METRICS FOR COMPARISON BETWEEN PREFABRICATION PROJECTS BASED ON

SAFETY, QUALITY, COST & TIME: A CASE STUDY ON TWO MULTI-FAMILY

PROJECTS

By

KARAN KUNDAN DAREKAR

A THESIS PRESENTED TO THE GRADUATE SCHOOL

OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF SCIENCE IN CONSTRUCTION MANAGEMENT

UNIVERSITY OF FLORIDA

2020

© 2020 Karan Kundan Darekar

To my parents and friends

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ACKNOWLEDGMENTS

Firstly, I would like to express my deep and sincere gratitude to Dr. Aaron Costin of M.E.

Rinker’s School of Construction Management at the University of Florida, for allowing me to

research in the field of prefabrication. His deep knowledge of construction and passion towards

his students has been prevalent. His constant motivation and guidance helped me in completing

my thesis.

Secondly, I would like to thank ARCO National construction for the opportunity to work

with them and supporting me throughout the research.

Thirdly, I would also like to thank my committee members, Dr. Masoud Gheisari and

Dr.Bryan Franz for their valuable suggestions and constant support throughout this research.

Finally, I would like to thank my parents, Mrs. and Mr. Darekar for being supportive and

caring at the same time. My friends and family for motivation and encouragement.

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TABLE OF CONTENTS

page

ACKNOWLEDGMENTS ...............................................................................................................4

LIST OF TABLES ...........................................................................................................................7

LIST OF FIGURES .........................................................................................................................8

ABSTRACT .....................................................................................................................................9

CHAPTER

1 INTRODUCTION ..................................................................................................................11

Overview .................................................................................................................................11

Statement of Purpose ..............................................................................................................12 Objective .................................................................................................................................12

Scope of Research ...................................................................................................................12

2 LITERATURE REVIEW .......................................................................................................14

Prefabrication ..........................................................................................................................15 Advantages and Disadvantages of Prefabrication ..................................................................16

Factors Affecting Prefabrication .............................................................................................20 Safety ...............................................................................................................................20 Quality .............................................................................................................................22

Cost ..................................................................................................................................23 Time .................................................................................................................................24

3 RESEARCH METHODOLOGY ...........................................................................................26

Illustration of Steps in Research Methodology ......................................................................26 Step 1. Data Collection ...........................................................................................................26

Step 2. Identify the Parameters and Create Metrics for Comparison .....................................30 Project Safety and Project Site Waste .............................................................................30 Project Quality .................................................................................................................31 Project Cost .....................................................................................................................32 Project Schedule ..............................................................................................................33

Step 3. Comparison ................................................................................................................34 Step 4. Results and Discussion ...............................................................................................40

4 RESULTS AND DISCUSSIONS...........................................................................................41

Results.....................................................................................................................................41 Safety: HUB 1 vs HUB 2 ................................................................................................41 Quality: HUB 1 vs HUB 2 ...............................................................................................42 Cost: HUB 1 vs HUB 2 ...................................................................................................43

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Schedule: HUB 1 vs HUB 2 ...........................................................................................43 Discussion ...............................................................................................................................46

5 CONCLUSION, SIGNIFICANCE AND LIMITATIONS ....................................................48

Conclusion ..............................................................................................................................48 Significance of Research ........................................................................................................49 Limitations and Future Work..................................................................................................49 Recommendations ...................................................................................................................50

LIST OF REFERENCES ...............................................................................................................51

BIOGRAPHICAL SKETCH .........................................................................................................53

7

LIST OF TABLES

Table page

2-1 Difference between Prefabrication and on-site construction ...........................................19

8

LIST OF FIGURES

Figure page

2-1 Advantages and disadvantages of prefabrication ..............................................................18

3-1 HUB on Campus Gainesville Third Avenue ....................................................................26

3-2 HUB on Campus Gainesville University ..........................................................................27

3-3 Drone Captures of HUB 2.................................................................................................28

3-4 Participants in the site-specific interviews ........................................................................30

3-5 Safety and site waste data collected at HUB 1 & HUB 2 projects ...................................35

3-6 Safety and Site waste data comparison between the two projects ...................................35

3-7 Quality data collected at HUB 1 & HUB 2 projects .........................................................36

3-8 Quality comparison between the two projects .................................................................36

3-9 Cost data collected at HUB 1 & HUB 2 projects ..............................................................37

3-10 Cost comparison between the two projects ......................................................................37

3-11 Time data collected at HUB 1 & HUB 2 projects ............................................................39

3-12 Time comparison between the two projects .....................................................................40

9

Abstract of Thesis Presented to the Graduate School

of the University of Florida in Partial Fulfillment of the

Requirements for the Degree of Master of Science in Construction Management

METRICS FOR COMPARISON BETWEEN PREFABRICATION PROJECTS BASED ON

SAFETY, QUALITY, COST & TIME: A CASE STUDY ON TWO MULTI-FAMILY

PROJECTS

By

Karan Kundan Darekar

May 2020

Chair: Aaron Costin

Major: Construction Management

Prefabrication in construction has in recent years increased drastically attributing to the

fact that it is advantageous in terms of time, quality, cost and safety. Unlike traditional

construction, prefabrication requires planning, coordination, and rigorous control in the field.

Various elements can be used as indicators to measure how effective or ineffective prefabrication

is under categories like time, quality, cost, and safety. However, these indicators are not fully

addressing the challenges faced on the construction site, which necessitates the existence of

standard metrics to observe and analyze prefabrication projects.

The main aim of this research is to identify metrics from potential indicators on

prefabrication projects that would help in enhancing the performance and efficiency of

prefabrication projects. A qualitative analysis was conducted including site participation,

preliminary surveys, and direct observations. This is tested by collecting data on two nearly-

identical multifamily projects in Gainesville which have prefabricated wall panels as a common

construction element. This would facilitate the understanding of hindrances faced on

prefabrication sites which if avoided or improved would lead to better results. These indicators

would help in potentially understanding the importance of site-specific conditions, environment,

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site waste, management and pre-planning on the success of these projects. The data will create a

foundation to identify the indicators which would be grounds for comparison between these

projects. Also, the research would highlight the importance of site location, site waste,

environmental factors and management in the prefabrication construction projects. Further, the

comparison would help to come to conclusions based on the results. These conclusions can be

significant on similar projects which would help in finding ways to improve the productivity of

work, save time, achieve better quality, ensure safety, save budget and deliver the project in time.

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CHAPTER 1

INTRODUCTION

Overview

The construction industry contributes majorly to the economy of the united states and the

infrastructural development is a key economic indicator for a country. The past 50 years have

changed the face of construction as population increase and technological advancement have

increased hand in hand (Darekar, 2020). Unlike other industries construction is essentially

different because every construction project being unique. Unlike other industries, there are

factors such as environment, soil conditions, labor productivity, machinery, politics, etc. which

vary from location to location. One of the advancements is prefabrication or offsite construction

which is replacing the traditional way to construct. This art of construction offsite and then

transporting the elements to the site and assembling is not new to humankind. The oldest

engineered road known called the sweet track in England built in 3800 BC was made from

prefabricated timber sections that were assembled on-site (New scientist, 2020). The practice

was in use but not popular due to the myths about higher cost and lack of machinery to assemble

bigger units.

Today buildings can be manufactured in days using prefabrication. A recent example is

the 1500 bed specialty hospital built in 10 days in china In the wake of the novel coronavirus

outbreak (ABC News, 2020). There are buildings assembled as all finished units which are

popularly called modular construction.

There are various benefits of using prefabrication but it has its limitations too. It is not

feasible for smaller projects as logistics and cost are a problem (Hashemi, 2015). The availability

of a manufacturing plant nearby is also one factor. But, this research analyzes the factors which

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are majorly controlled in the field and have an impact on the time, cost, quality and safety of the

project.

Statement of Purpose

Execution in the field is not necessary as planned and unforeseen instances can lead to

delays, cost changes, poor quality, and unsafe work conditions. These conditions can hamper the

benefits offered by prefabrication. The implementation of productivity improvement techniques,

training, quality control, practical planning, and effective coordination can be ways to improve

the conditions. This research identifies main factors affecting the time, cost, quality and safety of

two multi-family prefabricated projects and draws a comparison between the two based on these

factors. This research is supported by the data collected on these sites in the form of

questionaries, interviews and site data collection. This research contributes results that can be

used by project managers, superintendents and site personnel working on prefabrication projects.

