The Professional Constructor - October 2013

THEPROFESSIONALCONSTRUCTORJOURNAL OF THE AMERICAN INSTITUTE O F C O N S T R U C T O R S

O C T O B E R 2 0 1 3 | V O L U M E 3 7 | N U M B E R 0 2

I N T H I S I S S U E :

● Identification of Team Performance Attributes Impacted by Building Information Modeling (BIM) Practice

● Sustainable Construction of Roadway Surfaces and Bases

● Key Factors in Constructability Success: Perception of Construction Professionals in Developing Countries

● Time Motion Study Applications Using Prevention through Design (PtD) Innovations in Construction

● Descriptive Construction Methods through BIM-based Collaboration

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Founded in 1971, the American Institute of Constructors mission is to promote individual professionalism and excellence throughout the related fields of construction. AIC supports the individual Constructor throughout their careers by helping to develop the skills, knowledge, professionalism and ethics that further the standing of the construction industry. AIC Members participate in developing, and commit to, the highest standards of practice in managing the projects and relationships that contribute to the successful competition of the construction process. In addition to membership, the AIC certifies individuals through the Constructor Certification Commission. The Associate Constructor (AC) and Certified Professional Constructor (CPC) are internationally recognized certifications in the construction industry. These two certifications give formal recognition of the education and experience that defines a Professional Constructor. For more information about the AIC please visit their website at www.professionalconstructor.org.

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1980 Clarke E. Redlinger, FAIC

1981 Robert D. Nabholz, FAIC

1982 Bruce C. Gilbert, FAIC

1983 Ralph. J. Hubert, FAIC

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THEPROFESSIONALCONSTRUCTORJOURNAL OF THE AMERICAN INSTITUTE OF CONSTRUCTORS

AIC BOARD OF DIRECTORS 2013|2014David Fleming, CPC, DBIA AIC National President Sundt Construction

Saeed Goodman, CPC, DBIA, PMP Vice President United States Navy – NAVAIR

Paul Mattingly, CPC Treasurer BosseMattingly Constructors

Mike W. Golden, FAIC, CPC Secretary MW GOLDEN CONSTRUCTORS

David Bierlein, CPC (National Elected) (2011-2014) KBR

Dennis Bausman, FAIC, CPC (National Elected) (2011-2014) Clemson University

E. Terrence Foster, FAIC, CPC (National Elected) (2011-2014) University of Nebraska

Joe DiGeronimo (National Elected) (2011-2014) Precision Environmental Co.

Mark Hall, CPC (National Elected) (2012-2015) Hall Construction Company, Inc.

Joseph Rietman, CPC (National Elected) (2013-2016) Kitchell Contractors, Inc.

Jim Nissen, CPC (National Elected) (2013-2016) Pepper Construction Company

Jim Hoskinson, CPC (National Elected) (2013-2016) TMG Construction Corporation

David Jones, CPC (National Elected) (2013-2016) ActionCOACH Business Coaching

Greg Carender, CPC, PMP (National Elected) (2012-2015) PricewatterhouseCoopers

John Kiker, CPC (Chapter Appointed – Tampa) Kiker Services Corporation

Scott Moffat, AC Chapter Appointed – DC Metro) TMG Construction Corporation

David Dominguez, CPC (Chapter Appointed – Arkansas) Nabholz Construction Company

Kevin Kasner (Chapter Appointed – Northern Ohio) The Chas. E. Phipps Co.

Bradley Monson, CPC (Chair, Membership Committee)

Matt Conrad, CPC (Chair, Constructor Certification Commission) The Christman Company

Seth O’Brien, CPC (Chair, Programs and Education Committee) Pittsburg State University

Tanya Matthews, FAIC, DBIA (Chair, Inter-Industry Committee) TMG Construction Corporation

Articles:

Identification of Team Performance Attributes

Impacted by Building Information Modeling (BIM) Practice ..................................5 Sydney Eisenmann, LEED GA Borinara Park, Ph. D., LEED AP Dan Brown, Ph.D.

Sustainable Construction of Roadway Surfaces and Bases ................................13 Ross Talbot, MCSM

Dennis C. Bausman, PhD, FAIC, CPC

Key Factors in Constructability Success: Perception of Construction

Professionals in Developing Countries ................................................................20

Daniel Yaw Addai Duah

Time Motion Study Applications Using Prevention through Design (PtD)

Innovations in Construction .................................................................................28

Justin Weidman, Ph.D.

Nicholas Rozier

Otero, Yuanivel, MS

Descriptive Construction Methods through BIM-Based Collaboration ................37

Marcel Maghiar, Ph.D.

Avi Wiezel, Ph.D., PE

The Professional Constructor (ISSN 0146-7557) is the official publication of the American Institute of Constructors (AIC), 700 N. Fairfax St. Suite 510 Alexandria, VA 22314. Telephone 703.683.4999, Fax 703.683.5480, www.professionalconstructor.org.

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O C T O B E R 2 0 1 3 | V O L U M E 3 7 | N U M B E R 0 2

EDITORJason D. Lucas, Ph.D., Assistant Professor, Clemson University

OCTOBER 2013 — Volume 37, Number 02The American Institute of Constructors | 700 N. Fairfax St., Suite 510 | Alexandria, VA 22314 | Tel: 703.683.4999 | www.professionalconstructor.org

5Identification of Team Performance Attributes

Impacted by Building Information Modeling (BIM) Practice

Sydney Eisenmann, LEED [email protected], McCarthy Building Companies Inc., St. Louis, MO USA

Borinara Park, Ph. D., LEED AP [email protected], Illinois State University, Normal, IL USA

Dan Brown3, Ph.D. [email protected], Illinois State University, Normal, IL USA

Keywords: Building Information Modeling (BIM), Team Performance, Team Attributes INTRODUCTION

The topic of Building Information Modeling (BIM) has exploded in popularity in the last ten years, because of the proposed benefits it is suggested to have on the building design and construction processes (Chan & Chan, 2004; Hardin, 2010; Jernigan, 2007). BIM promotes a practice that professionals, including designers, architects, contractors, construction managers, engineers, and MEP trades are involved early in project to solve building conflicts and encourage innovative design solutions before construction begins. Therefore, BIM may support professionals working together better, allowing them to see challenging projects full of possibilities, rather than costly obstacles (AIA Calif., 2007).

Implementing a new process and technology is not simple, as it impacts each project team member. Practicing BIM is a change from the traditional project delivery approach and will change the way building teams interact. In an interactive BIM environment professionals ask questions, share ideas, and exchange project information among the various professions and trades involved (Rekola, Kojima, and Makelainen, 2010). As project teams work in BIM, not only does communication change, but relationships, project responsibilities, and ultimately the execution of the project (Hardin, 2010). Mechanical engineers and architects may be less likely to experience conflict in their project plans; because they share ideas, plans, and utilize clash detection in the initial design phases to reduce conflicts prior to construction, ultimately saving time, money, and frustration out on the site. Even facilities managers would modify their typical maintenance program based on new information acquired from the BIM model. BIM could be a tool that

ABSTRACT: As a managerial tool, BIM facilitates teams to achieve their project goals and objectives in a more efficient and effective manner. By putting this new practice into use, building professions are challenged to change the way they approach a project. The construction industry is striving to understand how to react to and understand the impacts BIM makes on how teams perform. This paper seeks to answer the following specific question: To what extent does the use of BIM technologies and processes potentially relate to the performance level of project teams? An extensive review of team performance literature has been conducted to identify team attributes commonly found in successful project teams. This research used qualitatively a collection of various BIM adoption cases to systematically analyze the relationship between BIM and its impact on team performance. The collected BIM cases confirmed that the team performance overall improved in most of the team attributes with occasional negative impacts.

Ms. Sydney Eisenmann, BIM Engineer in the BIM department at McCarthy. She provides project support across the nation related to BIM implementation and issues. Dr. Borinara Park, Associate Professor in the Construction Management program at Illinois State University. His specialty includes BIM-based management and construction visualization.Dr. Dan Brown, Professor in the Technology Graduate Program at Illinois State University. His specialty includes project initiation and leadership.


6 Identification of Team Performance Attributes Impacted by Building Information Modeling (BIM) Practice

can be used from project inception to decommission. If this is a true potential of what BIM provides when it is fully embraced, the industry may never be the same.

As a tool, BIM facilitates teams to achieve their project goals and objectives in a more efficient and effective manner. By putting this new practice into use, building professions are challenged to change the way they approach a project, how they interact with one another, and ultimately how they seek to achieve their project goals on budget, on time, efficiently, and with the highest quality. As a managerial tool that encourages these outcomes, BIM could revolutionize the building industry (Hardin, 2010; Jernigan, 2007). However, there is no guarantee that BIM will have a positive outcome on all projects or for all project teams. Teams may not experience the advertised benefits of BIM initially, or ever. Does this mean that BIM is not an effective tool, or that only certain types of project teams can effectively execute BIM, or that BIM is only effective on certain types of projects? As more information becomes available about these BIM technologies and processes, the industry is striving to understand how to react to and understand the impacts of BIM related to these questions (Rekola, et al. 2010).This research, based on the investigation of the reported BIM adoption cases, seeks to answer the following questions: To what extent does the use of BIM technologies and processes potentially relate to the performance level of project teams?

LITERATURE REVIEW

Team Attributes

For the purpose of this study, it is essential to identify team attributes that are vital to successful team performance. An extensive review of team performance literature has been conducted to identify 45 team attributes . The attributes listed were identified by the authors of the articles commonly found in successful project teams (Brenner, 2007; Carr, Garza, Vorster, 2002; Chan et al, 2004; Ling 2002; Mathieu & Schulze, N.D; Thorton & Smalley, 2008; Van Scotter & Motowidlo, 1996). These attributes are combined, based on their similarities, into critical 20 team attributes and then grouped into 5 major categories as listed, in Table 1. The purpose of this was to try and clearly identify team

attributes that were as mutually exclusive as possible. The resulting team attribute categories are: 1) project communication; 2) project clarity; 3) organizational leadership; 4) interactive planning; and 5) team intangibles; as shown in the second column of Table 1. These categories were identified to provide mutually exclusive topic areas within team performance.

These team attributes are specific characteristics of team performance. They were investigated in this study first, because they can be utilized to further relate team performance to BIM. The literature review of the team performance reveals that, if specific team attributes are not prevalent in a team, it is believed that a decrease in the team’s performance level is expected. Team attributes are important in all fields, but especially in the construction industry where teams change from project to project. Thus, adapting to these changes and working as a team are essential to leading construction projects to success (AIA Calif., 2007; Ling, 2002; Van Scotter & Motowidlo, 1996).

Building Information Modeling Related to Team Attributes

In the BIM literature, there is a strong support for the idea that, to increase the benefits of BIM technology, project teams need to evaluate their performance after each project and assess the lessons learned (AIA, 2009). There are numerous sources discussing the possible benefits of BIM in the construction industry.

Team Attributes Categories

• Conflict Management • Project Information Exchange • Communication with Client • Project Team Communication

Project Communication

• Accuracy of Design • Knowledge of Constructability • Early Goal Definitions • Meeting Expectations • Goal Oriented

Project Clarity

• Key Person Involvement • Team Leadership • Project Efficiency

Organizational Leadership

• Brainstorming/Charrette • Decision-Making • Collaboration • Innovative Solutions

Interactive Planning

• Coordination • Project Team Dedication • Flexibility • Trust/Transparency

Team Intangibles

Table 1. Team Performance Attributes and Categories


7Identification of Team Performance Attributes Impacted by Building Information Modeling (BIM) Practice

However, it is difficult to find literature that provides a balanced view of both the positives and negatives of BIM’s impacts. There are very few sources that analyze project team’s BIM experiences to further improve project team performance in the future (Rekola, et al. 2010). It is therefore deemed essential to have a well-rounded understanding of the industry’s perspective on how much they perceived BIM affected their project execution and performance level (Keyton, et. al, 2010; Rad & Anantatmula, 2009).

METHODOLOGY

This research used qualitatively a collection of various BIM adoption cases to systematically analyze the relationship between BIM and its impact on team performance. This allowed for a wide range of building projects from various locations in the world to be compiled into a database, which would provide the linkage between the roles of BIM and the team attributes experienced by construction project teams. 18 published BIM case studies, found in 9 articles, were reviewed (Buckley, 2009; Carroll, 2009; Dossick & Neff, 2010; Greer, 2008; Jay, 2009; Khanzode, 2008; Pollak, 2003; Rowlinson, 2010; Thorton) and no new case studies were created by the authors.

Operational Definitions on Factors

One of the frequently discussed factors affecting BIM’s impact on team performance was how much project teams had previous experience with BIM technology (Carroll, 2009; Dossick, 2010; Hardin, 2009; Rowlinson, 2010; Jarnigan, 2007). Teams using BIM for the first time in their projects might not gain the same team experience compared to others who used BIM several times for a few years. The literature also implied that the level of project complexity would affect BIM team’s performance differently. Use of BIM to a structurally and mechanically complex and innovative hospital project, for example, might not have the same effect when it would be used for a regular retail building project.

For the purpose of this research, these two factors, 1) the level of team experience with BIM; and 2) the level of project complexity, are operationally defined as follows.

Low complexity projects use very conventional, standardized, and repetitive construction practices. These projects are simple and straightforward in the construction methods used, and lack challenges and situations that require creative problem solving. If a case study suggested instances in which 3 or more of these descriptions were applied, the project was categorized as a low complexity one. High complexity projects involve new, innovative, and unconventional practices and are under logistically and geographically challenging situations. Additionally construction may severely interfere with existing infrastructure, resulting in complex coordination. If a case study suggests instances in which three or more of these descriptions can be applied, the project was considered one with high complexity in this research. Medium complexity projects seek some innovation in their design/ construction processes, while still heavily depending on traditional practices. For the purpose of this research, medium complexity projects are defined as cases with the complexity between the Low and High complexity levels.

The following criteria are used to categorize the project teams’ level of experience with BIM. Operational definition is as follows; Low-level BIM experience: 1-2 years of experience in which the team used BIM, and/or 0-2 completed projects in BIM. Medium-level BIM experience: 3-5 years of experience in which the team used BIM, and/or 3-5 projects previously completed in BIM. High-level BIM experience: 6-10 years of experience in which the team used BIM, and/or 6+ projects completed in BIM.

Analysis Procedure

First, the identified team attributes and categories from Table 1 were listed as part of the matrix for the analysis as shown in Table 2 below. 18 BIM cases were then separately reviewed. Each reviewer identified external factors as they reviewed each project case and categorized it to low, medium, or high project complexity and low, medium, or high for the project team experience. For example, in the table, a BIM project case (Buckely, 2009) by the Gilbane company was considered a project with medium BIM experience level and medium project complexity.



Second, each case study was reviewed to determine if there were any instances in which the team attributes listed in Table 2 were reported to have been impacted by the implementation of BIM and to what extent. For example, in the aforementioned Gilbane BIM case (Buckely, 2009), the following instance was reported. “Virtual coordination of building trades brought the most apparent benefits. Rather than passing paperwork back and forth between the trades, the team worked together within the model to identify conflicts before they appeared in the field… The team cut expected coordination time from four months to two and a half months.” This specific instance confirms a situation where the use of BIM impacted the team’s performance, particularly the team’s “conflict management” and “coordination” attributes.

Third, once the instances and the impacted attributes were identified in the case, then it had to be determined to what extent the team attribute was impacted. The following operational definitions and criteria were used to that end. Very Positive (++): A case study reports, with high regard, benefits related to the use of BIM and suggests that the project team experienced exceptionally successful results from adopting BIM on their project. These project team members report high levels of benefit and potential for project team success while using BIM. Positive (+): A case reports positive project outcomes related to the use of BIM, while experiencing some

related challenges as well. Overall these case studies’ positive results far outweigh any related challenges and, overall, the project team sees the benefits associated with BIM to be worth the minor challenges. Neutral ( ): A case study experiences neither clearly positive, nor clearly negative effect related to the use of BIM in the project. Project team members in these cases are neither strong advocates for presence or absence of BIM on a project. Negative (-): A case reports having had more negative than positive project outcomes, potentially related to their use of BIM. Project team members in these case studies were overwhelmed by the negative setbacks and challenges that BIM presented in their project and did not experience potential benefits associated with BIM processes.

