MAPUA UNIVERSITY

School of Graduate Studies

4th Quarter S.Y. 2018-2019

RESEARCH PRESENTATIONS

In partial fulfillment of the requirements for the course of

CE226 – EARTHQUAKE ENGINEERING
For the degree
Master of Science in Civil Engineering
Major in Structural Engineering

Submitted by:

BALBUENA, Ronald C.
DIOMAMPO Jr., Venancio R.
PADUNAN, Kenneth Roy R.
PADURA, Alyssa Mae J.
SUGUE, Karen Grace T.
TUMANENG, Berna Jane A.

Submitted to:

Dr. Gilford B. Estores

 CONTENTS

Presenter Topic Author

Muriel NAGUIT, Phil
Towards Earthquake-Resilient Buildings:
BALBUENA, CUMMINS, Mark
Exposure/Damage Database for the 2013
Ronald C. EDWARDS, Hyeuk RYU
Bohol Philippines Earthquake
& Matthew JAKAB

DIOMAMPO Recent Earthquakes and the Need for a Jiro TAKAGI & Akira
Jr., Venancio R. New Philosophy for Earthquake-Resistant WADA
Design
A Comparative Study on Structure in
SUTRISNO, RUSNARDI
PADUNAN, Building Using Different Partition
Rahmat Putra, and
Kenneth Roy R. Receiving Expense Earthquake
GANEFRI
PADURA, Alyssa Study on Bearing Capacity of Airport Yukimoto TSUBOKAWA,
Mae J. Pavement Damage Due to the 2011 Naoya KAWAMURA,
Tohoku Region Pacific Coast Earthquake Junichi MIZUKAMI and
Ryota MAEKAWA
SUGUE, Karen Performance Review of Prefabricated Satheeskumar
Grace T. Building Systems and Future Research in NAVARATNAM, Tuan
Australia NGO, Tharaka
GUNAWARDENA, &
David HENDERSON
TUMANENG, Mid-Column Seismic Pounding of Kabir SHAKYA, Anil C.
Berna Jane A. Reinforced Concrete Buildings in a Row WIJEYEWICKREMA,
Considering Effects of Soil and Tatsuo OHMACHI
2013 Bohol
earthquake
TOWARDS EARTHQUAKE-RESILIENT
BUILDINGS: EXPOSURE/DAMAGE DATABASE
FOR THE 2013 BOHOL PHILIPPINES
EARTHQUAKE
 ❖ A comprehensive database featuring both damaged and
undamaged structures related to the M7.2 Bohol Philippines
earthquake is assembled. It accounts for over 25,000 buildings
located at various earthquake intensity levels, in urban and rural
areas.

❖ Each structure in selected sites is described based on

• Structural materials
Introduction • Building use
• Height
• Occupancy
• Site morphology
• Construction era
• Damage sustained during the event
 ❖ Seismic fragility functions represent the relationship between
earthquake damage and a ground motion parameter following
either one or a combination of these approaches:

• empirical analysis based on statistical evaluation of post

earthquake damage data
• analytical analysis using numerical simulations of structural models
• heuristic analysis based on engineering judgement and expertise
Introduction ❖ Study specifically explores the risk factors that have played key roles
(Cont.d) in the outcome of the M7.2 Bohol Philippines earthquake. The Bohol
earthquake has the essential ingredients required in furnishing a
meaningful seismic risk assessment, a step towards building
earthquake-resilient structures

❖ The Exposure/Damage Database for Bohol Earthquake

• Post-event Survey
• Building Typology
• Site Selection
 ❖ Study highlights

• The key role of empirical data in validating

building fragility
• Vulnerability models for improved seismic
regulations
Problem • Credible impact forecasts

Statement
 Fostering resilience against earthquakes necessitates proper
evaluation of building performance. The core elements at risk
whenever a huge earthquake occurs are the people and the
buildings. While an exposure database describes these elements
at risk before an earthquake happens, the damage database

Significance provides an inventory of damage incurred during the event. In this

study, a comprehensive database featuring both damaged and
undamaged structures related to the M7.2 Bohol Philippines
& earthquake is assembled

Methodology
Results & Discussion
Results &
Discussion
(Cont.d)
Results &
Discussion
(Cont.d)
Results &
Discussion
Results &
Discussion
 An exposure/damage database has been assembled to account for the
observed structural damage due to the M7.2 Bohol Philippines
earthquake. Prevalent building classes that emerge from this database
include wood (W1), confined masonry (C1), concrete hollow blocks (CHB)
and low masonry skirt walls with wood (MWS). These include low-rise
buildings sampled in both urban and rural settings at various construction
vintages. Furthermore, the dataset features four well-represented damage
states with good variation of intensity spanning from VI to IX.

For the earthquake performance of structures, W1 seems to be the most

Conclusion resilient building type among the four types evaluated in this study. W1
returns lower likelihood of exceeding the damage thresholds. The
proportion of damaged buildings is less for modern buildings than the old
ones, perhaps reflecting an improvement in seismic code over time. Also,
structures in urban areas seem to perform much better than rural
structures, probably due to the variation in construction practices.
For future undertakings, the vulnerability curves corresponding to
selected building types can be validated. Information on costs of repair
and reconstruction costs sourced from local engineers and contractors can
constrain and update these vulnerability models.
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/309399740

Towards Earthquake-resilient Buildings: Exposure/Damage Database for the

2013 Bohol Philippines Earthquake

Conference Paper · September 2016

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TOWARDS EARTHQUAKE-RESILIENT BUILDINGS:
EXPOSURE/DAMAGE DATABASE FOR THE 2013 BOHOL
PHILIPPINES EARTHQUAKE

Muriel Naguit1, Phil Cummins1,2, Mark Edwards2, Hyeuk Ryu2 and Matthew Jakab2
1
Research School of Earth Sciences, Australian National University
2
Geoscience Australia, Canberra, Australia
Phone: +612-6125-5590, email: muriel.naguit@anu.edu.au

ABSTRACT

Fostering resilience against earthquakes necessitates proper evaluation of

building performance. The core elements at risk whenever a huge
earthquake occurs are the people and the buildings. While an exposure
database describes these elements at risk before an earthquake happens,
the damage database provides an inventory of damage incurred during
the event. In this study, a comprehensive database featuring both
damaged and undamaged structures related to the M7.2 Bohol Philippines
earthquake is assembled. It accounts for over 25,000 buildings located at
various earthquake intensity levels, in urban and rural areas. Interviews
were conducted involving health workers and local officials. Each structure
in selected sites is described based on structural materials, building use,
height, occupancy, site morphology, construction era and damage
sustained during the event. With full range of parameters defining the
structures, this allows for a meaningful seismic risk assessment where the
earthquake performance of buildings is investigated. This study highlights
the key role of empirical data in validating building fragility and
vulnerability models for improved seismic regulations and credible impact
forecasts.

Keywords: Bohol earthquake, building fragility, exposure database,

seismic risk assessment, vulnerability models

INTRODUCTION

A new set of programs for disaster risk reduction and management has
been formulated in Sendai, Japan as part of an ongoing effort in
promoting resilience against disasters. Succeeding the Hyogo Framework
for Action (HFA) and integrating global platforms aligned with the
Millennium Development Goals of United Nations International Strategy
for Disaster Reduction (UNISDR), the Sendai Framework recognizes the
need to understand elements of disaster risk including exposure, hazard
and vulnerability in strengthening disaster risk governance (Aitsi-Selmi et
al., 2015).
Seismic risk assessment is one of the components of disaster risk that
needs to be addressed especially for earthquake prone areas. With the
end goal of achieving building resilience, it requires enough knowledge on
exposure, hazard and vulnerability related to building structures. This
study highlights the importance of an empirical exposure/damage
database in the conduct of a credible seismic post-event assessment –one
aspect that would immensely contribute to the Sendai Framework.

While empirical data best capture the actual conditions in the field, there
have been few attempts to assemble detailed exposure/damage
databases especially in Asia. With the scarcity of post-earthquake data,
this inhibits proper empirical seismic risk analysis and loss estimation
modelling (So & Pomonis 2012 and Jaiswal, Wald & Hearne 2009). This
study demonstrates how actual conditions and available information on
site can be developed into useful tools for evaluating the earthquake
performance of structures. It offers a baseline strategy which is of prime
importance to developing countries like the Philippines, where there is
paucity in post-earthquake data even though the risk of impacts to
earthquakes is very high.

Reliable information on building fragility and vulnerability is a key factor

in the convolution of fundamental seismic risk elements. Seismic fragility
functions represent the relationship between earthquake damage and a
ground motion parameter, the application of which in various engineering
structures is well documented (Baker 2015, Noh, Kiremidjian & Lallemant
2015, Nasserasadi et al. 2008, Padgett & Des Roches 2008, Sengara et
al. 2010 and Straub & Der Kiureghian 2008) following either one or a
combination of these approaches: (1) empirical analysis based on
statistical evaluation of post-earthquake damage data; (2) analytical
analysis using numerical simulations of structural models; or (3) heuristic
analysis based on engineering judgement and expertise (Lallemant,
Kiremidjian & Burton 2015).

Furthermore, this study specifically explores the risk factors that have
played key roles in the outcome of the M7.2 Bohol Philippines earthquake.
This event showcased a devastating impact brought about by strong
ground shaking, leaving over 70,000 buildings with partial or total
damage corresponding to more than a quarter of the total housing units
in the island (EMI, 2014). With the notable structural damage in building
systems and the wide spread of intensities inferred to have shaken the
island, the Bohol earthquake has the essential ingredients required in
furnishing a meaningful seismic risk assessment, a step towards building
earthquake-resilient structures.

THE EXPOSURE/DAMAGE DATABASE FOR BOHOL EARTHQUAKE

Bohol is the 10th largest island in the Philippines, covering an area of

4,821 square kilometres and accommodating over 1.25M population.
Based on the 2010 census conducted by the Philippine Statistical
Authority (PSA), the total housing units in Bohol sums up to 259,520
wherein 34% have outer walls made of concrete, brick or stone, 26%
have bamboo, cogon or nipa and 22% utilize a combination of both
materials (EMI, 2014). The unaccounted percentage, which was not
reported, would probably represent makeshift houses. The October 2013
earthquake resulted in 14,480 collapsed structures and 57,405 with
partial damage (EMI, 2014). These details set the context of exposure
wherein buildings are taken into account as the main elements at risk.

Post-event Survey

In creating the database, the survey consisted of interviews with the local
officials and health workers who conduct monthly visits to each housing
unit for health care administration and related services. Through a series
of field visits and pilot interviews, the coherency of the method and the
completeness of the survey form were tested and found adequate.

The main objectives during the interview include characterizing the

existing structures prior to the occurrence of the earthquake and
acquiring information on the type of damage in accordance with defined
damage thresholds. These are achieved by using a simple digital form
equipped with the requisite attributes in a drop-down menu format.
Figure 1 depicts the survey form and the typical building types found in
the study area.

Figure 1. Left panel: Survey form featuring the structural attributes

considered in the interviews. Right panel: Typical building systems found
in Bohol
Each structure in the selected village is described based on building use,
number of storeys, occupancy, construction era, site morphology, damage
state and structural materials used for wall, roof and flooring. Most of
these attributes can be described with ease except for the construction
era. In this case, the interviewees were encouraged to select the most
suitable option that would best describe the structure.

The construction era is defined in accordance with the structural code

amendments in the Philippines (ASEP, 2010). Represented by three
vintages, this attribute is distinguished by the years 1972 when the first
edition of the code was released and 1992 when a contemporary code
was instigated. Pre-code stands for structures constructed before 1972,
low-code for structures erected from 1972 to 1992 and high-code for
buildings built after 1992 (UPD-ICE, 2013).

On the other hand, damage thresholds delineated the susceptibility of

each structure to earthquake loads. The severity of damage is categorized
in four damage states: (1) No Damage: covers minor tilting for wooden
structures and no visible cracks for concrete buildings; (2) Minor Cracks:
for structures with hairline or slight cracks that do not warrant any repair;
(3) Repairable: corresponds to structures that are still standing but has
endured extensive damage, thereby requiring reparation; and (4)
Collapse: for structures rendered inefficient to repair and require total
reconstruction.

Building Typology
The vast majority of the buildings in the compiled database are of
residential type, with one or two storeys, housing one to seven people
and constructed in flat terrain. From the mix of construction types present
in Bohol, a large proportion of buildings utilize wood, concrete hollow
blocks, a combination of both or confined masonry for walls, galvanized
iron sheets for roofing and concrete slab for the flooring.

As previously featured in Figure 1, the database revealed four

predominant building stocks: (1) wood with light frame [W1]; (2)
confined masonry [C1]; (3) concrete hollow blocks with wood or light
metal [MWS]; and (4) concrete hollow blocks [CHB].

To be able to validate the fragility models for these structures, the

building definition and nomenclature were aligned with the building
typology formulated by local engineers who proposed the fragility and
vulnerability models for key building types in Manila –the capital city of
the Philippines (UPD-ICE, 2013).

Site Selection
A total of 100 barangays –the Filipino term for villages, were selected for
interview, the locations of which are depicted in Figure 2. This accounts
for more than 25,000 structures located at various inferred earthquake
intensity levels. These sites were selected after considering several
factors like earthquake intensity (USGS, 2013), existing damage
reports/surveys (CEDIM, 2013 & UNOCHA, 2013) and urban and rural site
classification (PSA, 2010).

Figure 2. The strategic locations of selected barangays in Bohol where

post-event interviews were conducted. Inset shows the island of Bohol in
yellow, nestled in central Visayas, Philippines.

DISCUSSION AND RESULTS

Improving knowledge of seismic building fragility requires two pertinent

details: (1) a detailed earthquake source model; and (2) a reliable
statistical description of building damage. The source model translates
into a ground motion estimate which can then be calibrated to the
exposure/damage database for seismic risk estimation.

The Bohol Philippines earthquake, the seismic hazard considered in this

study, is an inland quake as a result of the movement along a previously
unknown thrust fault called the North Bohol Fault. Further details of the
tectonic framework in the region are described in PPDO (2014) and Naguit
et al. (2015). For the earthquake source model, the USGS model (USGS,
2013) is considered in this analysis. This finite fault model is derived
using teleseismic broadband seismic data resulting to a southeast dipping
rupture plane as illustrated in Figure 3. Also shown in the same figure is
the USGS shake map where the intensity estimates were extracted.

Note that the cross correlation between the source model and damage
estimates shows that the structures with high proportion of Repairable
and Collapse levels are confined within the fault plane, implying that the
damage data conforms quite well with the location of the source model. A
few villages away from the fault zone that exhibit substantial Repairable
damage levels are possibly influenced by site effects.

In this analysis, each building type is well represented in the surveyed

barangays, although CHB has relatively low sample size as compared to
other types. As shown on the left panel of Figure 3, aside from the full
scale interview covering all buildings in a barangay, additional ten
barangays were targeted for CHB interviews only in order to increase the
number of CHB data, resulting to a total of 1,112 CHBs in the database.

Figure 3. Left panel: Contours of intensity levels based on USGS shake

map, with the island of Bohol and selected sites superimposed on the
map. Right panel: Distribution of damage per barangay and the surface
projection of the USGS fault model.
Different eras for MWS and C1 appear to exhibit similar performance. As a
percentage of the total building count in each class regardless of era, 5%
is in Collapse and 18% is in Repairable for C1 while for MWS, the
respective percentages are 4% and 22%. On the other hand, CHB yields a
poor performance with at least 25% of the total population in need of
repair. This is most likely due to lack of steel reinforcement while some
CHB walls followed a non-staggered fashion in layering and were
supported by weak framing, as shown in Figure 4.

Figure 4. (a) Residential dwellings under the CHB building class; (b) Weak
walls due to absence of steel bars; and (c) CHBs piled on top of the other
Moreover, data binning divides the total sample in each building class with
respect to intensity contours, construction era and damage states. An
intensity value is assigned to every village, depending on its geographical
location. The fraction of the total number of buildings for a certain
damage state in each intensity level and era are computed.

Figure 5 summarizes the proportion of damage in each bin. All building

classes follow a general trend wherein severe damage states become
visible with increasing earthquake intensity. High-code buildings are
expected to yield an improved earthquake performance as opposed to
lower and pre-code buildings, but this observation is clearly visible only
for W1.

Figure 5. Earthquake performance of dominant building types in Bohol at

various eras of construction
From these statistical estimates, the structure-specific fragility models for
these building types are validated as depicted in Figure 6. The scatter
plots of actual damage observations were compared against the existing
fragility curves. Among the four building types, W1 established a better
trend in probability estimates. This improves as the vintage progresses.
Other building types show a wider scatter of probabilities with CHB
displaying an irregular pattern of distribution especially for Minor Crack.

