Journal of Construction Engineering and Management

Worldwide calls for integration in construction translate into needs for relational alignment of both structural and operational arrangements, in order to successfully streamline the combined efforts of diverse interacting parties, for improved project delivery. Appropriate applications of relational contracting (RC) principles can help to achieve such integration. As such, the aims of the reported study are to examine the relative usefulness of various potential factors and strategies and to offer suitable contractual and noncontractual incentives, for building an RC culture and building integrated project teams (IPTs) in construction. Results from statistical analyses of 224 questionnaire responses from five countries are presented. Trust and trust-based operational arrangements are seen to effectively offer the required incentives for implementing various RC-based arrangements in construction where top management commitment and their support play a vital role. The choices of country-specific approaches suggest various patterns of integration through project-based partnering type RC, e.g., cliental initiative and removing client related barriers in Hong Kong, removing uncongenial organizational and/or system-based barriers from the client’s side in Australia, teamworking by cliental initiatives through contractual arrangements in The Netherlands, removing organizational and/or system-based barriers in the U.K., importance of trust and communication-related factors in Singapore, with no specific strategy in this respect. The outcomes also suggest the need for a highly interrelated and consolidated approach for spreading RC. Outcomes of this study are expected to benefit both industry practitioners and researchers in exploring, designing, and implementing various RC-based working arrangements.

Production rate estimation of major construction activities in a project play an important role in the planning of resources, tracking project progress, and determining contract time of construction projects as these activities typically fall in the critical path of the project schedule. This paper discusses the possiblity that readily available data from highway agencies such as Daily Work Reports (DWRs), soil data, average traffic information, and weather information can be successfully used to identify and assess significant factors that must be considered in estimating the production rates of major highway activities and to develop production rate estimation models. Common production rate estimation methods such as expert opinion, engineering judgment, and production rate charts may lead to erratic production rate estimation by comparing the production rates calculated and estimated through different methods. Actual project data–based production rate estimation might be the most reliable method. An Excel-based software program was developed in this study for estimating the production rates of controlling highway construction activities when project information is given as input data.

Variation, defined for this research as the time difference between what was planned and what actually happened, is important as it can affect the productivity performance of construction tasks. The construction process is complex and consists of a large number of interdependent tasks. When the starting time and/or duration of one task varies, it can affect other downstream tasks and result in disruptions to the schedule and/or decreased productivity. This research examined the effect of using a risk assessment matrix in conjunction with the Last Planner System (LPS) method to reduce and/or eliminate task duration variation. A case study was conducted involving a mechanical contractor who specializes in plumbing, heating, ventilation, and air conditioning. The company compared the performance of two separate, but similar projects. The LPS method was used with one of the projects and the company’s traditional planning system was used with the other (i.e., not using the LPS system). A total of 16 weeks’ worth of data was collected for each project. Variation, productivity, and cost savings were analyzed using a risk assessment matrix and benefit–cost procedures. The project that used the LPS method had a 35% higher productivity performance than the traditionally planned project and resulted in a benefit–cost ratio of $13:1$. The research findings fill a gap in the body of knowledge by analyzing how planning can reduce variation with real project data. The results of this research illustrate the effect the LPS method can have on reducing variation and improving project productivity performance. The findings also serve as an example of an effective planning strategy for project managers and field managers in their efforts to improve project performance.

The United States Green Building Council (USGBC)-sponsored Leadership in Energy and Environmental Design (LEED) green building program represents the largest program in the United States for the measurement, verification, and certification of green buildings. A recent study found that LEED-certified buildings have accounted for a higher injury rate than comparative traditional non-LEED buildings. This finding served as the impetus for the present study, which aimed to identify and evaluate the safety and health risks associated with the design elements and construction management practices implemented to achieve LEED certification. To explore this topic, six detailed case studies and two validation case studies were conducted following a strict protocol developed from guiding literature. The results indicate that (1) workers on LEED construction projects are exposed to work at height, with electrical current, near unstable soils, and near heavy equipment for a greater period of time than workers on traditional projects; (2) workers are exposed to new high-risk tasks such as constructing atria, installing green roofs, and installing photovoltaic (PV) panels; and (3) some credits result in a positive impact on construction worker safety and health when low volatile organic compound (VOC) adhesives and sealants are specified. It is expected that these results can be used by practitioners to focus attention and resources on new highrisk work environments.