Based on these criteria, for example, the instance presented above in the Gilbane BIM case (Buckely, 2009) was determined to have a very positive impact on the “conflict management” and “coordination” attributes as shown in Table 2 as noted with ‘++’ symbols right next to those attributes.

Inter-Rater Verification

To assure validity of the analysis process performed by the authors, 3 industry professionals were invited to conduct the same research analysis independently. Upon receiving the results from the raters, the authors compared the own research analysis results to the raters’ to qualitatively validate the research analysis conducted by the researchers. Initial agreement in analysis between the researchers and raters was 79%, indicating for the most part the analysis was done reasonably objectively. When inconsistencies were noted, consensus was sought.

DATA ANALYSIS & RESULTS

BIM’s Impact on Team Performance

Table 3 below shows the summary of all the instances analyzed through the 18 published BIM case studies and their relationships to the team performance attributes and categories. In the table, each letter/ number combination represents a BIM/ team-related instance from a case in an article. For example, the

Table 2. Snapshot of the BIM and Team Attribute Impact Matrix



aforementioned instance, which came from the 1st case study of the article written by Buckely (2009), is denoted “B1” and this can be found at the “conflict management” and “coordination” attribute lines under the “Very Positive” column in the table (for more specific explanations of the other combinations, see the bottom of the table).

The table shows strong support how BIM helped the teams perform better in achieving project goals. The cases confirmed that the team performance improved: the team attribute categories (“organizational leadership”, “interactive planning”, “project clarity”, “project communications”, and “team intangibles”) were all positively impacted by the teams using the BIM technology as part of the project managerial process. BIM seemed to play a critical role to improve the majority of the team attributes such as “key person involvement”, “project efficiency”, “decision making”, “early goal definition”, “goal orientation”, and so on.

There were some instances, however, where the projects experienced lowered team performance when the BIM technology was used. They testified challenges regarding some of the team attributes as shown in Table 3. The studied projects, for example, occasionally reported negative impacts on “team leadership”, “collaboration”, and “conflict management”, to name a few. This observation is meaningful because it helps the current and future BIM user community realize that BIM is not an absolute management tool to have better teams in all situations.

To explain further the varying degrees of impacts BIM made on team performance, in the next sections, more in-depth analyses are performed to show how the factors (<1> team’s BIM experience; and <2> project complexity) affect the BIM’s impacts on team attributes.

Relationship between Teams’ BIM Experience and BIM’s Impact on Team Performance

The team attributes and categories impacted by BIM in Table 3 are rearranged in Figure 1 according to the teams BIM experience level and in Figure 2 with respect to the project complexity. Each figure contains 5 graphs displaying how each major team attribute category was affected by BIM in relation to the experience and complexity factors. To better visualize this potential relationship, the graphs in Figure 1 and Figure 2 were divided into three levels on the X-axis; low, medium, and high. The Y axis is divided into positive (++), positive (+), neutral (o), and negative (-) impact levels for impact of BIM on the team performance.

As the graphs suggest in Figure 1, the majority of the project teams in the analyzed case studies had a medium or high level of BIM experience with very positive or positive team impacts from using BIM in managing their projects. A few case studies that reported having a high level of experience reported some of the higher levels of successful team performance. The case study by Pollak (2003), reported having a highly experienced team with a BIM manager on the project resulted in producing very positive project results. All 5 team attribute categories in Figure 1suggests that, as the project teams’ BIM experience level increases, their performance may proportionally improve. Pollak (2003) described that the project team experienced very

Table 3. Team Attributes Impacted By BIM



positive results in team communication, interactive planning, and organized leadership.

A few of the project teams that had a low level of experience with BIM, however, reported negative impacts of BIM on team performance as shown in most team attribute categories in Figure 1. In the case studies by Dossick and Neff (2010), the project team reported having very negative experiences while using BIM, but the team was described to be very inexperienced with BIM and did not have upper management acting as a strong advocate or managing implementation of the new BIM process. This suggests that with poor organizational leadership and experience with the BIM process, the project team may not reap the benefits the BIM could provide to team performances.

Relationship between Project Complexity and BIM’s Impact on Team Performance

The graphs in Figure 2 represent the compiled reports of BIM’s impact on the five team performance attribute categories with respect to the project’s complexity level. They suggest that, as the project’s complexity level increases, so do the potential benefits a team may experience from using BIM processes. Rowlinson, et al. (2010), reported projects with very complex and unconventional structural designs but yet with the implementation of BIM produced a well performing and successful team.

On the other hand, if a project is conventional and not challenging, BIM’s impact on team performance is negligible or, in some situations, negative, as shown in Figure 2. This points out a fact that BIM should work as a tool to improve the communication and creativity, not as a communication barrier or technological burden.

Figure 1. Project Team BIM Experience and BIM’s Impact on Team Performance

Figure 2. Project Complexity and BIM’s Impact on Team Performance



CONCLUSION

The purpose of this study was to identify how the use of BIM technologies and processes may impact the way project teams perform. The collected BIM cases confirmed that the team performance overall improved in most of the team attributes with occasional negative impacts on team performance. To explain these variations, additional factors were considered. It was inferred that as a team’s level of BIM experience increased, the perceived positive impact on team performance level also appeared to increase. As projects became more complex, an increased positive impact on team performance was observed as well. It was shown that BIM-based project management impacts on the different team performance attributes.

BIM may not equally affect all team performance attributes the same way. The outcome of this study helps identify what level of performance project teams might be able to anticipate when they adopt the BIM technology in their management practice by relating their project team’s experience and project complexity. The results on what specific aspects of team performance BIM impacts and why the impact varies are informative, because it is not as simple as using BIM on a project and automatically experiencing higher team performance, or saving time and money immediately.

As project team’s experience level increased, their team’s performance level of the team attributes also tended toward a positive increase. Also, the more complex projects saw a greater potential impact from the use of BIM, and improved their team’s performance levels. This information is important for industry professionals to take note of as they practice BIM and make decisions about using BIM on projects. It will be important to recognize that BIM is not simply a technology or process, but a complete paradigm shift. It impacts the way team members interact with each other, how they plan, and manage a project, and ultimately how a project is effectively executed and completed.

The current research has not utilized all the BIM cases: the authors intended to provide a qualitative snapshot

of the BIM-based management practice on team performance. As the BIM practice continues to grow and more cases become available, there is a need for more quantitative and complete investigation so that industry has clearer and more definite information on BIM’s effect.

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Chan, A., Scott, D., & Chan, A. (2004). Factors affecting the success of a construction project. Journal of Construction Management and Engineering-ASCE, 130(1), 153-155. Retrieved from EBSCOhost.

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Mathieu, J., & Schulze, W. (2006). The influence of team knowledge and formal plans on episodic team process-performance relationships. Academy of Management Journel, 49(3), 605-619. Retrieved from EBSCOhost.

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Rekola, M., Kojima, J., & Makelainen, T. (2010). Towards Integrated Design and Delivery Solutions: Pinpointed Challenges of Process Change. Architectural Engineering & Design Management, 6(4), 264-278. doi:10.3763/aedm.2010,IDDS4

Rowlinson, S., Collins, R., Tuuli, M. M., & Yunyan, J. (2010). Implementation of building information modeling (BIM) in construction: A comparative case study. AIP Conference Proceedings, 1233(1), 572-577. doi:10.1063/1.3452236

Sebastian, R., & van Berlo, L. (2010). Tool for benchmarking BIM performance of design, engineering and construction firms in the Netherlands. Architectural Engineering & Design Management, 6(4), 254-263. doi:10.3763/aedm.2010.IDDS3

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Identification of Team Performance Attributes Impacted by Building Information Modeling (BIM) Practice


13

Sustainable Construction of Roadway Surfaces and Bases

Ross Talbot, MCSM, [email protected] C. Bausman, PhD, FAIC, CPC,

[email protected] University, Clemson, SC USA

Keywords: roadways, transportation, green construction, sustainable materials

INTRODUCTION

Roadways are a vital part of the United States economy and the daily life of each citizen. In 2012, vehicles on U.S. roadways traveled more than 2.9 trillion miles (LaHood, 2012) and each year the United States spends about $100 billion in roadway construction (Muench, 2010). Highway and street construction comprises more than nine percent (9.2%) of all construction in the United States (U.S. Department of Commerce, 2013). Roadways facilitate a mobile society and the transportation of goods. They are essential to a nation’s economic growth and competiveness. (LaHood, 2012).

Inherent with road construction is the destruction or degradation of the environment. The short-term impacts include destruction of habitat, significant alteration of the landscape, the generation of vast quantities of construction debris, runoff that can contaminate the groundwater and congest the sewer

systems, and the creation of noise and air pollution by the equipment used to build the roadways. In the long-term, the construction of roadways leaves society with less nature and more impervious and heat producing pavement (Shuster, 2010).

Buildings have some of the same negative impacts on the environment as roadways but consume more energy than industry and transportation combined (Pérez-Lombard et al. 2008). To combat environmental concerns the commercial and residential segments of the construction industry have embraced sustainable development and construction materials and techniques (Laustsen 2009, USGBC). “Green building is growing around the world and quickly becoming an industry standard” (Bernstein & Russo, page 1, 2013). Evidence is also emerging that sustainable practices are a worldwide trend in the horizontal construction industry (The High Road, 2010). Currently, some of the sustainable products or techniques being utilized include fly ash concrete, reclaimed surface and base products, and warm mix asphalt.

ABSTRACT: Sustainable systems and materials have widespread application in vertical construction and sustainability is starting to gain traction in horizontal construction. The objective of this study is to survey roadway contractors and State DOTs in the United States to determine current and future industry acceptance and application of sustainable techniques and materials on roadway construction. The findings are that porous concrete, porous asphalt, recycled glass base, and reclaimed asphalt shingles have minimal application. Conversely, fly ash concrete, reclaimed asphalt paving, recycled crushed concrete base, and warm mix asphalt have widespread use that is expected to expand. Contractors and DOTs state that the use of sustainable materials has little impact on initial or operational costs. However, when faced with a choice budgetary considerations and roadway lifespan take precedence over the incorporation of sustainable materials. In general, industry believes that the use of sustainable materials drives down the cost of roadway construction and in the future the majority of roadways built will incorporate recycled materials and sustainable techniques.

Ross Talbot is a Masters Candidate in Clemson University’s Construction Science & Management Department. He is from Baton Rouge, LA and is a 2008 graduate of Louisiana State University.Dennis C. Bausman, PhD, FAIC, CPC is a Professor and Endowed Faculty Chair in the Construction Science and Management Department at Clemson University

Sustainable Construction of Roadway Surfaces and Bases


14 Sustainable Construction of Roadway Surfaces and Bases

Fly ash is a by-product of coal-fired electric generating plants and has been used as an ingredient in concrete in the United States since the early 1930’s (US Department of Transportation, 2011). It offers environmental advantages and also improves the performance and quality of the concrete (Sustainable Sources, 2013).

Reclaimed (reused) materials reduce landfill waste and lower demand for production of new products. Reclaimed surfacing materials include reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS). These materials are reclaimed from original products that contain asphalt and/or aggregate. RAP and RAS are generated when the original products are removed and then properly crushed, segregated, and screened (Newcomb, n.d., CalRecycle, 2012). Reclaimed base materials include reclaimed glass and reclaimed concrete. Recycled glass base is recycled crushed glass that is known as glass cullet. This glass cullet is used as an aggregate in place of, or mixed with, traditional aggregate (Finkle, 2006). Reclaimed concrete is existing concrete that is removed, crushed and properly screened to produce acceptable roadway base material (MacDonald, 2011).

“Warm mix asphalt, by definition is Hot-Mix Asphalt (HMA) that is produced at temperatures 35°F - 100°F cooler than normal production HMA temperatures. This temperature reduction is done through the use of techniques that reduce the viscosity of the asphalt cement allowing coating of the aggregate at lower production temperatures.” (APAI, n.d.) Lower product temperature results in lower energy demand for production.

“Porous materials are widely recognized as a sustainable building material, as it reduces storm water runoff, improves storm water quality, may recharge groundwater supplies, and can reduce the impact of the urban heat island effect.” (page 522R-1) Porous materials are defined as a type of hardened material with connected pores that allow water to pass through easily. (ACI Committee, 2010)

To what extent have sustainable building materials and practices permeated the horizontal construction industry? The objective of this study was to investigate sustainable practices in roadway construction in order

to identify the extent of current and forecast use of sustainable roadway construction techniques and materials.

METHODOLOGY AND OBJECTIVE

Study Objective

The objective of this study is to investigate current and future trends for sustainable practices in horizontal construction. The key areas of focus are to:

• Determine what construction companies and State Department of Transportation services are currently doing to make roadway construction more sustainable.

• Investigate how, if at all, the use of sustainable practices will change in the future.

• Determine if cost, government mandate, or other factors are driving sustainability in roadway construction.

Population and Sample Selection

The population selected for this study is a combination of United States (U.S.) Departments of Transportation and U.S. roadway contractors. The Department of Transportation of all 50 states plus Washington D.C. were included in this study. Surveys were sent to the head engineer of Roadway Design and the head engineer of Roadway Construction in each state DOT. In addition, the CEO and/or Division Manager of the 232 firms listed in Engineering New Record’s regional lists of “Top Contractors” who report one percent or more of their annual volume in transportation, were solicited for participation in this study.

Questionnaire Design

A three page, self-administered survey was developed to solicit input from the selected sample of DOTs and contractors. The first section of the survey is designed to collect general information about the organization including location, size, and type of organization. The body of the questionnaire is divided into three sections with statements/questions, each with response options on a five-point Likert scale. The first section investigated how often sustainable techniques / materials are


15Sustainable Construction of Roadway Surfaces and Bases

used on current roadway projects. The second section is designed to ascertain the participant’s view of the industry’s support of sustainable techniques/ materials in roadway construction both currently and how they see its use changing in the future. The third section examined a wide range of topics, including costs associated with sustainable techniques and materials. Respondents are also asked to provide any additional insight (comments) regarding the use of sustainable practices for their organization.

FINDINGS

By the close of the data collection period 47 of the 106 Department of Transportation participants surveyed responded (44%) and 26 of the 232 contractors surveyed responded (12%). The total responses were 73 of 338 (22%).

Testing

Survey responses were subjected to statistical means testing using a confidence level of 95%. Additionally, t-tests with a significance level of 0.05 (assuming unequal variances) were conducted between contractors and DOTs. These statistical tests are illustrated in Tables 4 & 6.

Current Use on Publicly Funded Projects

In the first section of the questionnaire respondents are asked to indicate how often their organization used certain sustainable techniques and materials on their privately and publicly funded projects. Response options ranged from 1 (almost no projects) to 5 (almost all projects). Since only the contractors would have experience with privately funded work, any comparative analysis between DOTs and contractors focused solely on publicly funded work. Table 1 lists the response rates for current use of sustainable techniques/materials on publicly funded projects for both contractors and DOTs.

As noted in Table 1, the findings are:

• Porous concrete and porous asphalt are seldom used on roadway construction. Only twelve percent (12%) of the respondents utilize porous concrete on some to almost all of their projects and seventy-four percent (74%) of the respondents used porous asphalt on almost none or few of their projects.

• Fly ash concrete is often utilized. Fly ash concrete is used on the majority of publicly funded projects with 30% of respondents using it on most projects and 36% of respondents using it on almost all projects.

• Reclaimed asphalt paving is often utilized whereas reclaimed asphalt shingles are seldom incorporated into roadway construction. Reclaimed asphalt pavement (RAP) was used by 42% of respondents on most projects and 32% used it on almost all projects. Conversely, more than two-thirds (71%) of the respondents utilized reclaimed asphalt shingles on almost none or on few of their projects.

• Warm mix asphalt has moderate use. Seventy-five percent (75%) of the respondents used warm mix on some to almost all of their projects.

• Reclaimed crushed concrete base has moderate use with a majority of the respondents (59%) indicating that they use it on some to almost all of their projects. Conversely, recycled glass base has minimal application. Eighty-three percent (83%) of contractors and DOT’s used recycled glass base on almost none of their projects. Considering a comparative analysis of the mean responses of DOTs and contractors for work on current publicly funded jobs, only porous concrete showed a significant difference. The findings indicate that contractors more often utilize porous concrete.

