Role of Prefabrication in the Construction Industry to improve sustainability and economy of Civil Engineering projects

1. Role of Prefabrication in the Construction Industry
to improve sustainability and economy of Civil Engineering projects
Abstract
With increase in labor costs, lack of skilled labors for different trades, demand for faster
construction, increased considerations for safety and environment, and above all meeting these
demands at an economic and reasonable price requires us to change the approaches we take to
build our project. Prefabrication or modular construction is one such solution to all these issues
which can help in building the project on time, safe, greener, and within reasonable cost.
This paper discusses the various advantages that are possible to achieve if we utilize prefabrication
strategy on construction projects by replacing the traditional construction methods. The role played
by prefabrication throughout the history of civil construction is also discussed in brief. It also
focuses on some of the difficulties in its path which have been there that have hindered its
application on a wide scale. The role of Owners, Architects, Engineers, Contractors and
Manufacturers in resolving these issues is also discussed in this research.
Finally, two case studies are done to reinforce the advantages offered by prefabrication and
modularization in the construction industry. Case Study of Fort Sam Houston Medical Education
and Training Complex in San Antonio, Texas, and The Stack Rental Apartments in New York are
discussed.
Keywords: Prefabrication, Modularization, Modular Construction, the Stack, Fort Sam Houston

2. Introduction
Prefabrication, a construction industry term, is used to describe a building or structural components
that are manufactured in industrialized/factory conditions and then transported to construction sites
to be assembled into a building, and civil engineering works. So, it is a process in that a whole
structure or building or a component of it is completely fabricated at an offsite location. These
offsite locations can be considered as equivalent to an industrialized manufacturing facility, where
things are built in controlled plant conditions. The construction is done as per the same design,
codes and specifications, and using the same materials as in the traditional onsite construction
approach. The offsite construction process takes relatively less time than the tradition onsite
construction method. These offsite fabricated buildings or components are then transported to the
construction site and then erected in place using cranes. As these have to be transported from
offsite location to onsite location, there is a limitation on the maximum permissible dimensions of
these components that majorly depend on the ergonomics of the roads, and highways through that
they will move. So, these buildings cannot be built in one piece, and thus, they are broken down
into small and manageable components. These small and manageable components are termed as
modules. When these modules are stacked together as per the plan, then they combine to form the
whole building that provides same facilities, functionality, and comfort as its cast in-situ
counterpart. These reflect the identical design intent and specifications of the most sophisticated
site-built facility without compromise.
If we consider the structural strength and structural feasibility of the prefabricated buildings, then
it is found that these buildings are stronger and more structurally sound than the convention onsite
constructed buildings. This increase in structural strength can be attributed to the fact that each
module of these buildings is engineered to independently withstand various loading conditions it

3. is expected to face during the transportation and erection phase. Once these modules are erected,
combined and sealed together they act as an integrated unit that is structurally and ergonomically
sound for the purpose it was constructed.
History
Prefabrication or Modular construction may sound like a new term to many, but this practice of
construction has been used for a long time. Its roots can be traced to the Rome in AD-43, where
the Romans used prefabricated building elements to build their forts quickly and efficiently. There
was a continuous construction of forts and stockade in the Roman Empire. Romans understood the
fact that these forts and stockades used a large number of same and repeating components. Thus,
to expedite the construction process, the Romans started prefabricating standard dimensions of
these components. Timbers were cut into specific sizes, grooves were also pre-cut ready for fast
construction, and the blacksmiths made iron nails in all different sizes and shapes. All this factors
combined helped the Romans build their bases with unbelievable speed.
Not only the Romans, but the Britishers also transported simple prefabricated houses by ships to
their new settlements in the colonies to provide comfortable European Style living to its officers
in these colonies. Prefabrication method also helped address British and European housing
shortages during Post World War I era. And, again during the Post Second World War era,
prefabrication came to rescue, as it alleviated the shortage of skilled labor in the midst of the
population outburst due to the baby boom.
Among most iconic structures in the world, The Eiffel Tower was also a result of utilizing the
method of prefabrication in the convention construction environment. Eiffel Tower was built as a
temporary exhibit structure for the Centennial Exhibition in Paris in the year 1889 for the

4. celebrating the French Revolution of 1789. And, today, it is known as one of the most renowned
structures in the world, a symbol of love and romance.
Figure 1: Gustave Eiffel
It measured 984 feet or 300 m in height and was the tallest building in the world for about 40 years.
The title was then taken over by the Chrysler Building in New York City in the year 1930. The
Eiffel tower consists of prefabricated iron parts that were mass produced at an offsite location. The
different iron parts were manufactured according to the design drawing and specifications. These
parts were then taken to the site and assembled to build a structure that is still considered as a
symbol of the city of Paris and the country France. The 984 feet tall structure was completed in a
time-period of just over two years with a menial investment of 8 million francs. The investment
capital was earned in the first year of its construction as people throughout the world visited to
witness this marvelous structure.