They can alter the factors and recommendations made in the research based on their site-specific

conditions and avoid achieve the milestones planned on the project schedule at the desired cost,

superior quality and importantly without compromising safety.

Objective

The objective of this research is to create and validate metrics by identifying potential

indicators on prefabrication projects which would help in enhancing the performance and

efficiency based on safety, cost, quality and time and provide best practices.

Scope of Research

The scope of this research involves analyzing the data collected on two nearly identical

multifamily prefabrication projects in Gainesville. The data is in the form of field data that would

help in defining factors under safety, quality, time and cost. The projects in consideration are

essentially made up of cold-formed steel wall panels on the exterior. The research analyzes only

13

these two projects and draws up conclusions based on variances between the two job sites. The

lessons learned from the research will be general recommendations for such jobs in the future.

14

CHAPTER 2

LITERATURE REVIEW

In the past few decades, urban cities and towns around the world have seen an enormous

increase in population. This has generated a swift need for more infrastructure, resources, and

employment to cater to the growing public while maintaining safe and productive construction

projects (Costin et. al 2019). This need has been a subject of research for many people around

the world. The construction industry contributes majorly to the infrastructure in terms of

buildings, bridges, roads, dams, utilities, etc. (Costin et.al, 2018). Traditionally construction is

done in field or cast-in-situ. Prefabricated or offsite construction is a newer approach to field

construction that offers great benefits (Rezkenari et..al 2019; Qi et. al, 2018; Abanda et. al, 2019;

Yin et. al, 2019).

Former Olympian, Pamela Bell who has revolutionized prefabricated construction in

New Zealand famously promoted it as a smarter and complicated Lego game, but one people can

construct with voluminous components (Stuff, 2020). More, technically the elements involved in

the project are manufactured or cast in an offsite facility, transported to the site and then

assembled as parts to form the structure. Much research has been done advocating the benefits of

prefabricated construction. Firstly, prefabricated construction reduces the project duration by

eliminating the lead times for material procurements, assembly, casting, curing and shoring

removal. Secondly, the quality attainted by prefabricated construction is superior to cast-in-situ

due to better quality control and controlled environment. Thirdly, the use of prefabricated

construction is sustainable as there is a reduction in waste and recycling is possible. Finally,

safety is improved on the offsite facility due to lesser risks about moisture, environmental

hazard, and dirt (Hashemi, 2015).

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As Einstein once famously said “the only source of knowledge experiences”, thus

understanding and building prefabricated construction has proved to be more different then it

looks on paper. There needs to be intricate planning attributing to delivery dates and installation

procedures of the prefabricated elements. Safety is also a prime concern as these members are to

lift by cranes and forklifts, must be placed in exact locations and orientations. Rigging failures

can be catastrophic, hence communication and training are key. Tower cranes are majorly used

in construction sites for lifting these heavy components at enough height (to avoid obstruction)

and then placing them safely in position. Effective crane management is also very necessary to

make the most out of the crane time available.

Construction projects are people-oriented involving manpower from different trades who

are specialized and have a defined scope work of work. In any type of contract, the contractor is

bound by a schedule in which the signing company agrees to abide. Prefabrication is one among

the all other activities which run simultaneously on the project site. Hence, coordination becomes

pivotal as the task of prefabrication includes planning, scheduling, designing, material

procurement, casting, transporting, safely installing and finishing. All these activities must be

coordinated with the other trades for achieving substantial completion.

Prefabrication

Prefabrication is an innovative construction method designed to minimize the

construction activities on-site and transfer many activities to the factory to ensure the

development of a product with higher quality and safety and a shorter project delivery time (K

Chauhan et al., 2019).

Prefabrication is the process of fabricating the parts of a factory so that construction

consists mainly of assembling and uniting standardized parts. This art of manufacturing is not

limited to construction but has been widely used in ships, aircraft, vehicles, and machines.

16

Talking about the history of the prefabrication, which dates back to the roman empires and then

prevalent back in the 19th century. Prefabrication is also safer and more environment-friendly

compared to conventional construction. This technology suits different types of construction

projects (Steinhardt et al., 2019).

An alternative modern way of construction is prefabricated construction. Despite the

potential benefits of the prefabricated methods of construction (Hashemi, 2015), the adoption of

the prefabricated construction is rather slow around the world, except in a few countries such as

Japan and Sweden (Barlow et al., 2003).

The main reasons for the lagged adoption of prefabrication in the construction industry

include insufficient R&D expenditures and the lack of necessary government regulatory efforts

to promote prefabricated construction (Steinhardt et al., 2013; Cantu et. al, 2019; Qi et. al, 2019)

Prefabrication—often associated with the terms “offsite,” “assembly,” or just simply

“fabrication”—can be viewed as stuck in the trenches of nineteenth-century conventions of

standardization and twentieth-century modernism. Common construction means have not

changed drastically over the last 80 years. For architecture to come into fruition to be built it

takes many years, requires heavy investment, and is fraught with confrontation, value

engineering, headaches, and inevitable heartache. This is not to say that new materials and

methods of production have not advanced other industries, on the contrary (Steinhardt et al.,

2019).

Advantages and Disadvantages of Prefabrication

Prefabrication has been around for a lot of decades and the analysis of the projects has

highlighted certain benefits constructing offsite and assembling has over the conventional

construction. Various papers have highlighted the cost savings, increased safety, time savings,

increased job-site coordination and increase in overall quality.

17

The advantages and disadvantages of prefabricated construction have been widely

researched. However, there are still limited studies that measure the benefits of prefabricated

construction compared to conventional construction methods (Blismas, Pasquire and Gibb 2006).

As stated by several studies, the major drivers to use prefabrication are time, cost and quality

(Pan et al. 2007). Prefabricated construction also explores the use of technologies and

information systems which enhance productivity, quality control, supply management, data

collection, and data integration. Kamali and Hewage also emphasize that using prefabrication

can lead to lower environmental impacts compared to conventional construction. Overall, there

are high expectations that the prefabrication process could potentially reduce the environmental

impacts caused by conventional construction. There are opportunities to improve sustainability in

all phases of prefabricated construction, but mainly during the design and manufacturing

processes (Fenner and Kibert 2017). Figure 2-1 summarizes the advantages and disadvantages of

prefabricated construction highlighted in some recent studies.

There needs to be a consideration for the time which is spent in the design,

manufacturing, and shipping. This time is substantial and can affect the time on the site

installation if delayed.

Today sustainability is one of the biggest concerns for people around the world.

Prefabrication is very much sustainable and green due to various reasons. The biggest advantage

of offsite construction is that there is minimum waste and the carbon footprint for this type of

construction is lesser than the traditional construction. To a disadvantage is the transportation of

these of huge elements. But this is dependent on the distance of these manufacturing plants from

the construction site. Offsite construction also advantages in warehouse construction which

involves similar or identical members.

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Ad

van

tag

es

Tim

e

Simultaneous construction work and site

preparation

Reduced disruptions due to weather

Reduced of on-site vandalism

Shorter schedule on-site

Guaranteed delivery, more certainty over the

program, reduced management time

Dis

ad

van

tag

es

Tim

e

Difficulty to make changes when

product is being manufactured

Extra engineering effort during

the design phase

Higher pre-project planning time

Co

st

Avoided delays due to weather or site severe

conditions

Reduced on-site labor

Increased cost certainty

Lower overheads

Reduced on‐site damage and waste

Co

st

Availability of knowledgeable

experts such as engineers and

designers

Availability of cheap labor in the

area

The larger initial investment to

run modular services

Saf

ety

Reduced elevated work and dangerous activities

Reduced site congestion

Reduced workforce exposure to weather

Neg

ativ

e p

erce

pti

on

The negative perception of new

construction methods

Qu

alit

y

Controlled manufacturing facilities

Repetitive processes and operations

Automated machinery

Reduced material exposure to harsh weather

conditions

Product tested in factory

Tra

nsp

ort

atio

n R

estr

ain

ts

Difficulty to transport modules

for longer distances

Time delays due to late transit

permits

Dimensional constraints for

transportation

Customs delays in borders when

transporting internationally

Su

stai

nab

ilit

y Potential for waste reduction and management

Reduced disturbance on-site

Easy application of energy performance and

efficient strategies

Possibility to disassemble and reuse materials

Durability

Su

stai

nab

ilit

y

Increased transportation

emissions

So

cial

Reduced community disturbance

Affordability

Influence on the local economy So

cial

Need for increased and more

detailed coordination in all stages

of a project

Difficulty to get full project team

committed

Figure 2-1. Advantages and disadvantages of prefabrication (Fenner et al., 2018)

Table 2-2 below states the difference between prefabrication and on-site construction

based on factors like quality, speed, cost, versatility, site space, and side refuse.