Sustainable Technique/Material

Almost No

Projects

Few Projects

Some Projects

Most Projects

Almost All

Projects Porous concrete 63% 25% 7% 4% 1% Porous asphalt 37% 37% 16% 5% 4% Fly ash concrete 4% 7% 23% 30% 36% Reclaimed asphalt paving 5% 7% 14% 42% 32% Reclaimed asphalt shingles 49% 23% 15% 8% 5% Warm mix asphalt 5% 19% 37% 23% 15% Crushed concrete base 15% 26% 30% 19% 10% Recycled glass base 83% 14% 1% 1% 0%

Table 1: Current Publicly Funded Use for Contractors and DOTs



The distribution of responses is shown in Figure 1. This figure visually illustrates the response distribution and supports the finding of the comparative analysis that contractors use porous concrete more often than DOTs. In summary, seventy-one percent (71%) of the state DOTs use porous concrete on almost none of their projects while a majority of contractors (52%) use porous concrete on a few to almost all of their projects.

Current Use on Privately Funded Projects

Table 2 summarizes the distribution of responses from Contractors regarding the current use of sustainable techniques and materials on privately funded projects.

On privately funded jobs 45% of contractors report using porous concrete on almost no jobs and 40% state they use it on few projects. Porous asphalt has similar response rates with 37% of contractors stating they use it on almost no projects and 42% stating they use porous asphalt on only a few projects. The use of porous materials on privately funded jobs is slightly higher than those on publicly funded projects but both are overwhelmingly used on few or almost no projects.The response rates for fly ash concrete and for reclaimed asphalt pavement on privately funded projects are similar to those in the public sector. Twenty six percent (26%) of contractors indicated that they use fly ash concrete on most projects and 42% use it on almost all private projects. In addition, approximately two-thirds (65%) of the contractors participating in the study used reclaimed asphalt pavement on most or all of their projects compared to 74% of the respondents for publically funded projects. Conversely, on privately funded projects reclaimed asphalt shingles and recycled glass base are used almost never used by 63% and 85% of the contractors respectively.

Current and Future Industry Support

The next section of the questionnaire asks respondents to indicate the current and future support that the industry participants (both buyers & contractors) have for the use of certain sustainable techniques and materials for roadway construction. The combined mean support (both current and future) for contractors & DOT representatives for each technique/material is graphically shown in Figure 2.

Current industry support is the highest for use of reclaimed asphalt, fly ash concrete, warm mix asphalt, and crushed concrete base. More than two-thirds of the respondents indicated a high or very high level of support for reclaimed asphalt and fly ash concrete. A majority purported a high to very high support for warm mix asphalt. Conversely, industry participants have a lower level of support for porous asphalt, porous concrete, and reclaimed asphalt shingles with recycled glass base having the lowest level of support. More than 88% of the respondents indicated very little to no current industry support for recycled glass base.

Survey participants were also asked to forecast future industry support for these same sustainable materials/techniques. Table 3: Contractor & DOT Forecast Support, summarizes the distribution of the responses.

Support for porous concrete, porous asphalt, and fly ash concrete is forecast to increase by 36%, 39%, and 48% of the respondents respectively. Only 10% or less of the respondents forecast a decreased use in any of these materials. The use of warm asphalt mix and reclaimed asphalt received the highest level of future support – greater that two-thirds of the respondents forecast an increased use of these two materials.


Almost No

Projects

Few Projects

Some Projects

Most Projects

Almost All

Projects Porous concrete 45% 40% 5% 5% 5% Porous asphalt 37% 42% 11% 5% 5% Fly ash concrete 16% 5% 11% 26% 42% Warm mix asphalt 22% 22% 17% 17% 22% Reclaimed asphalt paving 15% 5% 15% 30% 35% Reclaimed asphalt shingles 63% 16% 11% 0% 11% Crushed concrete base 5% 10% 40% 35% 10% Recycled glass as base 85% 5% 5% 5% 0%

Table 2: Current Use on Privately Funded Projects (Contractors)

Figure 2: Current Support for Sustainable Materials



A statistical analysis of the data confirms that contractors and DOT representatives forecast an increased use of all but one of these sustainable materials/techniques. Support for recycled glass base is forecast to remain stable at the current low rate of use.

Table 4 tabulates the mean response for both contractors and DOT personnel for current use and forecast change in support. The contractor and DOT responses of current and forecast support for each material were statistically compared. Any finding of significance is also noted in Table 4.

As indicated in Table 4, contractors and DOT’s perceive similar levels of current industry support for the sustainable materials with the exception of recycled glass base. Both parties state that the industry has low support for recycled glass base, but DOT’s perceive a lower level of support than contractors.

With the exception of recycled glass base, both contractors and DOT’s forecast increased support for the use of the remaining sustainable materials. However, contractors forecast a higher level of increased support for both fly ash concrete and reclaimed asphalt for roadway construction. Response options were 1 (almost no projects), 2 (few projects), 3 (some projects), 4 (most projects) and 5 (almost all projects).

Use and Cost Effectiveness of Sustainable Techniques/Materials

The last section of the questionnaire asks participants to indicate their level of agreement with statements concerning the future use and costs associated with sustainable techniques and materials. Response options were on a Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). The combined response distribution for contractors and DOTs is shown in Table 5.

As noted in Table 5, a majority of respondents (77%) submit that budget takes precedence over sustainability and 58% of the sample states that increasing the lifespan of a roadway is more important than using recycled materials. Industry’s perception regarding cost implications for the use of sustainable materials is mixed. However, a majority does not believe that the use of recycled concrete base increases initial roadway cost.

More than two-thirds of the respondents assert that in the near future, the majority of new roadways will incorporate recycled materials for both the base and the roadway surface. Sixty-three percent (63%) believe that a majority of asphalt produced in the future will be warm mix and an even higher percentage (87%) forecast the use of reclaimed asphalt paving in the


Greatly Decrease Decrease No

Change Increase Greatly Increase

Porous concrete 3% 7% 54% 35% 1% Porous asphalt 1% 7% 53% 36% 3% Fly ash concrete 3% 1% 48% 30% 18% Warm mix asphalt 0% 3% 21% 44% 32% Reclaimed asphalt 0% 1% 21% 48% 30% Reclaimed asphalt shingles 4% 4% 43% 40% 9% Crushed concrete base 1% 1% 36% 44% 17% Recycled glass as base 6% 12% 74% 6% 3%

Table 3: Contractor & DOT Forecast Support

Sustainable Techniques & Materials

Current Future Contract

or DOT Significance Contractor DOT Significa

nce Porous concrete 2.70 2.43 No 3.27 3.24 No Porous asphalt 2.85 2.60 No 3.38 3.30 No Fly ash concrete 4.00 4.00 No 3.96 3.40 Yes Warm mix asphalt 3.50 3.70 No 3.88 4.20 No Reclaimed asphalt 4.12 4.30 No 4.32 3.90 Yes Reclaimed asphalt shingles 2.68 2.50 No 3.40 3.50 No Crushed concrete base 3.62 3.20 No 3.88 3.70 No Recycled glass as base 1.90 1.50 Yes 2.75 3.00 No

Table 4: Means and Comparative Analysis for Current Use & Future Support

Table 5: Use and Cost Effectiveness Response Distribution

Statement/Question Strongly Disagree Disagree Neither Agree Strongly

Agree The industry perceives that sustainable materials increase initial cost. 5% 30% 32% 26% 7%

When faced with a choice, budget considerations take precedence over sustainability. 0% 4% 19% 47% 30%

Using recycled concrete as a base is more expensive than traditional methods. 15% 47% 27% 10% 1%

Using recycled glass as a base is more expensive than traditional methods. 0% 9% 54% 25% 13%

Substituting recycled glass for a base material will have a wide application. 23% 41% 30% 1% 4%

The use of sustainable materials reduces maintenance costs. 4% 25% 56% 12% 3%

In the near future, the majority of all new asphalt roadways will have a porous top layer. 18% 32% 29% 18% 3%

In the near future, the majority of new roadway bases will incorporate some type of recycled material. 1% 4% 18% 48% 29%

In the near future, the majority of new roadway surfaces will have some type of recycled material incorporated into the surface.

0% 5% 15% 44% 36%

In the near future, the majority of asphalt will be produced via warm mix. 0% 7% 31% 35% 28%

In the near future, RAP (Reclaimed Asphalt Pavement) will be used in the majority of asphalt production. 0% 4% 8% 38% 49%

In the near future, RAS (Reclaimed Asphalt Shingles) has very limited application in asphalt production. 1% 30% 36% 24% 9%

Increasing the lifespan of a roadway is more important than using recycled materials. 1% 7% 34% 37% 21%

Offering sustainable materials makes our company more competitive. 0% 6% 54% 26% 14%

Table 5: Use and Cost Effectiveness Response Distribution



production of asphalt. However, widespread use of recycled glass base and a porous top layer for the road surface is not forecast by a majority of the respondents.

Table 6: Use and Cost Effectiveness Analysis tabulates the means and results of a comparative analysis for contractors and DOTs regarding the use and effectiveness of sustainable materials.

The statistical findings of this statistical analysis are as follows:

• When faced with a choice, budget considerations take precedence over the use of sustainability materials.

• Contractors and DOTs are neutral on both the initial cost impact of the use of sustainable materials and on whether the use of sustainable materials reduces maintenance costs.

• Increasing the lifespan of a roadway is more important than using recycled materials and contractors feel more strongly about this than DOTs.

• Recycled concrete base is not more expensive than traditional methods.

• Recycled glass base is more expensive than traditional methods and has limited application.• In the near future, the majority of new roadway bases and roadway surfaces will incorporate recycled material.

• In the near future, the majority of asphalt will incorporate reclaimed asphalt pavement.

• In the near future, the majority of asphalt will be warm mix and DOTs feel stronger about this than contractors.

• Contractors believe that the future use of RAS (Reclaimed Asphalt Shingles) has very limited application while DOTs are neutral regarding its use.

• Both contractors and DOTs maintain that offering sustainable materials, makes contractors more competitive.

CONCLUSIONS

Use of Sustainable Techniques/Materials

Currently, porous concrete and porous asphalt are seldom used on publicly and privately funded roadway construction projects and neither contractors nor DOTs expect to see a significant increased use of these products in the future. Similarly, the current use of reclaimed asphalt shingles and recycled glass base are very limited. Recycled glass base is viewed as a more expensive alternative to traditional base and its use is not expected to increase in the future. However, there is some support for an increased use of reclaimed asphalt shingles.

Conversely, fly ash concrete and reclaimed asphalt paving have widespread application in both private and public projects and their use is expected to expand. Recycled crushed concrete base is often incorporated into roadway construction and its use is also forecast to increase. In addition, warm mix asphalt has widespread application and again both contractors and DOTs expect its use to expand.

Sustainable Material Cost and Application

Contractors and DOTs believe that the use of sustainable materials typically has little impact on initial construction costs or operation/maintenance costs. However, when faced with a choice, budgetary considerations/constraint take precedence over the use of sustainable materials. They also believe that increasing the lifespan of a roadway is more important than incorporating recycled materials or sustainable techniques.

Statement Mean Signifi-cance Contr. DOT

The industry perceives that sustainable materials increase initial cost. 3.00 3.00 No When faced with a choice, budget consideration takes precedence over sustainability. 4.00 4.00 No

Using recycled concrete as a base is more expensive than traditional methods. 2.40 2.34 No Using recycled glass as a base is more expensive than traditional methods. 3.60 3.33 No Substituting recycled glass for a base material will have a wide application. 2.50 2.10 No The use of sustainable materials reduces maintenance costs. 2.96 2.80 No In the near future, a majority of new asphalt roadways will have a porous top layer. 3.16 2.23 Yes

In the near future, the majority of new roadway bases will incorporate some type of recycled material. 4.10 3.90 No

In the near future, the majority of new roadway surfaces will have some type of recycled material incorporated into the surface itself. 4.00 4.10 No

In the near future, the majority of asphalt will be produced via warm mix. 3.44 4.00 Yes In the near future, RAP (Reclaimed Asphalt Pavement) will be used in the majority of asphalt production. 4.20 4.40 No

Future use of RAS (Reclaimed Asphalt Shingles) has very limited application. 3.40 2.90 Yes Increasing the lifespan of a roadway is more important than using recycled materials. 4.00 3.50 Yes

Offering sustainable materials makes our company more competitive. 3.80 3.30 Yes

Table 6: Mean & Significance for Contractors & DOTs



However, industry participants believe that offering sustainable materials makes contractors more competitive which ultimately drives down the cost of roadway construction. In the near future, contractors and state DOTs both claim that the majority of new roadway bases and roadway surfaces will incorporate some type of recycled material. The incorporation of sustainable materials and techniques into roadway construction is considered mainstream and expected to expand on future projects.

REFERENCES

ACI Committee 522 (2010). Report on Pervious Concrete. American Concrete Institute. 522R-1.

Asphalt Paving Association of Iowa (APAI) (n.d.). Warm Mix Asphalt. Retrieved April 14, 2013, http://www.apai.net/warmmixasphaltwma.aspx

Bernstein, H. M., & Russo, M. A. (2013). Report Shows Green Building Is Growing Around the World. ENR: Engineering News-Record, 2701.

California Department of Resources Recycling and Recovery (CalRecycle) (2012). Asphalt Roofing Shingles in Aggregate Base. Retrieved April 14, 2013, http://www.calrecycle.ca.gov/ConDemo/Shingles/AggregBase.htm

Finkle, I, Ksaibati, K., & Robinson, T. (2006, August). Recycled Glass Utilization in Highway Construction. Transportation Research Board Annual Meeting. Retrieved April 13, 2013, http://docs.trb.org/prp/07-0929.pdf

LaHood, R (2012, August 2). Highway grants keep Americans moving forward. Welcome to the FastLane: The Official Blog of the U.S. Secretary of Transportation. Retrieved April 8, 2013, http://fastlane.dot.gov/2012/08/highway-grants-to-keep-americans-moving-on-down-the-road.html#.UW7jyr9bOmA

Laustsen, Jens (2009), Factor 4 –The role of policies for Zero Energy Buildings, International Energy Agency IEA, 6/9/09, http://www.iea.org/work/2009/zero_energy/Laustsen.pdf

MacDonald, K. (2011), Crushed Concrete: Will it become mainstream as sustainable construction grows more prevalent?. Concrete Construction. Retrieved April 17, 2013, http://www.concreteconstruction.net/sustainability/crushed-concrete.aspx

Muench, S.T. (2010). Roadway Construction Sustainability Impacts: A Life Cycle Assessment Review. Transportation Research Record 2151, National Research Council, Washington, D.C., pp. 36-45.

Newcomb, D. (n.d). SR-191 Five Ways to Save Your Asphalt!...And Still Build a Sexy Pavement. National Asphalt Pavement Association Special Report.

Pérez-Lombard, L., Ortiz, J. and Pout, C. (2008). "A review on buildings energy consumption information." Energy and Buildings 40: 394-398.

Shuster, L. A. (2010). GREENER ROADS AHEAD. Civil Engineering (08857024), 80(9), 78-81. Sustainable Sources (2013). Flyash Concrete. Retrieved April 14, 2014, http://flyash.sustainablesources.com

The High Road. (2010). PM Network, 24(5), 16-17.

US Department of Commerce (2013, April 1). February 2013 Construction at $885.1 Billion Annual Rate. US Census Bureau News.

US Department of Transportation (2011, April 7). Fly Ash. Retrieved April 14, 2013 from http://www.fhwa.dot.gov/infrastructure/materialsgrp/flyash.htm


20

Keywords: Constructability, Construction Professionals, Developing Countries

INTRODUCTION

The construction industry is an important industry for almost every country in the world irrespective of their economic growth and socio-economic development. It serves as a key indicator of economic growth, contributes around 10% of the global gross domestic product (GDP), is a major employment generator, and provides employment to almost seven percent of the working population worldwide (Economy Watch 2013a; Ofori 2012).