Figure 6. Validation of fragility curves for predominant building types in

Bohol, Philippines
The foregoing analysis highlights the extent by which an earthquake
source model can explain the pattern of damage when correlated with a
complete exposure/damage database. Using the Bohol earthquake as a
case study, this empirical approach allows placement of observational
constraints on building fragility functions, where knowledge on how fragile
and vulnerable buildings are become apparent.

CONCLUSION

An exposure/damage database has been assembled to account for the

observed structural damage due to the M7.2 Bohol Philippines
earthquake. Prevalent building classes that emerge from this database
include wood (W1), confined masonry (C1), concrete hollow blocks (CHB)
and low masonry skirt walls with wood (MWS). These include low-rise
buildings sampled in both urban and rural settings at various construction
vintages. Furthermore, the dataset features four well-represented
damage states with good variation of intensity spanning from VI to IX.

For the earthquake performance of structures, W1 seems to be the most

resilient building type among the four types evaluated in this study. W1
returns lower likelihood of exceeding the damage thresholds. The
proportion of damaged buildings is less for modern buildings than the old
ones, perhaps reflecting an improvement in seismic code over time. Also,
structures in urban areas seem to perform much better than rural
structures, probably due to the variation in construction practices.

Linking various facets of building components and construction to

earthquake intensity resulted in improved seismic fragility modelling using
empirical data. Although the fragility analysis presented herein is limited
to the four predominant building types in the database, results show that
in general the UPD-ICE fragility curves are conservative especially for
severe damage states. However, estimates of probabilities at Slight/Minor
Crack are higher as justified by actual damage observations.

For future undertakings, the vulnerability curves corresponding to

selected building types can be validated. Information on costs of repair
and reconstruction costs sourced from local engineers and contractors can
constrain and update these vulnerability models.

REFERENCES

Aitsi-Selmi, A., Egawa, S., Sasaki, H., Wannous, C., & Murray, V. (2015). The
Sendai Framework for Disaster Risk Reduction: Renewing the Global
Commitment to People’s Resilience, Health, and Well-being. International
Journal of Disaster Risk Science 6, 164-176.
ASEP (2010). National Structural Code of the Philippines, 6th edition, ISBN:
2094-5477, Association of Structural Engineers of the Philippines.
 Baker, J.W. (2015). Efficient analytical fragility function fitting using dynamic
structural analysis. Earthquake Spectra 31(1), 579-599.
CEDIM (2013). Center for Disaster Management & Risk Reduction Technology
Forensic Disaster Analysis Bohol Earthquake Report No. 6.
EMI (2014). The Mw7.2 15 October 2013 Bohol, Philippines Earthquake,
Earthquake & Megacities Initiative Technical Report TR-14-01.
Jaiswal, K.S., Wald, D.J. & Hearne, M. (2009). Estimating casualties for large
earthquake worldwide using an empirical approach, US Geological Survey
Open-File Report OF 2009-1136.
Lallemant, D., Kiremidjian, A. & Burton, H. (2015). Statistical procedures for
developing earthquake damage fragility curves. Earthq. Eng. Struct. Dyn. 44,
1373-1389. DOI:10.1002/eqe.2522
Nasserasadi, K., Ghafory-Ashtiany, M., Eshghi, S. & Zolfaghari, M.R. (2008).
Developing Seismic Fragility Function of Structures by Stochastic Approach.
Journal of Applied Sciences 8(6), 975-983.
Naguit, M., Cummins, P., Edwards, M., Ryu, H. & Jakab, M. (2015). Earthquake
Performance of Structures in Bohol: A Post-event Assessment of the M7.2
October 2013 Bohol Philippines Earthquake. Proceedings of the 10th Pacific
Conference on Earthquake Engineering, 6-8 November 2015, Sydney,
Australia.
Noh, H., Kiremidjian, A. & Lallemant, D. (2015). Development of empirical and
analytical fragility functions using kernel smoothing methods. Earthq. Eng.
Struct. Dyn. 44(8), 1163-1180.
Padgett, J.E. & Des Roches, R. (2008). Methodology for the development of
analytical fragility curves for retrofitted bridges. Earthq. Eng. Struct. Dyn. 37,
1157-1174.
PPDO (2014). Post-great Bohol Earthquake Rehabilitation Plan, Provincial
Planning & Development Office Technical Report.
PSA (2010). Philippine Statistics Authority, Urban/rural classification. Retrieved
May 2016, from
http://www.nscb.gov.ph/activestats/psgc/province.asp?provcode=071200000
Sengara, I.W., Suarjana, M., Beetham, D., Corby, N., Edwards, M., Griffith, M.,
Wehner, M. & Weller, R. (2010). The 30th September 2009 West Sumatra
Earthquake Padang Region Damage Survey, Geoscience Australia, Record
2010/44, 201pp.
So, E.K.M. & Pomonis, A. (2012). Derivation of globally applicable casualty rates
for use in earthquake estimation models. Proceedings of the 15th World
Conference in Earthquake Engineering, 24-28 September 2012, Lisbon,
Portugal.
Straub, D. & Der Kiureghian, A. (2008). Improved seismic fragility modelling
from empirical data. Structural Safety 30(4), 320-336.
UNOCHA (2013). United Nations Office for the Coordination of Humanitarian
Affairs, Philippines: Bohol Earthquake Displaced Population and Damaged
Shelter (as of 23 October 2013). Retrieved from
http://reliefweb.int/map/philippines/Philippines-bohol-earthquake-displaced-
population-and-damaged-shelter-23-october.
USGS (2013). M7.1 4km SE of Sagbayan, Philippines. Retrieved May 2016, from
http://earthquake.usgs.gov/earthquakes/eventpage/usb000kdb4#impact_shak
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UPD-ICE (2013). Development of Vulnerability Curves of Key Building Types in
the Greater Metro Manila Area, Philippines, University of the Philippines-
Institute of Civil Engineering, GMMA-RAP Report.

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Recent Earthquakes
a n d the N e e d for a
New Philosophy for
Earthquake-Resistant
Design
JIRO TAKAGI
AKIRAWADA
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING, 2019
PRESENTED BY ENGR. VENANCIO R. DIOMAMPO, JR.
Introduction

Modern design allows structures to undergo ductile plastic

deformations. This implies that large numbers of buildings m a y b e
significantly d a m a g e d and those that did not collapse, were not
functional anymore and were later demolished rather than being
repaired. Earthquake-resistant design philosophy should now b e
revised from just being “life-saving” to “business continuity” for modern
and resilient societies. Structures should b e designed to b e quickly
restored to full operation with minimal disruption and cost following a
major earthquake.
Statement of the Problem

How c a n structures/buildings b e designed to prevent collapse

while retaining its structural quality to b e still functional after a major
earthquake?
Objective of the Study

Determine a design approach philosophy where d a m a g e s of

an earthquake will be minimized in order to prevent a building’s
collapse while retaining its structural integrity for it to b e qualified as
still functional and prevent eventual demolition.
Significance of the Study

Determining a new philosophy of design approach will allow

structures to b e quickly restored to full operation with minimal disruption
and cost following a large or major earthquake.
Review of Related Literature

Buckling-Restrained Braces
Steel braces h a v e long b e e n used for both wind- and seismic-
resistant structures. In the seismic field of application, r e p e a t e d
buckling in compression is the source of strength and stiffness
degradation. A relatively recent development is the “buckling-re-
strained brace” (BRB), which is a special t ype of b r a c e with global
buckling inhibited by an appropriate system. The a v o i d a n c e of global
buckling implies a compression force displacement behaviour very
similar to the response exhibited under tension forces
( Della Corte, 2011 )
Review of Related Literature

Sustainable Development Goals

Sustainable design, which is one of the most important considerations in an y structural design project
nowadays, implies many factors such as environmental friendliness, energy c o m p e t e n c e , functionality,
adaptability a n d efficient use of world's resources. Sustainable design is not only the realization of a n
architect's vision, but also the notion of the structural engineering regulation. As a result of close c oop eration
b e t w e e n architects a n d structural engineers, many brilliant a n d elegan t structures h a v e b e e n built all over
the world in the years. O n the other hand, with the increasing c onc ern over the environment the architects
a n d structural engineers find themselves o n c e again f a c e d with new challenges. For example, if a structure is
not well designed to survive extremely devastating earthquakes, in the economical life of the structure, it will
either n e e d to b e strengthened or demolished to b e rebuilt. Considering the n ew material which will b e
consumed for these operations, the environmental effects will b e high from the view point of sustainable
construction. With this respect, earthquake disaster reduction a n d sustainable develop ment h a v e equally
supportive goals. Technological developments to support earthquake resistant design such as seismic isolations,
dampers, durable and flexible structural systems are practical solutions to mitigate the risks against earthquake
hazards. Ifproperly designed they may lead to structuresthat are more efficient in materials and also potentially
earthquake resistant without the need for either straightening or demolishing for rebuilding.
The leadership of structural engineers adop tin g new conceptions of functional a n d structural design a n d the
related innovative techniques for use in sustainable design a n d minimizing the environmental impact of
structures l o c a t e d in seismic areas will b e the main focus of this p ap er. Also, this p a p e r intends to o p e n the
discussion among engineers a n d architects towards a more a c t i v e contribution to the use of innovative
technology for seismic resistant structure within the context for sustainable construction. ( Coskun, 2010 )
Methodology
Methodology
 Methodology

1the mechanism for supporting the

superstructure in the vertical direction

2the mechanism for exhibiting a

restoring force in the horizontal direction

3 - the mechanism for absorption of energy in the

relative displacement between the superstructure
and the foundations
Results & Discussions
C o n clusio n

It would b e effective to design building structures in which the

structural components play separate roles. The primary structure will
support the gravity load and the seismic members will mainly resist
earthquakes. D a m a g e in the primary structure should b e minimized
during large earthquakes for modern, sustainable and resilient
societies. The ultimate goal of the development of seismic engineering
technologies by researchers and engineers is to provide better
structures to our society.
Following this new philosophy of design approach will allow
structures to b e quickly restored to full operation with minimal disruption
and cost following a large or major earthquake.
Additionally, the construction cost of a seismically isolated building
is lower than that of an alternative design with ductile frames satisfying
the strong-column-weak-beam-conditions.
 Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Contents lists available at ScienceDirect

Soil Dynamics and Earthquake Engineering

journal homepage: www.elsevier.com/locate/soildyn

Recent earthquakes and the need for a new philosophy T

for earthquake-resistant design
⁎
Jiro Takagia, , Akira Wadab
a
Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, Japan
b
Tokyo Institute of Technology and Member, Science Council of Japan, Japan

A R T I C L E I N F O A B S T R A C T

Keywords: Modern seismic design and construction technologies have undergone significant developments over the last 100
Sustainable development goals (SDGs) years. In order to prevent collapse of buildings under large earthquakes while maintaining reasonable con-
Earthquake disasters struction costs, structures are allowed to undergo ductile plastic deformations under current design and detailing
Seismic design philosophy methods. This implies that large numbers of buildings may be significantly damaged and not only individual
Damage control
buildings but also entire cities may lose their function following extreme earthquake events. In recent large
earthquakes, it has been observed that many properly designed and constructed buildings, which did not col-
lapse, were no longer functional and were later demolished rather than being repaired. Considering such si-
tuations, the earthquake-resistant design philosophy developed in the previous century should now be revised to
meet modern social and economic requirements and Sustainable Development Goals (“SDGs”). The seismic
design philosophy for building and infrastructure should be changed from life-saving to business continuity for
modern and resilient societies. Structures should be designed to be quickly restored to full operation with
minimal disruption and cost following a large earthquake.

1. Introduction design approach to generate resilient building structures against large

earthquakes is needed [1–4]. Special structures, serving important
Development of seismic engineering technologies will never elim- functions, such as hospitals, fire-fighting stations and power plants, are
inate earthquake disasters. Humans will never be able to conquer normally designed to remain fully operational even after large earth-
nature and can only live in it with a better relationship. Seismic en- quakes. This structural design approach shall be expanded to more
gineering specialists have achieved only a limited understanding of general structures. Such structural design philosophy is required for
global crustal behavior. While predicting the magnitude, epicenter, and modern and resilient societies. In order to achieve this, increase of the
precise time of large earthquakes is very difficult and beyond our sci- initial construction cost is the issue; however, the disruption cost can
entific knowledge, earthquakes are certain to occur within a long en- overcome the initial cost to improve the structural performance. Al-
ough time period. The currently existing seismic design methods allow though quantitative cost evaluation with respect to the structural per-
structures to undergo plastic deformations under large earthquakes, formance or the seismic risk is not within the scope of this paper, the
while remaining elastic under small or moderate earthquakes. The fact that the additional initial cost can provide structural sustainability
plastic deformation dissipates earthquake energy and is intended to and business continuity shall be certainly recognized. The structural
prevent structural collapse. While this design method is highly effective design approach toward more reliable structures shall be more com-
for protecting human lives, it does not fully account for people's lives monly accepted (Fig. 1).
after the earthquakes. People may be unable to return to their damaged
houses and may be forced to stay inconveniently in evacuation shelters 2. Damage by recent earthquakes
for a long recovery term. They may be unable to work and consequently
may fall in financial difficulties. In this recent matured and complex The number of deaths and missing people caused by natural dis-
society, people's demand for building structures has increased and asters in Japan was fewer than 1000 per year for the 34 years before
many people expect buildings to remain fully operational after large 1995, when the Great Hanshin (Kobe) earthquake occurred [5]. In
earthquakes. Corresponding to such societal demands, a new seismic 1995, people noticed that the relatively few number of deaths and

⁎
Corresponding author.
E-mail address: jtakagi@tmu.ac.jp (J. Takagi).

https://doi.org/10.1016/j.soildyn.2017.11.024
Received 2 September 2017; Received in revised form 6 October 2017; Accepted 20 November 2017
Available online 31 January 2018
0267-7261/ © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/BY/4.0/).
J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 1. Relationships between human achievements and nature.

Fig. 2. Damaged and demolished residential building in 1995 the Great Hanshin earthquake.

missing people that lasted for a period of time was not a proof that however, the building was eventually demolished rather than being
seismic engineering technology had overcome earthquakes. repaired (Fig. 2b).
Seismic design provisions in Japan were revised in 1981. In this Fig. 3 shows a residential building damaged by the Great East Japan
revision, evaluations of failure mechanisms and ultimate lateral earthquake in 2011. The columns, beams and non-structural reinforced
strengths became required for larger buildings. Plastic deformations are concrete walls were damaged. The damage in the non-structural walls
allowed for large earthquakes under the assumption of ductile behavior was particularly severe and they failed in shear. This type of damage is
in reinforced concrete and steel members. The goal of this revision was not critical for building stability. In this sense, this damage had been
to protect economically human lives against large earthquakes by al- expected and the structure behaved as predicted in the design. The
lowing building damage. Therefore, building damage was considered as damaged walls had absorbed the seismic energy; however, the walls
the trade-off saving lives. were no longer functional as the building's exterior. While the structural
Fig. 2a shows a reinforced concrete residential building designed designer or seismic engineering specialist may consider the design to
and constructed to comply with the 1981 revision. It was significantly have been successful, lay people, including the residents, may not have
damaged by the Great Hanshin earthquake in 1995. As shown in the agreed. The building was red tagged in the emergency evaluation and
figure, major flexural cracks were observed in many beams near the the residents were prohibited from returning to their homes. The
column connections. This damage had been expected in the design. As building was later demolished.
designed, the plastic deformation dissipated the earthquake energy and Although repairing the damaged building may have been less ex-
saved human lives. In this sense, the building was successfully designed; pensive than demolishing it and reconstructing a new building,

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 3. Damaged and demolished residential building in the Great East Japan earthquake.

Fig. 4. Damaged buildings in 2011 Christchurch earthquake.

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 5. Damages by the 2016 Kumamoto earthquake.

demolition was nonetheless chosen. During the earthquake, residents While only two buildings had completely collapsed in the
likely experienced significant shaking, heard components breaking or Christchurch earthquake in New Zealand in 2011, approximately 1700
fracturing, and may have imagined that the building might collapse. out of 2400 buildings were demolished due to cracking or tilting. Fig. 4
The reason that demolition was selected may have been to prevent the illustrates the repaired and demolished buildings. The white and red
future possibility of residents having a similar experience in the event of squares indicate the repaired and demolished buildings, respectively.
a later large earthquake if the building was brought back to its original Note that more buildings were demolished than repaired.
condition by simply repairing the damage. Other possible reasons may In the 2016 Kumamoto earthquake, the vulnerability of old wooden
have been that the Japanese government provided financial support for houses, which is well known in the engineering community, was again
demolition or that neighbors requested that the damaged building be observed (Fig. 5a). In a reinforced concrete hospital building of con-
removed. ventional design, the equipment fell due to the large acceleration.