19

Table 2-1. Difference between Prefabrication and on-site construction (W M Wong et al. 2020)

Factor Prefabrication On-site

Quality In a climate-controlled

environmental using efficient

equipment by well-trained people

Uncertain weather can result in less-

than-expected construction

Speed Speedy process (up to 70% less) Time consuming. The process can

be delayed by weather or scheduling

conflicts

Cost Greater control over manufacturing

results dramatically reduces the

chance of cost overruns

Uncontrolled variables such as

weather and scheduling can increase

the construction cost

Versatility Less More

Site space Panels arrive on a flatbed trailer are

installed with enough listing plants

Bigger space is needed. Also, costly

scaffolding is often necessary for

installation

Site refuse Less waste is generated at the site A significant amount of waste

produced and removed from the

site, which is often added to cost.

An inherent weakness of modular construction is its design limitations. Due to the

production process implemented in modular construction, it poses some limitations on the

designers and builders that could weaken the proliferation of the modular construction, for

example, double floors and walls, lateral systems, modules cutoffs are among the design

complications involved in modular construction. Also, the design should be locked as early as

possible so that the fabrication of the modules can start. This leads to the need for earlier design

decisions and a resistance to change orders. The lack of proper design, regulatory and contractual

frameworks to support modular construction also weakens the adaptation of modular

construction. This construction method needs new delivery and integrated practices.

Underinformed management and, in general, lack construction industry knowledge and

understanding about the construction technique damage the extent that modular construction is

considered an option in early project planning. These issues along with poor management and

20

coordination in construction companies call for cultural reform. The lack of expertise and

standard practices led to lower productivity in the fabrication workshops (Fenner et al., 2018).

Factors Affecting Prefabrication

However, despite all the advantages and the increasing interest in offsite technologies and

innovative building processes from industry advisors and experts, the use of these methods in the

US remains behind other similar economies. As part of the business development, several

strategies were suggested to increase the use of modular construction in the industry. Among

them, the increase in research, marketing, and professional development workshops have become

a priority in the last few years for main organizations, such as the Modular Building Institute

(MBI). To achieve higher market shares, collaborative efforts among industry and academia are

still needed to bridge the current information gap. (Fenner et al., 2018)

Various factors affect prefabrication in direct or indirect ways. But this research is

focused on four main parameters. The four main parameters are listed below:

• Safety

• Quality

• Cost

• Time

Safety

The construction industry is one of the most dangerous industries in terms of safety. In

2012, the construction industry had the highest count of fatal work-related injuries (U.S. Bureau

of Labor Statistics, 2014a). construction sites are dynamic and complex. The dynamic nature is

attributed to the fact that humans (labors, superintendents, project managers, foreman, etc),

materials and machinery are continuously moving on a construction site. The complex nature of

the site is due to the space constraints on construction projects due to urbanization in recent

years. The balance between the above two parameters would create an environment for all

21

elements to continue working safely. Construction accidents included but were not limited to

falls from roofs and other structures, falls from scaffolds, electrocution, improperly operated

power tools, and working close to heavy equipment such as the loader, cranes, and forklifts. Key

factors that cause hazards include changing and unfamiliar work environment, exposure to

severe weather conditions, and using unskilled and temporary workers (Fard et al., 2015). This

research helped in identifying site waste as an important parameter and the effect of site waste on

the safety.

Modular/prefabricated buildings differ from mobile buildings, such as mobile homes.

Mobile buildings usually contain integrated frames and axles for transport, which also function

as a structural floor support. In contrast, a modular building is similar to on-site stick-built

construction; and when it arrives at its final location, it is hoisted off its conveying trailer and

installed on its foundation (Becker et al. 2003). This research helps to understand the

transportation element of prefabrication which

Modular/prefabricated building construction is usually claimed to have a safer work

environment compared to traditional on-site building construction due to the following factors

(McGraw Hill Construction, 2013; Modular Building Institute, 2014; Vanguard Modular

Building Systems, 2014):

• Stable work location, where workers are used to their tasks and are familiar with the risks

• Avoiding work in tight spaces at the site

• Performing off-site or on-ground assembly instead of working from heights,

• Not being exposed to harsh weather,

• Easier ways to monitor unsafe activities,

• Fewer contractors and workers required on site.

According to a survey about safety management in the construction industry conducted

by McGraw Hill Construction (2013), 50% of the respondents believed that prefabrication and

modularization have better safety performance compared to traditional construction. Only 4% of

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the contractors using prefabricated or modularization claimed that this method of construction

has negative impacts on safety performance. The respondents in the survey were asked to

indicate three parameters impacting modular/prefabricated safety. The highest percentage (78%)

of the general contractors responding to the survey considered ‘complex assembly done at

ground level/offsite’ as one of the attributes of prefabrication and modularization which

increases safety performance, while 59% of specialty contractors considered this parameter as an

impacting factor. 69% of specialty contractors and 69% of general contractors believed that

fewer workers’ onsite working on different aspects of building’ is also a factor in improving

modular/prefabricated construction. Number and rate of fatal occupational injuries, by industry

sector, 2012 (U.S. Bureau of Labor Statistics, 2014a). safety. 58% of general contractors and

47% of specialty contractors indicated that ‘reduced need to work from heights’ is another

influencing factor on the safety performance of modular/prefabricated construction. (Fard et al.,

2015)

Quality

The quality of construction is one of the matters of the greatest concern for people

working in the construction industry. Quality is one of the biggest benefits of prefabricated

construction as the members are manufactured under strict technical supervision and in a

controlled environment. When compared to the cast-in-situ, factory equipment, machinery, and

tools can offer added quality assurance. Also, safety is improved due to assembly line

manufacturing.

As per the preliminary survey 72% of the participants, the impact of offsite construction

on project quality is very high (Karan,2020). This makes it evident that quality is a good

motivator for opting for offsite construction.

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The construction industry like any other production industry is faced with challenges that

affect the performance and output of the endeavor. Identifying potential critical factors that affect

the quality performance of small scale contractors before the commencement of projects will

ensure client satisfaction after the project. Identifying the potential critical factors will however

not eliminate the problem of quality but to a large extent, help the project team to avoid such

negative factors and strictly adhere to project specifications to reduce errors which will call for

re-work by both consultants and contractors. Quality Performance (QP) is a management tool

that is aimed at giving the necessary information to identify quality improvement opportunities

for better performance and productivity (Abdul, 2011).

The quality of production and quality of design are the two most vital parameters which

are taken into consideration in the construction industry. As soon as the quality of production

improves, the structure becomes more standardized, while a highly customized design inevitably

reflects a lack of efficiency in production. Prefabrication technology can prominently increase

the precision of the products and allow superior control over each aspect of quality. In addition

to increased precision the prefab components less divergence and variance. Prefabrication limits

the risk of errors and eliminates the unknowns in a highly multivariable construction (Patil,

2020).

Cost

The single most important factor in the development of a project is the project budget.

The fact that money could serve as a common denominator to reduce all components like

manpower, equipment, materials and time. The cost of prefabrication is one of the reasons for

owners opting out of prefabrication and using traditional construction. Cost is a very dependent

variable, as the cost of prefabrication varies from project to project. The cost of manufacturing is

the same, as the cost of materials varies less but the driver is the transportation cost is a deciding

24

factor. Thus, the project cost increases or decreases depending on the level of prefabrication,

schedule, material availability, equipment available and location of the project concerning the

offsite manufacturing facility.