The construction industry usually places emphasis on projects in the urban areas, which generally include construction of real estate properties and associated infrastructure. The repairing and alterations to existing buildings and infrastructure is another aspect of the construction industry (Economy Watch 2013b). Typically, three major parties involved in a construction

project are: owners or clients, including home owners, private property developers, and public/governmental agencies; designers who transform the vision of the owner from concept to design and construction documents; and builders or contractors who either construct or manage the construction of the facility (Syal & Duah 2012).

For operational and analytical purposes, the World Bank classifies economies using the gross national income (GNI) per capita as the main measure. Based on its GNI per capita, every economy is classified as low income, middle income, or high income (World Bank 2012). Countries in the low-income category are generally classified as developing countries. Smith and Desai (2000) assert that, common economic features of developing countries permit them to be viewed in a broadly similar framework. They classify these common characteristics into the following six broad categories: (1) low levels of living, comprising low incomes, high inequality, poor health and inadequate education, (2) low levels of productivity, (3) high

Key Factors in Constructability Success: Perception of Construction Professionals in Developing Countries

Daniel Yaw Addai Duah, [email protected]

Michigan State University, East Lansing, MI USA

ABSTRACT: The objectives of constructability are enhancing early scoping, minimizing scope changes, reducing design related change orders, minimizing the need for redesigns during construction, enhancing quality of final product, optimizing construction staging, promoting construction safety, reducing conflicts/disputes, and ensuring a buildable project. The goal of this research was to identify the most important factors contributing to the success of constructability in order to improve the efficiency of delivery of construction projects in developing countries. This was based on the perception of construction professionals in Ghana. A total of 90 questionnaires drawn from Architects (N = 30), Contractors (N = 22), Quantity Surveyors (Cost Engineers) (N = 20), and Structural Engineers (N = 18) were collected and used for this study. The descriptive survey method was used and this involved qualitative data gathering through semi-structured interviews at the pilot survey stage, and quantitative surveys using questionnaires. Multi-attribute and relative index analytical methods were used in the data analyses. Results showed that, all four construction-related professionals identify the integration of construction knowledge and experience as the most important factor. Other important factors are project planning and scheduling, integration of constructability, and cost effective construction.

Daniel Yaw Addai Duah is a Fulbright Scholar and Lecturer in Architecture at the Kwane Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana where he teaches in the graduate and undergraduate programs. He is also a practicing architect belonging to the Ghana Institute of Architects. Daniel is currently a PhD candidate in Planning, Design, and Construction at the Michigan State University, USA. His main area of focus is “Energy Efficiency in Buildings”.

Key Factors in Constructability Success: Perception of Construction Professionals in Developing Countries


21Key Factors in Constructability Success: Perception of Construction Professionals in Developing Countries

rates of population growth and dependency burdens, (4) high and rising levels of unemployment and underemployment, (5) significant dependence on agricultural production and primary product exports, and (6) dominance, dependence, and vulnerability in international relations.

Located on the west coast of Africa, Ghana has a population of 24,658,823 (Ghana Statistical Service 2012). Ghana had a gross domestic product growth of eight percent in 2010, 14.4% in 2011 and about seven percent for 2012, prompted by strong cocoa production, construction and transport, continued increased gold output and the commercialization of oil. Inflation eased to 8.8% in December on the back of declining food price inflation, but producer price inflation is at 17% (World Bank 2013). As a result of the common characteristics of the economies of developing countries, Ghana was used as a case study to represent developing countries in this research.

Despite the differences between the construction industries of developing and industrialized countries, several construction industry concepts such as Constructability, Integrated Project Delivery, Lean Construction etc. continue to be introduced to the industry with the aim of improving the efficiency in delivering successful construction projects.

Within the context of this study, the terms constructability and buildability are used interchangeably. For the sake of consistency, constructability is used more often except when referencing or quoting from authors who use buildability.

CONSTRUCTABILITY CONCEPT

The Construction Industry Institute (CII 2013) defines constructability as ‘‘the optimum use of construction knowledge and experience in planning, engineering, procurement and field operations to achieve overall objectives.’’ Sidwell and Francis (1996) describe constructability as an approach that links design and construction process, which has been traditionally isolated in the construction industry. As projects become more complex, it is increasingly becoming difficult for designers to be aware of the effect of their

designs on construction costs. It is therefore important to take advantage of construction knowledge in the early stages of a project where the ability to influence cost is greatest and makes sense in practical and financial terms.

The concept of constructability emerged in the U.S. and U.K. in the late 1970s, evolving from studies into the need for increased quality and cost efficiency in the construction industry (Sidwell & Francis 1996). The constructability concept recognizes that, designers and contractors have different perspectives of a project and that, optimizing the project requires the knowledge and experience of both parties to be applied to the planning and design processes (Gibson 1996).

The Construction Industry Institute Australia (CIIA 1992) defines constructability as being “a system for achieving optimum integration of construction knowledge in the building process and balancing the various project and environmental constraints to achieve the maximization of project goals and building performance. Holroyd (2003) adds that in buildability, “construction work has to be designed to enable safe and cost effective construction, maintenance, alteration and demolition to take place”.

Buildability is seen as the result of fragmentation between design and construction practitioners (Moore 1998). According to Griffith (1984), buildability is the share of the responsibility of those disciplines that constitute the multi-disciplinary building team including Architects, Engineers, Surveyors, Building Contractors and Sub-Contractors, and not the individual responsibility of the Architect. Ashworth (1992) posits that, buildability is the extent to which the design of a building facilitates the ease of construction subject to the overall requirements of the completed building. Good constructability will therefore take into account how easy it is to translate design to construction, how easy it is to maintain, replace and adapt for reuse hence throughout the life cycle of the building from conception to demolition. Contractors according to Holroyd (2003), seek involvement in the design process in order to simplify the process. They bring the benefit of their construction experience to the designer with the goal of achieving safe and simple construction processes.


22 Key Factors in Constructability Success: Perception of Construction Professionals in Developing Countries

According to the transportation department of the state of New Jersey (2011), the goals of constructability can be summarized as: enhance early scoping, minimize scope changes, help reduce design related change orders, minimize the need for redesigns during construction, enhance quality of final product, optimize construction staging, promote construction safety, reduce conflicts/disputes, and make sure the project is buildable.

According to McGeorge and Palmer (2003), “the CIIA advocates a structured approach which identifies the following five stages in the procurement process: Feasibility Studies, Conceptual Design, Detail Design, Construction and Post Construction”. The CII and CIIA have developed fundamentals of constructability that are outlined in a set of principles that apply to the five stages of a projects life cycle (See Appendix A). Based on the principles of constructability developed by CII and CIIA (CII 1986; CIIA 1992), the author identified 17 factors, which may influence the achievement of the objectives of constructability:

1. Integrating construction knowledge and experience 2. Integration of constructability3. Safe construction4. Cost-effective construction5. Maintenance 6. Alteration7. Environmental impact8. Modularization/preassembly9. Formal constructability program10. Project planning and scheduling11. Aesthetics12. Construction methodology13. External factors14. Site layout/accessibility15. Specifications ad material supply16. Construction innovation17. Feedback

The efficient delivery of construction projects is a recurring problem especially in developing countries. The objective of this research was to identify the most important factors to achieving constructability success in order to improve the efficiency of delivery of construction projects in developing countries. This was

based on the perception of construction professionals (architects, contractors, cost engineers, and structural engineers) in Ghana. The research also strives to support the construction of efficient, economic, and quality buildings in developing countries using the concept of constructability.

METHODOLOGY

130 construction professionals in Ghana, who were registered members of their respective professional bodies, were identified via geographic location (major cities) and size (small and medium sized companies) for this study. They included 40 Architects and 30 each of Contractors, Quantity Surveyors/Cost Engineers, and Structural Engineers. Of the survey questionnaires sent, the fully usable responses were 90: 30 (representing 75% for Architects), 22 (representing 73% for Contractors), 20 (representing 67% for Quantity Surveyors/Cost Engineers), and 18 (representing 60% for Structural Engineers). The non-usable responses were mainly from highly uncompleted forms, unqualified categories and respondents such as recent graduates. Majority of the respondents belonged to their respective professional associations.

There were six categories: the general section sought information about the respondent, their area of expertise, experience, and professional associations if any. The next five categories sought the opinion of the professionals on the effect of the factors on achieving the objectives of constructability at the different stages of procurement (McGeorge & Palmer 2003). Depending on the effect in the procurement stages of construction, the different principles have varied importance. For instance, McGeorge and Palmer (2003) have noted that, whilst ‘external factors’ is of very high importance at the feasibility stage, it is highly important at the conceptual design stage but of lesser importance at the detailed design stage, and of no influence on the construction and post construction stages.

Using a six point rating scale and based on their experience, the respondents were asked to rate the levels of influence of constructability principles to achieving the objectives of constructability at the feasibility studies, conceptual design, actual design,



construction, and post construction stages of a project. The six point rating scale for levels of influence range from 1 (no effect), 2 (very low) 3 (low), 4 (moderate), 5 (high) to 6 (very high). Respondents were also asked to rate the frequency of occurrence for each identified factor influencing the achievement of the benefits of constructability. A five point rating was used for the frequency of occurrence which ranged from 1 (no frequency), 2 (rare) to 5 (very frequent).

The analyses involved the use of computations of the Influence Index (II) and Frequency Index (FI) by Nkado and Mbachu (2002), which indicate the levels of influence and frequency of occurrence of each factor within a subset of factors respectively. In each computation, the total number of respondents (TR) rating each factor was obtained and used to calculate the percentages of the number of respondents associating a particular rating point to each factor. These according to Nkado and Mbachu (2002) are then used to compute the Influence Index (II) and Relative Influences (RII) as follows:

Influence Index (II)This is computed as the sum of the products of each rating point (RP) and the corresponding percentage response (R%) to it, out of the total number of responses (TR) involved in the rating of the particular factor. The computation of the Influence Index is given in Equation 1:

Where: II = Influence IndexRpi = Rating point I (ranging from 1-6) Ri% = Percentage response to rating point i

Relative Influence Index (RII):This is used to compare the II values of the factors in a given subset. It is computed as a unit of the sum of Influence Indices in a given subset of factors as shown in Equation 2:

Where RII = Relative Influence Index II = Influence Index and = Sum of all Influence Indices of the constraints in a subset

The FI and the Relative Frequency Index (RFI) are compared in the same manner.

Having determined the Relative Influence and Relative Frequency Indices for the four professionals under the five stages of a projects life cycle, the average for all four at each stage was then determined, thus, obtaining one view from all four professionals at each stage.

RESULTS AND DISCUSSION

Feasibility Studies

Respondents were given a number of factors, which must be considered to achieve the benefits of constructability at this stage of the procurement process. They were asked to indicate, based on their experiences, the levels of influence and frequencies of occurrences of each factor. The average responses for all the professionals at the feasibility studies stage are summarized in Table 1.

Summary of Magnitudes and Frequencies of Occurrences of Factors of ConstructabilityATR: Total average number of respondents rating a particular factorAII: Average Influence Index (Equation 1) of a given factor; ARI: Relative Influence (Equation 2)R: Rank of each factor corresponding to its average level of influence (ARi) or Average Frequency of occurrences (ARf)AFI: Average Frequency Index (as for AII); ARF: Average Relative Frequency (as for ARI)REM: Remarks; A/AV: Above Average; B/AV: Below Average; V/Low: Very Low

From Table 1, it can be noted that, integrating construction knowledge and experience is the most influencing (0.178) and frequently occurring (0.176)

Table 1. AVERAGE RESPONSES (Feasibility Studies)FEASIBILITY STUDIES

LEVELS OF INFLUENCES FREQUENCIES OF

OCCURRENCES Factors of Constructability ATR AII REM ARI ARi AFI REM ARF ARf Integrating construction knowledge and experience

22.5 5.45 High 0.178 1 5.32 High 0.176 1

Environmental Impact 22.5 4.57 A/AV 0.151 2 4.52 A/AV 0.150 2 Alteration 22.5 3.98 B/AV 0.131 5 4.11 B/AV 0.136 5 Formal constructability program 22.5 4.25 B/AV 0.140 4 4.14 B/AV 0.137 4 Construction methodology 22.5 4.50 A/AV 0.148 3 4.50 A/AV 0.149 3 External factors (politics, traditions etc.) 22.5 3.81 B/AV 0.125 7 3.77 B/AV 0.125 7 Site layout/accessibility 22.5 3.86 B/AV 0.127 6 3.85 B/AV 0.127 6 Total 30.42 1 30.21 1

CONCEPTUAL DESIGN

LEVELS OF INFLUENCES FREQUENCIES OF OCCURRENCES

Factors of Constructability ATR AII REM ARI ARi AFI REM ARF ARf Integrating construction knowledge and experience

22.5 5.00 A/AV 0.071 1 4.92 A/AV 0.071 1

Integration of constructability 22.5 4.93 A/AV 0.070 2 4.62 A/AV 0.066 3 Safe construction 22.5 4.61 A/AV 0.065 5 4.37 A/AV 0.063 7 Cost-effective construction 22.5 4.81 A/AV 0.068 4 4.40 A/AV 0.063 7 Maintenance 22.5 4.26 B/AV 0.060 11 4.25 B/AV 0.061 12 Alteration 22.5 4.19 B/AV 0.059 13 4.19 B/AV 0.060 13 Environmental impact 22.5 4.08 B/AV 0.058 14 4.08 B/AV 0.059 14 Modularization/preassembly 22.5 4.32 B/AV 0.061 9 4.29 B/AV 0.062 9 Formal constructability program 22.5 4.59 A/AV 0.065 5 4.59 A/AV 0.066 3 Project planning and scheduling 22.5 4.83 A/AV 0.069 3 4.63 A/AV 0.067 2 Aesthetics 22.5 4.57 A/AV 0.065 5 4.61 A/AV 0.066 3 Construction methodology 22.5 4.26 B/AV 0.060 11 4.31 B/AV 0.062 9 External factors 22.5 3.50 Low 0.050 16 3.61 Low 0.052 16 Site layout/accessibility 22.5 3.76 B/AV 0.053 15 3.89 B/AV 0.056 15 Specifications & material supply 22.5 4.29 B/AV 0.061 9 4.32 B/AV 0.062 9 Construction innovation 22.5 4.50 A/AV 0.064 8 4.54 A/AV 0.065 6 Total 70.5 1 69.62 1



factor of constructability respectively. This conforms to the assertion by Sidwell and Francis (1996) about the importance of taking advantage of construction knowledge in the early stages of a project where the ability to influence cost is greatest and makes sense in practical and financial terms. Environmental impact is rated second both for most influencing (0.151) and frequently occurring factor (0.150). External factor was rated least at this stage of the project.

Conceptual Design

This section sought to find out the influence of a number of factors of constructability when options and alternatives are considered with the view to forming a conception of the best option in design. Table 2 presents a summary of the average responses for all professionals.

From Table 2, it can be noted that, the highest for levels of influence and frequencies of occurrence were: integrating construction knowledge and experience (0.071 and 0.071 respectively); integration of constructability (0.070 and 0.066 respectively); and project planning and scheduling (0.069 and 0.067). This conforms to literature where the indication is that, the earlier the involvement of other professionals, integration of constructability and planning, the better it is as any changes in the project can be done here (Sidwell & Francis 1996; McGeorge & Palmer 2003; Gibson 1996; CIIA 1992; Moore 1998; Griffith 1984; Holroyd 2003).

It can also be noted that, modularization/preassembly which leads to increased predictability and an easier assembly and better levels of safety of construction, has

a below average influence level (0.061) and frequency of occurrence (0.062). At this stage of a project life cycle, the factor must be considered at the design stage of project procurement. McGeorge and Palmer (2002) note that, cost effective solutions to construction have the greatest influence on the overall cost of a construction project. Though rated below average, it must be considered as more of a priority in order to achieve the objectives of constructability.

Other aspects of constructability rated above average in terms of levels of influences and frequencies of occurrences are formal constructability program (0.065 and 0.066 respectively), safe construction (0.065 and 0.063 respectively), aesthetics (0.065 and 0.066 respectively), and construction innovation (0.064 and 0.065 respectively).

Actual Design

This section relates to the detailed design stage of a project’s life cycle where all associated planning schedules, procurement, resources and budget are prepared. Again based on their experiences, respondents were asked to indicate the levels of influences and frequencies of occurrences of each identified factor of constructability. Table 3 presents a summary of the average response from all four professionals.