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Table 1 design approach in which plastic deformation of beams, columns and

Fundamental goals of seismic design against large earthquakes. walls is expected; however, the ductility based on this deformability is
equivalent to the damage of a structure. This damage is easily re-
Current seismic design approach New seismic design approach
cognized by people after large earthquakes, while the seismic perfor-
H Human lives likely to be saved Human lives surely to be saved mance is hardly evaluated, even by specialists. Damage should there-
B No certainty of future building use with Building to be used with some fore be more strictly controlled during large earthquakes.
repair repair
C No continuous operation after Continuous use even after
earthquake earthquake
3. New seismic design philosophy

Minor cracks were observed in the columns and walls (Fig. 5b, c). Al- Table 1 compares the fundamental goals of the current and newly
though these types of damage do not affect the seismic performance of proposed seismic design approaches. These goals are described from
the structure, people in the building, including 300 patients and doc- three points of view, “H”, “B”, and “C”, which refer to “Human lives”,
tors, had to be moved to other hospitals (Fig. 5d) and the hospital was “Building future use” and “Continuous operation”, respectively. It is
not used for rescue activities. seen that the current design approach may be insufficient to support
Another seismically isolated hospital building (Fig. 5e) experienced modern sustainable and resilient societies without pursuing the con-
large movement, with a maximum amplitude of 900 mm (i.e. a max- tinuous use of buildings after earthquakes. On the other hand, buildings
imum displacement of 450 mm) (Fig. 5f). This is the largest displace- designed under the new approach would achieve these goals easily for
ment ever recorded in past earthquakes. Despite experiencing this large small and moderate earthquakes and likely even for large earthquakes.
displacement, the superstructure was almost intact and the building In order to achieve the goals of the new seismic design approach
was fully active after the earthquake and was able to accommodate the shown in Table 1, an effective method of design would allow structural
Disaster Medical Assistance Team (DMAT). Many structures designed components play separate roles. The primary structure supports the
by new technology have not fully experienced severe earthquakes nor gravity load and the seismic members mainly resist earthquake loads.
proved their performance; however, there are certainly some structures Therefore, the seismic members protect the primary members against
like this hospital had experienced and no damage. large earthquakes. Similar systems to protect the main body are often
Reviewing the facts described above, we understand that there is found in nature and industrial products. Collarbones are broken to ease
some room to improve the current seismic design practice. People do forces on the human body (Fig. 6a). Bumpers in cars are obviously
not stay in buildings that are red tagged in post-earthquake evaluations. components to protect the main body (Fig. 6b). Fuses in computers are
Most structural engineers understand the rationale behind a seismic buffers to protect the main system against excessive electric currents
(Fig. 6c).

Fig. 6. Buffers in nature and industrial products.

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 7. Buckling restrained braces (BRBs).

Fig. 7a illustrates the concept of a structural system with seismic shown in Table 1. The structure has 20 stories and is 91.35 m in height.
members and a primary structure. Buckling Restrained Braces (BRBs) Columns of the superstructure consist of concrete-filled square tube
represent the seismic members, which are separated from the primary (CFT) columns, and all beams are made of steel wide flange sections.
structure. The ductile BRBs will yield and absorb the earthquake energy The seismic lateral forces are significantly reduced by the effect of
to the buildings (Fig. 7b, c). They protect the primary structure, which seismic isolation and the number of the CFT columns is 16, which is
remains elastic, and the goals of H, B and C for the new seismic design fewer than that in ordinary structural systems. The seismic isolation
approach in Table 1 can be satisfied.
Fig. 8 schematically shows the seismic isolation system [6]. The
superstructure is flexibly connected to the foundations by mechanisms
(1), (2), and (3).
where,

(1) the mechanism for supporting the superstructure in the vertical

direction
(2) the mechanism for exhibiting a restoring force in the horizontal
direction
(3) the mechanism for absorption of energy in the relative displace-
ment between the superstructure and the foundations

Fig. 9 shows seismically isolated buildings at the Tokyo Institute of

Technology (TITech) designed under the new seismic design approach Fig. 8. Schematic diagram of a seismically isolated structure.

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 9. Seismic isolated building in TITech.

system consists of 16 rubber bearing isolators, 14 steel dampers, and 2

oil dampers. The braces are placed in the outer frames to resist earth-
quakes in the transverse direction. The inner frames are moment frames
and most of the lateral forces in the transverse direction are carried by
the two outer frames. Due to the concentration of the lateral forces and
the large aspect ratio, the overturning moment of the outer frames is
large. Therefore, the isolators are required to work even under the uplift
forces. The isolators at the 4 corners in the outer frames (i.e. isolators
shown in Fig. 9b) are connected by the anchor-bolts through the conical
spring washers, and the bottom plate of each isolator sits on a circular
hole made in the base-plate (Fig. 9c). Accordingly, the uplift forces
against the devices are relieved by this mechanism. The outer frames
are securely connected to the adjacent inner frames with strong beams
in the longitudinal direction and the uplift of the columns does not
exceed more than 20 mm in large earthquakes (Fig. 9b). The con-
Fig. 10. Relationships between earthquake ground motion and damage or repair cost.
struction cost is lower than that of an alternative design with ductile
frames satisfying the strong-column-weak-beam conditions.

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

Fig. 11. Safety design of vehicles and buildings.

Fig. 12. Desired seismic design of buildings in big cities.

The possibility of unstable modes of failure cannot be completely places. Therefore, the damage is limited to a single or a limited number
eliminated even in new construction practices and new technological of vehicles. On the other hand, if most buildings would be designed
devices. Therefore, varied and comprehensive discussions and pre- with the same approach against large earthquakes, many non-func-
parations of countermeasures for cases that exceed certain performance tional buildings would be generated simultaneously near the epicenter
limits are necessary. In this building, the spring washers in Fig. 9b were of the large earthquakes (Fig. 12a). This is the situation similar to what
installed as stoppers for exceedance of the vertical uplift of more than occurred following the Christchurch earthquake in 2011 (Fig. 4). If this
20 mm. were to occur in a big city, the entire city would lose its functionality
Fig. 10 shows conceptual relationships between earthquake ground and recovery activities would be highly restrained. Evacuation shelters
motion and the damage or repair cost for different structural systems, would not be sufficiently provided. Such a situation is not acceptable
which are: ductile frame structures, strength-oriented structures, pas- for modern resilient societies. The design approach for buildings should
sive controlled structures and seismically isolated structures; where, the be different from that for vehicles. New design philosophy for buildings
passively controlled structures are those equipped with energy dis- with minimal damage against large earthquakes shall be accepted
sipating devices such as BRBs or oil dampers, and the strength oriented especially for big cities (Fig. 12b).
structures are conventional structures primarily relying on elastic lat-
eral strength to resist seismic forces. The damage or repair cost is the 4. Conclusions
lowest in the seismically isolated structures, followed the passive con-
trolled structures, strength-oriented structures and ductile frame The existing seismic design approach has been developed to allow
structures. Since the ductile frame structures dissipate seismic energy for ductility of building structures to resist large earthquakes econom-
through damage of the main structure, the repair cost is consequently ically. While structures are designed to remain elastic in small or
high. Although quantitative discussions on this issue are difficult, re- moderate earthquakes, they are allowed to experience plastic de-
silient structures such as seismically isolated structures or passive formations in large earthquakes to prevent their collapse and save
controlled structures are effective for the SDGs and continuous use of human lives. This design approach has been effective in terms of pro-
the buildings, described as the goals of the new seismic design approach tecting people; however, it may not be sufficient for modern, complex
in Table 1. societies. In past large earthquakes, many buildings that were damaged
Fig. 11 illustrates the difference in safety design between vehicles but did not collapse were eventually demolished rather than being re-
and buildings. The design philosophy of protecting the lives of drivers paired. It should be noted that there is a large gap between structural
and passengers by sacrificing the engine or main body of the vehicle is safety levels that specialists consider acceptable and the expectations of
desired for major traffic accidents (Fig. 11a) [7]. These traffic accidents lay people for buildings against large earthquakes. If most buildings in
are generally local events and do not happen simultaneously in multiple large cities are designed under this design approach they would be

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J. Takagi, A. Wada Soil Dynamics and Earthquake Engineering 119 (2019) 499–507

badly damaged in future large earthquakes, and the cities would have merely develop new technologies, but more spontaneously act to have
difficulties in recovery activities and could experience catastrophic loss such technologies implemented.
of function. Corresponding to people's expectations from buildings, the
goals of a modern seismic design philosophy should be changed from References
solely life-safety to also ensuring post-earthquake use and operation.
For this goal, it would be effective to design building structures in [1] Wada Akira, Mori Nobuyuki. Advanced seismic design of buildings for the resilient
which the structural components play separate roles. The primary city. In: Proceedings of the 11th world conference on seismic isolation, energy dis-
sipation and active vibration control of structures. Guangzhou, China; November 17-
structure will support the gravity load and the seismic members will 21 2009.
mainly resist earthquakes. Damage in the primary structure should be [2] Wada Akira, Mori Nobuyuki. Seismic design for the sustainable city – a report on
minimized during large earthquakes for modern, sustainable and re- japanese practice. In: Proceeding of the structures congress 2008. Canada; April 24-
26 Vancouver, British Columbia, Canada; 2008.
silient societies. Over the last 100 years, seismic engineering technol- [3] Wada Akira, Connor JeromeJ, Iwata Mamoru, et al. Damage tolerant structure, ATC-
ogies have undergone significant development. More importantly, 15-4. In: Proceedings of the fifth U.S.-Japan workshop on the improvement of
buildings with higher seismic performance can be constructed less ex- building structural design and construction practices. San Diego, California;
September 8–10 1992.
pensively than before. The seismically isolated building at TITech is an
[4] Takagi Jiro, Tamura Kazuo, Wada Akira. Seismic design of big cities. In: Proceedings
example realizing significantly higher seismic performance with lower of 2017 NZSEE Conference. Wellington, New Zealand; April 27–29 2017.
construction cost compared with an alternative conventional design. In [5] White Paper on Disaster Management, Cabinet Office, Government of Japan; 2014.
[6] Architectural Institute of Japan (AIJ). Design Recommendations for Seismically
the future, there must be more opportunities to apply these developed
Isolated Buildings; 2015.
technologies to buildings. The ultimate goal of the development of [7] Stephen A. Mahin said Designed to protect life in extreme event, but damage is ex-
seismic engineering technologies by researchers and engineers is to pected using the photograph (Figure 11a) in his presentation at TITech; 2012.
provide better structures to our society. These specialists should not

507
 A COMPARATIVE STUDY ON
STRUCTURE IN BUILDING
USING DIFFERENT PARTITION
RECEIVING EXPENSE
EARTHQUAKE
SUTRISNO, PUTRA, GANEFRI

PRESENTED BY: ENGR. PADUNAN

Introduction
In a planning for an earthquake resistant building, it is necessary to apply principles
regarding ductility, shape configuration, diaphragm, strong bond floor.

As of today, there are many types of material choices used in building wall partition.
Partitions may be brick, concrete block and light weight concrete.
V- Story

■ Regular building structure can be planned against nominal earthquake assessment

under the influence of earthquake plans in each direction of the main axis of the
structure plan, in the form of nominal static earthquake load equivalent.
Theoretical Review

■ V-Story
■ Deflection Control
■ Equivalent Static Analysis
V story is defined as follows:

■ If the category of the building has a Virtue Factor I, according to Table 1 and the
structure to a direction of the major axis layout structure and at the direction of loading
Earthquake Plan has an earthquake reduction factor (R) and Fundamental natural
vibration (T) then nominal shear load equivalent static (V) is happening on the ground
level can be calculated according to the equation :
CI
■ V= w
R

where:
C = Seismic Response Coefficient Fundamental
T = Natural Vibration Period T, whereas
W = Total Weight Of The Building (including live load)
R = Response Modification Factor
■ Nominal basic shear load V should be distributed throughout the building structure
height to become equivalent Fi of nominal static earthquake load that captures the
center of mass of the i-th floor level according to equation :
Wi zi
– Fi = σn
V
i=1 Wi zi
■ Equivalent Static
Analysis to determine
shear force base
Deviation (Deflection Control)

■ Deviation ∆M between the level should not exceed 0.02 times the structure level
Equivalent Static Analysis

■ This method uses the assumption that the response of building against earthquake
loads occur on the first dynamic variety, which is equivalent to a variety of static. For
this reason this method is called Equivalent Static Analysis.
■ The response that occurred in the building that is less than 10 floors is often
assumed to be linear
Methodology
Equivalent Static Analysis Steps

1. Calculate the natural vibrating time of building.

2. Determine the base shear force coefficient that satisfies.
3. Calculate the base shear force (V) based on total weight of the building. Basic nominal shear
force formulated as follows :

4. Distribute the base shear force for each floor of the building structure (F) horizontal shear force
for each floor (Fi) which was formulated as follows :

5. Analyze the structure with the influence of lateral loads to gain V-story, deviation (deflection
horizontal) dan column reinforcement with SAP2000 software.
SAP2000 Operation Step

■ 1. Defining the individual units, the individual units are selected based on units present in the structure
that analyzed.
■ 2. Drawing geometry, geometry described by size and selected unit.
■ 3. Defining the material, the material is defined reinforced concrete according to the building that is
analyzed.
■ 4. Defining the frame section and put it, frame section is the size of beam and column then put it.
■ 5. Defining the load and put it, the loads acting on the structure is defined, dead load, live load, and
earthquake load then put it down.
■ 6. Defining load combination that are adapted to the regulations and the work load. Structure,
component, and foundation should be designed in such way so that the design strength is equal or
exceed to the effect of the factored load in a combinations of the following:
– a. 1.2D +1.0E+L+0.2S
– b. 0.9D+1.0E
– D, E, L and S respectively are dead load, live load, earthquake and snow.
Analysis and Discussion
■ Floor typical height 3.5 m
■ Column Dimension is assumed equal as 50 x 50 cm
■ Beam Dimension is assumed equal as 30 x 50 cm
■ Floor plate thickness 12 cm
■ Concrete (fc’) = 30 Mpa
■ Steel (fy) = 400 Mpa
■ The building was used as office.
Earthquake Data

■ The building location is in an earthquake zone 4 and medium soil conditions

Load Data

■ Brick density : 2000 kg/m3

■ Concrete block density : 1000 kg/m3
■ Light weight concrete (hebel) density : 650 kg/m3
■ Additional dead load on each floor (screed + ceramics, ceiling, mechanical,
electrical) = 1.6 kN/m2
■ additional dead load on the roof (ceiling, mechanical, and electrical) = 0.5 kN/m2
■ Live Load (LL) on each floor = 2.5 kN/m2
■ Live Load (LL) on the roof = 1.5 kN/m2
Calculation
■ 1. For medium soil acquired bedrock peak acceleration = 0.2 g and peak ground
acceleration Ao = 0.28 g
■ 2. Tc = 0.6 second, Am = 2.5 A0 = 0.7 g and Ar = Am x Tc = 0.42
■ 3. For a regular office building, virtue factor structure (I) = 1.0
■ 4. Earthquake reduction factor, R = 8.5

Determining c value with a graph

Result of the dead load and live load calculation

Dead Load (kN)

Floor Column Beam Floor Additional Load Live Load (kN)
10 210 544 1036.8 180 540
9 420 544 1036.8 576 900
8 420 544 1036.8 576 900
7 420 544 1036.8 576 900
6 420 544 1036.8 576 900
5 420 544 1036.8 576 900
4 420 544 1036.8 576 900
3 420 544 1036.8 576 900
2 420 544 1036.8 576 900
1 630 544 1036.8 576 900
Result of load partition calculation
Partition Load (kN)

Floor Brick Concrete Block Lightweight Concrete

10 526 263 171
9 869 434 282
8 869 434 282
7 869 434 282
6 869 434 282
5 869 434 282
4 869 434 282
3 869 434 282
2 869 434 282

1 1326 663 431

Total load calculation result per floor
Wxhx (N)

Floor Brick Concrete Block Lightweight Concrete

10 93061.5 83860.4 80639.9

9 117047.7 103366 98577.4

8 104042.4 91880.9 87624.3

7 91037.1 80395.8 76671.3
6 78031.8 68910.7 65718.3
5 65026.5 57425.6 54765.2
4 52021.2 45940.4 43812.2
3 39015.9 34455.3 32859.1
2 26010.6 22970.2 21906.1
1 15340.5 13020.2 12208.1

Total 680635 602225 574782

Calculation result of lateral force equivalent per portal

F Lateral, Fx (kN)