5. Figure 2: Crew that worked on Eiffel Tower
The labor force required for its construction was also very less, as it required only 300 workers to
construct it. It is also considered amongst the safest construction project of the time, as there was
only one fatality during its construction. Thus, Eiffel Tower is a structure that signifies modernity,
progress in technology, and an important chapter in the history of prefabrication industry.
History of Prefabricated Construction in the USA
As previously stated, the Britishers shipped prefabricated houses to its colonies in 1600’s. And
further during the gold rush in California, prefabricated readymade homes were transported to San
Francisco from all around the world to provide cheap housing solution. In 1908, Henry Ford’s car

6. factory and the assembly line concept largely influenced the American Prefabricated house
industry as Henry Ford’s Model T, the first affordable automobile, successfully demonstrated and
established the technique of mass production to manufacture high-quality products at a lower cost.
Many companies started to offer high quality, precut and prefabricated houses in various
customizable sizes, styles and design. Thus, began a trend of “House by Mail” that was pioneered
by Sears, Roebuck & Co. The company was able to sell more than 100,000 units of these houses
during 1908-1940. A “house by Mail” kit included all the components required to make a home
encompassing everything from lumber, nails and shingles to windows, doors and paint. The buyers
also had the option to customize these homes as per their needs and desire. People could purchase
these ready-to-assemble homes by placing an order through the mail. And these houses could then
be shipped in boxes to any place that was accessible utilizing rail or other means of transportation.
These homes were meticulously designed, and exceptionally tough and sturdy.
Figure 3: House by Mail by Sears, Roebuck & Co. of Chicago

7. With the advancements in the field of information technology and the interaction between the
construction process and these technologies, has greatly influenced prefabrication and modular
construction. Now, the industry is starting to develop more efficiently as the new technology has
provided more options and flexibility. The advancements in the field of computer and digital
technology have helped in the industry in both the manufacturing as well as the design process.
The words like CAD, CAM, CNC, and BIM, that stand for Computer Aided Design, Computer
Aided Manufacturing, Computer Numeric Control, and Building Information Modelling
respectively, have become common words in the vocabulary of architects, engineers, contractors
and manufacturers. They help in making a realistic model of the finished product in a digital
format. This digital representation can be changed, tweaked and modified on a computer screen
without the need of any physical material required. The Building Information Modelling (BIM)
software has helped the architects and engineers to see their project clearly in a 3D Model, just
like if it was constructed on site, and thus, they can understand the various challenges they might
face during the actual construction and find solutions for the same. BIM 3D models play a very
vital role when the building components are produced in a factory setting as it allows the
production team in the factory to see any individual building component from a whole building
model. With the introduction of BIM, prefabrication is now a day viewed as the future of the
construction industry.
Why Prefabrication
There are many factors that can be attributed to causing a positive impact on the use of
prefabricated structures in building and civil construction works. Some of these factors can be
summed up as follows:-

8.  As discussed earlier, there has been a sporadic demand for prefabricated buildings and
facilities throughout the history during British Colonization, World War, and Post World
War era
 With the ever-increasing population, there has been a rapid development in the residential
as well as the commercial field that demanded faster construction techniques
 In the times of distress when natural disasters like earthquake and cyclones etc. occur, they
cause huge damage to civil property and buildings. It becomes necessary to restore them
to bring back the life of the people to normal that requires a rapid construction of building
and facilities to restore the affected areas
 The labor cost has reached all-time high levels in the recent times. This increase in labor
cost has led to bringing changes in the construction processes to effectively utilize the
resources to extract maximum productivity at minimum additional cost
 Also, there has been a shortage of skilled labor workforce that further necessitates creating
workspaces that guarantee stable jobs for the skilled labors
 The new technological advancements and interaction of information technology with civil
engineering has led to the development of various 2D and 3D design software in the past
that has helped the construction industry a lot. And, there have been more dramatic changes
in the construction industry with development of software for Building Information
Modelling (BIM), which are becoming a trend and more commonly used throughout the
world
 The health and safety concerns for the construction workers has led to making changes in
the construction procedures on the field. Taking the construction process from field to a