Construction methodology and site layout/accessibility were rated in terms of levels of influences and frequencies of occurrences as above average (0.061 and 0.062) and low (0.047 and 0.047) respectively. At this stage, a low consideration given to construction accessibility even though it leads to the ease of construction. Modularization/preassembly though

Table 2. AVERAGE RESPONSES (Conceptual Design)

FEASIBILITY STUDIES



22.5 5.45 High 0.178 1 5.32 High 0.176 1

Environmental Impact 22.5 4.57 A/AV 0.151 2 4.52 A/AV 0.150 2 Alteration 22.5 3.98 B/AV 0.131 5 4.11 B/AV 0.136 5 Formal constructability program 22.5 4.25 B/AV 0.140 4 4.14 B/AV 0.137 4 Construction methodology 22.5 4.50 A/AV 0.148 3 4.50 A/AV 0.149 3 External factors (politics, traditions etc.) 22.5 3.81 B/AV 0.125 7 3.77 B/AV 0.125 7 Site layout/accessibility 22.5 3.86 B/AV 0.127 6 3.85 B/AV 0.127 6 Total 30.42 1 30.21 1

CONCEPTUAL DESIGN



22.5 5.00 A/AV 0.071 1 4.92 A/AV 0.071 1

Integration of constructability 22.5 4.93 A/AV 0.070 2 4.62 A/AV 0.066 3 Safe construction 22.5 4.61 A/AV 0.065 5 4.37 A/AV 0.063 7 Cost-effective construction 22.5 4.81 A/AV 0.068 4 4.40 A/AV 0.063 7 Maintenance 22.5 4.26 B/AV 0.060 11 4.25 B/AV 0.061 12 Alteration 22.5 4.19 B/AV 0.059 13 4.19 B/AV 0.060 13 Environmental impact 22.5 4.08 B/AV 0.058 14 4.08 B/AV 0.059 14 Modularization/preassembly 22.5 4.32 B/AV 0.061 9 4.29 B/AV 0.062 9 Formal constructability program 22.5 4.59 A/AV 0.065 5 4.59 A/AV 0.066 3 Project planning and scheduling 22.5 4.83 A/AV 0.069 3 4.63 A/AV 0.067 2 Aesthetics 22.5 4.57 A/AV 0.065 5 4.61 A/AV 0.066 3 Construction methodology 22.5 4.26 B/AV 0.060 11 4.31 B/AV 0.062 9 External factors 22.5 3.50 Low 0.050 16 3.61 Low 0.052 16 Site layout/accessibility 22.5 3.76 B/AV 0.053 15 3.89 B/AV 0.056 15 Specifications & material supply 22.5 4.29 B/AV 0.061 9 4.32 B/AV 0.062 9 Construction innovation 22.5 4.50 A/AV 0.064 8 4.54 A/AV 0.065 6 Total 70.5 1 69.62 1

Table 3. AVERAGE RESPONSES (Actual Design)

ACTUAL DESIGN



22.5 5.15 A/AV 0.067 1 5.03 A/AV 0.066 1

Integration of constructability 22.5 4.74 A/AV 0.061 5 4.78 A/AV 0.062 5 Safe construction 22.5 4.90 A/AV 0.063 3 4.82 A/AV 0.063 3 Cost-effective construction 22.5 5.21 A/AV 0.067 1 5.01 A/AV 0.064 2 Maintenance 22.5 4.68 A/AV 0.060 9 4.53 A/AV 0.059 10 Alteration 22.5 3.77 B/AV 0.049 15 3.64 Low 0.048 15 Environmental impact 22.5 4.59 A/AV 0.059 12 4.44 B/AV 0.058 13 Modularization/preassembly 22.5 4.60 A/AV 0.059 12 4.55 A/AV 0.059 10 Formal constructability program 22.5 4.66 A/AV 0.060 9 4.61 A/AV 0.060 9 Project planning and scheduling 22.5 4.87 A/AV 0.063 3 4.84 A/AV 0.063 3 Aesthetics 22.5 4.48 B/AV 0.058 14 4.50 A/AV 0.059 10 Construction methodology 22.5 4.73 A/AV 0.061 5 4.72 A/AV 0.062 5 External factors 22.5 3.33 Low 0.043 17 3.68 Low 0.048 15 Site layout/accessibility 22.5 3.64 Low 0.047 16 3.61 Low 0.047 17 Specifications and material supply 22.5 4.75 A/AV 0.061 5 4.73 A/AV 0.062 5 Construction innovation 22.5 4.64 A/AV 0.060 9 4.48 B/AV 0.058 13 Feedback 22.5 4.69 A/AV 0.061 5 4.64 A/AV 0.061 8 Total 77.43 1 76.61 1



considered just above average, is rated 12th and 10th in terms of levels of influences (0.059) and frequencies of occurrences (0.059) respectively.

Other factors rated above average are integration of constructability (0.061 and 0.062 respectively), safe construction (0.063 and 0.063 respectively), environmental impact (0.059 and 0.058 respectively), maintenance (0.060 and 0.059 respectively), formal constructability program (0.060 and 0.060 respectively), project planning and scheduling (0.063 and 0.063 respectively), construction methodology (0.061 and 0.062 respectively), specifications and material supply (0.061 and 0.062 respectively) and feedback (0.061 and 0.061 respectively).

Construction

All 17 factors of constructability were included at this stage and the results are shown in Table 4.

According to the principles of constructability, the use of innovative techniques during construction will enhance constructability. From Table 4, this factor is rated below average for both levels of influences (0.059) and frequencies of occurrences (0.059). Construction innovation involves being abreast with contemporary technological inventions and applying them to the industry, having the requisite skills and tools or equipment, having the requisite basic training. This is lacking in the construction industry of most developing countries hence a low level of innovation in their construction practices.

Though project planning is rated above average (0.063 and 0.063 respectively), it must go hand in hand with a high rating for external factors which is the least

rated (0.042 and 0.045 respectively). There is generally no control over external factors in any construction project; hence it must be integrated in the planning and scheduling process of these projects.

Other factors rated above average in terms of levels of influences and frequencies of occurrences include formal constructability program (0.064 and 0.063 respectively), aesthetics (0.060 and 0.061 respectively), construction methodology (0.064 and 0.062 respectively) and specifications and material supply (0.063 and 0.062 respectively).

Post Construction

After a project has been handed over, there is the need for regular maintenance, upgrade and expansion and eventual disposal. A number of factors do influence these thus the respondents were asked to indicate how the listed factors of constructability influenced them as well as their frequencies of occurrences at this stage of a project life-cycle. Table 5 presents a summary of responses for all professionals.

Feedback is enhanced on similar future projects if the team undertakes a post-construction analysis. This is rated above average both in terms of levels of influences (0.112) and frequencies of occurrences (0.108). Ashworth (1994) notes that, ‘the life-cycle cost of a building or structure incorporates the total cost associated with it from inception to eventual demolition and also recurring costs which may be either annual or periodic in nature and incurred whilst the project is in commission by the owner or occupier’. Maintenance therefore is of paramount importance at the post construction stage. This is rated high both in terms of levels of influence (0.114) and frequencies of occurrence (0.112).

Table 4. AVERAGE RESPONSES (Actual Construction)

CONSTRUCTION LEVELS OF INFLUENCES

FREQUENCIES OF OCCURRENCES


22.5 5.43 High 0.068 1 5.13 High 0.066 1

Integration of constructability 22.5 5.17 A/AV 0.064 4 5.16 A/AV 0.064 4 Safe construction 22.5 5.26 High 0.066 2 5.3 High 0.066 1 Cost-effective construction 22.5 5.32 High 0.066 2 5.2 A/AV 0.065 3 Maintenance 22.5 4.47 B/AV 0.056 12 4.47 B/AV 0.056 12 Alteration 22.5 3.97 B/AV 0.05 15 3.91 Low 0.049 16 Environmental impact 22.5 4.06 B/AV 0.051 14 4.19 B/AV 0.052 14 Modularization/preassembly 22.5 5 A/AV 0.062 9 5 A/AV 0.062 7 Formal constructability program 22.5 5.1 A/AV 0.064 4 5.03 A/AV 0.063 5 Project planning and scheduling 22.5 5.06 A/AV 0.063 7 5.01 A/AV 0.063 5 Aesthetics 22.5 4.84 A/AV 0.06 10 4.86 A/AV 0.061 10 Construction methodology 22.5 5.11 A/AV 0.064 4 5 A/AV 0.062 7 External factors 22.5 3.39 Low 0.042 17 3.61 Low 0.045 17 Site layout/accessibility 22.5 3.95 B/AV 0.05 15 4.12 B/AV 0.051 15 Specifications and material supply 22.5 5.02 A/AV 0.063 7 5 A/AV 0.062 7 Construction innovation 22.5 4.7 B/AV 0.059 11 4.69 B/AV 0.059 11 Feedback 22.5 4.37 B/AV 0.054 13 4.26 B/AV 0.053 13 Total 80.22 1 80.12 1

Table 5. AVERAGE RESPONSES (Post Construction)

POST CONSTRUCTION LEVELS OF INFLUENCES FREQUENCIES OF OCCURRENCES

Factors of Constructability ATR AII REM ARI ARi AFI REM ARF ARf

Integrating construction knowledge and experience

22.5 4.47 High 0.114 1 4.60 A/AV 0.110 2

Integration of constructability 22.5 4.34 A/Av 0.104 5 4.38 A/AV 0.106 5

Maintenance 22.5 4.74 High 0.114 1 4.63 A/AV 0.112 1 Environmental impact 22.5 4.03 B/AV 0.097 6 4.04 B/AV 0.100 6 Aesthetics 22.5 4.43 A/AV 0.107 4 4.41 A/AV 0.107 4 Construction methodology 22.5 3.75 B/AV 0.090 9 3.80 B/AV 0.092 8 External factors 22.5 3.25 B/AV 0.078 10 3.28 B/AV 0.079 10 Site layout/accessibility 22.5 3.83 B/AV 0.092 7 3.81 B/AV 0.092 8 Construction innovation 22.5 3.81 B/AV 0.092 7 3.88 B/AV 0.094 7 Feedback 22.5 5.59 A/AV 0.112 3 4.46 A/AV 0.108 3 Total 41.59 1 41.29 1



The findings of this research revealed that, throughout the five stages, integrating construction knowledge and experience is rated high by all professionals as vital to achieving the objectives of constructability. Next, integration of constructability, project planning and scheduling, and cost-effective construction are rated above average by the professionals.

CONCLUSIONS

Since designers, contractors, quantity surveyors, and structural designers have different perceptions of a project, in order to ensure that the objectives of constructability are met for construction projects in developing countries, the application of the knowledge and experience of each party to the planning and design processes is required. The integration of construction knowledge and experience was considered an important factor in order to achieve the objectives of constructability.

The research also established that, despite the importance of construction knowledge and experience to the success of constructability, knowledge in this domain is limited. For instance, standardization and simplification, an important factor to be considered in constructability, was rated below average at the conceptual design stage and just above average at the actual design stage. In addition, construction accessibility and external factors were rated below average at the feasibility and conceptual design stages though it is at this stage that most influence can be achieved.

Though a relatively new concept in the construction industry of developing countries, the prospects for achieving the objectives of constructability are immense. The author recommends that, formal training and development of the understanding of constructability knowledge, is made available to interested professionals. In addition, various professional bodies must be encouraged to be at the forefront of this campaign to ensure that previous projects where constructability has been successfully implemented are used as a benchmark for integrating constructability into the construction industry in developing countries.

REFERENCES

Ashworth A (1994), Cost Studies of Buildings, Longman Group Limited, Second edition.

Construction Industry Institute (CII) (2013). SP3-3 – Constructability Concepts File. Available at: https://www.construction-institute.org/scriptcontent/more/sp3_3_more.cfm?CFID=803489&CFTOKEN=10443458. Accessed February 16, 2013.

Construction Industry Institute (CII) Constructability Task Force (1986). Constructability, A Primer. Publication 3-1, Austin, Texas.

Construction Industry Institute Australia (CIIA) (1992). Constructability Principles File. University of South Australia, Adelaide.

Economy Watch (2013a). Construction Industry. Available from: http://www.economywatch.com/world-industries/construction/. Accessed February 18, 2013.

Economy Watch (2013b). World Construction Industry. Available from: http://www.economywatch.com/world-industries/construction/world.html. Accessed February 18, 2013.

Gibson, G. E. Jr. (1996). Constructability in Public Sector. Journal of Construction Engineering & Management, Vol. 122 No. 3, pp. 274-80.

Ghana Statistical Service (2012). 2010 Population and Housing Census: Summary Report of Final Results. Sakoa Press Limited, Accra.

Griffith, A. (1984). Buildability: The Effect of Design and Management on Construction. Heriot-Watt University.

Holroyd, T. M. (2003). Buildability – Successful Construction from Conception to Completion. Thomas Telford.

McGeorge, D. & Palmer, A. (2003). Construction Management-New Directions. Blackwell Publishing, Second Edition.

Moore, D. (1998). Analysis Skills for Production Strategies: The Use of Buildability and System Tools. Oxford, Chandos.



New Jersey Transport Department (2011). How to Use Constructability Guidelines. The State of New Jersey. Available at: http://www.state.nj.us/transportation/capital/pd/documents/How_to_use_the_Constructability_Guidelines.pdf. Accessed February 18, 2013.

Nkado, R. N. & Mbachu, J. I. (2002). Factors constraining successful building project implementation in the South African building industry: construction project managers' perspectives. Proceedings of the 1st CIB-W107 International Conference, pp.359-368

Ofori, G. (2012). Reflections on the Great Divide: Strategic Review of the Book. In Contemporary Issues in Construction in Developing Countries. SPON Press, London, New York.

Sidwell, A.C. and Francis, V.E. (1996). The application of constructability principles in the Australian construction industry. In The Organization and Management of Construction Shaping Theory and Practice, Vol. 2, pp. 264-72.

Syal, M.G.M.S. & Duah, D.Y.A. (2012). Construction Project Management, in Civil Engineering,[Eds. Kiyoshi Horikawa, Qizhong Guo], in Encyclopedia of Life Support Systems(EOLSS), Developed under the Auspices of the UNESCO, EOLSS Publishers, Oxford ,UK, [http://www.eolss.net] [Retrieved February 5, 2013].

West, J. and Desai, P. (2000). Diverse Structures and Common Characteristics of Developing Nations. Retrieved from: http://www.c3l.uni-oldenburg.de/cde/OMDE625/Todaro/Todaro%20Chapter%202.pdf. Accessed May 27, 2013.

World Bank (2013). Ghana Overview. Retrieved from: http://www.worldbank.org/en/country/ghana/overview. Accessed May 30, 2013.

World Bank (2012). How We Classify Countries. Retrieved from: http://data.worldbank.org/about/country-classifications. Accessed August 4, 2012.


28 Time Motion Study Applications Using Prevention through Design (PtD) Innovations in Construction

Key Words: Prevention through Design (PtD), Diffusion, Innovation, Time Motion Study

INTRODUCTION

Innovation in Construction

Compared to other industries, the construction industry has seen few benefits from advancements in cost reduction and quality improvement mechanisms (Winch, 1998). Most sources that influence the adoption of innovations in the industry exist outside the construction firm. Consequently, construction firms often act as interceptors, meaning that they capture the innovations produced in other industries and adapt them to their needs (Gann, 1997). Firms rely

heavily on these external influences to optimize their processes rather than spearheading the development themselves (Winch, 1998). Figure 1 gives an illustration of how construction firms intercept innovations based on relationships that exist eternal to the firm, and then implement them actively on their projects to increase their understanding. Studies conducted by governments have shown that construction companies have relatively low investment in research and development (R&D). It has also been recognized that the connection between construction academia and industry is weak, in addition to the connections between the construction industry and other industries. This could be acting as a barrier to the implementation of new technologies that are being explored (A.M. Blayse, 2004).