Floor Height (m) Brick Concrete Block Lightweight Concrete

10 35 67.5 60.5 58.1
9 31.5 84.9 74.6 71
8 28 75.5 66.3 63.1
7 24.5 66 58 55.2
6 21 56.6 49.7 47.4
5 17.5 47.2 41.5 39.5
4 14 37.7 33.2 31.6
3 10.5 28.3 24.9 23.7
2 7 18.9 16.6 15.8
1 3.5 11.1 9.4 8.8
V-story and building level relationship graph
 Difference in V-Storey value per level
V Story, Vx (kN) Difference (kN)
Floor Brick Concrete Block Lightweight Concrete B-CB B-LC CB-LC
10 225 201.8 193.7 23.2 31.3 8.1
9 507.9 450.5 430.5 57.4 77.4 20
8 759.4 671.6 640.9 87.8 118.5 30.7
7 979.5 865.1 825.1 114.4 154.4 40
6 1168.1 1030.9 983 137.2 185.1 47.9
5 1325.3 1169.1 1114.5 156.2 210.8 54.6
4 1451.1 1279.7 1219.7 171.4 231.4 60
3 1545.4 1362.6 1298.7 182.8 246.7 63.9
2 1607.3 1417.8 1351.3 189.5 256 66.5
1 1645.4 1449.2 1380.6 196.2 264.8 68.6
Graph displacement relationship building level

Tingkat = Level
Bata = Brick
Batako = Concrete Block
Hebel = Lightweight Concrete
 Difference of Horizontal Deflection value per level

Displacement (mm) Difference (mm)

Floor Brick Concrete Block Lightweight Concrete B-CB B-LC CB-LC
10 244 213 204 31 40 9
9 236 206 197 30 39 9
8 222 194 186 28 36 8
7 203 177 170 26 33 7
6 179 157 150 22 29 7
5 151 132 127 19 24 5
4 120 105 100 15 20 5
3 87 76 72 11 15 4
2 52 45 43 7 9 2
1 19 17 16 2 3 1
Graph of relationship between column reinforcement area with building
level

Tingkat = Level
Bata = Brick
Batako = Concrete Block
Hebel = Lightweight Concrete
Lusa Tulangan = Area of Reinforcement
 Difference in value of the column reinforcement area per level

Column Reinforcement (mm2) Difference mm2)

Floor Brick Concrete Block Lightweight Concrete B-CB B-LC CB-LC
10 3600 3600 3600 0 0 0
9 4517 3795 3600 722 917 195
8 6722 5700 5399 1022 1323 301
7 8186 7219 6850 967 1336 369
6 9297 8175 7844 1122 1453 331
5 10210 8933 8576 1277 1634 357
4 11073 9522 9130 1551 1943 392
3 11689 9837 9395 1852 2294 442
2 13632 11059 10460 2573 3172 599
1 16985 14635 13792 2350 3193 843
Conclusion

Both V-story, Deflection Horizontal and column reinforcement greatest value contained
in the building using brick material partition, while the smallest is the building using
lightweight concrete material partition.

The decrease percentage of the building using lightweight concrete partition compared
to building with brick partition for V-story, deflection horizontal and column
reinforcement are 16,1% ; 16,4% ; 18,0%.

The analysis showed that the use of materials with small mass can reduce the value of
V-story , deflection horizontal and column reinforcement.
 International
International Journal of Journal
GEOMATE, Sept., 2017, of GEOMATE,
Vol. Sept.,
13, Issue 37, pp. 34-392017, Vol. 12, Issue 37, pp. 34-39
Special Issue on Science, Engineering & Environment, ISSN: 2186-2990, Japan
DOI: http://dx.doi.org/10.21660/2017.37.TVET019

A COMPARATIVE STUDY ON STRUCTURE IN BUILDING USING

DIFFERENT PARTITION RECEIVING EXPENSE EARTHQUAKE
*Sutrisno1 ,2 Rusnardi Rahmat Putra, 3 and Ganefri
1
Students of Technology and Vocational Education, Padang State University, Indonesia
2
Civil Engineering Department, Padang State University, Indonesia

3
Electrical Engineering Department, Padang State University, Indonesia

*Corresponding Author, Received: 01 Agust 2015, Revised: 01 Dec 2015, Accepted: 15 July 2016

ABSTRACT: Light weight building is one of the principles earthquake resistant building design. The size of the
seismic forces that building received depends on the total weight of the building and the earthquake that hit the
acceleration (F = ma). The heavier a building, the greater the seismic forces that will occur in the building. This
study will show the comparison of the behavior V-story building structure, deviation (deplection horizontal) and
the reinforcement columns for three diffrent types of building which is using different materials partition, ie
partition with material brick, concrete block and lightweight concrete (Hebel). It was simulated using software
SAP2000 to get all three. Simulated object is a 10 storey building with 35 m total height which is 3.5 m height
for each floors, located in an earthquake zone 4, the criteria and the soil being analyzed by static method
equivalents. The simulation results showed that the bigest value of V-story, deviation and reinforcement column
contained in the building material brick partitions, while the smallest is the partition material Hebel. Hebel
partitions large percentage decrease compared to brick partition for V-story, deviation and reinforcing successive
columns are 16.1; 15.3%; 18.0%.

Keywords: buildings, earthquake, V-story, deplection horizontal, reinforcingcolumns.

1. INTRODUCTION concrete differ in terms of the load on the building.

Favorable circumstances and impediments of the
Planning for an earthquake resistant building it is utilization of chose progressed and reasonable
necessary to apply some of the principle. Among materials in structural building tasks are examined.
them the building should be ductail, homogen A weighted scoring philosophy for enhanced
building shape configuration, diaphragm and a assessment of their points of interest and burdens,
strong bond floor, and the relationship between the with a perspective to helping choices, is proposed
structure has a relatively homogen strength in all [7].
direction. The earthquake resistant building should This study will show the comparison of the
also has a light weight building, the light weight behavior V-story building structure, deviation
reduces the seismic forces received, because the (deplection horizontal) and the reinforcement
magnitude of seismic force received depends on the columns for three diffrent types of building which is
amount of the buildings total weight and the using different materials partition, ie partition with
earthquake that hit the acceleration (F = m.a). The material brick, concrete block and lightweight
heavier a building, the greater the seismic forces that concrete (Hebel).
will occur in the building.
The structure that receives the load will deform 2. THEORITICAL REVIEW
or change the shape of the structure due to the
imposition received. A structure must be able to 2.1 V-story
accept the load, both on the rod tip structure or at the Regular building structure can be planned against
rod assembly or nodal structure. For planners, nominal earthquake assessment under the influence
understanding the behavior of the structure due to of earthquake plans in each direction of the main
the work load is necessary, because it is useful in axis of the structure plan, in the form of nominal
determining the next step. static earthquake load equivalent, which in turns is
Currently there are a wide variety of material defined in the article bellow [4]:
choices in building wall partition. Such as brick, 1. If the category of the building has a Virtue
concrete block, and light weight concrete (hebel). Factor I, according to Table 1 and the structure to
Each has advantages and disadvantages. In addition a direction of the major axis layout structure and
to the differences in quality and size, as well as at the direction of loading Earthquake Plan has
between concrete block, brick, and light weight

34
 International Journal of GEOMATE, Sept., 2017, Vol. 12, Issue 37, pp. 34-39

an earthquake reduction factor R and

Fundamental natural vibration T1, then nominal
shear load equivalent static V is happening on
the ground level can be calculated according to
the equation : (1) where C1 is the
Earthquake Respons Factor values obtained from
Spectral Respons Plan for Fundamental natural
vibration period T1, whereas Wt is the total
weight of the building, including live load
accordingly.
2. Nominal basic shear load V under Article 6.1.2
should be distributed throughout the building
structure height to become equivalent Fi of
nominal static earthquake load that captures the
center of mass of the i-th floor level according to
Figure 2. Displacement of Portal.
equation : (2) .
2.3 Equivalent Static Analysis
Where Wi is the weight of the i-th floor level,
including live load appropriate, zi is the height of the Equivalent static analysis is a method that is
floor level of the i-th measured from lateral simple and wide used to determine seismic load plan.
clamping level under Article 5.1.2 and Article 5.1.3, This method uses the assumption that the response
while n is the number of the top level floor. of building against earthquake loads occur on the
first dynamic variety, which is equivalent to a
variety of static. For this reason this method is called
Equivalent Static Analysis. Response occurred,
particularly in the building less than 10 floors, it is
often assumed to be linear [1].
For the building structure, equivalent static
analysis can be performed on a regulatr structure
building. The provisions concerning regular building
structures mentioned in article 4.2.1[4].
If the building has an irregular structure, then in
addition to an equivalent static analysis is also
required further analysis, the dynamic response
analysis. Calculation of an irregular building
dynamic structure response against earthquake
loading, can use a wide spectrum analyzer method or
methods of analysis dynamic response time history.
Figure 1. Equivalent Static Analysis to determine Article 7.1.3, if the final dynamic response values
shear force base [1]. are espressed in the base shear force nominal, the
value should not be less than 80% of the base shear
2.2 Deviation (deplection horizontal) force resulting from equivalent static analysis.

In the design of earthquake resistant structure, 3. RESEARCH METHODS

deviation ∆M between the level should not exceed
0,02 times the high level is concerned to limit the To get the desired goal, researchers should
possibility of the collapse of building structures that simulate the comparison three buildings contained of
can cause human fatalities. These limits specified in 10 floor and height 35 m with a height between each
SNI 1726 Ps 8.2.2. it should be noted. Unlike on the floor 3,5 m. the object is assumed to be in an
UBC, SNI limit performance serviceability limit earthquake zone 4 with medium soil criteria then
between the rate structure should not exceed 0,03/R analyzed by equivalent static method using
x height level or 30 mm, the smallest value is SAP2000 software.
applicable. This brick work is intended to prevent
tensile strenght of steel and concrete excessive 3.1 Equivalent Static Analysis Step
cracking [2]
Here are the Equivalent Static Analysis steps :
1. Calculate the natural vibrating time of building.

35
 International Journal of GEOMATE, Sept., 2017, Vol. 12, Issue 37, pp. 34-39

2. Determine the base shear force coefficient that

satisfies.
3. Calculate the base shear force (V) based on total
weight of the building. Basic nominal shear force
formulated as follows :

4. Distribute the base shear force for each floor of

the building structure (F) horizontal shear force
for each floor (Fi) which was formulated as
follows :

5. Analyze the structure with the influence of

lateral loads to gain V-story, deviation
(deplection horizontal) dan column a. Sketch b. Cross-section
reinforcement with SAP2000 software. Figure 3. Sketch and Cross-section.
6. Estimate V-story, deviation (deplection
horizontal) dan column reinforcement. 4.2 Earthquake Data :

3.2 SAP2000 Operation Step The building location is in an earthquake zone 4

and medium soil conditions as explained basic input
1. Defining the individual units, the individual units at located design [8,9]
are selected based on units present in the
structure that analyzed. 4.3 Load Data :
2. Drawing geometry, geometry described by size
and selected unit. Brick density : 2000 kg/m3, concrete block
3. Defining the material, the material is defined density : 1000 kg/m3, light weight concrete (hebel)
reinforced concrete according to the building that density : 650 kg/m3, additional dead load on each
is analyzed. floor (screed + ceramics, ceiling, mechanical,
4. Defining the frame section and put it, frame electrical) = 1,6 kN/m2, additional dead load on the
section is the size of beam and column then put it. roof (ceiling, mechanical, and electrical) = 0,5
5. Defining the load and put it, the loads acting on kN/m2, Live Load (LL) on each floor = 2,5 kN/m2
the structure is defined, dead load, live load, and and Live Load (LL) on the roof = 1,5 kN/m2.
earthquake load then put it down.
6. Defining load combination that are adapted to 4.4 Calculation
the regulations and the work load. Structure,
component, and foundation should be designed 1. For medium soil acquired bedrock peak
in such way so that the design strength is equal acceleration = 0,2 g and peak ground
or exceed to the effect of the factored load in a acceleration Ao = 0,28 g (Table 5. Article 4.7.2
combinations of the following [3,6]: SNI 1726-2002).
a. 1,2D +1,0E+L+0,2S 2. Tc = 0,6 second, Am = 2,5 A0 = 0,7 g and Ar =
b. 0,9D+1,0E Am x Tc = 0,42 (Table 6. Article 4.7.6 SNI 1726
D, E, L and S respectively are dead load, live -2002).
load, earthquake and snow.
7. Analyzed.

4. ANALYSIS AND DISCUSSION

4.1 Building Data as showed at figure 3.

4.2 Floor typical height 3,5 m, column dimension is
assumed equal as 50 x 50 cm, beam dimension
is assumed equal as 30 x 50 cm, floor plate
thickness 12 cm, quality concrete (fc’) = 30 Figure 4. Determining C value with a graph
MPa, quality steel (fy) = 400 Mpa, the building
was used as offices. 3. For a regular office building, virtue factor
structure (I) = 1,0 (Table 1. Article 4.1.2 SNI
1726 -2002)

36
 International Journal of GEOMATE, Sept., 2017, Vol. 12, Issue 37, pp. 34-39

4. Earthquake reduction factor, R = 8,5(Table 3. The graph in figure 6 illustrates that the building
Article 4.3.6 SNI 1726 -2002). using hebel partition, the V-story value is smaller
than the concrete block and brick partition. The
percentage value reached 11,9% compared to using
concrete block partition and 16,1% compared to
using brick partition. Difference pattern of V-story
value shows that the deviation become larger when
the height level towards to the lowest level. The
biggest difference found in the building with hebel
partition material to brick partition material in 1st
floor, that is 264,76 kN (Table 5).

Table 4. Calculation result of lateral force equivalent

Figure 5. Division of the load calculation. per portal.
Table 1. Result of the dead load (DL) and live load
calculation (LL)

Table 2. Result of the load partition calculation.

Figure 6. V-story and building level relationship

graph.

Table 5. difference in V-story value per level

Table 3. Total load calculation result per floor.

37
 International Journal of GEOMATE, Sept., 2017, Vol. 12, Issue 37, pp. 34-39

Graph in figure 7 illustrates that the building Table 7. Difference in value of the column
using hebel partition, the horizontal deflection value reinforcement area per level.
is smaller than the building using concrete block and
brick partition. The percentage value reached 12,7%
compared to using concrete block partition and
16,4% compared to using brick partition. The
difference pattern of horizontal deplection value,
showing comparisons become even greater when the
height of the level to the highest level. There are
biggest difference on the 10th floor of the building
with hebel material partition to brick material
partition, by 40 mm (Table 6).

Figure 7. Graph displacement relationship building

level.

Table 6. Differences of Deflection Horizontal value

per level.

Figure 9. Graph of relationship between reduction

percentage of bulding mass with V-Story,
Deflection Horizontal, and column
reinforcement area in the building.

The graph in figure 8 illustrates that the buildings

which is using large hebel partition needs less
column reinforcement area than the building using
concrete block and brick partition. The percentage
value reached 5,8% compared to using concrete
block partition and 18,8% compared to using brick
partition. Difference pattern of the needs in column
reinforcement area, showing the comparison to be
increasing when the height of the level to the lowest
level. There are biggest difference on the 1st floor of
the building with hebel material partition to brick
material partition, by 3193 mm2 (Table 7).
Graph in figure 9, shows the percentage of
impairment and impairment prediction of V-story
value, deflection horizontal and column
reinforcement when the mass percentage decreases.