Prefabrication technology is known to be cost coherent to a greater extent as compared to

other methods of construction. The cost inculcated in the construction industry consists of three

aspects on which prefabrication has a significant impact effect: material, labor and time. The

initial approach to reduce cost is to diminish the amount of material implemented in a

construction project. In a construction project, materials are ordered abundantly to ensure a

sufficient quantity for the task to be completed and to get a discount as the material is ordered in

a large quantity. As prefabrication technology may save considerably concerning managing

materials, factory-produced components may initially be extortionate. In the case of small

projects, due to the less number of components, it is economically inimical. Miscellaneous

expenditure that may be incurred with prefabrication technology includes transportation and

erection expenses.

As per the preliminary survey, 72% of the respondents said that the impact of

prefabrication on the project budget is very high to high (Darekar,2020)

Reviewing the literature for potential factors that affect quality performance, Jha and Iyer

(2005) identified among other factors; lack of management commitment to continual quality

improvement; lack of quality training of staff; management leadership; and efficient teamwork

among stakeholders. It was further stated that material and equipment costs rarely affect the cost

performance in construction projects (Emmanuel et al. 2020).

Time

In project management, the schedule is listing of project milestones, activities and

deliverables usually with an intended start date and end date. The main reason for the owner and

25

contractors to choose offsite construction is the time savings. Prefabrication is a manufacturing

process, pre-planning can be done in terms of deliveries and installations. Prefabrication is one of

all the activities and hence all the other activities to follow the project schedule are equally

important. For instance, the wall panels can be installed until the slab is poured and set. This is

dependent on the metal deck laid and secured. Hence, planning along with strong execution

makes a good project schedule.

As per the preliminary survey, 67% of respondents suggest that there is a high impact on

the project schedule and 27% suggest there is a low impact (Karan,2020).

The savings in time, as well as cost, come with the practice to concurrently construct in

the factory while work is being completed on site. In the case of conventional traditional onsite

construction processes, subcontractors have to wait until the predecessor contractor has

completed its work, in a factory, teams may collaborate by allowing portions to be constructed

by more than one trade. Time savings may also come by way of employing simultaneous

production techniques. Decisions regarding prefabrication are pre-planned so that schedule

savings may be perceived from the beginning of construction activity (Patil, 2020).

The main reason for selecting offsite construction is the time savings in comparison to

traditional construction. The offsite members have to be stored at the site and these members are

voluminous. This is a major issue in congested construction sites and cities, were are limited

spaces and maintenance of traffic a big problem. Especially in sites that are located in or close to

residential and institutional zones. The storage of such members also requires special care in

terms of logistics and safety.

26

CHAPTER 3

RESEARCH METHODOLOGY

Illustration of Steps in Research Methodology

The research methodology involved the following steps related to the HUB 1 and HUB 2

project

• Step 1. Data Collection

• Step 2. Identify the parameters and create metrics for comparison

• Step 3. Comparison

• Step 4. Results and Discussion

Step 1. Data Collection

Case study. Hub on Campus, Gainesville

Scope of the project. Design built of two multi-family construction following Florida

codes and meeting the delivering the project in time with desired quality.

The project includes two student housing multi-family construction located in Gainesville

and owned by Core Spaces, the first project’s name is Hub on campus third avenue, and it has

58000 square-feet, the front facade of the building is shown in Figure 3-1.

Figure 3-1. HUB on Campus Gainesville Third Avenue (Dareker,2020)

27

. The design of the project was created by Myfeski Architects for Hub on Campus

University and Antonovich Architects for the Hub on Campus third avenue. The specifications

for the project were 2900 pages and 900 pages for the Hub1 & 2 projects respectively. The

project duration is 81 weeks and the facilities are expected to complete in August 2020.

Hub 2 is a much bigger mix-use multifamily project with an estimated cost of 45 million

dollars. The project has similar features as mentioned for Hub 1 except for the fact that the

project has three times the wall panels, two times the size and more accessible. The storage yard

is bigger and there are more project participants compared to HUB 1.

The second building is Hub on-campus university, and it has 33000 square feet and the

front façade of the building is shown in figure 3-2.

Figure 3-2. HUB on Campus Gainesville University (Dareker,2020)

Hub 1 is a mix-use multifamily project built at the cost of 34 million dollars. It has offsite

manufactured wall panels forming the exterior skin of the building. These panels are installed

28

using a 110 ft long tower crane which is located at a location that would cover all parts of the site

and extend to the yard where the panels are stored. The wall panels are stored on trailers and

arrive at the site following a pre-decided schedule. A superintendent and safety manager are

responsible for the supervision of the execution from the general contractor along with a crew

from the sub-contractor.

Both the projects were Design built and the lowest bidders for the different trades were

selected and assigned works. The construction can be majorly classified as prefabricated type as

the walls were designed and manufactured offsite and transported to the site, where they were

safely lifted using a 180 ft high and 3000 kg capacity tower cranes.

Figure 3-3. shows the drone capture of the HUB 2 project which helps in capturing the

progress of the project.

Figure 3-3. Drone Captures of HUB 2 (Dareker,2020)

The author had an opportunity to work as a superintendent intern at the HUB 1 and HUB

2 project located in Gainesville. During this period the project sites were visited daily, drawings

29

and specifications were studied, and prefabricated construction was observed closely. The

project consists of a residential and retail mixed-use development project housed in the midtown

region of Gainesville and is near the University of Florida. The project will also house new

restaurants, shops, and public spaces.

The subcontractors manufacturing, installing, and inspecting the prefabrication wall

members were identified. Also, the submittals for the prefabricated constructed were procured

and the examined.

The constants between the projects are

• Both the projects have the same wall panel system

• The company installing the wall panels is the same

• There is a tower crane on both the jobs for wall panel install

• The general contractor on both the projects is the same

• The wall panels are manufactured at the same plant

• The location of the projects is in the same town (Gainesville)

• The environmental conditions are similar

The differences between the projects

• The budget and schedule requirements are different on the projects

• Hub 1 has three light poles along its periphery

• Hub 1 is smaller in size than Hub 2

• The storage space at Hub 1 is approximately the half-size in the area as compared to Hub

2

• The access roads and maintenance of traffic plans are different on both the jobs

• Hub 1 has post-tensioned slabs and Hub 2 has no post-tensioned slabs

• Hub 1 had major management changes initially and no such changes were made at HUB

2

After studying the projects and identifying the project participants the preliminary

survey was conducted. The main purpose of the preliminary survey was to identify the people

involved in the construction site, the factors affecting prefabrication and technologies emerging

30

in the construction industry. Figure 3-4 depicts the project participants which took part in the

site-specific interviews.

The survey had two parts, which are explained below:

Part A: Respondent background. The section included six questions that all were

dedicated to the understanding of the background of the respondent.

Part B: Prefabrication. This section included questions about prefabricated

construction, in general. The main purpose of this section was to identify the key factors which

have an effect on the offsite construction industry and capture trends from the participants in

terms of increase, decrease or no effect. There were twelve questions in this section

Figure 3-4. Participants in the site-specific interviews (Dareker,2020)

Step 2. Identify the Parameters and Create Metrics for Comparison

The metrics are identified and used for comparison

Project Safety and Project Site Waste

The number of construction-related accidents on the construction site. The accidents

directly related to prefabricated wall panels on the project site, which were reported and recorded

along with an accident report filed by the contracting company recorded from the start of the

current day of the project. This may include accidents occurring during the transportation,

HUB 1

•Superintendent

•Project Manager

•Prefabrication PM

•Prefabrication Foreman

HUB 2

•Superintendent

•Project Manager

•Prefabrication PM

•Prefabrication Foreman

31

storage, rigging, layout, installation, and finishing of the wall panel system. The joist system

over the wall panels is also part of the prefabricated wall assembly, hence includes the accidents

about laying of the joist.

The number of construction near misses on the construction site. The near-misses

relating to prefabricated wall panels on the project site, which were reported and recorded along

with an accident report filed by the contracting company recorded from the start of the current

day of the project. This may include accidents occurring during the transportation, storage,

rigging, layout, installation, and finishing of the wall panel system. The joist system over the

wall panels is also part of the prefabricated wall assembly, hence includes the accidents about

laying of the joist. The accidents occurring indirectly relating to wall panels are included.

