An Introduction to the Field of Civil Engineering

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Civil engineering is the oldest and broadest engineering discipline among all the engineering fields. The
field deals with the planning, designing, and construction of buildings and various other structures. From
huge dams to sky high buildings, from suspension bridges to offshore drilling platforms, every physical
concrete structure comes under civil engineering.
The usage of civil engineering dates back to the ancient times. Most of the seven wonders, including
Egyptian pyramids and the Taj Mahal, are the creation of flawless civil engineering skills. Some of the
world’s oldest civilizations such as Harappa and Mohenjo-daro are also the product of immaculate civil
engineering. After all, how can one ignore the magnificent architecture of Rome’s Coliseum or the unique
design of the great Eiffel tower?

Sub-Branches of Civil Engineering

Civil engineering is the most diverse field of all the engineering branches. Technically speaking, civil
engineering is the creator of the whole world’s infrastructure. Structures such as tunnels, dams, sewers,
bridges, highways, canals, industrial plants, residential buildings, railway lines, airports etc come under the
category of civil engineering. Moreover, as the population of the world increases and the technology
becomes more advanced, the need for better infrastructure will increase around the world. Civil engineering
continues to cater to these needs in all the sectors and aspects of human life.
The need for infrastructure has increased by leaps and bounds in each and every sector. In order to
concentrate and manage the construction process in each sector, the field of civil engineering has been
divided into various sub-disciplines. This means that on the basis of applications, the stream of civil
engineering has been segregated into several branches to make the construction process easier and more
manageable. Some of the main branches include – bridge engineering, construction engineering, coastal
engineering, geotechnical engineering, environmental engineering, transportation engineering, surveying
etc.

Application and Process

An ideal process of civil engineering will include the construction of a concrete structure right from the
planning to the maintenance of the structure even after it is made. Civil engineers are the professionals who
perform the functions involved in a construction process. They plan, design and analyze each and every part
of the structure before starting the actual construction process. Designs of all the parts of the building along
with precise specifications are drafted on drawing sheets prior to the construction process. A study of
various forces that can act at each of the building corners is made and on the basis of that further
modification in the design is done. Even the minutest corner of the planned structures is scrutinized to check
the amount of stresses and strains that might arise when the structure is built or in the process of making.
Apart from this, the structures are also provided with tolerance levels to adjust deviations due to wind,
seismic activities, or natural calamities. These tolerances allow the building to resist the natural forces and
thus stand strong without being impacted.
Thus civil engineering deals with setting up reliable structures with guaranteed longevity. Also, with an
increase in awareness towards renewable sources of energy, the applications of civil engineering have also
increased. Environmental engineering, a sub-branch of civil engineer, deals with constructing structures that
have low impact on the environment and leave no carbon foot prints. Environmental engineering also deals
with creating structures on both onshore and of shore sides in order to make efficient and environmentally
friendly sources of energy. Some of these applications include various methods to purify the contaminated
air and water, utilizing solar energy, generating fresh water, utilizing wind and water energy, and protecting
the marine environment.
Civil engineering is becoming more and more diversified with the increase of applications. Moreover, the
guidelines of constructing structures have also become more stringent, stressing issues such as human safety
and resistance to natural and man-made calamities
 Types Of Reinforced Concrete
Fibers are utilized in cement to manage the cracking characteristics and reduce permeability. The
surrounding concrete protects the steel used for reinforcement. Glass fiber reinforced concrete is used for
architectural products and steel fibers are mostly used for paving and inside tunnels.
History of Reinforced Concrete

Fibers have been used for concrete reinforcement since prehistoric times though technology has improved
significantly, as is applicable for other fields. In the early age, straw and mortar were used for producing
mud bricks, and horsehair was used for their reinforcement. As the fiber technology developed, cement was
reinforced by asbestos fibers in the early twentieth century.
During the middle of the twentieth century, extensive research was in progress for the use of composite
materials for concrete reinforcement. Later, the use of asbestos for concrete reinforcement was discouraged
due to the detection of health risks. New materials like steel, glass, and synthetic fibers replaced asbestos for
reinforcement. Active research is still in progress on this important technology. Fiber Reinforced Concrete
is considered to be one of the greatest advancements in the construction engineering during the twentieth
century.