5. CONCLUSION

1. Both V-story,Deflection Horizontal and column

Figure 8. Graph of relationship between column reinforcement greatest value contained in the
reinforcement area with building level. building using brick material partition, while the

38
 International Journal of GEOMATE, Sept., 2017, Vol. 12, Issue 37, pp. 34-39

smallest is the building using hebel material akibat gempa dinamis”, Jurnal Konstruksia
partition. Volume 5 Nomor 2, Agustus 2014, pp 79-102.
2. The decrease percentage of the building using [6] BSN, “Beban Minimum Untuk Perancangan
hebel partition compared to building with brick Bangunan Gedung dan Struktur Lain SNI 1727-
partition for V-story,deflection horizontal and 2013”,Badan Standarisasi Nasional, Jakarta,
column reinforcement are 16,1% ; 16,4% ; 2013.
18,0%. [7] David S Thorpe, ”Uptake Of Advanced And
3. The analysis showed that the use of materials Sustainable Engineering Materials In Civil
with small mass can reduce the value of V- Infrastructure Projects”, International
story,deflection horizontal and column journal of Geomate, Vol. 8, No.1, pp. 1180-
reinforcement.
1185, 2015, Japan
[8] Rusnardi Rahmat Putra, Kiyono, Ono, and
6. REFERENCES
Syahril,"determine soil characteristic of Palu in
Indonesian by using microtremor observation".
[1] Paulay, T & M. J. N. Priestley, “Seismic Design
International journal of Geomate, vol.10, No.2,
of ReinforcedConcrete and Masonry Buildings,
pp 1737-1742, 2016, Japan
New Jersey, USA: John Wiley & Sons, Inc, 1992.
[2] Purwono, R, “Perencanaan Struktur Beton [9] Rusnardi Rahmat Putra, Kiyono, Furukawa,”
Bertulang Tahan Gempa”, Surabaya: ITS Press, Vulnerability assessment of non engineered
2005. houses based on damage data of the 2009 Padang
[3] BSN, “Tata Cara Perhitungan Struktur Beton earthquake in Padang city, Indonesia”,
untuk Bangunan Gedung SNI – 03-2847- International Journal of Geomate, Vol.7, No.2,
2002”,Badan Standarisasi Nasional, Bandung, pp. 1076-1083, 2014, Japan
2002. Copyright © Int. J. of GEOMATE. All rights
[4] Puskim, “Standar Perencanaan Ketahanan reserved, including the making of copies unless
Gempa Untuk Struktur Bangunan Gedung SNI – permission is obtained from the copyright
1726 – 2002”, Bandung, 2002. proprietors.
[5] Basit A. H, dan Haryo K. B, “Analisis pengaruh
shear wall terhadap simpangan struktur gedung

39
 STUDY ON BEARING CAPACITY
OF AIRPORT PAVEMENT
DAMAGED DUE TO THE 2011
TOHOKU REGION PACIFIC
COAST EARTHQUAKE
Yukimoto Tsubokawa, Naoya Kawamura, Junichi Mizukami and Ryota
Maekawa

Presented by: Alyssa Mae J. Padura

 Abstract
■ The 2011 Tohoku Region Pacific Coast Earthquake struck
off Tohoku and Kanto regions of Japan on 11 March 2011.
■ The researchers conducted investigations of structural and
surface damage to pavement in the runway, taxiway and
apron at Sendai Airport for the purpose of re-opening the
airport for commercial flights.
■ Many cracks were confirmed in the asphalt pavement in the
runway and taxiway. However, it was clarified that these
cracks except the one in the taxiway were not fatal
structural damage that would hinder the provisional use of
the airport.
■ Large settlement was confirmed in a part of the asphalt
pavement in the taxiway
and concrete pavement in the apron due to liquefaction. It
was confirmed that these settlement areas needed to be
reconstructed for the re-opening of the airport.
■ Furthermore, the effect of the void underneath the cement
concrete slab on FWD deflection was clarified.
Introduction : Tohoku Region Pacific Coast
Earthquake
■ The 2011 Tohoku Region Pacific
Coast Earthquake struck off Tohoku
and Kanto regions of Japan
at 14:46 JST on 11 March 2011)
with a moment magnitude
of 9.0 and epicenter 170km east of
Sendai Airport as shown in Fig.1.
Sendai Airport was severely
damaged due to both the
earthquake and the
tsunami.

Epicenter of 2011 Tohoku Earthquake

Introduction : Summary of Recovery Works

■ The authors investigated the asphalt pavement (runway and taxiway) and the
concrete pavement (apron) between March 21-27,2011
INTRODUCTION
Summary of Damage to Sendai Airport
Damage to Asphalt Pavement-Visual Inspection
Damage to Asphalt Pavement-Visual Inspection
Damage to Asphalt Pavement by using FWD
Damage to Asphalt Pavement by using FWD
Damage to asphalt pavement using FWD
Damage to Concrete-Using FWD
Effect of Void Underneath Cement
Concrete Slab on FWD Deflection
Conclusion
■ (1) There were several cracks in the asphalt pavement and large
settlement due to the earthquake. Cracks in Runway B and the
taxiway were not fatal damage. Settlement at the taxiway-highway
crossing point due to liquefaction was too large for aircraft to use the
taxiway. However, no settlement due to liquefaction occurred at the
other three crossing points (runway-highway, runway-river and taxiway-
river) at which soil improvement had already been conducted
before the earthquake.
■ (2) Damage to the concrete pavement consisted of many cracks and
large settlement in the apron
due to the earthquake. The cause of many cracks seemed to be the
large settlement due to liquefaction of the ground. As a result of
inspection, large void due to settlement was confirmed underneath
the cement concrete slabs.
Conclusion
■ (3) FWD deflection in a distance from loading plate of the
slab with the void could be close to the deflection at the
center of the loading plate because the slab with the void
was not supported by a base layer due to the void
underneath the slab. Thus, the normalized deflection of the
slab with the void tended to be larger than that in the
slab without the void.
 Journal of JSCE, Vol. 5, 58-67, 2017
Special Topic - Restoration and Recovery from the 2011 Great East Japan Earthquake（Paper）

STUDY ON BEARING CAPACITY OF AIRPORT

PAVEMENT DAMAGED DUE TO THE 2011
TOHOKU REGION PACIFIC COAST
EARTHQUAKE

Yukitomo TSUBOKAWA1, Naoya KAWAMURA2,

Junichi MIZUKAMI3 and Ryota MAEKAWA4
1Member of JSCE, Airport Dept., National Institute for Land and Infrastructure Management,
Ministry of Land, Infrastructure, Transport and Tourism (Nagase 3-1-1, Yokosuka, Kanagawa 239-0826, Japan)
E-mail: tsubokawa-y92y2@mlit.go.jp
2Member of JSCE, Airport Dept., National Institute for Land and Infrastructure Management,
Ministry of Land, Infrastructure, Transport and Tourism (Nagase 3-1-1, Yokosuka, Kanagawa 239-0826, Japan)
E-mail: kawamura-n92y2@mlit.go.jp
3Service Center of Port Engineering (Kasumigaseki 3-3-1, Chiyoda-ku, Tokyo 100-0013, Japan)
E-mail: jmizukami@scopenet.or.jp
4Member of JSCE, Technical Research Institute, Okumura Corporation
(Ohsuna 387, Tsukuba, Ibaraki 300-2612, Japan)
E-mail: ryota.maekawa@okumuragumi.jp

The 2011 Tohoku Region Pacific Coast Earthquake struck off Tohoku and Kanto regions of Japan on 11
March 2011. We conducted investigations of structural and surface damage to pavement in the runway,
taxiway and apron at Sendai Airport for the purpose of re-opening the airport for commercial flights. Many
cracks were confirmed in the asphalt pavement in the runway and taxiway. However, it was clarified that
these cracks except the one in the taxiway were not fatal structural damage that would hinder the provi-
sional use of the airport. Large settlement was confirmed in a part of the asphalt pavement in the taxiway
and concrete pavement in the apron due to liquefaction. It was confirmed that these settlement areas needed
to be reconstructed for the re-opening of the airport. Furthermore, the effect of the void underneath the
cement concrete slab on FWD deflection was clarified.

Key Words : earthquake, asphalt pavement, concrete pavement, liquefaction, airport

1. INTRODUCTION

The 2011 Tohoku Region Pacific Coast Earth-

quake struck off Tohoku and Kanto regions of Japan Sendai Airport
at 14:46 JST on 11 March 20111) with a moment Epicenter
magnitude of 9.0 and epicenter 170km east of Sendai
Airport as shown in Fig.1. Sendai Airport was se- 170km
verely damaged due to both the earthquake and the
Tokyo
tsunami.
Table 1 shows a summary of recovery works from
11 March 2011 to 13 April 2011, for the provisional
re-opening of the airport. According to the recovery
works by the airport operator (the Japan Civil Avia-
tion Bureau (JCAB)) in cooperation with the Japan
Self-Defense Force (JSDF) and the United States
Armed Forces (USAF), Sendai Airport was Fig. 1 Sendai Airport and epicenter.

58
 Table 1 Summary of recovery works.
Date Elapsed days Activity
14:46 Earthquake occurred.
14:49 Tsunami Warning was issued (expected tsunami height: 6m).
11 Mar. 0 15:14 Tsunami Warning was increased (expected tsunami height: greater than 10m).
15:59 Tsunami struck Sendai Airport.
Tsunami height was 5.7m at terminal building2).
07:30 Tsunami Warning was decreased to Tsunami Advisory.
13 Mar. 2
17:58 Tsunami Advisory was cleared.
The Japan Civil Aviation Bureau began removal of debris and recovery works of
14 Mar. 3
airport facilities.
A part of Apron and Runway B (600m eastwards) were re-opened for helicopters
15 Mar. 4
(limited to emergency transportation).
Runway B (1,500m eastwards) was re-opened for aircrafts (limited to emergency
16 Mar. 5
transportation).
The Japan River Bureau began drainage works of tsunami water in the airport (part
20 Mar. 9
of the works had been started from 13 Mar.).
Runway B (3,000m) was re-opened for aircrafts (limited to emergency transporta-
29 Mar. 18
tion).
Airport was re-opened provisionally.
13 Apr. 33
Temporary commercial domestic flights started.

600
400
NS, max: 410.69gal
200
0
-200
-400
-600
0 50 100 150 200 250 300
600
Acceleration (gal)

400
EW, max: 353.23gal
(a) Apron 200
0
-200
-400
-600
0 50 100 150 200 250 300
600
400 UD, max: 253.86gal
200
0
-200
-400
(b) Parking Area
Photo 1 Sendai Airport soon after tsunami struck. -600
0 50 100 150 200 250 300
time (s)
Fig. 2 Strong-motion record of earthquake at Iwanuma City3).

59
 Runway B

Apron
Parallel Taxiway
Runway A
Terminal Building

(a) Before earthquake (September 21, 2006)

Runway B

Parallel Taxiway Apron

Runway A Terminal Building

(b) After earthquake (2 p.m., March 12, 2011)

Photo 2 Sendai Airport (photographed by Geospatial Information Authority of Japan).

Highway River
Underpass Underpass

R1 R2 R4 R5 R6 R7 R8 R10 R11
Runway B RJ1
R3 R9
T3 T4 T6 T7 T9 T10 T11
Parallel T5
T8
Taxiway T1 T2 Apron
S1: Very small  S2: Large  S3: Very small 
settlement settlement settlement Terminal
Building
Runway A
Crack
Settlement due to liquefaction S4: Large settlement

Fig. 3 Damage to airport pavement.

60
re-opened provisionally and commercial domestic 3. DAMAGE TO ASPHALT PAVEMENT
flights re-started temporarily on 13 April, 33 days
after the earthquake. The runway and taxiway in the airport were as-
The authors investigated the asphalt pavement phalt pavements. The CBR value of subgrade used
(runway and taxiway) and the concrete pavement for the asphalt pavement thickness design was 10%
(apron) between 21 to 27 March, 2011 to evaluate the (16% in part). The thicknesses of each layer are
structural and surface damage to the airport pavement shown in Table 2.
for the purpose of re-opening the airport for com-
mercial flights. (1) Visual inspection
This paper describes the summaries on structural Visual inspection of Runway B and the taxiway
and surface damage to the airport pavements due to showed 12 cracks on Runway B and 11 cracks on the
the earthquake. Furthermore, the effect of the void taxiway. All the cracks except one were in transverse
underneath the cement concrete slab on deflection direction and throughout the width of runway and
measured by FWD (Falling Weight Deflectometer) is taxiway as shown in Photo 3. The crack width was
clarified. about 1-3 mm and 5 mm maximum. Though there
was 5 mm faulting across crack R10 as shown in
Fig.3, there was no faulting across other cracks.
2. SUMMARY OF DAMAGE TO SENDAI
AIRPORT Table 2 Thickness of asphalt pavement (Unit:cm).
Layers Runway Taxiway
Sendai Airport is located 16 km south of Sendai Asphalt concrete 28-42 27-39
City whose population is about one million. There Surface course 5 4
Binder course 10-11 10-11
are two runways in the airport. Runway A with a
Asphalt stabilized
length of 1,200 m and a width of 45 m is used for 13-26 13-24
base course
small aircraft and Runway B with a length of 3,000 m
Granular material
and a width of 45 m is the main runway in the airport. 18-56 18-56
(subbase course)
There are twelve aircraft stands at an apron in front of
the passenger terminal building.
Since the tsunami struck off the airport as shown in
Photo 1, JCAB began recovery works on the airport
facilities after the tsunami advisory was cleared.
Since about 370,000 m3 of debris and 2,000 or
more vehicles were drifted to the airport, one of the
most serious matters in the recovery works was to
remove these debris and vehicles.
While 47 small aircrafts and 20 helicopters were
flooded by the tsunami, fortunately there were no
large passenger aircraft in the airport when the
earthquake occurred and the tsunami struck the air-
(a) crack R9 (b) crack R10
port.
Photo 3 Transverse crack in runway.
Fig.2 shows a strong-motion record of the earth-
Bottom of asphalt concrete layer
quake measured at ground surface by the seismo-
graph of K-NET3) at Iwanuma City where the airport
is located. This earthquake was characterized by a
long duration of the earthquake motion.
Photo 2 and Fig.3 show a plan of the airport and
damage to the airport pavement. It was confirmed
that there were 12 cracks in Runway B, 11 cracks in
the taxiway and large settlement due to liquefaction
occurred in the taxiway and in the apron.

Surface of asphalt concrete layer
Photo 4 Core sample of asphalt concrete layer at crack R1.

61
 West North

Taxiway shoulder Taxiway

East South

Photo 5 Large settlement at taxiway-highway crossing point

(length of red and white rod is shorter than settlement width).

Longitudinal Direction of Taxiway (2) Structural inspection by using FWD

To evaluate the bearing capacity of pavement,
Settlement structural inspection was conducted by using FWD
Pavement (maximum load was 200 kN and diameter of loading
plate was 300 mm) at Runway B and the taxiway.
FWD loading was conducted at the cracks, 10 m
Highway apart from the cracks, runway-highway crossing
Box Culvert point and taxiway-highway crossing point. Fig. 5
shows the loading positions at Runway B and the
Back Filling Soil Ground Soil taxiway.
To evaluate the bearing capacity of asphalt pave-
Fig.4 Cross-section of highway underpass. ment, an evaluation method described in the “Manual
and guideline of Airport Pavement Maintenance and
As a result of core boring at cracks R1, R10, and Rehabilitation4)” issued by JCAB was used. In this
R11 shown in Fig.3, it was confirmed that the cracks method, deflection ratio calculated as equation (1) is
extended from the surface to the bottom of the as- used to evaluate the bearing capacity of asphalt
phalt concrete layer as shown in Photo 4. pavement.
Highway and river cross under the runway and the
taxiway as shown in Fig.3. Since liquefaction due to R = D0 / D0-cri (1)
earthquake had been forecasted at four crossing
points (runway-highway, runway-river, taxi- where R is deflection ratio; D0 (m) is deflection
way-highway and taxiway-river) before the earth- measured at the center of loading plate with a load of
quake, soil improvement works had been completed 200 kN; and D0-cri (m) is critical deflection at the
by 2010 at three crossing points and were being center of loading plate with a load of 200 kN. This
prepared at one residual at taxiway-highway crossing manual indicates that there could be some structural
point in 2011. problems and other structural inspections such as an
As a result of visual inspection of Runway B and excavation survey may be needed in case the deflec-
the taxiway, large settlement due to liquefaction was tion ratio is larger than 1.0.
confirmed at the un-improved taxiway-highway The critical deflection D0-cri was calculated by
crossing point as shown in Photo 5 though no large multi-layered elastic theory in the actual conditions
settlement occurred at the other three points, which of FWD load 200 kN, 300 mm diameter of loading
had already been improved. The width of the set- plate, thickness of each layer at loading position and
tlement was about 5 m at both sides of the box culvert in the common condition of elastic modulus of each
of the highway and the settlement was about a few layer as shown in Table 3, which was the same as in
decimeters in the taxiway shoulder. the manual. Since the elastic moduli of asphalt con-
Fig.4 shows a cross-section of this point. Since the crete layer (surface course, binder course and asphalt
settlement was confirmed at both sides of the box stabilized base course) vary depending on tempera-
culvert and along the highway, the cause of the liq- ture and have a great influence on the result, they
uefaction seemed to be the low compaction of back were estimated by surface temperature of pavement
filling soil beside the box culvert.

62
 10m 2.0
Runway Runway Runway-Highway
Crack in Runway B
West East Near Crack Crossing Point
10m apart from Crack 4.5m South from CL
Loading Plate Loading Plate 18.0m South from CL
Deflection Sensor Deflection Sensor 1.5
Box Culvert

Deflection Ratio
Crack Asphalt Concrete
1.0

Granular Base

0.5
Near Crack 10m away from Crack

(a) crack on runway and taxiway

0.0

RW1
RW0
RW2
R11

RE2
R10

RE2
RJ1

RE1
R9
.