9. factory setting has also gained reputation for improving health and safety of workers as it
provides a comparatively safer work environment
 There has also been a shift towards promoting greener and sustainable construction
practices that require changing how things are done in the construction industry today
The factors listed above are getting popular day by day, and their influence on the construction
industry is also increasing at a rapid rate. Prefabrication is one such method that provides a
satisfactory solution to all the demands discussed above.
Construction on sites involving prefabrication begins simultaneously with the site work. For
Example, as the excavation work proceeds on site, prefabrication of superstructure and can be
started on an offsite location, which will significantly save construction time and allow the projects
to be completed in lesser time when compared to tradition construction practices. As the work in
completed inside a factory, it mitigates the risks of delays in construction schedule due to bad
weather. The building and facilities constructed employing prefabrication can be sold or leased
sooner as the construction is completed ahead of time that in turn leads to faster returns on
investment. Prefabricated structures are built with same materials, using same codes and
specifications as the traditional construction, and once fully assembled; they are virtually
indistinguishable from their site-built equivalents.
As the prefabrication work is done in a factory setting, it provides an indoor construction
environment for the workers to do their work. This indoor work environment reduces the risks of
accidents and thus, reducing the liabilities related with them. Factory setup of construction also
promotes stable jobs for the skilled workers. Here the productivity is also high as compared to
traditional construction practices that help in obtaining maximum productivity from the workers

10. at minimum cost and thus improves project economics. Integrating BIM further adds to these
advantages and makes prefabrication a worthy alternative over traditional construction methods.
Sustainability of a project is also enhanced by using prefabrication it uses factory controlled setup.
Less waste is generated when building in a factory that eliminates the need for the significant
quantity of waste recycling. Less material waste also means less investment in buying new
materials that mean lesser inventory control. The majority of the prefabrication work is done
indoors and away from the construction site, which greatly minimizes onsite traffic and onsite
labor cost.
Prefabrication – Present and Future
Prefabrication is on the agendas of the government and commercial sectors in various countries
across the world. A major consideration is given by Europe, Canada, United States, New Zealand
and Australia. Prefabrication is considered as an important way of improving quality, safety,
sustainability and value within the slow changing construction industry. The scale and demand for
prefabrication is increasing day by day as it offers various merits over the traditional construction
practices. The increase in construction products manufactured and produced in factories at an
offsite location and brought to the site for assembly and erection is now slowing becoming a
common trend as it offers better quality control, more efficient site processes, more
environmentally friendly manufacturing, and an overall reduction in the project cost. The demand
for prefabrication and modular construction is growing, and also is the complexity related with it.
Back in the old days, you would typically see a prefabrication and modular construction being
utilized in the construction of temporary housing and accommodations, but now it is being used in
advanced projects to create permanent buildings and facilities ranging from single family housing

11. to residential apartments, and large commercial buildings. Prefabrication has allowed the
construction of these buildings and facilities with cost savings and timeframes that were earlier
not achievable.
The use of prefabrication/ modularization has not witnessed a steady increase over time. It has
seen fluctuations in its demand throughout the history of building construction whenever there was
a drastic need for speed and efficiency in times of colonialization, wars, and economic boom.
However, the technological advancements that have taken place in that last two decades have led
to increase in capabilities of what the prefabrication process can accomplish in the construction
industry. Building Information Modelling (BIM), modern high-quality materials, and advanced
manufacturing facilities these days offer substantial enhancement in the productivity on projects
that was not possible earlier. Recently, a committee of experts selected by National Research
Council recognized the fact that prefabrication/ modularization will play a central role in
improving the efficiency, affordability and competitiveness of the U.S. construction industry in
near future. With U.S. construction market facing acute shortage of onsite skilled labors, and also
where the stakeholders are trying to be greener and more sustainable, a majority of them
understand that this is the right time, more than ever, for extensive implementation of offsite
prefabrication and modularization solutions on a major scale in the construction industry.
Prefabrication surely offers a potential alternative to traditional construction practices, but there
have been many hindrances in its applications to realize its full potential. Some of the key factors
that block its path are as follows:-
 Higher initial construction cost and time: - It requires high initial investment as many of
the companies have to start from scratch. Most of this investment will go on in hiring