The number of construction reportable on the construction site. The reportable

injuries on the construction site during the transportation, storage, rigging, layout, installation,

and finishing of the wall panel systems. The accidents caused due to the project waste or bad

housekeeping are a part of reportable.

The number of construction accidents/near misses/reportable due to site waste. The

accidents/near misses/reportable caused on the construction site due to poor housekeeping of site

waste and not implementing daily cleanup on the site.

Project Quality

The number of panels rejected per 100 panels. The number of panels that were

rejected to be used on the construction site due to issues about the size, quality, opening

dimensions, damage during transportation, overweight or wrong delivery timing per 100 panels

received on site.

32

The number of panels needing modifications per 100 panels. The number of panels

that needed modifications after received on-site about the size, opening dimensions, quality,

damage during transportation and overweight per 100 panels received on site.

The number of damaged panels per 100 panels. The number of wall panels which

were substantially damaged in terms of structural damage during transportation. The structural

damage includes the cracking of the wall, rust and unsafe loose ends needing remanufacturing.

The average number of panels installed per week. It is the average number of panels

installed on the construction site per week. The average is of panels installed over eight weeks.

On an average 38 wall panels are installed on the HUB 1 project and 73 wall panels on the HUB

2 project (Darekar,2020).

Project Cost

The average cost for the manufacturing of one wall panel. The average cost in US

dollars to manufacture one wall panel for the construction site at the offsite manufacturing

facility including the cost of materials, manufacturing, design, technical supervision and profits.

The average cost for transportation of one wall panel. The average cost in US dollars

to transport one wall panel from the offsite manufacturing facility (Missouri) to the project site

location (Gainesville). This includes the cost of loading, packing, fuel, driver charges and tolls

on the way.

The average cost for the installation of one wall panel. The Average cost in US

Dollars for installation of one wall panel on the construction site includes the cost of rigging,

technical supervision, layout, installation, and finishing. This does not include the cost of the

crane as it is with the general contractor.

33

Project Schedule

The average time in minutes for installing a wall panel. The average time in hours for

installing a wall panel on the construction site which includes the time required for rigging the

wall panel, placing the wall panel and then holding it with the tower crane until secured with

braces.

The average time in minutes for creating a layout for wall panel. The average time in

minutes for creating the layout for the wall panel on the slab floor. This includes the time taken

to identify the wall panel, mark dimensions and finalize with the chalk.

The average time in minutes to finish a wall panel. The average time is taken to finish

a wall panel after it's been secured and ready for waterproofing, window and door install. This is

the time required to de brace the wall panel and making it ready for further activities.

Schedule comparison. The average time in weeks that the project is behind in achieving

the milestones for the prefabrication schedule.

The average crane time allotted to prefabrication in one week (F). It is the average

time in a week in hours that are devoted to the prefabrication elements install. The average crane

time for a week is 60 hours. Assuming 10 hours of work hours every day and six working days

per week.

The average crane time used for panels installation in one week (G). It’s the average

crane time in hours which is used for the installation of the wall panels in one week. It can be

calculated by multiplying the average time for installing wall panels to the average number of

panels installed in a week.

𝐺 = 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑎𝑛𝑒𝑙𝑠 𝑖𝑛𝑠𝑡𝑎𝑙𝑙𝑒𝑑 𝑖𝑛 𝑜𝑛𝑒 𝑤𝑒𝑒𝑘 𝑎𝑡 𝐻𝑈𝐵 1 𝑜𝑟 2

𝑥 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑇𝑖𝑚𝑒 𝑖𝑛 𝑚𝑖𝑛𝑢𝑡𝑒𝑠 𝑓𝑜𝑟 𝑖𝑛𝑠𝑡𝑎𝑙𝑙𝑖𝑛𝑔 𝑎 𝑤𝑎𝑙𝑙 𝑝𝑎𝑛𝑒𝑙 𝑎𝑡 𝐻𝑈𝐵 1 & 2 (3-1)

34

Crane productivity in % (Y). The productivity for the crane can be calculated by the following

formula

𝑌 𝑖𝑛 % = 𝑇ℎ𝑒 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑐𝑟𝑎𝑛𝑒 𝑡𝑖𝑚𝑒 𝑢𝑠𝑒𝑑 𝑓𝑜𝑟 𝑝𝑎𝑛𝑒𝑙𝑠 𝑖𝑛𝑠𝑡𝑎𝑙𝑙𝑎𝑡𝑖𝑜𝑛 𝑖𝑛 𝑜𝑛𝑒 𝑤𝑒𝑒𝑘 (𝐺)

𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑐𝑟𝑎𝑛𝑒 𝑡𝑖𝑚𝑒 𝑎𝑙𝑙𝑜𝑡𝑡𝑒𝑑 𝑡𝑜 𝑝𝑟𝑒𝑓𝑎𝑏𝑟𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑖𝑛 𝑜𝑛𝑒 𝑤𝑒𝑒𝑘 (𝐹) (3-2)

Considering the variables between the two projects the following was understood

Step 3. Comparison

The testing of the Metric is done on two multifamily prefabrication projects located in the

town of Gainesville, Florida. The main reason for the selection of these projects was that they

had one common prefabrication element which was wall panels. another reason was permission

to collect the data and observe the site installation practices.

In this research, we refer to the projects as Hub 1 and Hub 2. Both projects have wall

panels manufactured from the same company and installed by the same sub-contractor. A direct

comparison is possible but a more needed is one which is based on technical and practical

aspects. These aspects have been defined in the last step and then used to compare. The

construction safety, construction quality, construction cost and the schedule for construction

have been analyzed in this step.

This step mainly focuses on testing the data collected on the construction site to find the

efficiency of the framework and check if the hypothesis is valid or not. Figure 3.5 depicts the

data used to test the framework against safety, quality, cost, and schedule. Figure 3-6 depicts the

comparison between the two projects based on safety and site waste data collected at the HUB 1

and HUB 2 projects located in Gainesville, Florida. These project details have been discussed in

the previous chapters and there significance, location, manufacturing, and nature have been

studied in great detail.

35

Figure 3-5. Safety and site waste data collected at HUB 1 & HUB 2 projects (Dareker,2020)

Figure 3-6. Safety and Site waste data comparison between the two projects (Dareker,2020)

The Figure 3.7 shown below depicts the data collected on the site based on the parameter quality.

12

16

21

4

7

12

14

3

N U M B E R N U M B E R N U M B E R N U M B E R

X Y Z U

1 . N O O F C O N S T R U C T I O N

R E L A T E D A C C I D E N T S O N T H E S I T E

2 . N O O F C O N S T R U C T I O N N E A R M I S S E S O N T H E S I T E

3 . N O O F C O N S T R U C T I O N

R E P O R T A B L E O N T H E S I T E

4 . N O O F C O N S T R U C T I O N

A C C I D E N T S / N E A R M I S S E S / R E P O R T A B L E D U E T O S I T E W A S T E

SAFETY

HUB 1 HUB 2

Factors Parameters Title Unit HU

B 1

HU

B 2

%

differenc

e

between

HUB 1 &

hub 2

Safety

1. No of Construction related

accidents on the site X Number 12 7 71.5

2. No of Construction near

misses on the site Y Number 16 12 33.4

3. No of Construction

reportable on the site Z Number 21 14 50

4. No of Construction

accidents/near misses/reportable

due to site waste

U Number 4 3 33.4

36

Along with that Figure, 3-8 is graphical of the data to show the comparison between Hub 1 and

HUB 2 projects.