R6
R7
R4
R3

R5

R8
R1
R2
Highway
Runway West Underpass Runway East Fig.6 Deflection ratio in runway.

10 Runway Shoulder 4.0

Crack in Taxiway Taxiway-Highway
Near Crack Crossing Point
10m apart from Crack 5.5m South from CL
11.0m South from CL
3.0 KD0S

Deflection Ratio
45 2.0 Box Culvert
RE0   RE1   RE2 Runway
4.5 RW2  RW1  RW0

5        5     2 2     5        5
18
1.0
RW2S  RW1S  RW0S RE0S  RE1S  RE2S

5        5      2 2      5        5

10 Runway Shoulder 0.0

KD5
KD4
T11

KD1
KD2
KD3
T10

KD7

KD0
KD6
T8
T9
T3

T5

T7
T4

T6
T2
T1

.
(b) runway-highway crossing point Fig.7 Deflection ratio in taxiway.

Highway Fig.6 shows the deflection ratio in Runway B.

Taxiway West Underpass Taxiway East
Though the deflection ratios exceeded 1.0 at a few
cracks, generally the deflection ratios were less than
7.5 Taxiway Shoulder Large Settlement
1.0. In particular, the deflection ratio at the run-
way-highway crossing point was not much larger
23.0
than those at other points of the runway. This indi-
Taxiway KD7   KD6    KD0   KD1    KD2     KD3    KD4     KD5 5.5 cates that soil improvement works as liquefaction
11
5 5        5        5        6.6         5        5 countermeasure were effective.
7.5 Taxiway Shoulder
KD0S
Fig.7 shows the deflection ratio in the taxiway.
The deflection ratio exceeded 1.0 at T8 due to crack
(c) taxiway-highway crossing point and at the taxiway-highway crossing point due to
Fig.5 FWD loading position (Unit:m). liquefaction. In particular, the deflection ratio at a
distance from the box culvert at the taxiway-highway
Table 3 Conditions to calculate critical deflection4). crossing point was not large. This indicates that the
Elastic modulus effect of liquefaction on the bearing capacity of the
Layer Thickness
(MPa)
pavement was limited in the narrow width beside the
Asphalt Actual thickness
Estimated value box culvert.
concrete (27-42 cm)
Granular Actual thickness
material
200
(18-56 cm)
(3) Recovery works
Subgrade 10 times of
Based on the results of these inspection, JCAB
Infinite reconstructed the pavement at the taxiway-highway
sand design CBR (%)
crossing point S2 where large settlement due to liq-
measured at loading positions5). The box culvert was uefaction occured and the pavement around crack T8
ignored for calculation of the critical deflection at the in the taxiway where the deflection ratio was rela-
pavement on the box culvert since the box culvert tively large by the time of airport re-opening on 13
was located at the ground much deeper than the April 2011.
subgrade of the pavement.

63
 Terminal Building Side（South）
GG FF EE DD CC BB AA A B C D E F G H I J K L M N O
2.050
1
2.150 1 2.100
2.150
2 2.200 2 2.200
2.300 2.250
3 3
2.300
4
2.250
4 2.350
2.350 2.400
5 5 2.450
2.400 2.500
6 6
2.550
7 7 2.600
2.450 2.650
8 8 2.700
9
2.500
9
2.750
2.550
10
2.400
10
標高 (m)
Elevation (m)
11 2.600 11

12 12
2.650
Crack 13 13
In March
2.700
14 14
In May
15 15 Originally, downward slope was 0.5%
16 16
from this line toward north and south.
Aircraft Stand #1 Aircraft Stand #2 Aircraft Stand #3
17
Center Line Center Line 2.700 Center Line17

Runway B Side (North)

Fig.8 Crack and elevation of apron (one square is 7.5m x 7.5m concrete slab).

Terminal Building Side（South）
GG FF EE DD CC BB AA A B C D E F G H I J K L M N O

1 1
Less than 300 m
　300μm未満

2 2
300 – 400 m
　300μm以上400μm未満

3 2 64 16 9 1 68 24 6 1 77 66 5 18 4 3 400 – 500 m
　400μm以上500μm未満

4 3 04 20 9 4 76 20 4 1 90 39 0 2 32 19 3 18 2 1 99 17 7 4 More than 500 m
　500μm以上

5 34 7 2 83 2 82 28 2 2 26 26 6 2 39 18 2 2 02 16 9 18 7 1 97 20 7 5

6 19 8 2 06 2 89 28 2 1 44 14 4 5 05 24 6 1 70 29 0 26 4 1 76 19 6 6

7 21 4 1 99 1 38 50 6 1 38 15 1 1 60 16 3 2 80 24 3 28 0 3 31 17 5 7

8 19 5 2 27 3 89 23 4 2 41 15 3 1 54 25 4 4 66 18 3 21 2 2 46 47 3 8

9 21 1 2 00 4 17 12 7 1 39 18 3 1 73 19 0 2 06 44 0 22 1 2 14 21 0 9

10 20 6 2 05 2 26 15 2 1 47 20 7 4 79 21 9 5 06 21 6 30 1 2 61 19 0 10

11 20 5 2 07 1 88 16 3 3 43 18 1 2 08 39 8 2 19 26 8 22 9 2 34 19 1 11

12 19 7 1 90 1 84 23 2 1 62 41 8 2 78 42 1 6 15 25 9 18 1 2 20 20 4 12

Crack 13 20 2 1 97 2 61 15 9 2 10 19 0 4 17 36 9 3 46 41 9 1 79 18 7 13
In March
14 22 6 1 90 1 94 28 2 2 81 24 9 6 15 44 0 2 31 19 7 21 1 3 19 32 7 14
In May
15 23 2 2 31 4 17 35 5 3 57 43 5 4 42 41 0 2 49 30 0 33 1 2 03 17 5 15

16 22 8 2 02 2 40 23 0 2 20 42 0 2 08 22 5 2 23 25 3 21 5 2 58 18 7 16

17 26 4 2 22 1 89 18 9 2 18 21 2 2 91 20 1 3 55 19 6 23 1 2 04 21 9 17

Aircraft Stand #1 Aircraft Stand #2 Aircraft Stand #3

Center Line Center Line Center Line
Runway B Side (North)
Fig.9 Deflection D0 at center of each slab (unit:m).

4. DAMAGE TO CONCRETE PAVEMENT stands No.1, No.2, and No.3 as shown in Fig.8 and
Photo 6. In particular, maximum settlement was
The apron in the airport was jointed concrete about 18 cm between aircraft stands No.2 and No.3.
pavement. Design thickness of slab was 42 cm and Since the cracks occurred around uneven settlement
design K75 value of granular base was 70 MN/m3. area, the cause of these cracks seemed to be uneven
large settlement due to liquefaction.
(1) Visual inspection New cracks were confirmed in May as shown in
As a result of visual inspection of the apron, large Fig.8. These cracks might have occurred because
settlement and many cracks about 1-3 mm wide were groundwater level in May became lower than that in
confirmed in the cement concrete slabs at aircraft March due to the drainage work.

64
 (a) slab J11 and K11 photographed from slab J12 Photo 7 Void with a depth of 7cm.

(3) Recovery works

Based on the results of inspections, JCAB decided
to close aircraft stands No.1, No.2, and No.3 tem-
porarily as it would be difficult to repair these slabs in
time for the airport re-opening. Reconstruction of the
concrete pavement and soil improvement for lique-
faction in this area were conducted after the airport
was re-opened provisionally.
In recovery works, voids with a depth of 7 cm and
20 cm underneath the cement concrete slabs were
confirmed by the removal of two cement concrete
slabs as shown in Photo 7.
(b) slab F5 and G5 photographed from slab G6
Photo 6 Crack and settlement in the apron.

800 5. EFFECT OF VOID UNDERNEATH

CEMENT CONCRETE SLAB ON FWD
600
DEFLECTION
Deflection D0 (m)

As mentioned in Sections 3 and 4, the relationship

400 between FWD deflection D0 and surface settlement
due to liquefaction was not clear in the concrete
200 pavement though the deflection ratio was very large
at the taxiway-highway crossing point in asphalt
pavement where settlement was large. To determine
0
0 5 10 15 20 the effect of the void underneath the cement concrete
Settlement (cm) slab on FWD deflection, we compared the deflec-
Fig.10 Relationship between D0 and settlement. tions at the settlement area and the non-settlement
area in the apron.
(2) Structural inspection by using FWD The precise position of the void underneath the
To evaluate the bearing capacity of pavement, cement concrete slab in the apron was unknown since
structural inspection was conducted by using FWD we did not conduct sufficient inspection to confirm
(200 kN load and 300 mm diameter of loading plate) the position of the void. Thus, we estimated and de-
at the center of each cement concrete slab. fined “slab with void” where both the settlement and
Fig.9 shows FWD deflection D0 at the center of the deflection were large around aircraft stands No.2
each slab. However D0 at the settlement area between and No.3, and “slab without void” where both the
aircraft stands No.2 and No.3 tends to be larger than settlement and the deflection were small around air-
that at the non-settlement area around aircraft stand craft stand No.1. To examine the effect of the void
No.1, the relationship between D0 and settlement is underneath the cement concrete slabs on FWD de-
not clear as shown in Fig.10. flection, deflection data of 20 slabs in each area were
used.

65
(1) Normalized deflection the slabs in column N are somewhat small in the
The shape of the deflection basin was examined. apron; nevertheless, these slabs are very close to the
Fig.11 shows a normalized deflection NDx calculated settlement area.
as shown in equation (2). Fig.16 shows the results. There may be a void
underneath the slab of N7 since this slab is plotted in
NDx = Dx / D0 (2) the group of the slab with the void. On the other hand,
there may not be a void underneath the slab of N14
where NDx is normalized deflection at x (mm) apart though the deflection at the center of this slab is 331
from the center of the loading plate; Dx (m) is de- m, which is one of the largest deflections among the
flection measured at x (mm) apart from the center of slabs in column N.
the loading plate; D0 (m) is deflection measured at As a result, it is possible that the void underneath
the center of the loading plate. the cement concrete slab is easily detected by using
The normalized deflection of the slab with the void the normalized deflection and the peak time differ-
tended to be larger than that of the slab without the ence measured by using FWD.
void. Furthermore, it was also observed that the
0.0
normalized deflection of some slabs with the voids

Normalized deflection, NDx = Dx / D0

Slab with void
exceeded 1.0, which meant that Dx was larger than 0.2 Slab without void
(lines mean average value)
D0. These phenomena indicated that FWD deflection
in a distance from the loading plate of the slab with 0.4

the void could be close to the deflection at the center 0.6

of the loading plate because the slab was not sup-
ported by a base layer due to the void underneath the 0.8
slab.
1.0

(2) Peak time difference of deflection 1.2

0 500 1000 1500 2000 2500 3000
The deflection data in time series were examined. Distance from center of loading plate, x (mm)
Fig.12 shows an example of deflection data in time Fig.11 Normalized deflection.
series. In this examination, we defined “peak time
difference, tx” as shown in equation (3) and Fig.12. 250
Load, F (kN) or Deflection, Dx (m)

Load Peak time difference, t300

tx = tx - t0 (3) 200 D0

D300
150
where tx (ms) is peak time difference of deflection at
x (mm) apart from the center of the loading plate; tx 100
(ms) is time when deflection Dx becomes maximum
in time series; and t0 (ms) is time when deflection D0 50
becomes maximum in time series.
Fig.13 shows the peak time difference in the slabs 0
0 10 20 30 40
with and without the void. The peak time difference
Time, t (ms)
in the slab with the void tends to be smaller than that Fig.12 Definition of peak time difference.
of the slab without the void. This indicates that not
only the center of loading plate but also portions in a 6.0
distance from the loading plate tend to deform at Slab with void
Peak time difference, tx (ms)

5.0 Slab without void

almost the same time in the case of the slab with the (lines mean average value)
void. 4.0

3.0
(3) Presumption of void
Fig.14 and Fig.15 show the relationship between 2.0
normalized deflection and the peak time difference.
As shown in these figures, the difference between the 1.0

slab with the void and the slab without the void can 0.0
be clearly verified by using these two indexes. 0 500 1000 1500 2000 2500 3000

We try to presume the possibility of the void un- Distance from center of loading plate, x (mm)
Fig.13 Peak time difference.
derneath the slabs in column N shown in Fig.9 by
using this method since deflections at the center of

66
 1.10
fatal damage. Settlement at the taxiway-highway
Slab with void crossing point due to liquefaction was too large
Normalized deflection, ND300 Slab without void
1.05 for aircraft to use the taxiway. However, no set-
tlement due to liquefaction occurred at the other
1.00
three crossing points (runway-highway, run-
way-river and taxiway-river) at which soil im-
provement had already been conducted before
0.95
the earthquake.
(2) Damage to the concrete pavement consisted of
0.90 many cracks and large settlement in the apron
0.0 0.5 1.0 1.5
Peak time difference, t300 (ms)
due to the earthquake. The cause of many cracks
seemed to be the large settlement due to lique-
Fig.14 Relationship between normalized deflection
and peak time difference at 300 mm.
faction of the ground. As a result of inspection,
large void due to settlement was confirmed un-
1.1 derneath the cement concrete slabs.
Slab with void
Slab without void
(3) FWD deflection in a distance from loading plate
Normalized deflection, ND1500

1.0 of the slab with the void could be close to the

deflection at the center of the loading plate be-
0.9 cause the slab with the void was not supported by
a base layer due to the void underneath the slab.
0.8
Thus, the normalized deflection of the slab with
the void tended to be larger than that in the slab
0.7
without the void.
0.6
(4) The peak time difference in the slab with the void
0.0 0.5 1.0 1.5 2.0 2.5 3.0 tended to be smaller than that in the slab without
Peak time difference, t1500 (ms) the void. This indicated that not only the center
Fig.15 Relationship between normalized deflection of loading plate but also portions in a distance
and peak time difference at 1500 mm. from the loading plate tended to deform at almost
1.1
the same time as in the case of the slab with the
void. It was possible that the void underneath the
Normalized deflection, ND1500

1.0 Slab with void

Slab without void
cement concrete slab was easily detected by us-
Slab number N7
D0 = 331m
Slab in column N in Fig.9 ing normalized deflection and the peak time
0.9
N4 N9 N5
197m
difference measured by using FWD.
199m 214m N13
0.8 N14 179m
319m
N6
176m REFERENCES
0.7 1) Japan Meteorological Agency: Prompt Report of Earth-
N8
N12 246m
N10
220m
261m quake and Tsunami of the 2011 Tohoku Region Pacific
0.6 N11 N17
234m N16 N15 204m
Coast Earthquake, Disaster Report, Vol. 1, 2011.
258m 203m
2) Takahashi, S. et al.: Urgent Survey for 2011 Great East
0.5
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Japan Earthquake and Tsunami Disaster in Ports and Coasts,
Peak time difference, t1500 (ms) Technical Note of the Port and Airport Research Institute,
Fig.16 Results of slabs in column N shown in Fig.9. No. 1231, 2011.
3) Kinoshita, S.: Kyoshin Net (K-NET), Seismological Re-
search Letter, Vol. 69, pp. 309-332, 1998.
4) Japan Civil Aviation Bureau: Manual and guideline of
6. CONCLUSION Airport Pavement Maintenance and Rehabilitation, 2015.
5) Heukelom, W. and Klomp, A. J. G. : Road Design and
Dynamic Loading, Proc. of AAPT, Vol. 33, pp. 92-125,
(1) There were several cracks in the asphalt pave- 1964.
ment and large settlement due to the earthquake.
Cracks in Runway B and the taxiway were not (Received March 24, 2016)

67
 Performance Review of
Prefabricated Building Systems
and Future Research in Australia

SATHEESKUMAR NAVARATNAM
TUAN NGO
THARAKA GUNAWARDENA
DAVID HENDERSON

DEPARTMENT OF INFRASTRUCTURE ENGINEERING

, THE UNIVERSITY OF MELBOURNE
COLLEGE OF SCIENCE AND ENGINEERING
JAMES COOK UNIVERSITY
,
FEBRUARY 3 2019

PRESENTED BY: KAREN GRACE T. SUGUE

 Abstract

It can not be denied that one of the alternative

solutions to changing the speed of conventional construction
methods at a fast rate is by prefabricated building systems .

In most developed countries, volumetric prefabricated

building construction is growing; for example, in Sweden the
market share of the housing industry was more than 80%.
However, in Australia only approximately 3–4% of new
building constructions are prefabricated buildings in a year.
 Due to limited publicly-available research and case
studies, independent designers and structural engineers are
relying on the strength of the structural and non-structural
element, as well as the connections of the prefabricated
building systems.