Glass Fiber Reinforced Concrete (GFRC)

Glass fiber reinforced concrete has been successfully used since the last 25 years for concrete reinforcement,
in addition to steel. GFRC is being manufactured into big panels with a simple configuration or into intricate
shapes by using special techniques. Originally, GFRC components were anchored directly with the buildings
by the use of metal studs. It was revealed that GFRC shifts considerably due to which the direct anchors are
being replaced by slip anchors. Several structures use GFRC for dissimilar facing like ceramic tiles, bricks,
and architectural purposes.

Steel Fiber Reinforced Concrete (SFRC)

Steel fiber reinforced concrete is a composite material that can be sprayed. It consists of hydraulic cements
with steel fibers that are dispersed randomly and possess a rectangular cross-section. The steel fibers
reinforce concrete by withstanding tensile cracking. The flexural strength of fiber reinforced concrete is
greater than the un-reinforced concrete. Reinforcement of concrete by steel fibers is isotropic in nature that
improves the resistance to fracture, disintegration, and fatigue. Steel fiber reinforced concrete is able to
withstand light and heavy loads

Different Types of Fibers Used for Concrete Reinforcement

Natural fiber reinforced concrete (NFRC) consists of cellulose fibers that are processed from pine trees.
This category is also producing good results. The recycled carpet waste has been successfully used for
concrete reinforcement by using the waste carpet fibers.
Polypropylene Fiber Reinforced (PFR) concrete: Polypropylene is a cheap and abundant polymer widely
used due to its resistance to forming chemical reactions.
Asbestos Fibers: These fibers are cheap and provide the cement with mechanical, chemical and thermal
resistance, although the asbestos fiber reinforced concrete appears to have low impact strength.
Carbon Fibers: These fibers have been recently used due to their very high modulus of elasticity and
flexural strength. Characteristics such as strength and stiffness are better than those of steel fibers, although
they are more susceptible to damage.

Engineered Cementitious Composite (ECC)

A fiber reinforced concrete has been developed recently that is called Engineered Cementitious Composite
(ECC). It is claimed that this concrete is 40 % lighter than normal concrete, resistance to cracking exceeds
500 times, and strain hardening exceeds several percent strain. Thus, the ductility is significantly greater
than normal concrete. It is also known as bendable concrete since it can easily be molded and shaped. It can
self-repair minor cracks by the reaction with carbon dioxide and rainwater, making the concrete stronger.
 Basic Methods of Waste Management
written by: Finn Orfano • edited by: Lamar Stonecypher •
After the industrial revolution, waste management became an important and necessary function. Learn some
of the main methods used in managing waste products today.
Waste management is the control of materials that have become redundant and therefore need to be
discarded. The process includes collection, transportation, sorting, recycling, clearance, and disposal of
waste materials. Waste management includes radioactive substances and other materials that are in a solid,
liquid, or gaseous state, and their management techniques also differ from each other.
Waste management is normally concerned with the materials produced by actions of humans, and unless
managed efficiently may have adverse effects on the environment and health of the community. It is an
important and complex process due to the multiple varieties of waste produced by industry, each producing
different types of materials that require special management techniques.

Techniques of Waste Disposal

Landfills
Landfills, being simple and economical, are globally the most common system of waste disposal. It involes
the burial of waaste materials. Landfills that are not properly designed or managed may create several
environmental hazards and diseases due to the dispersion of garbage by wind, the attraction of rats, and
other similar reasons.
Landfills are normally developed in unused pits located at a distance from the developed areas so that its
harmful effects can be avoided. The waste accumulated in the landfill is reduced in size by compaction to
permit maximum storage of waste, and is enclosed to avoid rats or mice. Some landfills include systems for
the extraction of gas that is used for the generation of electricity.
It is essential that the landfills do not pollute the surface water or the ground water, and this is ensured by
lining the landfill, compaction of the upper layer, and selection of sites that are not subjected to floods.
Leakage from landfill waste can be minimized by solidification with cement or asphalt.
Incineration
After landfills, incineration is the most widely used method to eliminate the solid, liquid, and gaseous waste.
Hazardous air contaminants are released by the burning of waste, due to which there are serious public
concerns regarding environmental pollution. The combustion is generally not complete in an incinerator, due
to which the gaseous emissions contain micro-pollutants that are not safe for the area near the incinerator. In
countries where adequate space is not available for landfills, incineration is more practicable.

