Journal of Construction Engineering and Management

The U.S. construction industry accounts for approximately 4% of the gross domestic product. Although quantifying and analyzing the cumulative ecological resource consumption of the construction industry is of great importance, it has not been studied sufficiently. This paper aims to account for the total ecological resource consumption of the construction industry, including its supply chains. This analysis is achieved by using an ecologically based life-cycle assessment model. The impacts on the ecosystem were calculated on the basis of the economic data in terms of cumulative mass, energy, industrial exergy, and ecological exergy. U.S. construction sectors are holistically evaluated by using various sustainability metrics, such as resource intensity, efficiency ratio, and loading ratio. Total ecological exergy values were generally found to be larger for the sectors with higher economic output values. Heavy construction industry sectors, including construction and maintenance of highways, bridges, or pipelines, were generally found to use fewer renewable resources and to have higher emission intensity.

This paper describes the results of field experiments conducted to evaluate the performance of temporary rumble strips at the edge of work zones as a new safety measure to prevent inattentive drivers from encroaching onto the work area in a manner similar to the way permanent rumble strips are used. The two main objectives of these experiments are to (1) analyze and compare the effectiveness of various layouts of temporary rumble strips and (2) provide practical recommendations to improve the design and layout of temporary rumble strips. The experiments evaluated the impact of five parameters on the effectiveness of temporary rumble strips and their generated sound levels: (1) rumble strip type; (2) number of strips per set; (3) strip spacing; (4) vehicle type; and (5) vehicle speed. A total of 162 different combinations of these parameters were tested to evaluate their individual and collective impact on the effectiveness of temporary rumble strips. The findings of this study indicate that temporary rumble strips at the edge of work zones generate adequate sound levels to alert inattentive drivers. The results of the experiments also indicate that the effectiveness of temporary rumble strips can be improved by (1) increasing the number of strips per set as practically as feasible and (2) using temporary rumble strips with larger widths.

Several researchers have attempted to formulate and solve different classes of the earthwork allocation problem. Linear programming (LP) and integer programming (IP) techniques have traditionally been applied to minimize transportation costs and mass-haul distances associated with earthwork processes. However, typical formulations of the earthwork allocation problem do not consider the sequence of equipment movement and are, therefore, limited in their ability to establish a practical and workable hauling plan. A more complex problem, which is formulated and solved in this research, is the least-cost route cut and fill problem (LCRCFP). The primary objective of the LCRCFP is to determine the specific route to be traveled and the quantities of soil that construction equipment must haul to meet the desired grade while minimizing the total distance traveled. In this research, the LCRCFP was formulated as a mixed binary optimization problem and solved using a traditional branch-and-bound method and a particle swarm optimization (PSO) technique. Accordingly, this solution can provide efficient and practical hauling plans for construction sites. Furthermore, a linear variation of the problem, which is common for linear roadwork or utility construction, was also formulated and solved. Extensive computational results are reported for several randomly generated instances of the LCRCFP. Realistic problems can be effectively solved using PSO. Thus, the derived plan can be used in mapping and path planning and by on-site engineers. It can also be used for the deployment of unmanned construction equipment in autonomous vehicle control systems.

Building information modeling (BIM) is an emerging tool in architecture/engineering/construction (A/E/C) industry that is used to design, document, and enhance communication among all the project stakeholders. Trim loss of rebar can be minimized with the use of discrete bars. To achieve this goal, a model to analyze reinforced concrete structure with one-dimensional (1D) cutting waste-optimization technique, integrated with BIM, is proposed. Building information modeling is selected as the hub in communicating project information among diverse design teams. This process permits project teams to utilize BIM models to simulate architectural and structural design requirements, and compare results speedily to make necessary changes in the designs to minimize rebar waste. The BIM rebar optimization analysis approach also supports cost-effective decision making during the design process. The proposed approach was validated with a two-story reinforced concrete structure, and the results indicated a high potential for budgetary savings. The proposed approach is also applicable for complex reinforced concrete construction projects, with repeated structural elements, and cost saving increases with the increase in the diameter of rebar.

Safety performance in the construction industry has improved significantly in the past four decades. This improvement has been attributed in part to the increased implementation of injury prevention strategies. Although the relative effectiveness of these strategies has been studied in previous research, there has been no attempt to evaluate their diffusion. To address this gap in knowledge, 12 highly effective administrative safety innovations were identified in literature, and 58 firms were interviewed to investigate their adoption rate. The diffusion patterns of the identified safety innovations were explored using four common innovation diffusion models: the internal, external, Bass, and Gompetz. The findings indicate that the internal and Bass models have the highest explanatory power and that internal factors are the most influential factors in adoption of safety innovations by construction firms. It was also found that project-specific training and safety meetings (91%), frequent worksite inspections (91%), and safety and health orientation and training (90%) are the three most commonly adopted safety innovations, and employment of a site safety manager (62%), subcontractor selection and management (64%), and substance abuse programs (69%) were the three innovations most infrequently implemented. The implication of the findings is that the construction industry has now reached saturation with respect to traditional injury prevention strategies and new safety innovations are needed.