This strength is estimated from the “commercial-in-

confidence” test of individual components by manufactures,
and it might result in undesired outcomes in design.
 This paper highlights the research needed on the
prefabricated building systems such as full-scale tests,
numerical modeling, hybrid simulations, case studies and
social and economic assessments. Being supported by sound
academic research will increase the market demand for
prefabricated building systems in Australia as well as in other
countries.
 1. Introduction

In Australia, the prefabricated building system has

been recognized as a one of the alternative solutions to
changing the speed of conventional construction methods
at a fast rate.

This prefabricated construction system also has been

promoted as one of the eight key “visions” to improving the
efficiency and performance of the Australian construction
industry vision 2020.
 Figure 4. Images from healthcare facilities built using modular construction in Australia,
Left - Ballarat Health Cancer Care Unit, Right - Pascoe Vale Health (Prebuilt Pty. Ltd., 2018)
[15].
 Previous Research Studies on the Benefits

Advantages Disadvantages
 Time  Intensive Planning
Reductions in construction time of about This requires more engineers, quality
40% occur, when compared to controllers and skilled laborers.
conventional construction practices.
 Cost
 Safety Usage of Special Construction Equipment
80%–85% reduction on risks Site
preparation  However, these cost and time
 Cost benefits are not very clear due to
Reduce Labor Cost by 25%
the lack of access to confidential
Reduce Transportation Cost information of projects (i.e.
financial and actual project plan),
 Environmental Benefit as well as to the use of new
Controlled Material technology and modern
Less Waste machineries .
 A case study by Lawson:
Noise and disruption are reduced by 30–50%.
Reduces landfill by a factor of at least 70%.

 A study by Aye
Shows that the reuse of materials in prefabricated steel buildings
saves about 81% of embodied energy and 51% of materials by mass.
Prefabricated houses also reduce CO2 operating emissions by
approximately 50% in annual households.
  Study by
Matic

Prefabricated
construction
systems
contribute
significantly to
improving
environmental
sustainability in
the construction
industry.
 Structural Performance of Prefabricated
Building Systems
 Structural performance data of prefabricated building structures
is limited, as little detail of engineering research and few case
studies have been published compared to the conventional
structures such as steel, concrete and timber-frames under any
natural and manmade loading.
 Due to a lack of knowledge in the load sharing and load transfer
of structural systems, prefabricated buildings may give rise to
non-optimal designs.
 The load sharing and load transfer in prefabricated building can
be complex, as the system uses multiple inter-component
connections between the modules, which can be influenced by
tolerances in the installation procedure.
 A Case Study by Lawson

Key Factors to be taken into account in the design of modular

buildings:

 1) influence of installation eccentricities and manufacturing

tolerances on the additional forces and moments in the walls;
 2) second-order effects due to sway stability of the group of
modules;
 3) mechanism of force transfer of horizontal loads to the
stabilizing system;
 4) robustness to accidental actions for modular systems;
 5) the minimum horizontal force in any tie between the modules
is taken as not less than 30% of the total load acting on the
module and not less than 30 kN.
 A Case Study by Gunawardena

Analyzed the static and dynamic behavior of the structure

using finite-element analysis techniques with the aid of a
three dimensional (3D) computer model.

 The study highlighted that the torsional or twisting effects

are a major problem for the designers for these type of
buildings.
 A Performance-Based Design

 A performance-based design approach was imposed in

many countries such as Australia, New Zealand, and the
USA. This approach requires an independent engineering
design for conventional and non-conventional houses such
as modular houses.
 Independent Engineering Design

 Involves laboratory tests and full-scale tests on the individual

components (i.e. wall, ceilings, roof, connections, etc.), as well as
structural analyses using finite element software.

 In Australia, the prefabricated modular houses and building

design are based on wind, fire and earthquake standards as well
as the National Construction Code.

 However, there are no specific standards or recommendations

for prefabricated building design, as there are limited
engineering research and case studies which evaluate the
performance of prefabricated building systems compared to
those of conventional building systems.
 Fire resistance and acoustic performance

 In prefabricated modular buildings, double-layer walls

and floor-ceilings are generally used. The fire barriers
and protection are installed between the modules and
internal face of the wall to prevent the spread of smoke or
fire in the cavity and between the modules.
 The double-layer walls and floor/ceiling offer significant
resistance to airborne and impact sound. Thin concrete
floor screed placed either on the light steel floor or as a
composite slab between the walls or edge beams in the
prefabricated building system also provides the
additional sound reduction and floor stiffness to
minimize vibrations.
 Computational Fluid Dynamics by Nguyen
Prefabricated, lightweight aerated concrete (PLAC) panels
in the modular construction achieved 30 minutes’ fire resistance
and provided low thermal conductivity compared to normal
concrete product.
 Performance of the structure under
Earthquake and wind load
 Annan
Modeled typical braced frames of Modular Steel
Buildings to evaluate their inelastic behavior under seismic
loads.
The results showed that the reserve strength of
Modular Steel Building braced systems was greater than that
of traditional braced systems .
This study recommended that the unique detailing
requirements of Modular Steel Building braced systems
should be taken into account during the design phase to
improve seismic response.
 Windstorms
Limited research and few case studies are available on
prefabricated building system responses. In prefabricated
building, lateral wind loads are resisted and transferred by
bracing elements and/or sheathing the walls, and then
conveyed to the foundation.
 Bathon
Developed a building using prefabricated wood-
concrete-composite panels. The structural response
of this system was assessed under hurricane loading
conditions with wind speeds up to 400 km/h.
 Conclusions

 Prefabricated building systems and construction hold high potential to

improve the efficiency and performance of the Australian construction
industry in a more sustainable sense.
 To ensure that these prefab building systems and construction deliver
substantial benefits economically, and in an environmentally- and
socially-friendly manner more research studies are needed.
 More case studies are needed to evaluate project planning, scheduling,
and the cost of small- and large-scale projects.
 More research and case studies are needed to develop and include the
design specifications and recommendation for prefabricated structures
according to Australian design standards.
 Previous study has highlighted that most often, structural performance
of prefabricated building systems is assessed by individual component
testing and numerical models.
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/330840928

Performance Review of Prefabricated Building Systems and Future Research in

Australia

Article  in  Buildings · February 2019

DOI: 10.3390/buildings9020038

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Review
Performance Review of Prefabricated Building
Systems and Future Research in Australia
Satheeskumar Navaratnam 1,*, Tuan Ngo 1,*, Tharaka Gunawardena 1 and David Henderson 2
1 Department of Infrastructure Engineering, The University of Melbourne, Parkville 3010, Australia;
tgu@unimelb.edu.au
2 College of Science and Engineering, James Cook University, Townsville 4814, Australia;

david.henderson@jcu.edu.au
* Correspondence: sathees.navaratnam@unimelb.edu.au (S.N.); dtngo@unimelb.edu.au (T.N.)

Received: 11 October 2018; Accepted: 24 January 2019; Published: 3 February 2019

Abstract: Volumetric prefabricated building construction is growing in most developed countries;

for example, in Sweden the market share of prefabricated building systems in the housing industry
was more than 80%. However, in Australia only approximately 3–4% of new building constructions
are prefabricated buildings in a year. A major hindrance to the growth of prefab construction in
Australia is that systems are developed under commercial and confidential conditions. There are
limited publicly-available research and case studies for certifiers, regulators, engineers and
academia to provide independent information on the performance, advantages and disadvantages
of prefabricated building systems. Independent designers and structural engineers are relying on
the strength of the structural and non-structural element, as well as the connections of the
prefabricated building systems. This strength is estimated from the “commercial-in-confidence” test
of individual components by manufactures, and it might result in undesired outcomes in design.
This paper provides an overview of available literature on structural performance, benefits,
constraints and challenges of prefabricated building systems. This paper also highlights the research
needed on the prefabricated building systems such as full-scale tests, numerical modelling, hybrid
simulations, case studies and social and economic assessments. Being supported by sound academic
research will increase the market demand for prefabricated building systems in Australia as well as
in other countries.

Keywords: prefabricated buildings; modular construction; structural performance

1. Introduction
In Australia, the prefabricated building system (i.e. pre-cut, panelised, modular, and mobile
home building system) has been recognized as a one of the alternative solutions to changing the speed
of conventional construction methods at a fast rate. This prefabricated construction system also has
been promoted as one of the eight key “visions” to improving the efficiency and performance of the
Australian construction industry vision 2020 [1]. Volumetric prefabricated building construction
systems comprise modular of volumetric units that are typically manufactured complete with
architectural finishes and services at an off-site, quality-controlled factory (See Figures 1 and 2). These
modules are then transported and installed on-site as one of many load-bearing structural blocks of
the building. Reductions in cost and time are the major advantages offered by the prefabricated
building systems when compared to conventional construction methods. Other benefits include
improved quality and accuracy in manufacture, speed of installation on-site, and can also be
dismantled and reused [2,3]. This form of prefabricated buildings also provides environmental
benefits, such as the reduction of construction waste and CO2 emissions, and less disturbance to the
building site’s neighbours by minimizing on-site noise and dust [4,5]. These advantages are the

Buildings 2019, 9, 38; doi:10.3390/buildings9020038 www.mdpi.com/journal/buildings

Buildings 2019, 9, 38 2 of 13

driving force within the European building industry for the growth of prefabricated building systems
[6–9]. Furthermore, due to population growth, other countries (i.e. US, Canada, Japan, etc.) also use
modular construction technology to build houses, apartments, offices, etc. [10,11].

(a) (b)
Figure 1. An image from the modular building ‘Little Hero’: (a) After being built and occupied; (b)
During its on-site assembly (Images by Tuan Ngo).

Figure 2. SOHO Apartments in Darwin, Australia [12].

Modular construction technology has been gaining more attention in the building industry over
the last few years in Australia. As a result, several low-rise apartments have been built. One example
is the ‘Little Hero’ low-rise apartment building in Melbourne, Australia [3]. However, only a low
percentage of all low-rise buildings were built using modular construction or volumetric
prefabricated building system [3,6,13]. This is in part due to limited knowledge of the applicability,
design and performance of prefabricated building systems in the building industry and the general
public. However, due to recent work by academia, industry and institutions such as prefabAUS in
creating awareness of such benefits, the prefab industry is increasing its numbers, especially in the
Buildings 2019, 9, 38 3 of 13

education and public services sectors. The Permanent Modular School Buildings Program (PMSB),
an initiative of the Victorian School Building Authority (VSBA) of Australia, has commenced the
replacement of old school buildings with newly-built modular classroom buildings targeting
hundreds of schools around Victoria, Australia where already 30 modular school buildings have been
completed and handed over. Figure 3 shows some of the exterior and interior images of those newly-
built facilities provided by the PMSB program.

Figure 3. New modular schools built by the PMSB program of VSBA in 2018 – Mt Waverly Heights
Primary School, Glengala Primary School, Yallourn North Primary School and Beaumaris North
Primary School respectively (Victorian School Building Authority [VSBA], © State of Victoria,
Department of Education and Training, 2018) [14].

Similarly, many public spaces in Australia such as new railway stations, police stations,
healthcare facilities (Figure 4) and community centres are now being built using volumetric modular
construction and other prefabricated methods with the assistance of the Australian government.
Therefore, it is quite evident from the recent advancements of the prefab industry in Australia how
the collaboration of industry, academia and government authorities can heavily impact the growth
of an industry for the ultimate benefit of society. However, limited awareness on the performance,
benefits, skills and knowledge required for prefabrication design and construction practice need to
be developed and strengthened to increase the number of prefabricated buildings and constructions
in Australia. This paper provides an overview of past research noting the limitations in the Australian
context and offers some recommendations on targeted research needed in the prefabricated building
system.
Buildings 2019, 9, 38 4 of 13

Figure 4. Images from healthcare facilities built using modular construction in Australia, Left -
Ballarat Health Cancer Care Unit, Right - Pascoe Vale Health (Prebuilt Pty. Ltd., 2018) [15].

2. Previous research studies on the benefits

2.1. Cost and Time

Reducing cost and time are major anxieties for both consumers and manufactures in the building
industry. When compared to conventional construction methods, the prefabricated construction
system provides significant reductions in both cost and time [2,4,5,16–19]. In a prefabricated
construction system, the phases of site preparation and construction of the modules can be run
simultaneously, while in conventional construction, the construction phase happens after the site
preparation phase [4,17,20]. With construction phase activities occurring at the same time as the
prefabricated construction, reductions in construction time of about 40% occur, when compared to
conventional construction practices [4,17,20–23].
However, pre-project planning is quite intensive for prefabricated construction systems, as their
design has different complexities from conventional design. For example, features such as when
modules are lifted, transported to the final project site, placed on the foundation, and joined to form
the building need to be taken into account in the design phase. This requires more engineers, quality
controllers and skilled labourers [24]. These requirements will increase the cost and duration of the
design phase, but they reduce the cost and time of the on-site construction phase significantly in
prefabricated construction compared to conventional construction. Furthermore, the construction
activities in conventional construction are significantly affected by any climate change or weather
condition interruptions. Meanwhile, in the prefabricated construction method, these kinds of
interruptions were negligible, as the majority, i.e., about 80–90%, of construction activities happen in
a factory. This also reduces the construction time and total cost of projects using the prefabricated
construction method when compared to conventional construction methods.
In prefabricated construction, the manufacturer can order material in bulk and fabricate several
modules at same time. This provides lower prices from suppliers and reduces the number of labours
and transportations. This will result in savings in cost and time of the project. Moreover, prefabricated
construction reduces the number of on-site laborers, which reduces the total labour cost by about 25%
compared to traditional construction methods [17,25–28]. However, these cost and time benefits are
not very clear due to the lack of access to confidential information of projects (i.e. financial and actual
project plan), as well as to the use of new technology and modern machineries [26,29–31].

2.2. Other benefits

In conventional construction, there are several safety issues, including working at height,
congestion, severe weather work place accidents, neighbouring construction operations, etc.
However, these problems were reduced by about 80%–85% in prefabricated construction, as the
majority of construction works, i.e., about 80%, occurs in factories [2,17,25–31]. This construction in
factories provides consistent products, as they are repetitive processes, and are typically undertaken
with automation [2,30,32,33]. Prefabricated construction systems also provide the environmental
benefit of less construction waste. This is because 80% of construction operations take place in a
factory, where waste materials can be controlled/reused/recycled [2,4,17,20,21,23,25–31,34].
Prefabricated building modules can be disassembled, relocated, or retrofitted and renovated to be
used in other projects, which reduces disposal waste.
Buildings 2019, 9, 38 5 of 13

A case study by Lawson [2] highlighted the fact that in prefabricated building construction, the
neighbouring buildings are not affected as much as in traditional building construction methods, as
noise and disruption are reduced by 30–50%. Lawson [2] also showed the prefabricated modular
construction reduces landfill by a factor of at least 70%. A study by Aye [19] shows that the reuse of
materials in prefabricated steel buildings saves about 81% of embodied energy and 51% of materials
by mass (Figure 5). Prefabricated houses also reduce CO2 operating emissions by approximately 50%
in annual households [5]. Studies by Matic [35] investigated the energy refurbishment of existing
buildings, and their conversion to energy efficient buildings with minimized loads. This study found
a significant reduction of thermal and cooling loads after refurbishment of existing buildings, when
compared to those buildings’ pre-furbished data. These research and case studies [2,4,35–41] indicate
that prefabricated construction systems contribute significantly to improving environmental
sustainability in the construction industry.

Figure 5. Total volume, mass and embodied energy of concrete and prefabricated steel and timber
building scenarios, with percentage of potential savings achieved from the reuse of materials through
Modular Construction [19].

