tests conducted in this study for the conventional slabs and bubble decks were bending strength and deflection, shear
strength, punching shear, dynamic punching shear, anchoring, fire resistance, sound insulation, and various other tests. According
to the study, Bubble Deck behaves like a spatial structure. The tests reveal that even if it is a hollow concrete floor structure, the
shear strength turned out to be even higher than the conventional slab system and this means the balls have a positive influence.
All the tests confirmed that Bubble decks act as a solid deck follows the same properties as that of the solid deck and lastly, it has
many considerable savings.

The factors that the researchers have considered constructing a bubble deck slab were the hollow balls made with HDPE (a
nonporous material that does not react chemically with the concrete and reinforcement bars), the bubble diameter that varies
between 180mm to 450mm, the depth that depends on the diameter which is between 230mm to 600mm, the distance between
bubbled which should be greater than 1/9th of the bubble diameter, the shape (can be spherical or elliptical, the concrete that is to
be used for filling the joints in the Bubble Deck floor system that has to be above class 20/25 and the reinforcement of the plates
that is made up of two meshes. According to this study, in the Bubble Deck, the steel bars are provided for tension zone and
concrete for compression zone. Plastic voided slab systems are constructed by two primary methods depending on the
manufacturer. These two methods are filigree method in which part of the system is precast off-site and the other method in
which the entire system is constructed on-site. The main component in both methods is the plastic balls containing void. These
voids vary from spherical, hollow, and made of recycled plastic. Since the voids are nearly weightless and it replaces the concrete
in the center of the slab, it allows the slab to be lighter than the usual concrete slabs. Another main component is the steel cage.
Steel reinforcement resists flexure and is added to the slab. A cage of thin steel is also used to keep the voids in place in the
center of the slab. The last main component is the concrete, which surrounds the voids, forms the slab and determines the slab
strength. Both methods use the same components but with different approaches.

The results of the investigation revealed that the continuous bubble deck with reduced volume of concrete has much lower self-
weight and the load carrying capacity has also increased compared to the conventional slab. The arrangement of the bubbles also
has an effect on the load carrying capacity of the slab. The alternative arrangement of bubbles causes an increase in the load
carrying capacity but is lower than the continuous bubble deck slab. Bubble deck slab also has much improved elasticity property
that is why the bubble deck slab deflect less as compared to conventional slab. It is also important to consider the number of
bubbles because it also affects the elasticity property. The most important factor in the bubble deck slab is the weight reduction
because the weight of the conventional slab is higher than that of the bubble deck slab. Similar to this test showed that bubble
deck slabs are more likely to fail due to shear. Bubble deck slab is designed exactly as conventional slabs so the bubbles are
usually placed near the columns, because design shear resistance is usually critical near the columns.

The researchers have concluded that Bubble Deck slab enables reduced foundation because the structural dead-weight is reduced
and reduced concrete usage means 1kg of recycled plastic replaces 100kg of concrete. Therefore, it is environmentally friendly.
They have also concluded that it makes the building soundproof and it helped to achieve much greater fireproof design compared
to using conventional slabs. Another good use of bubble deck slab on site is shortening the construction time since Bubble Deck
slabs can be precast. On the other hand, there is an increase in cost of production due to assembly and manufacturing of HDPE
spheres and skilled labor is required. Another major problem is that the punching shear capacity is low due to the decreased
weight of the Bubble Deck systems. Lastly, it is not applicable to slabs having limited thickness.

I find this study helpful for our research because it has provided materials, specifications and standards than we can
use and it contributed information regarding the shear strength, the elasticity of bubble deck as well as the convenience of using
it, but at the same time it provides the disadvantages of having Bubble Deck slabs instead of Conventional Slabs.

REFERENCE

Bhowmik, R., Mukherjee, S., Das, A. (2017). Review on Bubble Deck with Spherical Hollow Balls. Internatiomal Journal of
Civil Engineering and Technology (IJCIET). Vol. 08, Issue 08. Retrieved from: http://www.iaeme.com/MasterAdmin/
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