Factors Parameters Title Unit HUB

1 HUB

2

% difference between

HUB 1 & hub 2

Quality

1. No of panels rejected per 100

panels A

per

100 11 10 10

2. No of panels needing

modifications per 100 panels B

per

100 17 22 -22.8

3. No of damaged panels per 100

panels C

per

100 5 2 150

Figure 3-7. Quality data collected at HUB 1 & HUB 2 projects (Dareker,2020)

Figure 3-8. Quality comparison between the two projects (Dareker,2020)

11

17

5

10

22

2

P E R 1 0 0 P E R 1 0 0 P E R 1 0 0

A B C

1 . N O O F P A N E L S R E J E C T E D P E R 1 0 0 P A N E L S

2 . N O O F P A N E L S N E E D I N G M O D I F I C A T I O N S P E R 1 0 0

P A N E L S

3 . N O O F D A M A G E D P A N E L S P E R 1 0 0 P A N E L S

QUALITY

HUB 1 HUB 2

37

Figure 3-9 is a depiction of the data collected for the cost parameter and the comparison

between the projects is shown in figure 3-10.

Factors Parameters Title Unit HUB

1 HUB

2

% difference between HUB

1 & hub 2

Cost

1. The average cost for

manufacturing of one wall panel M Dollars $ 2400

3500

-31.5

2. The Average cost for

transportation of one wall panel N Dollars $ 900

1200

-25

3. The Average Cost for

installation of one wall panel O Dollars $ 425 700 -39.3

Figure 3-9. Cost data collected at HUB 1 & HUB 2 projects (Dareker,2020)

Figure 3-10. Cost comparison between the two projects (Dareker,2020)

24

00

90

0

42

5

35

00

12

00

70

0

D O L L A R S $ D O L L A R S $ D O L L A R S $

M N O

1 . T H E A V E R A G E C O S T F O R M A N U F A C T U R I N G

O F O N E W A L L P A N E L

2 . T H E A V E R A G E C O S T F O R T R A N S P O R T A T I O N

O F O N E W A L L P A N E L

3 . T H E A V E R A G E C O S T F O R I N S T A L L A T I O N O F O N E W A L L

P A N E L

COST

HUB 1 hub 2

38

Figure 3-11 is a depiction of the data collected for the schedule parameter and the

comparison between the projects is shown in figure 3-12.

There is a variation of time, and the field data collected helps to understand the time

taken to complete the various activities. Various factors were studied and then a comparison

between the HUB 1 and HUB 2 projects were done. The various factors like the average time to

install the wall panels, which is the time in minutes to pick up one panel and placing it on the

floor. The average time taken in minutes to create a layout for the wall panels is also recorded

and compared between the two projects. Then, the average time to finish wall panels which

includes reshoring the wall panels and preparing them for the finishes to be installed. The above

three factors are in minutes and provide a sound ground for comparison between the two

projects.

Also, the schedule is compared between the two jobs which are very essential to establish

and state the various reasons for the delay caused in the prefabricated construction. Lastly, the

time allotted to the crane is also recorded and studied in this research. The study of time is a very

important aspect of construction. The various aspects of time that are studied in this research are

not the only ones, there can be more research about productivity comparison between the

projects or among various parameters of the project. The relation of time with safety, quality and

cost are also studied. Increase in time can increase the cost of the project, and also affect the

quality and safety. There is also an effect of safety on the quality of the project. Various research

around the world has suggested that safer work environments have better quality. This research,

in particular, fins the time required to install wall panels, which is just one big element of

prefabrication in general and there are various other elements like slabs, columns, beams, lintels,

roofs, etc.

39

Figure 3-11. Time data collected at HUB 1 & HUB 2 projects (Dareker,2020.)

Factors Parameters Title Unit HUB

1

HUB

2

%

difference

between

HUB 1 &

hub 2

Schedule

1. Average Time in minutes

for installing a wall panel V Minutes 12.5 8 56.3

2. Average Time in minutes

for creating a layout for wall

panel

D Minutes 6 4 50

3. Average Time in minutes

to finish a wall panel R Minutes 14 7 100

4. Schedule comparison T In weeks 4 1.5 166.7

5. Average crane time allotted

to prefabrication in one week

(Avg hours per week = 60

hours)

F In hours 32 45 -28.9

6. The average time used for

panels installation in one

week ( On an average 38

panels are installed on HUB 1

and 73 panels are installed on

HUB 2)

G In hours 2.625 9.709 -73

7. Crane productivity in % Y In % 8.3 21.6 -61.6

40

Figure 3-12. Time comparison between the two projects (Darekar,2020)

Step 4. Results and Discussion

Finally, based on the metrics and the data collected, results could be found and then

discussion to understand the lesson learned was done.

12

.5

6

14

4

8

4

7

1.5

M I N U T E S M I N U T E S M I N U T E S I N W E E K S

V D R T

1 . A V E R A G E T I M E I N M I N U T E S F O R

I N S T A L L I N G A W A L L P A N E L

2 . A V E R A G E T I M E I N M I N U T E S F O R C R E A T I N G

A L A Y O U T F O R W A L L P A N E L

3 . A V E R A G E T I M E I N M I N U T E S T O F I N I S H A

W A L L P A N E L

4 . S C H E D U L E C O M P A R I S O N

TIME

HUB 1 HUB 2

41

CHAPTER 4

RESULTS AND DISCUSSIONS

Results

The data collected laid the basis for comparing the parameters between the projects and

intercomparing the factors based on various scenarios.

Comparison. Comparing the data between the two projects based on safety, quality, cost

and time.

Safety: HUB 1 vs HUB 2

The number of construction-related accidents on site. The number of construction-

related accidents at HUB 1 is 12 as compared to 7 at HUB 2. This suggests that HUB 2 has a

safer working environment as compared to HUB 1. The accidents caused at HUB 1 are majorly

due to tripping, rigging and inappropriate practices done during the install. Out of the 7 accidents

at Hub 2, 5 of them are due to fall from ladder and tripping.

The number of construction near misses on site. The number of near-misses at HUB 1

is 16 as compared to 12 at HUB 2. As observed above Hub 1 is more unsafe as compared to

HUB 2. The near-misses at both the project are due to miscellaneous reasons.

The number of construction reportable on site. The number of reportable at HUB 1 is

21 as compared to 14 at HUB 2. The fact that the site environment of HUB 1 is more complex

than HUB 2. There are is lesser space and storing material is not easy. The site has poor

housekeeping which is the main reason for the high number of reportable. The site has 3 main

power poles, which have attributed to the safety concerns on the site.

The number of construction accidents/near misses/reportable due to site waste. This

data includes all the construction accidents, near misses and reportable due to site waste

42

specifically. As mentioned above, poor housekeeping is a problem on HUB1 and hence there are

more safety concerns in terms of site waste at HUB 1 as compared to HUB 2.

Quality: HUB 1 vs HUB 2

The number of panels rejected per 100 panels. Comparing HUB 1 and HUB 2, the

number of panels rejected is almost the same. This suggests that the number of panels getting

rejected is not a variable of site or site conditions, It is more related to the manufacturing and

transportation phase of the wall panels. 60% of the panels rejected are due to issues about

dimensions, size of openings or damage during transportation. This is evident in both the job

sites. Rejection of panels costs more time and money, as the section cannot be completed until

the panels are delivered from the plant which takes about a week or more. This hurts the

milestone achievement as until the walls are completed, the joist and decking cannot be laid.

Hence, all the sequential activities get delayed.

The number of panels needing modifications per 100 panels. The number of panels

needing modifications at Hub 1 is 17 as compared to 22 at HUB 2. The fact that HUB 2 has three

times more panels per floor as compared to hub 1 dominates this factor. The modifications are

based on size, opening dimensions, quality, damage during transportation and overweight per

100 panels. Modifications to panels are done on the site by the subcontractors. The time taken is

2 days based on the level of modifications but less as compared to rejection. The cost of

modification is less compared to rejection.

The number of damaged panels per 100 panels. The number of panels damaged at

HUB 1 is 5 as compared to 2 at HUB 2. Damaged panels are rare situations, which are rejected

panels due to severe damage in terms of structural damage includes the cracking of the wall, rust

and unsafe loose ends needing remanufacturing. The number of damaged panels at HUB 1 is due

to a specific situation, wherein due to overloading, the panels loaded first severely cracked.

43

The average number of panels installed per week. The average number of panels

installed in HUB 1 is 38 as compared to 73 at HUB 2. The data were averaged based on the per

week panels installed for 4 weeks. The data is evident to judge the size and efficiency of the two

projects.