Safety management is becoming increasingly important in the construction industry. Effective safety management not only reduces contractors’ incident rates and compensation costs, it also enhances productivity and efficiency in project execution. In addition, better safety performance increases contractors’ competitive advantage in the market by providing better values to their clients. This paper presents a case study of an on-site safety management program launched by a general contractor (GC). The initial findings, based on quantitative measurement of incident rates and safety violations, are presented to evaluate the effectiveness of the program. Overall, the program is effective in reducing jobsite accidents/incidents and safety violations in the GC’s organization while having less effect on subcontractors’ safety performance. This research also finds no linear relationship between incident rates and safety violation rates, indicating that these two measurements are uncorrelated and that both of them need to be used in evaluating jobsite safety performance and the effectiveness of a safety program.

The present study attempts to distinguish the different critical success factors (CSFs) for different components of construction projects as perceived by different professions, i.e., civil and structural engineers, mechanical and electrical engineers, architects, and quantity surveyors. An analytical hierarchy process (AHP) is adopted to solicit the consistent subjective judgment of 27 experts in construction to identify the top 10 CSFs from 67 factors describing aspects of project characteristics, contractual arrangements, project participants, and interactive processes. The views of the different professionals are shaped by the experience they gained from their involvement in the respective components of the construction projects under their charge. It follows that the CSFs identified by the professionals are naturally relevant to the components of construction projects that they are familiar with. The present study reveals that the respective top 10 CSFs for the schedule, budget, and quality performance of architectural works, civil and structural works, and mechanical and electrical engineering works are markedly different. Moreover, the study shows that the judgment with regard to CSFs of respondents with less than 15 years of experience differs from that of the more experienced respondents and hence may not be good enough. It follows that studies reported in the existing literature that have included views of respondents with less than 15 years' experience in construction or based on the views of professionals predominantly from a particular discipline are likely to be biased and misleading.

Major roads and bridges in the United States are aging and deteriorating, which is causing significant human and economic losses. The required investments to rehabilitate these transportation networks exceed available funds and budgets. The rehabilitation efforts of these aging networks, therefore, need to be optimized to maximize their net benefits and reduce the effect of construction works on the traveling public. This paper presents the development of an innovative model aimed at aiding decision makers in planning and optimizing highway rehabilitation programs. This model provides new and unique capabilities, which include: allocating limited financial resources to competing highway rehabilitation projects, measuring the effect of rehabilitation efforts on network performance and road user savings, analyzing the expected benefits and costs of rehabilitation programs, and generating optimal tradeoffs between maximizing rehabilitation benefits and minimizing network service disruption using a genetic algorithm (GA)-based optimization module. An application example is analyzed to evaluate the performance of the proposed model and demonstrate its capabilities in identifying a wide range of optimal rehabilitation programs, in which each provides a unique and nondominated tradeoff between maximizing rehabilitation benefits and minimizing service disruption. This allows decision makers in departments of transportation to select and implement the rehabilitation programs that address their specific societal needs.

A key element in moving a highway construction project forward is the ability to acquire the right-of-way (ROW) in a timely manner. Delay in the acquisition process can lead to major delays to the construction phase. Identifying the delay factors will allow for a better acquisition management process. Thirty-five projects, with 1,478 parcels, acquired by the Mississippi Department of Transportation (MDOT) were randomly selected for analysis to determine the factors affecting acquisition duration. The data were analyzed using Statistica7 software with $t$-test, correlation, scatter plot, and analysis of variance to gain understanding of the dataset; to test the null hypothesis (Ho) that no correlation exists between the control and experimental variables; and to statistically quantify the factors that contribute to acquisition duration delay through significance and standard multi- regression analysis. Condemnation ratio, number of revisions (design changes), and number of parcels per project were identified as significant factors that contributed to acquisition delay. A ROW acquisition regression prediction model was developed and then tested with a separate set of data to prove its applicability and validity in general terms.

Build-operate-transfer (BOT) is a public-private partnership (PPP) project delivery system for the financing, development, and operations of highway projects around the world. Uncertainty about future traffic demands is one of the most important risk factors in the operations phase of a BOT project. There is a considerable amount of evidence indicating that the improper consideration of this uncertainty contributes to the financial failure of BOT projects. The inherent limitation of conventional economic analysis methods contributes to this uncertainty; most notably the net present value (NPV) approach that is typically used in the economic valuation of BOT projects. In addition, the NPV approach is insufficient to determine the correct market value of minimum revenue guarantee (MRG) options. The government offers MRG options to the concessionaire as a revenue risk-sharing strategy in BOT projects. The authors apply the real options theory from finance/decision science to explicitly price MRG options in BOT projects. This real options model has several prominent attributes that make it different from NPV models. It uses a market-based option pricing approach called risk-neutral valuation method to determine the correct value of MRG options. Unlike the other models, this approach treats the risk of underestimating future traffic demands internally and adjusts for the traffic market risk in the valuation of MRG options. The authors’ approach also describes a procedure for characterizing the concessionaire’s economic risk profile under uncertainty about future traffic demands. In addition, it uses real options analysis to price MRG and traffic revenue cap (TRC) options as compound options and determines their effects on the concessionaire’s economic risk profile. The probability distributions of when the concessionaire may request MRG and when the public sector may receive additional revenues as TRC options are also presented. Further, the distributions of the number of times that the concessionaire may request the MRG option and the number of times that the public sector may receive additional revenue are characterized. Finally, this model identifies the probability distributions of the present value of MRG options and the present value of total additional revenues recalled by the public sector. The proposed model can help public and private sectors better analyze and understand the economic risk of BOT projects under uncertainty about future traffic demands. The private sector can use this proposed model to make better entry decisions to BOT highway projects considering the level of support provided by the government. The government can also use this proposed model to identify the appropriate MRG levels to encourage private investments without comprising future budgetary strength.