3. Structural performance of prefabricated Building systems

The structural performance of conventional structures such as steel, concrete and timber-frames
under any natural (i.e. wind load, earthquake load, bushfire) and manmade (i.e. bomb-blast, vehicle
impact, etc.) loading has been evaluated by many researchers from around the world and
incorporated into the design of a range of approaches. However, structural performance data of
prefabricated building structures is limited, as little detail of engineering research and few case
studies have been published [3,42,43]. The structural design approach should ensure the stability of
the building structure under these natural and manmade loads, transferring such loads to the
foundation through their structural elements, non-structural elements and inter-component
connections. Although, these approaches have proved to be adequate, complex structural systems
such as timber-framed houses, non-conventional structures and prefabricated buildings may give
rise to non-optimal designs. This is due to a lack of knowledge in the load sharing and load transfer
of structural systems. The load sharing and load transfer in prefabricated building can be complex,
as the system uses multiple inter-component connections between the modules, which can be
influenced by tolerances in the installation procedure. The vertical and lateral loads are transferred
generally through inter-component connections and stabilizing elements such as vertical bracing or
core walls. In prefabricated systems with load-bearing walls, the axial load is transferred via direct
wall-to-wall bearing. Plasterboard or similar boards are often attached to the exterior of walls, and
these boards prevent the C-sections (i.e. generally used in the wall panel) from buckling in the in-
Buildings 2019, 9, 38 6 of 13

plane direction of the wall [2]. The tie forces at the corner of the modules provide resistance to
accidental loads, and the accidental limit state is generally taken as the self-weight plus one-third of
the imposed load [2].
A case studies by Lawson [2] recommended that the following key factors should be taken into
account in the design of modular buildings: 1) influence of installation eccentricities and
manufacturing tolerances on the additional forces and moments in the walls; 2) second-order effects
due to sway stability of the group of modules; 3) mechanism of force transfer of horizontal loads to
the stabilizing system; 4) robustness to accidental actions for modular systems; 5) the minimum
horizontal force in any tie between the modules is taken as not less than 30% of the total load acting
on the module and not less than 30 kN. Gunawardena [42] have analysed the static and dynamic
behaviour of the structure using finite-element analysis techniques with the aid of a three-
dimensional (3D) computer model. Their study highlighted that the torsional or twisting effects are
a major problem for the designers of these type of buildings. Results also show that elevator shafts
can be flexibly shifted around the plan without causing adverse torsional effects to the structure.
A performance-based design approach was imposed in many countries such as Australia, New
Zealand, and the USA. This approach requires an independent engineering design for conventional
and non-conventional houses such as modular houses. The independent engineering design involves
laboratory tests and full-scale tests on the individual components (i.e. wall, ceilings, roof, connections,
etc.), as well as structural analyses using finite element software. This approach is still adopted for
the structural design and construction of houses in Australia. Therefore, several full-scale and
individual components tests were conducted, including timber-framed houses and prefabricated
steel-framed panelised building systems [44]. In Australia, the prefabricated modular houses and
building design are based on wind, fire and earthquake standards, i.e., AS 1170.2 [45], AS 1170.4 [46],
AS 1530.4 [47] and AS 5113 [48], as well as the National Construction Code [49]. These standards are
developed by a number of research publications, case studies, laboratory tests, full-scale tests and
structural analyses. However, there are no specific standards or recommendations for prefabricated
building design, as there are limited engineering research and case studies which evaluate the
performance of prefabricated building systems compared to those of conventional building systems.

3.1. Fire resistance and acoustic performance

Fire safety is a major concern after the building collapse at the World Trade Centre (in 2001, New
York) and the Grenfell Tower (in 2017, London). These failures have led to more research and fire
safety testing on structural and non-structural elements as well as their connections. The collapses of
these buildings have also led to changes in building standards and to the banning of some building
materials such as combustible claddings. In Australia, buildings are facing the danger of bushfires
(e.g. Black Saturday in Victoria 2009, Ash Wednesday in Victoria 1983, Black Friday in Victoria 1939,
Black Tuesday in Tasmania 1967, and the Gippsland fires and Black Sunday in Victoria in 1926) and
their associated costs in terms of significant insurance payout and loss of life [50,51]. Therefore, the
fire resistance of buildings and their elements is important.
In prefabricated modular buildings, double-layer walls and floor-ceilings are generally used.
The fire barriers and protection are installed between the modules and internal face of the wall to
prevent the spread of smoke or fire in the cavity and between the modules [2].
The double-layer walls and floor/ceiling offer significant resistance to airborne and impact
sound. Thin concrete floor screed placed either on the light steel floor or as a composite slab between
the walls or edge beams in the prefabricated building system also provides the additional sound
reduction and floor stiffness to minimize vibrations [2]. However, the manufacturing and
construction of prefabricated building systems vary between countries, as well as some regions
within the country. This difference will create variations in the fire and acoustic performance of
prefabricated building systems in Australia compared to those in the Lawson [2] case studies.
Moreover, composite materials, light weight Structural Insulated Panels (SIPs), Cross Laminated
Timber (CLT), and Concrete-filled steel hollow sections have played a significant role in the
prefabricated construction industry over the past years [51–54]. Full-scale fire testing and
Buildings 2019, 9, 38 7 of 13

computational fluid dynamics by Nguyen [53] highlighted the fact that prefabricated, lightweight
aerated concrete (PLAC) panels in the modular construction achieved 30 minutes’ fire resistance and
provided low thermal conductivity compared to normal concrete product. Other fire tests on CLT
beams show that the current zero-strength layer fails to capture the necessary physics for robust
predictions of structural responses under non-standard heating, and recommended that more
detailed thermo-mechanical, cross-section analyses are needed to determine the structural
implications of real fire exposure [44]. These studies [52–56] assess the structural response of the
individual elements and connections under fire. The fire rating of individual elements and
connections could vary when compared to whole structure. Therefore, the structural responses of
whole prefabricated buildings or modules under fire conditions need to be evaluated.

3.2. Performance of the structure under earth quake and wind load
The finished panels or modules of a prefabricated system are transported to the site and erected
both horizontally and vertically using horizontal and vertical connections [57–59]. Lateral bracings
or core walls are used to achieve the lateral stability of the structure [2,42]. Annan [57] designed and
modelled typical braced frames of Modular Steel Buildings to evaluate their inelastic behaviour
under seismic loads. The results showed that the reserve strength of Modular Steel Building braced
systems was greater than that of traditional braced systems (i.e. specified in the Canadian code). This
study recommended that the unique detailing (i.e. frame type, special vertical connections at column)
requirements of Modular Steel Building braced systems should be taken into account during the
design phase to improve seismic response.
Further, a study carried out by Gunawardena et al. [42] investigated the earthquake performance
of corner-supported, multistorey modular structures. The outcome of a capacity spectrum analysis
(Figure 6) showed that the analysed 10-storey modular structure was past its linear deformation zone
at its performance points against all six earthquake time histories that it was analysed against.
However, the performance points were also far below the full capacity of the structure. Therefore, it
was concluded that the structure analysed in this study performed in the ‘Immediate Occupancy’ to
‘Life Safety’ range as per the performance levels introduced in FEMA 356 [60].

Figure 6. Outcome of the capacity spectrum analysis: 5% damped demand curves against the capacity
curve [42].
Buildings 2019, 9, 38 8 of 13

Windstorms is the one of major natural hazards in Australia as well as other countries such as
US, Canada, UK, India, etc. Many studies on structural responses to wind loading for conventional
building structures have been published. Limited research and few case studies are available on
prefabricated building system responses. In prefabricated building, lateral wind loads are resisted
and transferred by bracing elements and/or sheathing the walls, and then conveyed to the foundation
[61,62]. Bathon [63] developed a building using prefabricated wood-concrete-composite panels (see
Figure 7). The structural response of this system was assessed under hurricane loading conditions
with wind speeds up to 400 km/h. Although this current paper is focusing on volumetric
prefabricated buildings, the study by Bathon [63] focused on panel-based prefabricated buildings,
highlighting the importance of the connections between the prefabricated components. His results
demonstrated that the lateral load on the floor level was 429 kN/m (see Figure 8), and highlighted
that this wood-concrete-composite panels system provided more structural stability under wind
loads as well as seismic loads. Overall, this wood-concrete-composite panels system allows for a cost-
efficient hurricane-proof design and provides more resistance under seismic loads compared to
contemporary American and European building systems.

Figure 7. Elements of wood-concrete-composite buildings [63]: a) Wall; b) Floor; c) Roof.

Figure 8. Wind loads based on hurricane conditions [63].

Buildings 2019, 9, 38 9 of 13

A full-scale simulated wind load test was conducted on a prefabricated panelised steel framed
single storey building at the Cyclone Testing Station, Australia [64]. The testing evaluated the
transmission of load sharing (i.e. uplift and lateral loads) across the various panelised elements such
as the wall, ceiling, roof, connections, etc. The results show that the prefabricated panelised steel
framed building performed well when subjected to static loads simulating the lateral and uplift for
50 ms-1. However, during load cycling to simulate cyclonic wind load fluctuations, failure occurred
at the wall panel subfloor interface. This was due in part to the load cycles accentuating the eccentric
connection design resulting in fatigue of the rods. A similar type of prefabricated panelised steel
framed house structural system is currently being developed with new construction material, non-
conventional connections and advanced technology, and being built in some parts of Australia. Thus,
it essential to assess the structural responses of this type of building system under wind loads.

4. Constraints, challenges and future research

Project planning is one of the biggest challenges in prefabricated building construction, as
several factors must be considered, such as incorporating different components within a module
when they are lifted, transformation, placed on the foundation, and assembled the building [4,65].
This requires clear scope, more experience design and planning engineers, and skilled
manufacturing, and it also consumes more time and money. However, the accomplishment time of
modular houses or high-rise buildings was still less than that of conventional buildings [32]. Ramaji
and Memari [66] have highlighted that when the number of stories increases in a prefabricated
modular building, the time savings decrease considerably. This is because of system becomes more
complex, causing more challenges in project planning. Other constrains in the prefabricated system
are the module dimensions, the inability to make changes onsite, and transportation, which are the
most important factors needing to be considered before and after the design the structure.
Structural performance and the strength of the structural and non-structural elements and their
connections used in the prefabricated construction system are important to the design of the system.
Astonishingly, there has been limited published research on this system, because most of this
prefabricated system consists of patented elements. Also, prefabricated system development has
been undertaken under commercial and confidential conditions. The designers rely on the strength
of the structural and non-structural elements and their connections specified by manufacturers based
on commercial-in-confidence testing. In Australia, most of these tests were based on international
standards such as ASTM and European standards. This is because, in Australia, there are no specific
testing standards for most prefabricated structural and non-structural elements. Moreover, the
prefabricated structural design follows the normal conventional structural design standards. But
prefabricated structural systems are complex, non-conventional systems, and they use several non-
conventional connections. Therefore, Australian design standards need to be developed to include
the design specifications and recommendations for prefabricated structures. This requires more
research and case studies.
Furthermore, individual component testing (i.e. wall, ceiling, roof, connections), full-scale
testing and numerical models are the tools used to assess the performance of prefabricated building
structures. There is limited number of tests, and few numerical models have been conducted by
manufactures and researchers. In addition to this, there is only one full-scale test to have been
conducted on prefabricated, panelised, steel-framed housse [64]. Full-scale tests are important to
assess the performance of structures, as there are inherent redundancies in structural behaviour when
comparing individual component tests and full-scale tests [67]. This could create variations in the
design of wind, earthquake and fire-resistant loads that are estimated from simplification load
transmissions. The current uses of new materials and construction types in prefabricated construction
systems also need to assess their strength and structural system responses via sub assembly tests as
well as full-scale tests. The fire ratings of materials used in the construction industry are critical for
the performance of prefabricated building systems. For example, the CLT panels and façade system
used in the prefabricated system face issues in term of their fire ratings. Therefore, future research
needs to be focused on evaluations of the structural performance of prefabricated buildings via full-
Buildings 2019, 9, 38 10 of 13

scale tests, numerical modelling and hybrid simulation. Hybrid simulations offer a more efficient and
suitable way to assess how large prefabricated buildings respond to seismic loading by combining
physical testing and computer modelling. Researchers and the building industry should ensure that
the outcomes of future research are available for the public and design engineers. The outcomes
should also be used in construction practices and design methodologies to increase the prevalence of
prefabricated buildings in Australia.

5. Conclusions
In this paper, the performance of prefabricated building systems has been reviewed from the
available resources. This review shows that prefabricated building systems and construction hold
high potential to improve the efficiency and performance of the Australian construction industry in
a more sustainable sense. However, more research studies are needed to ensure that these prefab
building systems and construction deliver substantial benefits economically, and in an
environmentally- and socially-friendly manner. Here are some suggestions to increase the market
demand and to contribute to the development of prefabricated building systems in Australia.
 The limitations of transportation, regulations, and special traffic control in the construction area
are the main factors to be considered in transportation planning. Therefore, more case studies are
needed to evaluate project planning, scheduling, and the cost of small- and large-scale projects.
 More research and case studies are needed to develop and include the design specifications and
recommendation for prefabricated structures according to Australian design standards.
 Previous study has highlighted that most often, structural performance of prefabricated building
systems is assessed by individual component testing and numerical models. There could be an
inherent redundancy in the structural behaviour when the structural response between
individual components and the whole structure are compared. Therefore, numerical modelling,
hybrid simulations and full-scale tests need to be conducted on prefabricated whole buildings to
evaluate the structural responses and performance under fire, wind and earthquake loads.
 A lack of awareness on the performance, benefits, and affordability design and techniques
provided by the prefabricated systems is a major challenge for the marketing of prefabricated
building construction in Australia. This could have been achieved through social and economic
research. This research should focus on the following activities, such as questionnaires,
workshops, conferences and media interviews.
 Although a great deal of previous academic research has proven the sustainability aspects of
prefabricated construction, this knowledge needs to be more effectively communicated to the
general public. This needs to be accompanied by real case studies on public infrastructure
projects where the general public benefits from the performance of prefabricated structures.
 The skills and knowledge required for prefabrication design and construction practices in
Australia need to be developed and strengthened through relevant educational courses,
workshops, conferences and vocational training. Also, universities, TAFE and vocational
education institutes should consider including prefabrication design and construction in their
courses. This will increase the professional skills and knowledge required for the design and
construction practices, as well as increasing their productivity.
 The government and building industry need to encourage the building of some trademark
structures similar to the ‘Little Hero’ low-rise apartment building in Melbourne. This will
increase the market demand and development of prefabricated building systems in Australia.
Author Contributions: Conceptualization, S.N., and T.N.; Funding acquisition, T.N.; Investigation, S.N., T.G.,
D.H.; Writing—original draft, S.N., D.H., and T.G.; Writing—review & editing, S.N., D.H., T.G and T.N.

Funding: This research was funded by the Australian Research Council (ARC) Training Centre for Advanced
Manufacturing of Prefabricated Housing (Project ID: IC150100023) and the Asia Pacific Research Network for
Resilient and Affordable Housing (APRAH)

Acknowledgments: The authors gratefully acknowledge the funding support of the ARC Training Centre for
Advanced Manufacturing of Prefabricated Housing and the Asia Pacific Research Network for Resilient and
Affordable Housing (APRAH) of the Department of Infrastructure Engineering, University of Melbourne.
Buildings 2019, 9, 38 11 of 13

Conflicts of Interest: The authors declare no conflict of interest.

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a research presentation
 Reserachers:
Kabir Shakya, Anil C. Wijeyewickrema, and Tatsuo
Ohmachi

 General Objective:
To investigate the effects of soil on mid-column seismic
pounding of reinforced concrete buildings in a row

 Specific Objective:
Compare the Inter-story displacement, Impact Force-Time
History and Normalized Story Shear of the following:
◦ Fixed Foundation (No Pounding)
◦ Fixed Foundation (w/ Pounding)
◦ Flexible Foundation (w/Pounding)
 Anagnostopoulos (1988) simulated earthquake induced pounding between
adjacent structures by using a spring damper element where the damping
constant is represented in terms of the coefficient of restitution.

 Jankowski (2005) used a non-linear viscoelastic model to perform more accurate

simulations of structural pounding during earthquakes.

 The analysis results were compared with the results of experiments performed by
van Mier et al. (1991) and the characteristics of concrete-to-concrete impact and
steel-to-steel impact were also obtained.

 Karayannis and Favvata (2005) studied the influence of structural pounding on the
ductility requirements and seismic behavior of reinforced concrete structures with
equal and non-equal heights, designed according to Eurocode 2 and Eurocode 8.
Idealized models with a lumped mass system were considered using the program
DRAIN-2DX for the analysis.

 Rahman et al. (2001) highlighted the influence of soil flexibility effects on seismic
pounding for adjacent multi-story buildings of differing total heights, by using 2-
D structural analysis software RUAUMOKO, for which the discrete model proposed
by Mullikan and Karabalis (1998) was used.
*Finite element analysis software
SAP2000 is used to analyze the
buildings.
 5% damping ratio
 γc =24 kN/m3
 Ec = 24821 N/mm2
 νc = 0.2
 f 'c =27 N/mm2
 fy=414 N/mm
 live load = 2 kN/m2
 roof load = 1 kN/m2
 partition load = 1 kN/m2
 code requirements of ACI 318-02
 seismic class D area
 seismic use group II
 seismic design category A
 The buildings are provided with 150 mm thick slab and
350 mm x 600 mm beams
 Consideration of effects of underlying soil is
beneficial as the impact forces and peak shear
amplification factors are reduced. Also, soil effects
can modify the building response significantly.

 In general, the buildings under consideration are

more vulnerable to near-field earthquakes.