Time Motion Study Applications Using Prevention through Design (PtD) Innovations in Construction

Justin Weidman, Ph.D., [email protected]

Nicholas Rozier, [email protected] Brigham Young University, Provo, UT USA

Otero, Yuanivel, MS, [email protected] Virginia Tech, Blacksburg, VA USA

ABSTRACT: The adoption of innovations in the construction industry is perceived to occur at a much slower rate than other industries. Many processes used in construction have remained unchanged, despite the aid that technological advances can provide. Studies have been carried out based on the Diffusion of Innovation Model to describe how innovations in various industries are accepted or rejected, and why these results occur. This paper outlines how innovation occurs in the construction industry and how the use of Time Motion Studies could be utilized to support the diffusion of Prevention through Design (PtD) technologies. General characteristics relating to innovation are reviewed, followed by those characteristics that pertain to the construction industry specifically. Prevention through Design innovations are also briefly discussed with specific examples. A background of the Time Motion Study is then given, including its origins, methods, and specific examples of how it has been used to improve productivity. A study was conducted using students to demonstrate the time motion benefits of drywall sanding. Following this overview a proposal is made relating to the implementation of Time Motion Studies in the construction industry to support the adoption of PtD innovations.

Justin Weidman is an assistant professor at Brigham Young University. He obtained his PhD from Virginia Tech in Environmental Design and Planning in 2012 and is focused on safety and health research.

Nicholas Rozier is an undergraduate student at Brigham Young University. He is currently involved in a commercial construction internship and serves as a research assistant in the Construction Management Program.

Yuanivel-Otero graduated with her Master’s degree in Building Construction in 2011 from Virginia Tech. She currently works as a field engineer for Turner Construction Company.


29

This weak connection is attributed to the fact that contractors have an excess of products and services to coordinate, and consequently little if any resources to explore the value of implementing new technologies.

“The usual attitude of construction people, managers, and workers alike, is to get on with the job. This does not provide a climate, lead time, or a thoughtful, searching approach necessary to develop and carry out new or innovative ideas” (Oglesby, Parker, & Howell, 1989).

Contractors work to solve their immediate problems, rather than less urgent issues like innovation application. This is greatly due to a lack of incentive given by owners and managers to encourage innovation (Winch, 1998). It has been suggested that owners are the principal managers of innovation in construction, and thus become the main source of or barrier to incentives. Figure 1 shows that owners can act as a barrier or facilitator of innovation on a project. The degree to which an owner decides to innovate is a function of their experience, technical competence including conducting their own R&D projects, professionalism, and the nature of their relationships with the respective contractors and design entities (A.M. Blayse, 2004).

Additional studies concluded that:

“users of technologies (in construction, the contractors and trades) can be acknowledged as sources for potentially important innovations and modifications” (Slaughter, 1993).

It has been pointed out that although trade contactors do have a significant impact on innovation, they often lack the resources and capital to invest in new technologies. Their extreme sensitivity to the fluctuations in the construction market prevents them from developing and sustaining new technologies (Slaughter, 1993). Cost, more often than not, becomes the sole barrier to innovation for contractors and sub-contractors. Companies tend to utilize opportunities to innovate that are perceived as being immediately beneficial and of low cost, rather than those that are more expensive (Slaughter, 1993). The importance of innovation in the construction industry is recognized as a means to improve the quality of life, productivity and safety (Arditi, Kale, & Tangkar, 1997). The amount of information presented to the potential adopter can greatly influence the decision to adopt. The use of the Diffusion of Innovation Model can help aid the adoption of new technologies in construction through providing the information necessary for decision makers to adopt new technology. Using the diffusion model as a guide and focusing on elements of the diffusion model, researchers can determine the most effective ways to increase the diffusion of innovations in the construction industry.

The Diffusion of Innovation Model outlines five characteristics that an innovation should have which promote adoption of technology, these include: Relative Advantage, Compatibility, Complexity, Triability, and Observability (Rogers, 2003).

1. Relative Advantage - Potential adopters are more likely to integrate an innovation into their business if it can provide them certain benefits. An innovation that has relative advantage will be attractive to an adopter because it is expected to improve existing methods and increase productivity. On the other hand, and innovation that cannot provide for improvements in methods can decrease work productivity and outcomes (Toole, 1998). The most common form of relative advantage is manifest in an innovation’s ability to provide increased profits (Utterback, 1974).

2. Compatibility - An innovation that is compatible will require little effort from the adopter to integrate into their present systems. Those technologies that are viewed as being easily integrated with current

Time Motion Study Applications Using Prevention through Design (PtD) Innovations in Construction

Figure 1. Adapted model of construction innovation diffusion. (Winch, 1998)



work methods are more likely to be accepted than those that aren’t (Sexton, 2004). Consequently, innovations that are viewed as being a disruption to current work methods are less likely to be accepted (Toole, 1998).

3. Complexity - If an innovation is too complex, the probability of acceptance is decreased. An innovation can be made simple and easy to understand by providing adequate information relating to its functions as well as properly trained personal to assist with its use (Arditi et al., 1997).

4. Triability - Triability relates to the opportunity that a potential adopter has to test the product prior to acceptance. This hands-on experience allows the adopter to understand more about the innovation and assists them in making a decision in a risk free environment. The more experience a builder has with a potentially profitable innovation, the more likely they are too use it (Toole, 1998).

5. Observability - This relates to the ability of an innovation to produce results that are visible to others. When the results of the aforementioned characteristics are easily visible to other companies, the innovation is considered to be observable (Manseau & Shields, 2005).

This paper focuses on the potential use of Time Motion Studies to address the elements of relative advantage, compatibility, and complexity to improve the information available that construction companies can obtain when deciding to adopt Prevention Through Design (PtD) safety technologies. It is expected that Time Motion Studies will assist decision makers by demonstrating the relative advantage, compatibility and complexity of PtD innovations. PtD solutions presented in the construction industry should have data to support these critical characteristics of innovation.

Prevention through Design (PtD)

Prevention through Design can be defined simply as a method to improve the quality of productivity, safety, and life in a given situation (Arditi et al., 1997).

“The goal of PtD is to prevent work-related injuries and illnesses. To do so requires an understanding of the connection between design features and occupational injuries and illnesses” (Gambatese, 2008).

The first step in preventing work-related injuries through design is to gain an understanding of the various correlations that exist between working conditions and worker health. After an adequate study of these conditions is completed, processes can be re-designed to achieve desired outcomes related to working conditions and health. This re-designing can change work atmosphere, tools used, and the methods involved in using these tools (Gambatese, 2008). Examples of typical design inputs include using lighter materials, ergonomic tools, and noise reducing systems (Gambatese, 2008). After designs have been created, the value of these designs is measured relative to their financial requirements to determine if they provide an acceptable return on investment. Often times a lack of proof that a certain design can improve conditions acts as a barrier to acceptance (Toole, 1998). When proof is clear that a certain design brings desirable outcomes, the probability of acceptance is much greater than for that of methods like planning and productivity management that provide results to a project that are difficult to quantify (Oglesby et al., 1989). A few specific examples of PtD innovations in construction include using emissions control devices on asphalt machines to reduce worker exposure to fumes, using tie-in scaffolding to prevent worker falls, and using alternate drywall sanding techniques to prevent worker exposure to dust (Schulte, Rinehart, Okun, Geraci, & Heidel, 2008).

Examples of PtD Solutions in Construction

Asphalt mixing is the process of combining aggregates and liquid asphalt to form a material that can be used for road paving. Hot Mix Asphalt temperatures typically range between 250-320 F during the time of paving. Consequently, hazardous fumes are released into the air that present a health risk to asphalt workers. Beginning in 1993 a committee was formed named the Engineering Controls Task Force to study the effects of these fumes on workers and to come up with an engineered solution to the problem. Through their efforts two general methods were presented for use as reducing fume exposures. These included using clean water to dilute the fumes and using Local Exhaust Ventilation (LEV) systems to decrease fume levels. Both these are simple examples of Prevention through Design (K. R. Mead, Mickelsen, & Brumagin, 1999).


31Time Motion Study Applications Using Prevention through Design (PtD) Innovations in Construction

Another example of a PtD innovation is construction is tie-in scaffolding mechanisms. They serve to prevent worker fall related injuries and deaths. This PtD innovation was created because of a recognized need for increased safety in the construction industry. Among other industries, the construction industry has more injuries related to falls than any other. In 2006, 809 falls were recorded and attributed to the industry (Ghule, 2008). Tie-in scaffolding attempts to better secure workers into their respective positions. One specific tie-in system is referred to as the Fall Arrest System. It functions by using harnesses and hooks to connect workers to a cable that restricts their movement. In order for a tie-in system to be acceptable it must be rigid enough that a worker cannot fall more than 6 feet or come into contact with an underlying floor (Ghule, 2008).

The previous two examples have described PtD solutions that focus on worker health and safety conditions. Recently, PtD solutions have also been explored to help improve healthy working conditions for drywall sanding workers. Drywall dust exposure is of particular concern in relation to the health of drywall finishers. Prevention through Design (PtD) solutions for dust control technologies have been found effective in reducing the levels of drywall dust to which finishers are exposed (K. Mead, Miller, & Flesch, 2000). Several different methods exist for drywall sanding. The most commonly used methods are block sanding (manual sanding), ventilated sanding, and wet sanding. Block sanding, or traditional sanding, is the most widely used of the three. Extensive studies have been conducted which suggest that this method fails to meet the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit values for respirable silica dust (Akbar-Khanzadeh et al., 2007). In an attempt to reduce the amount of respirable suspended particulate matter, wet sanding and ventilated sanding techniques can be utilized. Wet sanding is done two different ways. The first method is completed by saturating the dry compound with water prior to commencing sanding activities. The second method involves using a tool that integrates a sponge and sanding screen. In a ventilated system a vacuum is attached to the sander, which in turn collects the dust in a storage container. Among the three principal sanding methods, studies conclude that ventilated

sanders have the greatest effect on lowering dust levels (Young-Corbett, 2009).

In addition to these methods, a compound has been developed by 3M Company which incorporates substances which reduce dust levels. Implementing this PtD solution as well as others has been a slow process in the industry (Young-Corbett, 2009). The main goal of research in this area is to lower the respirable dust from sanding activities to a level that is accepted by the ACGIH. It has been generally recognized that workers in this particular trade suffer from ‘disproportionately high rates of respiratory disease and disability’ (Young-Corbett, 2009). Conclusions have also been drawn which suggest that those who are employed in the finishing trades with high levels of respirable dust are more susceptible to asthma. Specific studies on drywall sanding showed that the permissible exposure limit (PEL) was exceeded by a factor of 10 (Young-Corbett, 2009).

Present conditions in the industry exhibit a lack of substance to prove to contractors that these various PtD solutions can provide a relative advantage. As previously stated, companies tend to utilize opportunities to innovate that are perceived as being immediately beneficial and of low cost, rather than those that are more expensive (Slaughter, 1993). Time Motion Studies are currently being used to produce data that will serve to provide an attractive relative advantage to potential adopters of PtD technologies related to drywall sanding.

Time Motion Study

The Time Motion Study has developed from the growing need for industries to maximize their efficiency. It involves using time to establish standards and develop efficient methods for completing tasks within an industry. Cost is used as the metric for comparison; reducing cost while maximizing efficiency is the ultimate goal (Fred E. Meyers, 2002). The most basic form of this study is using a stopwatch to measure how long it takes to complete a task, and then creating a time standard that can be used to analyze productivity. A time standard can be defined as the amount of time it takes for a skilled worker to complete a certain task at a normal speed (Fred E. Meyers, 2002). All three of these variables- time, worker skill, and task- must be carefully considered when conducting a Time Motion Study.



Frederick W. Taylor is considered by many to be the father of productivity management. He began studying the productivity of his co-workers in an effort to maximize efficiency. His first studies comprised of compiling data from measurements of their performances. He soon realized that these measurements were inaccurate, because they were based on methods that weren’t properly designed. In an attempt to optimize the worker’s performance, he began to associate his time measuring efforts with their specific tasks and methods. In other words, he made sure that the workers he was studying completed the job the same way, and that the way they worked was the most efficient method (Fred E. Meyers, 2002).

“Taylor’s full discussion on “The Present State of the Art of Industrial Management” for a Subcommittee on Administration of the ASME as follows:

The analytical work of time study is as follows:

Divide the work of a man performing any job into simple elementary movements.Pick out all the useless movements and discard them.Study, one after another, just how each of several skilled workmen makes each elementary movement, and with the aid of a stop watch select the quickest and best method of making each elementary movement known in the trade.Describe, record, and index each elementary movement, with its proper times, so that it can be quickly found.Study and record the percentage which must be added to the actual working time of a good workman to cover unavoidable delays, interruptions, and minor accidents, etc.Study and record the percentage which must be added to cover the newness of a good workman to a job, the first few times that he does it. (This percentage is quite large on jobs made up of a large number of different elements composing a long sequence infrequently repeated. This factor grows smaller, however, as the work consists of a smaller number of different elements in a sequence that is more frequently repeated.)Study and record the percentage of time that must be allowed for rest, and the intervals at which the rest must be taken, in order to offset physical fatigue (Karger & Bayha, 1987).

Time and Motion studies involve breaking down a task into its individual parts and then rearranging them into their most efficient order. There are two parts to the study, the ‘time’ aspect and the ‘motion’ aspect. The ‘time’ aspect of study focuses on controlling cost, while the motion aspect of the study focuses on reducing cost (Fred E. Meyers, 2002). Over the past century many industries have seen benefits from these studies. Among these benefits are a better work atmosphere, decreased physical efforts from workers, safer production methods, and more desirable ergonomic working conditions. Additionally, Meyers points out that a natural result of these studies is that more employees have more time to spend doing what they do best: thinking and solving problems (Fred E. Meyers, 2002). Time and Motion studies also make sense statistically. Companies that incorporate time standards into their processes perform on average at 85%, while those who don’t use them perform on average at 60%. Companies that incorporate both time standards and incentive systems achieve 120% performance (Fred E. Meyers, 2002). A simple example of this would be to look at the overall time it takes a subcontractor to complete their respective part of a job. A subcontractor that uses time standards will improve the time it takes to complete the job 25% (85%-60%).

Toyota has greatly benefited from the implementation of Time Motion Studies into their manufacturing activities. Following the end of the Second World War, the United States’ economy had a clear advantage over those of other developed countries. Consequently, Toyota lagged behind traditional American automotive manufacturers. In pursuit of a more effective company, Toyota developed a philosophy of eliminating ‘muda’ in their manufacturing. Muda is the Japanese word for ‘waste’. Through proper applications of time motion studies, Toyota was able to identify waste in processes and eliminate them or minimize their effects on their processes (Fred E. Meyers, 2002).

The analysis and optimization of processes by using Time Motion Study tools usually begins with a Macromotion Study, followed by a Micromotion study. Macromotion Studies seek to identify what activities are being performed in a process. Micromotion Studies then take each of these identified activities and analyze them to determine how they contribute to the process



and how they can be altered to maximize efficiency (Fred E. Meyers, 2002). Toyota identified the difference between these two types of studies, and accordingly conducted their value engineering. They identified the Macromotions of their products as the ‘flow of material in time and space’, and the Micromotions as the ‘ work or actions performed to accomplish this transformation’ (Shingo & Dillon, 1989).

Once these two parts of the desired system have been identified, studies begin with data collection. The use of time motion studies requires that an observer be present at all times, and that precise time measurements be taken (S A Finkler, 1993). Measurements can be recorded using computer spreadsheets and then used for analysis.

One specific study was carried out to determine the effectiveness of resident physicians at different hospitals. This study rose from the concern that the number of resident physicians and the time they had to work was decreasing. Following data collection alternate solutions to these problems were considered. Twenty Two students were hired to serve as ‘coders’, and were trained over a 7 hour time period on subjects related to the study. Sixty Seven categories were created to monitor the precise use of time by the residents. A difficult part of the study was identified to occur when coders were forced to decide if what the resident was doing was something that required professional education, or if it was an activity that could be performed by a non-physician. Through continual monitoring of each category and the time spent on each activity, a total of 13,383 minutes were recorded, with 7.75 minutes spent on average with each activity. One of the conclusions drawn from the study was that 46.7% of the time residents were performing activities that could only be completed by a physician (Knickman, Lipkin, Finkler, Thompson, & Kiel, 1992).