An accurate measure of the U.S. construction industry’s productivity remains a consistently perplexing challenge. The thread of previous research has produced contradictory results, which contributes to the differences in opinion regarding whether construction productivity has been improving or declining over the past several decades. Typically, macroeconomic studies involving industry aggregated output measures have shown a decline in construction productivity, while micro studies involving activity based data have shown an increase. A dominant theory to explain these opposing results is that current measurements of construction inflation do not adequately consider the change in quality and amenities provided in today’s structures as compared to when the measurements were first established. The U.S. Census Bureau (Census) New Single-Family Houses under Construction Price Index is one of the industry’s major measurements of construction inflation. Previous research suggests that omitted quality variables in the Census price index leads to an omitted variable bias which overestimates construction inflation, leading to both an underestimate of construction industry output and productivity. However, previous research has not formalized necessary changes to the price index to avoid this bias, nor has the bias been actually measured to quantify its direction or magnitude. Utilizing sales data of new home construction in Bowling Green, Kentucky, this study examines the magnitude of the bias for one geographic location, and provides a direction for potential changes to improve the accuracy of the price index as a whole. The writers compare the current hedonic model with a proposed model on the basis of the Bowling Green data, which includes quality variables that are not part of the current hedonic model. While this study is obviously limited to the differences measured on this small data sample, this paper’s primary contribution to the overall body of knowledge provides the first known documented evidence of omitted variable bias in the current Construction Price Index, albeit limited to a very small geographic region. Regardless, these findings have important ramifications on the accuracy of existing industry output measures and related efforts to use those output measures for measuring the productivity of the overall U.S. construction industry.

Front-end planning (FEP) is relatively new to the Singapore construction industry, and its importance is not yet well recognized or emphasized. Technological advancements and continuous fragmentation in the construction industry have resulted in a rapid increase in the complexity of projects, and yet this has not been matched by a concomitant increase in planning efforts. This study aims to identify the importance of FEP and its impact on project outcomes in order to encourage more organizations in Singapore to practice and benefit from it. To achieve this objective, a questionnaire was developed, and the responses from 27 companies were analyzed. The analysis revealed that only about 44% of the responding companies practiced FEP on their projects. In addition, the study quantified the amount of the budget allocated to FEP as well as the level of improvement in project performance achieved by implementing FEP. Once companies recognize their FEP implementation status, they will be at a starting point to understand its importance and impact and will be able to better manage their projects, ultimately allowing the Singapore construction industry to increase its opportunity for producing more successful projects overall.

Grouting control of shield tunneling is of paramount importance to reduce settlements of existing tunnels below-passed by shield tunneling along a curved alignment and in crowded urban areas. The methodology and scheme of the grouting control of shield tunneling is illustrated taking the first Earth Pressure Balanced (EPB) shield below-crossing existing interval tunnels from Kexueguan station to Dajuyuan station of the Shenzhen metro line No. 1, for example. A combination methodology of the “observational method” and the “predefined design method” was set up to deal with parameters concerning the grouting control of shield tunneling. Some parameters of the grouting control were predefined or suggested before the below-crossing, and other parameters might be adjusted during construction on the basis of the “observational method.” The scheme primarily consists of preparation work before the below-crossing, automatic motoring system used in operation tunnels, simultaneous backfilling grouting and grouting directly through segment holes. For the simultaneous backfilling grouting, enough grouting was filled in the tail void with shield advance. With the help of automatic motoring system, the grouting directly through segment holes was employed in light of the measured settlements of existing tunnels. The maximum of the final measured settlements of existing tunnels is about 70% of the predefined allowable settlement of 20 mm, which shows that the grouting control of shield tunneling is effective in reducing settlements of existing tunnels. The grouting practice can be used as references in similar conditions.