Recycling
Recycling is probably the most ideal way of managing wasate, but it can be costly and difficult to
implement. There are numerous products that can be recycled instead of thrown away including aluminum
and steel cans, glass bottles, paper, and scrap metal. It is becoming more popular to complete this process
and successful marketing is making recycled materials more likely to be purchased. In the long run,
recycling can save money and resources as well as keep the environment cleaner.
 Green Rooftops for Energy Efficiency
written by: John Moehring • edited by: Lamar Stonecypher • updated: 5/8/2013
The LEED system for energy efficient building construction, maintenance, and operation has led to renewed
interest in roof gardens and greenery. Several important considerations should be examined for retrofit and
new construction of such systems.
For over 70 years the concept of placing live ecosystems on top of buildings in the U.S. has been pursued as
an environmentally friendly alternative to traditional roofing materials. These systems range from discreet
box gardens covering minimal surface area to eave-to-eave plots covering the entire roof.
The idea of planting a live roof actually originated in Europe long ago, mainly as a cheaper and more readily
available alternative to more robust roofing systems at the time. And while the benefits and maintenance of
these “living roofs" is the subject of much discussion, the successful construction of these systems requires
attention to several factors: material specifications, structural loads, and water handling.

Greener Material Specifications

In order to sustain living plants, the planted roof must have soil. Just like any other planted area, the soil
must contain nutrients and have proper aeration and water. The construction materials selected for such a
system therefore must be able to resist exposure to soil chemistry and fertilizers, physical abrasion from
tilling, and contact with insects, animals, roots and soil, and to the constant presence of moisture. In
addition, failure of the selected roofing materials may require excavation which would be a considerable
undertaking for full roof plantings.
Most traditional roofing materials are not formulated for constant contact with soil chemistry, and are
designed to shed moisture and spend at least part of their life cycle in a dry, well ventilated state.
Membranes, insulation, drains, and containment supports should then be selected based on zero
maintenance, below grade specifications such as those used beneath pavements, foundations, and patios as
opposed to standard roofing criteria.

Structural Loads - Weight of Green Rooftops

One cubic foot of dry, agricultural dirt or loam typically used for a “green" roof weighs between 75 and 81
pounds. Saturated with water the weight can increase by as much as 35%, to around 100 to 110 pounds per
cubic foot. This means 100 square feet of planted roof containing soil 6 inches deep can add over 5000
pounds of dead load to the roof structure, roughly 50 p.s.f. or more.
Four discrete planter boxes or containers 6 feet long, 2 feet wide with 1 foot depth of soil applies a similar
load. Add a blocked water drain and the weight starts adding up at the rate of 5 p.s.f per inch of standing
water. Add a conservative snow load allowance for flat roofs of 15 p.s.f., and the design criteria can easily
exceed 70 p.s.f. dead load. For a modest building using 2500 sq.ft. of living roof construction this could
translate to 175,000 pounds of dead load on the roof top. Constructed in a seismic zone this can become an
unexpectedly live load directly above the heads of the building occupants.
Finally, if the planting is intended to be a tended garden additional live loads will be incurred by equipment,
gardeners, and visitors if applicable. Whether for new construction or for retrofitting existing roofs,
structural engineering design is required for anything more than a few square feet of planted roof area.

Watering and Drainage

Live plants not only need water to maintain growth, but need adequate drainage to prevent disease and rot. A
living roof also requires excellent drainage to prevent a flood event, which could have disastrous
consequences at rooftop level. Again, drains designed for below grade applications with constant soil
contact and zero maintenance are required as opposed to conventional roof drainage systems. A layer of
agricultural lightweight aggregate or pea gravel covered with a suitable filter fabric is usually adequate.
There are also proprietary formed drain systems available, such as synthetic fiber mats and cellular matrices,
which are thinner, lighter, and can increase drainage rates but usually at higher cost. Additionally the
drainage design should incorporate several collection points serving a given area in case one drain becomes
clogged. Finally, active irrigation needs to be closely monitored to avoid excess water weight as mentioned
previously.