Following the collection of data, a process chart can be created. Frank Gilbreth is widely recognized as the father of the process map, which is defined as

“a concise display of all the salient information required to design and implement ‘the best way’ of executing (a) job” (D.R., 2009).

Process charts allow individuals to implement ideas that promote working smarter and not harder. Natural outcomes of using process maps are increased efficiency in processes. Efficient processes lead to decreased working time, which increases the capacity of a given sector to produce (D.R., 2009).

Applications of Time Motion Study in Construction

The diffusion of innovations in the construction industry is restricted because more often than not innovations lack sufficient evidence to prove their worth to prospective adopters. As stated previously, innovations that are adopted tend to demonstrate a relative advantage, compatibility, and minimal complexity with the current working conditions of an adopter. Time Motion Studies can assist in demonstrating these key characteristics. Studies are currently being conducted using the time and motion methods to analyze the effectiveness of differing drywall sanding mechanisms. Results are being used to measure the variables that influence drywall sanding efficiency including: equipment set up time, equipment maintenance costs, average time to sand per square foot, and sanding finish quality and clean up time. Data is then being collected and analyzed using time motion techniques similar to those utilized by Manufacturing Engineer’s in manufacturing situations. Conclusions are being drawn concerning the relative advantage of using various sanding mechanisms.

Recent studies conducted by students at Virginia Tech University were made that demonstrate these advantages. Students used vacuum sanders and hand sanders and compared the results. Eight drywall panels (4’x8’) were prepared, with three lines of joint compound being applied to each board. For the hand sanding procedure, a full timed cycle included fixing the sand paper on a pole sander, sanding the joint flush, and removing the sand paper. The vacuum sander procedure included taking apart the sander, inserting the sand paper, reassembling the sander, plugging in the sander, sanding the joint, and then unplugging the sander. Figure two shows both procedures being completed at the same time.



The calculation of sample size for the study was calculated using the expression below:

Where, n = required sample size z = 1.65 for 90% confidence level p = estimate of idle proportion = 6% = 0.06 h = acceptable error of 9% = 0.09

Therefore, 19 was the sample size for the analysis.

The first manual sanding procedure was completed by 4 different individuals, and the second procedure was completed by 2 individuals. The following compares the results of the two methods:

Results from the study show that hand sanding generally has a shorter setup time, while the vacuum method has a shorter average sanding time. Thus, it may be assumed that desirable hand sanding results are mostly a function of the user, while desirable vacuum sanding results are more consistent regardless of the user. The time motion studies were successful in producing this data that serves as a means to inform potential adopters of either of these technologies. Further larger scale studies using industry professionals in various settings using both methods of sanding are being conducted by the authors.

Another possible use of time motion studies can be to measure the effectiveness of different concrete finishing activities. Concrete contractors have the option of using power floating machines for finishing or using hand floaters. Studies could be made to measure set up time for each method, the average time per square foot needed to float, and the quality of the concrete as a result of each method. The results attained from this study could serve to demonstrate a relative advantage of both the methods to potential adopters of either of the technologies. They could than use this data to make decisions about when and how they will use either power floating machines or hand floating machines.

A key part of any of these studies is to record the desired method being used multiple times. As discussed earlier, documenting the motions that take place during a given recording is just as important as documenting the time it takes to be completed (Oglesby et al., 1989). This can be a difficult task for any construction related activity like drywall sanding. Tasks such as set up and clean-up should be included in the overall time analysis. Projects are never the same and other variables exist like weather and job site conditions that can affect outcomes. It is therefore proper to take the most recordings possible of a single job site matching the conditions for each method in order to accurately analyze results.

CONCLUSIONS

PtD solutions can prove to greatly enhance working conditions on construction projects. Barriers exist that prevent the diffusion of these innovations and

Figure 2. Hand Sanding and Vacuum Sanding

Figure 3. Sanding Time Results



include a lack of relative advantage, comparability, and profitability. It is expected that by utilizing time motion studies to demonstrate that an innovation possesses these elements of the Diffusion of Innovation Model, PtD innovations will become more attractive to potential adopters. The data provided by time motion studies can serve as convincing evidence that a given solution is both effective and profitable. The adoption of PtD innovations in the construction industry can help to provide employees with an efficient work environment. The implementation of Time Motion Studies to evaluate PtD solutions also serves the construction industry by providing contractors the information necessary to evaluate the plausibility of adopting a given innovation without having to incur significant financial risks.

Results from a small scale Time Motion Study evaluating a PtD innovation in drywall sanding were presented and found to support the relative advantage, compatibility and complexity elements of the Diffusion of Innovation Model. The authors are currently working with industry professionals to conduct a large scale study to further support the data related to the effectiveness of different drywall sanding techniques. Through the use of time motion studies, similar drywall sanding procedures will be compared on current projects conducted by drywall subcontractors.

It is proposed that Time Motion Studies will positively influence the construction industry. While Time Motion Studies have proven to be effective in the manufacturing industry, they have yet to have a presence in the construction industry. Ultimately, the results of these studies will lead to an increase of adoption of PtD solutions. These solutions will provide more efficient processes and higher worker satisfaction. And, as observed by Toyota, Time Motion Studies will reduce ‘muda’ in construction processes. Profits collected by construction companies will consequently be increased due to these factors.

REFERENCES

A.M. Blayse, K. M. (2004). Key influences on construction innovation. Construction Innovation: Information, Process, Management, 4(3), 143- 154.

Akbar-Khanzadeh, F., Milz, S., Ames, A., Susi, P. P., Bisesi, M., Khuder, S. A., & Akbar-Khanzadeh, M. (2007). Crystalline Silica Dust and Respirable Particulate Matter During Indoor Concrete Grinding—Wet Grinding and Ventilated Grinding Compared with Uncontrolled Conventional Grinding. Journal of Occupational and Environmental Hygiene, 4(10), 770-779. doi: 10.1080/15459620701569708

Arditi, D., Kale, S., & Tangkar, M. (1997). Innovation in Construction Equipment and Its Flow into the Construction Industry. Journal of Construction Engineering and Management, 123(4), 371-378. doi: 10.1061/(asce)0733-9364(1997)123:4(371)

D.R., T. (2009). Frank Gilbreth and health care delivery method study driven learning. International Journal of Health Care Quality Assurance, 22(4), 417-440.

Fred E. Meyers, J. R. S. (2002). Motion and Time Study for Lean Manufacturing (3rd ed.): Prentice Hall.

Gambatese, J. A. (2008). Research issues in prevention through design. Journal of safety Research, 39(2), 153-156.

Gann, D. (1997). Should governments fund construction research? Building Research & Information, 25(5), 257-267. doi: 10.1080/096132197370228

Ghule, S. (2008). Suggested practices for preventing construction worker falls. University of Florida.

Karger, D. W., & Bayha, F. H. (1987). Engineered work measurement: the principles, techniques, and data of methods-time measurement background and foundations of work measurement and methods-time measurement, plus other related material: Industrial Press Inc.



Knickman, J. R., Lipkin, M. J., Finkler, S. A., Thompson, W. G., & Kiel, J. (1992). The potential for using non-physicians to compensate for the reduced availability of residents. Academic Medicine, 67(7), 429-438.

Manseau, A., & Shields, R. (2005). Building Tomorrow: Innovation in Construction and Engineering. Burlington: Ashgate.

Mead, K., Miller, A. K., & Flesch, J. P. (2000). Hazard Controls Control of Drywall Sanding Dust Exposures. Applied Occupational and Environmental Hygiene, 15(11), 820-821. doi: 10.1080/10473220050175689

Mead, K. R., Mickelsen, R. L., & Brumagin, T. E. (1999). Factory Performance Evaluations of Engineering Controls for Asphalt Paving Equipment. Applied Occupational and Environmental Hygiene, 14(8), 565-573. doi: 10.1080/104732299302567

Oglesby, C. H., Parker, H. W., & Howell, G. A. (1989). Productivity improvement in construction: McGraw-Hill New York.

Rogers, E. M. (2003). Diffusion of Innovations (Fifth Edition ed.). New York: Free Press.

S A Finkler, J. R. K., G Hendrickson, M Lipkin, Jr, W G Thompson. (1993). A comparison of work-sampling and time-and-motion techniques for studies in health services research. Health Serv Res., 28(5), 577-597.

Schulte, P. A., Rinehart, R., Okun, A., Geraci, C. L., & Heidel, D. S. (2008). National Prevention through Design (PtD) Initiative. Journal of safety Research, 39(2), 115-121. doi: 10.1016/j.jsr.2008.02.021

Sexton, M. (2004). The role of technology transfer in innovation within small construction firms. Engineering, construction, and architectural management, 11(5), 342-348. doi: 10.1108/09699980410558539

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Young-Corbett, D. E. N., M.A. (2009). Dust Control Technology Usage Patterns in the Drywall Finishing Industry. Journal of Occupational and Environmental Hygiene, 6, 315-323.


37Descriptive Construction Methods through BIM-based Collaboration

Key Words: BIM programs, technology ontology, estimating, construction methods, collaboration

INTRODUCTION AND LITERATURE REVIEW

A coordinated BIM approach can provide savings to clients in the operating of the building and offer benefits on the contractors’ side. Creating an increased visibility to critical information which most of the time is hindered by an incorrect construction method representation and on top of the building modeling, it grants owners the capability to streamline disjointed processes that create bottlenecks and loss of productivity. Therefore the need of indubitable development for clear definitions of construction method, construction technique and what represent a construction technology was considered by researchers for the past years.

Horizontal Systems’ BIM programs acquired by

Autodesk were rolled into Autodesk 360 improving collaboration among project members handling architecture, engineering and construction. The dynamics of the relationship between Architects, Engineers, Contractors, Owners and Operators (AECOO), in BIM context, is the basis for integration between teams of stakeholders in any construction projects. This will enable a BIM workflow from design through construction processes (Autodesk PLM360 2012).

Autodesk PLM 360 supports many of the PLM (Product Lifecycle Management) processes customers expect, such as program and project management, requirements management, supplier management, quality and compliance management. PLM 360 provides a collaboration and data management tool, offering business process coverage, product and project-related applications and lifecycle management of the product.

Descriptive Construction Methods through BIM-based CollaborationMarcel Maghiar, Ph.D., [email protected]

Georgia Southern University, Statesboro, GA USA

Avi Wiezel, PhD, PE, [email protected] State University, Phoenix, AZ USA

ABSTRACT: A coordinated Building Information Modeling (BIM) can provide savings to clients in the operating of the building and offer benefits on the contractors’ side. Autodesk 360 is improving collaboration among project members handling architecture, engineering and construction. This paper presents initial results of an effort to establish a consistent methodology to unequivocally classify and quantify construction methods so that they can be embedded in the BIM model. Such classification is referred to as a technology ontology. By introducing rigorous construction method descriptors it is possible to represent, in a matrix, all the available construction methods for any given project. The paper presents the construction method descriptors and a case study to prove the relevance of technology ontology for accurate estimating purposes. Selecting the most appropriate method for building objects can be integrated with BIM in early design phases. Cost savings made on a project through more efficient use of BIM (clear-cut construction methods) can be shared during design and in the same time it can improve collaboration.

Marcel Maghiar, Ph.D., is an Assistant Professor at Georgia Southern University, Construction Management. His research experience includes development of computer syntaxes to describe construction activities. Another research effort pertains to integrating field-level construction knowledge in Building Information Models.

Professor Avi Wiezel served as the Chairman of Del E Webb School of Construction and as the Director of Graduate Studies at Arizona State University. Dr. Wiezel constantly ranks among the top 5% of best teachers in the Ira A. Fulton School of Engineering and is the recipient of the Outstanding Faculty Member Award. His research focuses on the human activities in construction and includes models for improving the skills of craftsmen, crews, project managers and company executives.


38 Descriptive Construction Methods through BIM-based Collaboration

Savings can be generated using BIM, if the design process uses a unique building model through the project lifespan and if the construction methods for all processes are well identified and applied. Greater benefits can be found in “Information” part in BIM, when the right methods in the construction phases are identified and implemented early on.

The Vico Estimator 2009 provides a unique 3D-model-based estimating system, which comes along with improved accuracy. This is achieved through a user-defined Work Breakdown Structure, and the Conditional Method functionality. Vico Estimator supports large projects by enabling the merging of the quantities of any separate sub-models into one coherent project estimate and by providing comprehensive bid package tools and versioning functionality. Tight integration with the entire Vico Virtual Construction Suite assures model, cost, and schedule synchronization, and allows the clear visual communication of 5D processes.

Vico Recipe Model is enriching 3D model entities with construction Recipe data (Recipe is a breakdown of the Method data). Elements in the Virtual Building model can be associated with costs by assigning a cost Recipe to it. The Recipe assignment is defined as a property in the element’s settings. Another feature of the same modeling software provider, Vico Recipe Link Checker allows for increase accuracy and save time by easily identifying unassigned objects and defining links with the common database. This new feature provides one location for filtering and selecting elements, assigning and changing Recipe assignments. Therefore support for Conditional Methods is enhanced and provides superior integration with Vico Estimator. The Conditional Methods functionality introduced in Estimator 2009 is supported by offering functionality to select properties that are made available in Estimator. Selected properties are written into the common database and can be used with the Conditional Methods feature in Estimator (Vico Software 2012).

The research effort reported in this paper goes one step further and aims to establish a consistent methodology to unequivocally classify and quantify construction methods. Such classification, called technology ontology, is forming the basis for a consistent and complete representation of the construction methods in

models. During the design phase, structural designers can reason on a case-by-case basis how to use specific technologies in a virtual construction environment. During the construction phase of a project, the usage of technologies and specific methods become acute and is essential to the success (in terms of profits) of the overall project.

One of the early software tools (SEED-Config) for design environments is intended to assist structural designers in collaboratively exploring and extending the design of buildings (Fenves et al. 2000). A subsystem of this software tool allows for browsing, editing, selecting and applying of “technology nodes” which encapsulate structural design knowledge through “technology tags”, which further stores the name of the “technology node” that was used in designing of a building entity. In this approach, the application of a technology node to a building entity can be interpreted as making one decision about the design solution by refinement (more design details) or by elaboration (decomposing the building entity into new, less abstract building entities).

An approach to support construction cost estimating is through feature-based product models (Staub-French et al. 2002) where features of building components as penetrations, intersections or component similarities (parametric-based or macro features) directly influence the calculation of the construction costs. These features of building components are, in fact, estimator-focused product models and they can be reused from project to project from a given product model. In this sense, feature generator (FeaGen-Staub-French et al. 2002) prototype software was developed to implement the new concepts and to reveal the gain in the level of completeness of estimates generated by practitioners using this tool when compared to state-of-the-art tools. On the other hand, the estimating processes in the residential market exhibit differentiations mimicking the business practices in construction industry. For instance, the trend toward factory-based product bundling and kitting is synthesized in the concept of “Open Building” (Kendall 2002). This approach divides the entire residential unit (house) process and product in two decisional/technical clusters – Shell (or base building) and Infill (or fit-out) which integrates with the Shell. This design and production method balances



the production efficiency and consumer choices in the housing industry.

Therefore, the research endeavor carried out through this research is finding an appropriate system to describe and possibly attach information into a 3D model and in a useful and informative manner regarding a specific building element (object) in the construction phase. This will clearly help an estimator and a scheduler to identify the specific methods to be used in that process. Being able to present this information to stakeholders in a usable report format with verifiable data and overall costing information would be really useful, as well as tenancy, work orders and other particular construction method information.

DEFINITIONS OF CONSTRUCTION METHODS, TECHNIQUES AND TECHNOLOGY

An innovative Work Breakdown Structure (WBS) was developed by Oztemir & Wiezel (2003), representing every level of a construction activity, down to the level of intimate details of movements. The generality of Oztemir’s WBS was acquired from a masonry wall building root procedure, as part of an NSF research grant study.