12. professionals adept in this field and investing in software like BIM, which will make the
tasks smooth. Also, there is more effort required during the project planning phases to
efficiently integrate prefabrication in the project, and thus requires more initial time
 Inflexibility in changes: - As most of the construction is done in an offsite facility as per
initially agreed upon design drawings and specifications, and at the same time site work
for excavation and foundation also continues. Now, if there is a need to make some change
that arises due to site conditions during these phases, and if that component is already
prefabricated then it will lead to problems
 Lack of background information and lack of experience: - This is also a common problem
as many of the engineers and architects do not fully understand the ways in that they can
benefit from prefabrication. Haphazard efforts without prior knowledge often lead to
reverse effects and causes higher cost and delays instead of being economic and fast.
 Lack of demand for prefabricated structures: - Many investors are demanding economical,
greener and faster solutions for their construction projects, but many of them are hesitant
to employ prefabrication as a potential solution as they are uncertain of its success.
 Transportation issues: - Often there may be such site conditions that will not allow
transportation of large modules to and from the site that will limit the size of these modules
and thus increase the number of trips required to do the same job.
There is no doubt that prefabrication and modularization methods have a lot of merits and so proper
steps must be taken to educate people and spread the idea. To solve the problems stated above
owners, investors, architects, engineers, contractors, etc. play a very vital role.
Owners should consider using prefabrication and modularization process in their projects. Gone
are those days when prefabrication was just used for temporary establishments. With the precision

13. and details offered by software like BIM, flexibility offered by modern construction materials and
manufacturing facilities, etc. have contributed together to make prefabrication a worthy alternative
to obtaining a significant gain in the projects. Owner demand is the primary factor for architects
and engineers to include prefabrication in their project designs.
Architects should understand and also educate their clients about the benefits of prefabrication.
Architects are often the first people to meet a client on a new project, and also they have the greatest
influence during the design phase of the project in determining whether prefabrication will be used
or not. For being able to do this, architects have to understand the benefits of this method in
improving project productivity, making it more sustainable and increasing the Return on
Investment for the client and other stakeholders of the project. Architects should educate their
clients regarding the measurable benefits offered by prefabrication:
 Reduced project schedules – saving a month or more, and decrease in purchase and
installation cost of materials that ultimately decreases the project cost aiding in lean
construction
 Increase in construction site safety that results in fewer accidents and lowers the insurance
cost
 Reducing the construction waste significantly, and thus making the project greener and
more sustainable.
If an architect is able to convince the owner, then he should incorporate prefabrication his designs
from day one. The early inclusion in design process allows for maximum advantages.

14. Engineers are the one who are responsible for the structural integrity and efficiency of the buildings
in design and construction phases. Engineers must evaluate the quality and availability of the
prefabricated products and be the catalyst in promoting its use on the projects.
General contractors and construction managers are the people responsible for bidding and
constructing the projects. Thus, they must include the efficiency, green and sustainability factors
offered by prefabrication in their planning and bidding processes. This will not only lower the
project cost but will also make them more competitive in the market.
Manufacturers and specialty contractors are the central points in all this. If there are enough
manufacturers and specialty contractors who are adept at making prefabrication components, then
it will make the task of architects, engineers and contractors easy. Thus, the realization of the full
potential of prefabrication depends on the efficacy of manufacturer and specialty contractors who
must be encouraged to invest in this field.

15. Case Study
Fort Sam Houston Medical Education and Training Complex - Largest Modular Project in
North America Meets Army Needs
Figure 4: Fort Sam Houston Medical Education and Training Complex in San Antonio, Texas
The U.S. Army Corps of Engineers (USACE) recently incorporated permanent modular
construction (PMC) and onsite construction for its recent construction project in Fort Sam
Houston. USACE project was to build a Medical Education and Training Complex in the city of
San Antonio, Texas. Using PMC offered an effective solution to speed up the construction of the
project without compromising the quality, safety, and durability of the building. The Army has
strict requirements for its projects that aim at making each project a LEED Certified Project. The
alternative of PMC helped realize the Army’s requirements and made it a LEED certified building.

16. With a total square footage of one million sqft, - it the world’s largest military medical training
facility, and as it fused PMC into its project construction methods, it is also regarded as one of the
largest permanent modular construction projects in the world. This facility will house 2400
medical trainees. As part of the Federal Government’s Base Realignment Closure program
(BRAC), the dorm housing at Fort Sam Houston will signify an important stride towards modular
construction. The contractor for this project was Warrior Group that combined the merits of factory
built modules with traditional steel and concrete construction. This resulted in a state of the art
structure built at a reasonable price tag and in relatively short span of time.
Figure 5: Erection of PMC Module
To accomplish this task, three types of construction techniques were used in the design. First was
to include factory built dormitory modules that utilized a wooden shear wall design that helped in
resisting the lateral loads coming on the structure. Second methods employed was the steel frame
construction in the office areas that uses brace frame type of steel column and beam construction
giving the building an additional advantage in resisting lateral loads. The braces are inserted in