A recent study found that Leadership in Energy and Environmental Design (LEED) certified buildings have a recordable injury rate that is 9% higher than traditional, non-LEED buildings. A follow-up study showed that there are distinct aspects of the design elements and means and methods of construction used to achieve LEED certification that have negative impacts on worker safety. The research described in this paper builds on previous knowledge by quantifying the percent increase in base-level safety risk resulting from the design strategies and construction methods implemented to earn specific LEED credits. A total of 26 interviews and 11 validation interviews were conducted with designers and contractors who had completed an average of four LEED projects, 100 traditional projects, in their average of 18 years of experience in the architecture, engineering, and construction industry. The results indicate that design elements and means and methods of construction implemented to achieve 12 of the 49 LEED credits increase the frequency of injuries or exposure to known, high risk environments. The most significant impacts are a 36% increase in lacerations, strains, and sprains from recycling construction materials; a 24% increase in falls to lower level during roof work because of the installation of on-site renewable energy (e.g., PV panels); a 19% increase in eye strain when installing reflective roof membranes; and a 14% increase in exposure to harmful substances when installing innovative wastewater technologies. These results can be used to understand the safety impacts of sustainable building design, will enhance designer awareness, and help contractors to better prioritize safety resources.

Due to the increasing demand for energy in the United States, the Nuclear Regulatory Commission is currently reviewing permit applications for 26 new nuclear power reactors. However, the previous generation of U.S. civilian nuclear plant construction experienced significant cost and schedule overruns. Previous research identified “regulatory ratcheting” (continuous, retroactive change in nuclear plant regulations) as one of the primary causes of this poor performance. Regulatory ratcheting was enabled by the nuclear industry’s two-step permitting and licensing process for civilian power plant construction, which allowed society’s perception of the risks associated with nuclear plant operation to impact nuclear plant construction. How will public policy and societal risk perception affect the next generation of U.S. civilian nuclear plant construction? This question is investigated using a dynamic simulation model of the public policy and social feedback processes that impact U.S. nuclear plant construction. The research reveals that proposed strategies to address public policy and societal issues, such as a new nuclear regulatory process and smaller, less expensive reactors, may not prevent cost and schedule overruns on the planned next generation of nuclear plants. Results point to the critical role societal perceptions of nuclear power risk play in nuclear construction project success.

Greenhouse gas (GHG) emissions from onsite equipment usage have not been fully investigated despite their high reduction potential. This study presents a comparative analysis of the generation of GHGs by various equipment types used in different construction activities. Twenty-four cases involving a typical road construction project in Korea were selected for comparison. GHG emissions from onsite equipment usage for different activities were estimated using final design documents, which fully defined the construction project. This study also provides the expected ranges of such emissions according to equipment productivity related to site conditions of good, fair, and poor. For the major activities that produced most of the GHG emissions from onsite equipment, the value was estimated to be in the range of $256.52–376.70\mathrm{t}{\mathrm{CO}}_2\mathrm{e}$, with 282.17 $\mathrm{t}{\mathrm{CO}}_2\mathrm{e}$ for fair site conditions. A focus group interview (FGI) was conducted to identify guidelines that can be applied to improve equipment productivity to reduce GHG emissions. The proper selection of equipment and its components to deal with specific site conditions was one of the fundamental reduction methods derived through the FGI. These study results can be used to reduce GHG emissions from onsite equipment usage.

Construction is the most dangerous land-based work sector in Europe and the United States The cost of accidents has received much attention in the recent past, and online interactive tools were developed to assess the cost of accidents to organizations. Online tools and other sources of information on costs of accidents in the construction industry were a useful development but failed to support the decision-making process in regard to construction health and safety measures. A cost-benefit analysis (CBA) methodology is presented that would enable contractors to assess the true cost of accidents prevention and the associated benefits of accident prevention as part of pre- and postcontract project evaluation. The research investigated the cost and benefit of accident prevention, with a view to drawing attention to the economic consequences of effective/ineffective management of health and safety by contractors. A quantitative research methodology was employed in investigating these costs and benefits within the UK construction industry. The results of ratio analyses indicate that the benefits of accident prevention far outweigh the costs of accident prevention by a ratio of approximately $3:1$. Further, the results demonstrate that for every £1 spent on accident prevention, contractors gained £3 as benefits. The results also show that small contractors spend relatively higher proportions of their turnover on accident prevention than medium- and large-sized contractors and that small- and medium-sized contractors gain relatively higher proportions of their turnover, in total, as benefits of accident prevention than large contractors. It is concluded that the CBA method can provide a guide to contractor’s decision making in regard to accident prevention. When acted upon, the method has the potential to contribute to a reduction in costs, deaths, and injuries in the UK construction industry and possibly in other areas internationally.

Rooftop vegetation is becoming increasingly popular because of its environmental benefits and its ability to earn green-building certification credits. With the exception of one international guideline, there is little mention of worker safety and health in vegetated-roof codes and literature. Observations and field investigations of 19 vegetated roofs in the United States revealed unsafe access for workers and equipment, a lack of fall-protection measures, and other site-specific hazards. Design for safety strategies and the integration of life-cycle safety thinking with green-building credits systems are the preferred methods to reduce risk to workers on vegetated roofs. Design suggestions have been developed to add to the body of knowledge. The findings complement several National Institute for Occupational Safety and Health (NIOSH) construction and prevention through design (PtD) goals and are congruent with NIOSH’s Safe Green Jobs initiative. Organizations that install and maintain vegetated roofs can utilize the findings to understand hazards, take precautions, and incorporate safety into their bids.