Cost: HUB 1 vs HUB 2

The average cost for manufacturing for one panel. The average cost of manufacturing

at HUB 1 is $ 2400 compared to $ 3500 at HUB 2. The panels are manufactured at the same

location for both the job sites and the cost is average cost provided by the subcontractor

company. The cost of HUB 1 is lesser than HUB 2 due to the various factors.

• The size of panels at HUB 1 is smaller in size as compared to Hub 2

• The number of panels at HUB 1 is three-time more than HUB 2

• The panels at HUB 1 have lesser peculiar shapes than HUB 2

The average cost for transportation of one panel. The average cost of transportation of

one panel at HUB 1 is $ 900 as compared to $ 1200 for HUB 2. The transportation cost at HUB 1

is less because the number of panels installed per week at HUB 1 (32) is lesser than at HUB 2

(45). The cost of transportation is high in general due to the manufacturing plant location at 900

miles from the site location.

The average cost of installation for one panel. The average cost of install for install of

one panel at Hub 1 is $425 as compared to $700 at Hub 2. The cost is based on the cost of

rigging, technical supervision, layout, installation, and finishing. This factor depends upon the

number of riggers, number of supporting crews and the time taken to install.

Schedule: HUB 1 vs HUB 2

The average time in minutes for installing a wall panel. The average time taken to

install a wall panel at HUB 1 is 12.5 minutes as compared to 8 minutes at HUB 2. The time taken

at Hub 1 is more than HUB 2. The extra time taken can be attributed to the fact that the panels at

44

HUB 1 are smaller in size and hence more time is spent on hooking up, lifting, placing and

installing. The number of times it is done in a sequence is much more time is taken to install

even though lesser panels are to be installed at Hub 1. Also, the crew has lesser space to rig the

panels at HUB 1 as compared to HUB 2. Adding to the above point, the number of people

rigging panels on both the job is the same.

The average time in minutes for creating the wall layout for a wall panel. The

average time required for creating the layout for the wall panel is 6 minutes at HUB 1 and 4

minutes at HUB 2. The time was recorded for over 20 wall layouts made over 2 days in the

normal working conditions. The time taken at HUB 1 is more due to the site waste and wet floor

conditions. Site waste is much more at HUB 1 in comparison to HUB 2. More time is needed to

clear the waste to commence with the layout, which needs a clean floor for the chalk to be

visible. Rains on site were a factor, as the wet floor needs to be dried before layout.

The average time in minutes to finish a wall panel. The average time taken to finish a

wall panel is 4 minutes at HUB 1 as compared to 1.5 minutes for HUB 2. The time required to

finish wall panels is the time required to get the panel ready and de bracing. The time required to

finish wall panels at HUB 1 is more than HUB 2, due to the small size of the project and the

project has post-tension slabs. The screws required for drilling in a PT slab was a quarter-inch, to

not hit the dense cable profile below the flooring. The removal of these requires special care,

hence more time is required. There are no post-tension slabs at HUB 2.

Schedule comparison. The comparison of the most current schedule with the planned

schedule at HUB 1 shows that it is on average 4 weeks behind as compared to 1.5 weeks for

HUB 2. The schedule variance is due to various reasons

45

• The project conditions are more complex on HUB 1 attributing to the fact that the storage

space is small, there is various maintenance of traffic requirement due to zoning, the site

has proximity to three light poles, the neighborhood is residential.

• The delay is majorly due to the concrete subcontractor withdrawing from the project

when 30% of progress was achieved. The subcontractor was on both the projects, hence

the effect was the same on both the sites.

• HUB 1 has a post-tension slab for the first 5 floors. Post tension slab takes on average 2

times more time than the normal (reinforcement) slab.

• Lastly, the management at HUB 1 has not been as efficient as that HUB 2.

The average crane time allotted to prefabrication. The average crane time on both the

jobs is 60 hours. This is based on the assumption that the site is working 6 days a week and 10

hours on an average every day. The average crane time used at HUB 1 is 32 hours as compared

to 45 hours at HUB 2. The crane time majorly is distributed between the concrete subcontractor

and the prefabrication subcontractor. The crane time is a point of dispute and delay as it is very

dependent on weather and wind conditions. The crane cannot be operated in winds velocity

exceeding 30 miles per hour and lighting within 10 miles of the crane location. If there is a

delivery, then some sub-contractor have to give up his time which leads to delay. Crane

productivity needs to be analyzed and a more efficient crane schedule needs to be made.

The average time used for panel installation in one week. The average time used for

panel installation in one week at HUB 1 is 2.625 hours as compared to 9.709 hours at HUB 2.

This time is directly dependent on the time required to install one panel and the number of panels

installed in one week. HUB 1 has lesser panels and hence the factor is lesser as compared to

HUB 2.

Crane productivity for installation. The crane productivity is a calculated factor and

the above factors can be used to find the crane productivity. The crane productivity for

installation at HUB 1 is 8.3% while at HUB 2 it is 21.6%. The crane time at both the jobs is the

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same (60 hours) and the geographic location is also the same (0.2 miles apart). Hence, the crane

at HUB 1 is not efficient as compared to HUB 2.

Discussion

With the metrics created for the comparison of prefabrication projects, which is based on

four important parameters it would make studying and analyzing such projects more structured

and organized.

The reality of the advantages of prefabrication is much different than in literature

ascertaining the fact that there are many more factors that affect the success of a prefabrication

project. Time is the essence of such projects if more is spent on prefabrication than

manufacturing offsite would not be beneficial. The environment around the construction sites is

very crucial on prefabrication projects.

The cost of the manufacturing projects are more upfront as compared to conventional

construction, but prefabrication leads to savings in terms of time. Especially in design built

projects where the design progresses with construction. But the communication in terms of

changes, revisions and modifications should be done effectively to reduce the overheads.

Safety concerns are observed to be lesser on prefabrication sites, but it is only with proper

training, supervision and using the right techniques. Safety is a variant of site waste hence it is

very important to have a cleaner site to avoid tripping, fall hazards, and other safety hazards.

The quality is a controlled parameter and the manufacturing plant has more influence on

the same. But quality is one of the biggest advantages of prefabrication and a defect affects the

overall acceptability of prefabricated elements.

Based on the results one could discuss that HUB 2 had better performance than HUB 1 in

terms of prefabrication in terms of safety, time, cost and quality. The safety on an overall was

better on HUB 2 even though the site is bigger, has more wall panels and number of people

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(trades, workers, etc.) Based on the quality, it should be noted that HUB 1 and HUB 2 both had

issues about quality. There are more modifications at HUB 2, which could be reduced by

improving the coordination with the manufacturing plant.

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CHAPTER 5

CONCLUSION, SIGNIFICANCE, AND LIMITATIONS

Conclusion

After working on prefabrication projects, collecting the data, analyzing and observing the

installation, conclusions can be made based on the metrics and the variances.

Every prefabrication project has four critical factors that govern the success or failure of

the project and this framework identifies and lays the foundation for future prefabrication

projects. The framework can be referred and used by the superintendent’s project managers,

foreman and students to study such projects. The data collected during the preliminary survey

indicated safety, cost, time and quality have positive and negative effects on prefabrication

projects. On site-specific interviews with the main project participants on both the projects, the

factors which could be measured under these heads were established.

Before starting any prefabrication projects, there needs to be a properly planned approach

towards time, cost, quality, and safety. The data collected can be used as a guideline to create

preliminary schedules and preliminary cost estimates. This would help in making planning more

site-specific. The framework would serve as the basis for identifying the parameters like time

taken to install one panel, crane hours devoted to prefabrication, etc. These parameters help in

observing changes and working out productivity or performance improvement strategies.

There were several factors which have not been stressed in the past research like the

relation of poor housekeeping to site safety and overall productivity The relation of cost and

quality in the field. Along with the cost of manufacturing is one moderately standard panel, equal

attention needs to be given to panels that are rejected, damaged or modified when delivered on

the site.

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This research would help the students in identifying the potential of construction sites and

help them identify problems on such sites and work on research ways to overcome those

problems.