LEEDing The Way

With these construction considerations in mind, a properly designed and executed living roof can be an
excellent choice for building construction. Some estimates indicate more than 20 LEED points can be
obtained from such a system, not to mention the purely aesthetic improvements that can be achieved.
 How Heating and Ventilation Loads are Assessed
written by: Chief Engineer Mohit Sanguri • edited by: Lamar Stonecypher • updated: 12/27/2013
Before selecting the appropriate HVAC system, builders first need to determine the heating and ventilating
loads. Loads are determined by some environmental factors and design calculations. Learn more about why
its so important.
The most important element in the design and selection of a heating and ventilating system is the
determination of the heating and ventilation loads in the building where the system is to be installed.
Accurate assessment of these loads will facilitate the correct selection of the system for the required
building. A perfect system will function constantly with variable productivity, which is commensurate with
the heat load of the building as the climate changes. Such a system can be attained with accurate design
analysis of the heating load of the building and the selection of a proper heating system.

Factors of Heating and Ventilating Loads

The following factors should be taken into consideration while determining the heating and ventilating loads
of a structure:
• Amount of heat distributed through the area exposed to locations which are not heated.
• Amount of heat necessary for the air to become hot, which penetrates from the cracks adjacent to the
windows and doors, and also from the entrance, when persons come in or go out of the building.
• Heat which is necessary to make the air that has come mechanically into the building as ventilation air
hot.
• A variety of other loads.

Design Calculations
The basis for determining the heating load are the constant average temperature for winter nights and
any continuous supply of heat present at all times. The quantity of heat accumulated by the building must
be taken into consideration as well as the energy of any cooling equipment.

Method for Estimating Heating Load

The normal process for estimation of heat load is as follows:
• Carry out an assessment of the weather conditions prevailing outside the building, including humidity,
temperature, path of wind and speed.
• Determine the desirable inside air temperature to be maintained.
• Assess the temperature in adjoining locations which are not heated.
• Choose the coefficient of heat transmission.
• Establish the outside areas by which heat is dissipated.
• Estimate the losses by heat transference from glass, bricks, and base in the building.
• Calculate the heat loss from the underground area.

Structure Of Building
Design calculations, and the selection of heating system, are largely based on the structure of the building
and its use, including the exposure of building to wind, the direction of the sun, periods of occupancy and
part of day when the building will be used, and the expected financial impact of the equipment and fuel. All
these factors should be considered while assessing the heating and ventilating loads of a building

How a Hydroelectric Dam Works

written by: Suvo • edited by: Lamar Stonecypher • updated: 7/26/2013
The power of falling water is unlocked by a hydroelectric dam in the form of electricity. In this article, we
will look at how hydroelectric dams work, and what are their advantages and disadvantages.
Hydroelectric power produced by hydroelectric dams accounts for 20% of the world’s total production of
electrical energy. Although human beings have been using the power of water for around 2000 years now,
the idea of generating electricity from it only started in the mid-20th century.

How it Works

A hydroelectric dam converts potential energy (and/or kinetic energy) to electrical energy by means of a
turbine and alternator.
A typical hydroelectric dam has the following main parts:
Water Reservoir: A large quantity of water is stored in a reservoir (or dam). The height or depth of the
stored water determines how much electricity can be generated. As the depth increases, the generation of
electricity also increases.
Gate: A control gate is used for releasing/blocking water from the dam. Depending upon the electricity
requirements, the gate is opened.
Penstock: The released water from the dam reaches the turbine blade through the penstock. The proper
slope and diameter of the penstock is important for the efficiency of the dam.
Turbine: The turbine consists of a number of large fan blades and a spindle. The spindle rotates when
water strikes the blades. Thus the power of flowing water is converted to the rotational power of the
spindle.
Alternator: The spindle of the turbine is connected to the alternator, where rotational power of the
spindle is converted into electrical power. The produced electricity is then distributed to the grid.
River: The outflow of water from the turbine is released to a river.