17. office walls. The third approach was to utilize moment frame construction in their design that uses
rigid-welded connections at the intersection of a column and beam to resist lateral loads. This
provides the ability to create large open spaces for rooms without columns. This technique was
useful in building conference rooms and briefing areas. The project is able to meet the
government’s stringent Anti-Terrorism Force Protection Requirements that should include various
features like progressive collapse, strict air infiltration criteria, etc. It also met the requirements of
LEED Silver Certification standards. Thus, this project stands as a testament to the various
advantages concerning quality, safety, sustainability, and superior results that are achievable by
effectively utilizing prefabrication and modularization in the construction industry.
The Stack Rental Apartments, New York - Potential Solution for Much-Needed
Urban Housing
Figure 6: The Stack in Inwood, Manhattan

18. The Stack is a multifamily housing project in located in Inwood, Manhattan. It is the first modular
building in Manhattan. It is a seven-story building with 28 units. It is constructed on a relatively
small site measuring 50’ x 100’. It has a total area of 38000 sqft out of that 26000sqft is the
residential area. It aims at providing affordable housing. The building is designed to express that
it is built using prefabrication and modularization. Each of the 3D box structure or modules was
built at a factory facility in Pennsylvania and was shipped on site with the help of trailers and
erected with the help of cranes. Each module was almost completely built in the factory with all
the plumbing, electrical, and other fixtures installed in the monitored space of the factory. The
modular construction also gave the distinct advantage of creating the unique façade of the building.
The façade of the building consists of projections protruding out of the building that will not have
been possible with such ease if traditional construction practices were used in for building it. The
strategic step taken in this project was to develop small and left out portions of the city. These
small and left out portions are surrounded by many existing structures that escalate the per square
foot construction cost considerably. Prefabrication allowed the builders to get in and out of the site
in less time and thereby to cause the least amount of disturbances to the neighboring areas. The
excavation, foundation and first-floor slab construction of the building were done in the tradition
way. It took around three months to complete. During this three month period, the construction of
all the 28 modules of the building was finished in the offsite prefabrication yard in Pennsylvania.

19. Figure 7: Strategy to fill empty blocks
Figure 8: Prefabrication facility in Pennsylvania

20. Figure 9: Erection of fully completed module
The building is a combination of steel and concrete components. After finishing the first-floor slab,
the modules were transported to the site and erected one my one. The modules were literally
stacked on top of each other, and this is where the building gets its name “The Stack”. It took only
19 days to erect all the 28 units of the building, and then the finishing work was started that finished
in the next four weeks. So overall it took roughly 5months to construct the building. If we consider
the time spent in planning the project, then the total project duration was 12 months, which is
considerably less than traditional method that would have taken at least 16 months to complete.
From inside the building does not feel like it was not constructed in a traditional manner. It has all
the amenities required in a comfortable housing unit. The damage caused to the completed modules
during transportation and erection was also negligible, and was restored to pristine conditions after
minor repairs. Thus, construction of The Stack also reinforces the merits of prefabrication and

21. modularization in the construction industry providing various advantages over the conventional
methods of construction.
Conclusion
Lack of skilled labor, high cost of labor, unsteady jobs etc. are requiring urgent reforms in the way
construction is handled, and also as more and more consideration is given to sustainability while
keeping the project cost low, the process of prefabrication has the potential to provide a worthy
solution to all these problems.
From the case studies and the literature review in the research paper, it can be clearly concluded
that prefabrication has a huge prospective in improving economy and sustainability of project, and
also, reducing the construction schedule.

22. References
1. “Prefabrication & Modularization, Increasing Productivity in the construction Industry”
(2009), McGraw Hill Construction Report
2. Anders Björnfot and Ylva Sardén (2006) “PREFABRICATION: A LEAN STRATEGY
FOR VALUE GENERATION IN CONSTRUCTION”
3. “Building Modular- "The Stack" Case Study” 2015,
https://www.pinterest.com/pin/261208847113615119/
4. “Modular Building Institute (MBI)” http://www.modular.org/
5. “History of Prefab Houses” http://home.howstuffworks.com/prefab-house1.htm
6. “Prefab in History” http://www.prefabaus.org.au/what-is-prefab/prefab-in-history/
7. “OFFSITE CONSTRUCTION EXPO” (2015),
http://www.offsiteconstructionexpo.com/htmlPage.aspx?name=osce_home