The necessity of clear descriptors for construction methods is revealed in modeling, which will substitute other definitions interpretation and possibility for modeling integration. In essence, a construction method takes into account the type of the work package, which further takes the use of:

A. Resources: materials, labor (crews), equipment, subcontractors, production rates

B. Work Breakdown Structure (WBS), defined through the following breakdown: Project ➡ Job ➡ Operation ➡ Activity ➡ Assignment ➡ Task ➡ Subtask ➡ Action ➡ Movement

C. Responsible party (construction manager, owner, architect, etc.)

D. Constraints or requirements, which are needed to be satisfied before the Work Package can be performed

From jobsite studies, it can be observed that end-effectors are responsible for producing actions. In the

same time, materials (that go into the final product) or ancillaries (that do not remain in the final product) are sustaining the deployment of actions. Taking into account all the above considerations, a series of definitions were developed to better understand their descriptive nature in the construction methods when a full model is deployed in design-visualization phase. The terms are described below.

Assembly (product) or Assembly Breakdown Structure (ABS): Property sets of multiple construction objects; Work package: the total number of resources (material, labor-crews, equipment, subcontracting work, production rates) utilized to produce a specific assembly.

WBS: Work breakdown structure is the structure of the process aiming to create a specific assembly; WBS taxonomy: In the taxonomy of the WBS, the breakdown process is composed as follows: Project ➡

Job ➡ Operation ➡ Activity ➡ Assignment ➡Tasks ➡ Sub-Tasks ➡Action ➡ Movements; Levels of WBS taxonomy: According to this structure, the breakdown is generated by relevant changes reflected in: Site ➡ Trade ➡ Assembly ➡ Geometry ➡ Person (Laborer) ➡ Material ➡ Means (End-effectors and Ancillaries) ➡ Face ➡ Stop/Go (movements).

Ancillary: Ancillaries are furnishings and added support materials that do not remain in the final constructed product (assembly). They provide support either for the materials or for the activities taking place. Examples: mortar box, scaffold, concrete forms, nails and ties for false work.

End effector: Device, tool, or part of human body such as hand, acting upon materials, equipment, or ancillaries.

Constraint: requirements that need to be satisfied before or during production of the assembly. Examples: existence of supporting element such as wall frame for installing windows, access path, size of work-front, temperature, humidity, wind, previous work passing inspection.

Construction method: A construction method is a subset of materials or sub-assemblies that go into an assembly and end-effectors, as well as the constraints, needed to produce the said assembly. Applied to the same assembly and having the same constraints in place,



one method differs essentially from another method, through the subset of the materials used to construct the respective assembly and the way parts of the assembly (sub-assemblies) are joined for the common purpose of the assembly functionality.

Construction Technique: A subset of the construction method containing a complete set of ancillaries, the WBS taxonomy, and the party directly responsible for the production (mason, crew, superintendent, inspector, etc.) applied to a type of the work package. Applied to the same assembly and within the same method, one technique differs from another technique through the actions, moves and their sequence applied to the work package. In a masonry example, different techniques within the same method can be considered as follows: single-buttering of the blocks with mortar, double-buttering of the blocks with mortar or pre-buttering of blocks with mortar and laid on the course.

Construction Technology: A collection of construction methods suitable for the production of a building represents a construction technology. When applied to the same building, one technology differentiates from another through the collection of methods that can be feasibly applied to produce the constituent assemblies that function in the building. Related to masonry example again, a pre-stressed reinforced wall built in factory setting is employing different methods in building process than an in-site cavity concrete block wall, so the applied technology is different.

TECHNOLOGY ONTOLOGY FOR ESTIMATING – INTRODUCTION

Ontology is a knowledge representation in which the terminologies have been structured to capture the concepts being represented precisely enough to be processed and interpreted by people and machines without any ambiguity. Another general definition of ontology is perceived as the best structure of concepts from a given domain for effective computation (Gruber 1993). This second approach is the actual focus that started this study, and the authors have had in their minds computational reasons for general definition of ontology.

Ontology for estimating is a knowledge representation in which the terminologies (technologies) have been structured to capture the concepts being represented precisely enough to be processed and interpreted, without ambiguity, by computer models. This knowledge should have applicability and the representation should allow computer implementation.

The development of the ontology for estimating followed these steps:

• Identify key concepts and relationships in estimating: assemblies, work package, taxonomy of WBS, work breakdown structure - WBS, constraints, ancillaries, end-effectors, construction methods, and techniques.

• Produce precise and unambiguous textual definitions for concepts and relationships: all the above concepts have been defined accurately.

• Identify the terms that refer to concepts and their relationships in technologies.

This section is establishing that technologies will add value to the methods selection used in estimating processes and that there is an entire domain for estimate optimization. Estimates become increasingly sophisticated as more time and resources are devoted to developing the scope of the project. The accuracy of an estimate frees it from errors or mistakes. A precise estimate reflects a degree of exactness inherent in the estimating method or the technologies used in the project. With a technology domain (end-effectors, equipment and ancillaries) used in a given project the benefit of it is to save value in contractor direct costs, better utilizing the resources available (up to 60% of total cost) and the cost of estimating (up to 5% of total cost).

ONTOLOGY DEVELOPMENT – TECHNOLOGIES The connection between methods and techniques was already introduced. Both of them use available resources in a company setting. Activities, which are generated by the changes in geometry of the product (construction object), are required to use methods that are capable of producing the intended product. For example, a cast in place concrete column needs to have forms in place, which can be made of plywood, steel, plastic, or timber. There are different techniques (Table



1) of how to use and attach this formwork: one use, with tie wires, with steel ties, etc.

In the process of estimating, all resources are quantified and receive a price per unit. By definition, activity consumption is the amount of resources needed to produce one unit of an activity. So, when selecting methods and techniques to be used for an operation (making an assembly), materials, equipment, and labor are quantified and, before receiving a price, a consumption is assigned to each resource. The technology used to build the respective assembly is a combination of ancillaries, end-effectors, and equipment used to produce the assembly. For visualization, a flow chart is shown below (Figure 1):

Activity➡Methods➡Techniques➡Resources➡Resource role➡Consumption (Technology)

A method descriptor will have ancillaries, equipment (including tools), and end-effectors. For instance, in activity “Backfill, Structural Dozer or F.E. loader, 300’ haul, sand and gravel, 75 HP Dozer”, the method descriptor is 75 HP dozer. Using a 105 HP dozer would represent, in this case, a different method. Other examples of method descriptors are plywood forms (3rd uses), power saws, or hydraulic cranes, 55 tons capacity.

In the next section, the method descriptors provide an explicit representation of the available technologies for any particular project and allow the identification of method clusters. Method clusters take into account the possibility of sharing equipment and ancillaries among multiple activities, thus reducing costs. This

process, which normally takes place, implicitly, during the estimating and planning of the project, can now be explicitly incorporated into the construction process. Therefore, detailed estimates (unit price and schedule estimates) should take into account technologies along with effective means or methods for consideration of the productivity and quality of the constructed building elements during construction phase in the lifecycle of the building.

To further explain the application of the concept of method descriptors, authors used a simple project as case study. This project will also serve as validation of the concepts presented. From an activity center model of a commercial building, a reinforced concrete slab in the form of a square with 10 feet side and with 5” thickness will be constructed and therefore modeled initially. The slab should be elevated on a bed at 8” mixed gravel. For sewage, it is suggested an underground pipe of 8” diameter, starting from the center of the slab. On the slab structure (Figure 2), four reinforced concrete columns are to be placed at each corner with dimensions of 8”x 8”and with a height of 9 feet.

Assembly Activity Methods Techniques

Columns Forms

Plywood w/ tie wire, one use Steel w/ tie wire

Plastic w/ steel ties

Table 1. Methods and techniques for an activity

Assembly

MethodsActivitiesEnd-effectors

Ancillaries

Labor

Equipment

Material

Material

Equipment

TECHNIQUES

CONSUM

PTION

Assembly

MethodsActivitiesEnd-effectors

Ancillaries

Labor

Equipment

Material

Material

Equipment

TECHNIQUES

CONSUM

PTION

Figure 1. Technologies in estimating process

Figure 2. Project example for technology ontology development



CLUSTERS OF METHODS SELECTION FOR OPTIMIZATION

In the considered project, the major phases of construction are as follows:

• Pre-construction phase • Forms phase• Reinforcement phase• Concrete phase

The activities determined to complete the project follow the sequence below:

1. Excavation, 2. Backfill, 3. Piping, 4. Forms for footings, 5. Forms for slabs, 6. Reinforcements slab - beams and girders, 7. Concrete slabs, 8. Reinforcement’s columns, 9. Forms for columns, 10. Concrete columns.

To represent all technologies involved in this project, all activities necessary to complete the project from a pool of possible activities, materials, equipment, tools and ancillaries that might be available in a construction company setting, were considered. Labor and equipment rates were given by RS Means Construction Cost Data Catalog; also the crews’ daily costs are given. The pool of activities is obtained from Building Construction Cost Data with daily outputs, units and crews. Crew resources, with tools and equipment are also available. Materials and ancillaries are calculated, crews and their costs can be provided, and the calculation for consumption corresponding to labor and equipment for each individual activity can be determined. Based on the calculation of consumption for labor and equipment for all considered activities, these activities were selected as they were described above in estimating the project.

The estimate takes all equipment, tools and ancillaries corresponding to each activity and phase of construction. The consumption of each method descriptor is summed and a general number is obtained based on unit quantities of every element from method descriptors (Figure 3). An “x” is marked, in Figure 3, whenever the equipment, tool, or ancillary is used in one of the activities. Based on the sequence suggested to complete the project, the method descriptors are rearranged in an organized fashion to correlate the activity description with method descriptor (Figure

4). There are five possible alternatives for selecting the right methods based on method descriptors. These are called “clusters of group alternates for methods”, and they make the domain for optimization.

For example, looking at the matrix of alternate methods for this particular project in Figure 4, for concrete activities, the user can elect different technologies, like: direct chute, concrete pump (small), crane-80 tons and tools, gas engine vibrators, hydraulic crane - 55 tons or concrete bucket - 1 C.Y. Four of these can be used for pouring concrete in slabs and four of them can be used for pouring concrete in columns. The user should pick-up one for each activity. Therefore, the utility of the domain for optimization is proven (use of one technology for multiple activities, select technologies to be brought in site for low-cost considerations and fitted for activity, etc.)

DOMAIN FOR ESTIMATE OPTIMIZATION Technologies available in a company setting would add value to the methods selection used in estimating processes. The totality of these technologies and the resource allocation make up the domain for estimate optimization. In the given case study there were five possible alternatives for selecting the right methods based on method descriptors, but these clusters of group alternates for methods can be broken down in different arrays, derived from the purpose of the optimization, as explained below. Referring to clusters of group alternates for construction methods, the user should elect one method for each individual activity, using one of the technologies available for multiple activities. Through method selection, technologies for the site are selected. For example, in Figure 4, for backfill

Nom. Method descriptor

Equipment, Tools, Ancillaries 1 2 3 4 5 6 7 8 9 10Activity Backfill Excavation Piping Forms-slabs Forms-col. Forms-foot. Reinf. Slabs-B&G Reinf. Col. Conc. Slabs Conc. Col.

1 Backhoe Loader, 48 H.P. x x2 Concrete Bucket, 1 C.Y. x3 Concrete pump (small) x x4 Crane, 80 Ton, & Tools x x5 Dozer, 105 HP x x6 Dozer, 75 HP x x7 Gas Engine Vibrators x x8 Direct chute x9 Hyd. Crane, 55 Ton x10 Plywood for forms (no. of uses) x x x11 Fiberglass for forms (no. of uses) x x12 Metal forms (no. of uses) x x x13 On chairs-before gravel x14 Open trenchless -on ground -after gravel x15 HDD w/ porous concrete pipe x16 HDD w/Corrugated metal pipe(galv. Or AL) x17 Ties w/plastic spacers - on site x x18 Welded on chairs - in factory x x

Quantum (Q/activ)

QUANTITIES (method/activities)-->total: (quanta)

Pre-construction Forms Reinforcements Concrete

Figure 3. Method descriptors for technology ontology development



and/or excavation activity, the estimator can choose to bring three different types of equipment to the site. A further consideration related to quality optimization of the work or safety procedures for construction people in the site makes the actual scope or purpose of the optimization. Depending on the scope of optimization they can use: backhoe loader – 48 HP, dozer – 105 HP or dozer – 75 HP.

The domain of estimate optimization is relevant through the matrix existence of the alternate construction methods for a given project and establishment of clusters of group alternates for all possible construction methods for that particular project.

Concluding for this particular case study, taking the BIM data and linking information regarding the method usage through a database will help not only designers/modelers but also estimators and schedulers through 3D visualization and a programmatic selection process. The method descriptors linked to an activity descriptor can be stored in applications that are familiar and easy to integrate for estimators and schedulers like MS (Microsoft) Excel, MS Word and/or MS Access. For estimators, a better cost control is obtained by achieving a greater level of estimation accuracy. For schedulers, an accurate activity description is conferred through the right selection of the method by taking into account exact method descriptors. Authors consider that these pieces of information are to be shared as early as possible in design stages to the architects after taking into the BIM the 3D construction model, the 3D Mechanical, Electrical and Plumbing model, ensuring they all fit together and completing the actual 3D architectural model.

CONCLUSION AND RECOMMENDATIONS FOR FUTURE WORK

The present representation is comprised on the approach that there is an influence of using various construction methods reflected in the expected relative accuracy of estimating. The existing relationships between the items or assemblies generated in a new estimate and a specific technology built within the estimate, and recalled from various databases of the model estimate, is beyond the scope of this research. Once details of relationships are known, construction methods and available technologies may be automatically aggregated and computationally integrated into activities, therefore the whole construction process can be optimized for time, cost, quality, or safety. These considerations may be assigned as information in the developed models and analyzed by the BIM staff, as early as during the initial design phase.

A recommendation for further work is the actual domain of estimate optimization. The optimization of the estimate, based on the technology ontology, was not driving the purpose of this research. However, a series of new research opportunities, pertaining to the scope of optimization in the information models, may present valuable savings to companies in the construction industry.

For construction professionals, a valid approach to go is to use the client server-based application (database with 3D front-end) read in the 3D BIM, and then validate the model. Next, the work planners and estimators may use this system to interrogate the model with drill down searches (provide the contractor with all windows type X, in building at the 3rd floor in section Y, i.e.) because we want to ensure materials are delivered right before they are needed, and not in one big lump and any technology connected to a construction method is available right-away in the company setting. This identified resulting data can be exported to MS Excel and sent to suppliers with the request to add their information in predesigned columns and send it back together with all information on construction process, maintenance, warranty and any other pertaining information. When this information is returned, it is linked to these objects in

Figure 4. Alternates for project estimate optimization



the model. During construction phases, site engineers, project managers or superintendents carry all this information together with 2D drawings or even more the actual 3D model loaded on a rugged tablet. They may start adding information through method-driven tags (method descriptors) giving you a complete system for handover and a database that can port data to virtually any cloud-based site system (as virtually all of these are databases as well).

REFERENCES

Autodesk PLM360 – Cloud-based Product Lifecycle Management [WWW page]. URL http://www.autodeskplm360.com/. Accessed 4 September 2012

Fenves, S. J., Rivard, H., Gomez, N. (2000).SEED-Config: a tool for conceptual structural design in a collaborative building design environment. Artificial Intelligence in Engineering, 14 (4), 233-247

Gruber, T.R. (1993). A translation Approach to Portable Ontology Specification, Journal of Knowledge Acquisition, Volume 5, 199-220

Kendall, S. (2002). An Open Building Strategy for Balancing Production Efficiency and Consumer Choice in Housing. Proceeding of 10th International Symposium on Construction Innovation and Global Competitiveness, University of Cincinnati, 9-13 September, 2002, pp. 60-71

Oztemir, E., Wiezel, A. (2003). Skill Driven Optimization for Construction Operations. PhD. Dissertation, Arizona State University

Staub-French, S., Fischer, M., Kunz, J., Paulson, B., Ishii, K. (2002). A feature ontology to support construction cost estimating. Working Paper #69, Center for Integrated Facility Engineering, Stanford University

Vico Software webpage (2012) [WWW page]. URL http://www.vicosoftware.com/Portals/658/docs/Estimator%20view%202009.pdf. Accessed 4 September 2012

Vico Software webpage (2012) [WWW page]. URL http://www.vicosoftware.com/products/5d-bim-software-estimating/tabid/229126/Default.aspx. Accessed 4 September 2012


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