Advantages of Hydroelectric Dams

• Cheap Electricity: The operating cost of a hydroelectric dam is minimal as there is no costly fossil fuel
required. Hydroelectric dams also tend to last longer than thermal power plants.
• Less Emissions: Hydroelectric power plants produces less greenhouse gas emissions when compared to
a thermal power plant.

Disadvantages of Hydroelectric Dams

• Effect on Eco-Systems: The construction of a dam affects the eco-system of the river and surrounding
area. Some species of fish cannot increase their population because of dams.
• Relocation: Dams are often constructed in populated locations causing both humans and animals to
relocate.
• Green House Gas Emissions: Although hydroelectric dams have considerabley fewer emissions
than thermal power plants, the blocked water in the dam does cause the release of methane into the
atmosphere.
There are many advantages to using hydroelectric power, but no form of producing energy is without its
downfalls. We hope continued research and development will minimize the disadvantages.
 Road Construction: History and Procedure
written by: Tarun Goel • edited by: Lamar Stonecypher • updated: 5/17/2013
Road Construction Methods have changed a lot since the first roads were built in about 4000 BC. Read on to
learn more about road construction methods and procedures.

In ancient times, river transport was much faster and easier than road transport. The Romans were one of the
first to build stone paved roads in North Africa and Europe to support their military operations. Later the
Arabs built roads that were covered with tar. The roads were constructed by preparing earthworks and lifting
the road foundation at the center for water drainage. Road construction techniques gradually improved by
the study of road traffic, stone thickness, road alignment, and slope gradients. Initial road construction
materials were stones that were laid in a regular, compact design, and covered with smaller stones to
produce a solid layer.
The building techniques were simple but effective as they reduced the travel time considerably and
connected one place to another by land. The Appian Way in Rome still exists although it was constructed
2300 years ago. If Roman roads are considered the beginning of road construction, Telford Pavements are
known as the second step of this process, followed by the Macadam Pavements that ultimately lead to the
Bitumen Roads. Today, the concrete roads have added another dimension to stability and strength of the
roadways.

Road Construction Techniques

Modern road construction involves the removal of geographic obstacles, and the use of new construction
materials that are far more improved and durable. Rock and earth is removed by explosion or digging.
Embankments, tunnels, and bridges are constructed, and then vegetation is removed by deforestation, if
necessary. Finally, the pavement material is laid by using a range of road construction equipment.
Roadways are basically designed and constructed for use by vehicles and pedestrians. Storm drainage and
ecological considerations should be considered seriously. Sediments and erosion are controlled to avoid
damaging effects. Drainage systems are constructed so that they should be able to carry waste water to a
waterway, stream, river, or the sea.
Importance of Earthwork
Earthwork is one of the major works involved in road construction. This process includes excavation,
material removal, filling, compaction, and construction. Moisture content is controlled, and compaction is
done according to standard design procedures. Normally, rock explosion at the road bed is not encouraged.
While filling a depression to reach the road level, the original bed is flattened after the removal of the
topsoil. The fill layer is distributed and compacted to the designed specifications. This procedure is repeated
until the compaction desired is reached. The fill material should not contain organic elements, and possess a
low index of plasticity. Fill material can include gravel and decomposed rocks of a particular size, but
should not consist of huge clay lumps. Sand clay can be used. The area is considered to be adequately
compacted when the roller movement does not create a noticeable deformation. The road surface finish is
reliant on the economic aspects, and the estimated usage.
Bulldozers are some of the most important items of equipment used in road construction. Since a bulldozer
is expensive, economic usage factors should be considered when using one. Bulldozers are extremely useful
for road construction where it is possible to throw the waste excavated material on the road sides. Bulldozers
may only be used if the slopes at the sides are not excessively steep. However, work on steep slopes can be
accomplished by a bulldozer by using special techniques and expertise.
Construction of roads in challenging conditions is no more a difficult tasks because the binding agents and
admixtures make it possible for the roads to last long and carry the heavy loads without cracking under
tough environmental conditions. Use of recyclable materials for the construction of roads has added balance
to the enviroment too.