Significance of Research

The metrics can be used for comparing the past and future prefabrication projects based

on the safety, cost, time and quality. The research would be useful to people involved in the

design, planning, control and execution of prefabrication elements. This research would be

useful to project managers, superintendents, estimators, and workers. The collected data can be

used to make schedules and account for the site installation problems which have been identified

in this study. The recommendations can be used for future projects for improving productivity in

terms of quality of work. The time recorded in the data collection can be useful for making

schedules and safer practices can be implemented. Students in the construction industry, working

as interns on construction sites can use this research to understand elements to be observed and

use the opportunity to implement the research done already or find ways to improve methods on

site.

Limitations and Future Work

The limitations of this research are that the data collected was only on multi-family

construction projects which is just a part of the big construction industry. The commercial,

industrial, heavy civil and healthcare construction is not represented in this research. Also, both

the projects are located in Gainesville and are affected by the climatic and topographical

conditions around the region. Hence it does not represent the diversity of construction projects in

the united states. More data is needed to validate the results and metrics which would be a true

representation of the industry. There is a need to conduct future quantitative research studies

such as time trials or field tests to collect data to scientifically validate the work.

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In the future, more factors affecting prefabrication could be studied and more detailed

metrics could be created. These metrics should be tested by collecting data that would help in

creating a hypothesis. These hypotheses can be validated using statistical tools and would help

draw more comprehensive conclusions. The data set can be large to define the industry

appropriately and cover other diverse projects (e.g. industrial, commercial and heavy highway).

Recommendations

The recommendations are made based on the data collection and study performed.

• The site location plays an important role, which includes the zoning, maintenance of

traffic, proximity to main roads, site storage yard and light poles location

• Site waste is very critical, in terms of the effect on safety, quality, cost, and schedule of

the prefabrication projects. A clean/safer construction environment would improve

overall productivity.

• The effective use of available resources is very crucial. In this case, the effective use of

crane and labor crews is required along with strong leadership and organizational

decisions.

• The productivity can be improved by reducing the time taken to install, create the layout

and finish the wall panel. This would help in achieving the milestones and abiding by the

schedule.

• The cost overall which includes the manufacturing, transportation, and finishing can be

reduced by coordinating the most recent architectural, structural and MEP changes with

the manufacturing plant. This would help reduce the rejection, modifications, and damage

to wall panels.

• Pre-planning in terms of installation of prefabricated wall panels is needed. This means

setting up small milestones and rather than big and unpractical milestones.

• Lastly, a safer environment would help in achieving better quality on the construction

site.

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LIST OF REFERENCES

Abanda, F. H., Tah, J. H. M., and Cheung, F. K. T. (2017). BIM in off-site manufacturing for

buildings. Journal of Building Engineering, 14, 89-102.

Abdul, R.R. (2011) Quality Management in Construction, Taylor and Francis Group, USA.

Arman Hashemi (2015). Offsite Manufacturing: A Survey on the Current Status and Risks of

Offsite Construction in Iran. Journal of Civil Engineering and Architecture, 9(2).

Becker, P.E., Fullen, M.D., & Takacs, B. (2003). Safety hazards to workers in modular home

construction. Silver Spring, MD: The Center to Protect Workers’ Rights

Cantu, H., Canal, C., and Costin, A. (2019). Modular Construction: Assessing the Challenges

Faced with the Adoption of an Innovative Approach to Improve U.S. Residential

Construction. CIB World Building Congress, Hong Kong, June 17-21.

Costin, A., and Eastman, C. (2019). Need for interoperability to enable seamless information

exchanges in smart and sustainable urban systems. Journal of Computing in Civil

Engineering, 33(3), 04019008.

Costin, A., Wehle, A., and Adibfar, A. (2019). Leading Indicators—A Conceptual IoT-Based

Framework to Produce Active Leading Indicators for Construction Safety. Safety, 5(4),

86.

Costin, A., Adibfar, A., Hu, H., and Chen, S. S. (2018). Building Information Modeling (BIM)

for transportation infrastructure–Literature review, applications, challenges, and

recommendations. Automation in Construction, 94, 257-281.

Chauhan, K., Peltokorpi, A., Lavikka, R. & Seppänen, O. (2019). Deciding Between

Prefabrication and On-Site Construction: A Choosing-by-Advantage Approach In: Proc.

27th Annual Conference of the International Group for Lean Construction

(IGLC). Dublin, Ireland, 3-5 Jul 2019. pp 749-758

Darekar, K., 2020. Internship Report and Data Collection at HUB projects in Gainesville.

Emmanuel, A., Aigbavboa, C. and Dlamini, E. (2020). Factors Affecting Quality of Construction

Projects in Swaziland. 9th International Conference on Construction in the 21st century:

Dubai, UAE.

Fard, M., Terouhid, S., Kibert, C. and Hakim, H. (2015). Safety concerns related to

modular/prefabricated building construction. International Journal of Injury Control and

Safety Promotion, 24(1), pp.10-23.

Fenner, A., Razkenari, M., Shojaei, A., Hakim, H. and Kibert, C. (2018). Outcomes of the State-

of-the-art Symposium: status, challenges and future directions of offsite

construction. Modular and Offsite Construction (MOC) Summit Proceedings.

52

Jha, K.N. & Iyer, K.C. (2005). Factors affecting cost performance: evidence from Indian

construction projects. International Journal of Project Management, Vol. 23, No. 4,

pp.283-295.

McGraw Hill Construction. (2013). Safety management in the construction industry: Identifying

risks and reducing accidents to improve site productivity and project ROI. Bedford, MA:

McGraw Hill Construction.

New Scientist. 2020. Science: The Day the Sweet Track Was Built. [online] Available at:

<https://www.newscientist.com/article/mg12617212-800-science-the-day-the-sweet-

track-was-built/?ignored=irrelevant> [Accessed 9 March 2020].

News, A., 2020. Built-In 10 Days China's Virus Hospital Takes 1St Patients. [online] ABC

News. Available at: <https://abcnews.go.com/Health/wireStory/built-10-days-chinas-

virus-hospital-takes-1st-68715909> [Accessed 9 March 2020].

Patil, J. (2020). Prefabrication Technology -A Promising Alternative in the Construction

Industry. International Journal of Science and Research (IJSR) 8(8):220 - 224, 8(8):220 -

224.

Qi, B., Chen K., and Costin, A. M. (2018). RFID and BIM-enabled prefabricated component

management system in prefabricated housing production. Construction Research

Congress, New Orleans, 591-601.

Qi, B., Razkenari, M., and Costin, A. (2019). Challenges of Implementing Emerging

Technologies in Residential Modular Construction. CIB World Building Congress, Hong

Kong, June 17-21.

Razkenari, M., Qi, B., Fenner, A., Hakim, H., Costin, A., and Kibert C.J. (2019). Industrialized

construction: emerging methods and technologies. Computing in Civil Engineering,

2019: Data, Sensing, and Analytics, ASCE, Atlanta, 352-359.

Steinhardt, D., Manley, K., Bildsten, L. and Widen, K. (2019). The structure of emergent

prefabricated housing industries: a comparative case study of Australia and

Sweden. Construction Management and Economics, pp.1-19.

Smith, R. (2011). Prefab architecture. Hoboken, N.J.: John Wiley & Sons.

W M Wong, R., J L Hao, J. and M L Ho, C. (2020). Prefabricated Building Construction

Systems Adopted in Hong Kong.

Yin, X., Liu, H., Chen, Y., and Al-Hussein, M. (2019). Building information modelling for off-

site construction: Review and future directions. Automation in Construction, 101, 72-91.

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BIOGRAPHICAL SKETCH

Mr. Karan Kundan Darekar joined the M. E Rinker Sr. School of Construction

Management as a full-time graduate student in fall 2018. Mr. Darekar has completed his master’s

degree in construction management with a research interest in prefabricated construction. After

graduating in May 2020, Mr. Darekar planned to work in the preconstruction, estimation,

scheduling and project management fields of the construction industry. Before the start of Mr.

Darekar’s career as a graduate student at UF, he was devoted towards obtaining a Bachelor of

Technology degree in civil engineering from India's premier institute VJTI. Mr. Darekar also

holds a technical diploma in civil engineering which helped him gain knowledge in areas like

surveying, estimation, statistics, computer-aided programs, construction plans, and

specifications.