Construction Management of Roads

With ever increasing traffic and exponentially increasing vehicular load, construction management
techniques have become the need of the hour. Managing maximum traffic in optimal space is what the world
needs today. Safe designing of roads, highway space management and proper drainage of water are major
aspects that the site engineers have to take care of. Construction management includes putting all the pieces
of puzzle together, defining project objectives, dividing the project into modules and optimizing the
available resources. Time, money and resource management are important aspects. Time saved is money
earned, and that is where construction management techniques are helpful.
 What are Beam Bridges?
written by: Aggeliki K. • edited by: Lamar Stonecypher • updated: 2/3/2014
Simple beam bridges may use wood beams, but modern beam bridges use light and strong materials.
Construction of a multi-beam bridge involves the use of a bridge crane, beam clamp for holding, and other
tools. Bridge load rating is done to determine the loads that can be safely carried.

What is a Bridge?
A bridge is essentially a construction that is built to cover a road, valley, water body, or other natural
obstacles to provide a route over the barrier. Several bridge designs are used that depend upon their function
and the soil conditions of the site for bridge construction. A bridge is described normally by its form of
construction, like beam, truss, arch, etc. A bridge may also be characterized by the construction materials
used, like concrete, stone, and metal. A bridge may have different types of spans that include simple,
cantilever, continuous etc.

Beam bridges can be simple and made of wood beams. Heavy beams are carried by a bridge crane using a
beam clamp to hold the beams. Bridge load rating is executed to establish the loads that can be safely carried
by the beam bridges. It is essential to calculate the bending moments in a beam to establish a safe design of
the beam bridges.

Characteristics of Beam Bridges - Types of Beam Bridges

Beam bridges basically consist of beam that is laid across the piers or supports. The beam should possess the
strength to bear the loads that are expected to be placed on it. These loads are borne by the bridge piers. The
loads cause the beam top edge to be compressed, while the lower edge is being stretched and is under
tension.
Existing beam bridges are formed by girders, normally box girders, trusses or I-beams, that are supported on
strong piers.
• Box girders are stretched, box shaped elements that are more suitable to bear the twisting loads.
• Trusses consist of one or more triangular units connected at joints or nodes.
• I-beams economical and simple to fabricate. They are simply beams with an I-shaped or H-shaped
cross-section. The horizontal elements of the "I" design are flanges and the vertical is the web of the
construction.
Other beam bridges may be fabricated from concrete beams that are pre-stressed. These materials possess
the steel characteristics to endure loads in tension, and concrete strength to bear the compressive loads.
The beam bridge's strength is largely influenced by the distance between the piers. Therefore, the beam
bridges are normally not suitable for longer length, unless several such bridges are connected with each
other.
The beam bridge's span is dependent upon the beam weight and the materials strength. As the bridge
material thickens, its capacity to hold the loads increases. Therefore, the span could also be increased.
However, a sturdy beam may become too heavy, and sag. The beam bridges can be supported by the
utilization of trusses.

Beam Bridges Materials

With the advancement in technology, materials science has also advanced considerably. Beam bridges
materials being used are strong, light, and durable. The advanced materials for bridge construction have
good operational characteristics.
Such materials include reformulated concrete, composite materials that are reinforced with fiber, steel, and
pre-stressed materials. Pre-stressed concrete is well suited for beam bridge construction since it can endure
excessive compressive stresses. Steel rods are fixed in the concrete that can bear the tensile loads.
Furthermore, pre-stressed concrete is cheaper.
The current techniques include use of finite element analysis to improve the design of beam bridges.
Distribution of stresses on different bridge elements is analyzed to ensure strong beam bridges that can
endure the bridge loads. The beams should be held by piers at the ends to increase the bridge load bearing
capacity. Concrete, steel, or stones are normally used for the construction of piers. Since stones and non-
reinforced concrete are weak in tension, they are normally used for beam bridges that are designed for
lighter loads.