Journal of Construction Engineering and Management

Because of superior speed and productivity, slip forms were extensively utilized as a potential formwork candidate in constructing concrete structures for the past few decades. Typical projects that employ this formwork technique are: Core of high-rise buildings, silos, telecommunication towers, cooling towers, heavy concrete offshore platforms, etc. The research presented in this paper aims at studying slip-form application to cores and silos, assessing its productivity, and determining its appropriate speed as well as auxiliary resource combinations. Simulation models are developed in which the potential control units in a slip-form system are described for cores and silos. Data are collected from several case study projects. A set of charts has been developed to predict productivity considering different stoppages, core cross section area, slipping (jacking) rate, and concrete placing methods. These charts play an essential role in managing slip-form application to cores and silos. Results show that the developed simulation models predict the productivity of case study projects with 99.70 and 99.30% accuracy for cores and silos, respectively. The presented research is relevant to both researchers and practitioners. It provides practitioners with charts that assist in scheduling and managing the required resources for slip-form application. In addition, it provides researchers with simulation models and framework for implementing slip forms to core and silo construction.

The use of precast concrete systems offers several advantages such as speedy erection, higher quality, lower project cost, better sustainability, and enhanced occupational health and safety. In spite of these advantages, the share of precast concrete systems in the U.S. building construction market is very low. The factors behind this low market share are discussed in several studies. This study aims to identify the current factors that affect the use of precast concrete systems, compare them with the ones that prevailed in 1995, and figure out what has changed through the last $11\text{years}$ in the American precast concrete industry. The findings of an extensive survey indicate that most of the dominating barriers to the extensive use of precast concrete systems in 1995 are either eliminated or drastically reduced, while some of them still prevail. Practitioners should be well informed about the factors that affect the use of precast concrete systems if these systems are to be used more extensively.

Best-value becomes a well known procurement practice in many states in the country. The objective of this transformation from the old practice of lowest bid to best-value is to increase the value added to the project for each dollar added. This paper discusses a new concept of best-value modeling that is unique and tailored to each project. The model uses records of past projects to obtain specific evaluation criteria, from which a best-value score is determined for each contractor. Primary parameters that impact contractor selection are identified and analyzed based on which best-value model is designed. Data are collected from groups of experts in the Minnesota Department of Transportation. Two application methods are used to assess the best-value: (1) the weighted average method; and (2) the analytic hierarchy process. Although the paper is written to assist government agencies in selecting the best contractor(s), the research results shared in this paper are relevant to both academics and practitioners. The paper provides practitioners with a tool for ranking contractors based on best-value and provides academics with selection parameters, a model to evaluate this best-value, and a methodology of quantifying the qualitative effect of subjective factors.

This paper reports on results of research conducted at the University of Washington to investigate the means and methods for overcoming barriers to the implementation of Web-based project management systems (WPMS), and to develop a set of best practices in both the United States and Japanese construction industries. The United States and Japanese economies are high-tech intensive and both cultures have embraced technology. However, a relatively small sector of the construction industry in each country has implemented WPMS. The question posed here is why have these drivers not resulted in the industry’s adoption of this new technology, and further, perhaps there are lessons learned from those who have successfully implemented WPMS. This research seeks to broaden our understanding of implementation barriers that are limiting the use of WPMS tools as well as means and methods of overcoming those barriers based on successful implementation in both countries.

Generally, a contractor has three options in accelerating a construction schedule: working longer hours, increasing the number of workers, or creating an additional shift of workers. There has been a significant amount of research conducted on scheduled overtime on construction labor productivity. However, little information has been found in the literature addressing the labor inefficiency associated with working a second shift. This paper has qualitative and quantitative components. The qualitative part details why and how shift work affects labor productivity, and then addresses the appropriate use of shift work. The quantitative component determines the relationship between the length of shift work and labor efficiency. The results of the research show that shift work has the potential to be both beneficial and detrimental to the productivity of construction labor. Small amounts of well-organized shift work can serve as a very effective response to schedule compression. The productivity loss, obtained from the quantification model developed through this study, ranges from $-11$ to 17% depending on the amount of shift work used.

Existing research on women in construction focuses on engineers and entrepreneurs, yet little to no attention has been given to women in trades. Thus, the aim of this research is to review the literature on tradeswomen and to conduct a localized study to determine if demographic variables affect satisfaction with work, pay, opportunities, supervision, and people on the job for tradeswomen. These variables include age, education, number of dependents, number of trade years, duration of work, and frequency of work outside of the local area. Thirty-nine tradeswomen from the Cincinnati area were surveyed to assess their satisfaction or dissatisfaction with construction work. Currently, the literature review indicates that research on tradeswomen is limited and largely restricted to identifying measures that can attract and retain women in construction trades. Studies on motivation and job satisfaction of construction workers neither identify nor compare perceptions of tradeswomen about their work. Results of this exploratory study showed that pay, benefits, and job security are most important to women in their occupation. Although tradeswomen appear to be satisfied with the nature of work in construction trades, this is not the case in terms of pay, benefits, and job security. Demographic variables did not affect the level of job satisfaction for women in construction trades. Research on tradeswomen is essential and important as the industry tries to change its image and encourage diversity in order to mitigate labor shortage.

Building reuse is a linchpin to managing solid waste. Despite the various benefits beyond contributing to sustainability that can be realized through building reuse, including direct and indirect cost savings, truncated construction schedules, and reduced site disruptions, little formal consideration has been given to this topic, which places professional engineers at a disadvantage when considering this as a design option. As each building project has its own specific requirements, reuse is not always the most economical solution, but, in cases where reuse is in part motivated by other factors such as heritage protection, substantial economic and environmental savings can be realized in tandem. Based on nearly two decades of professional experience, a generalized assessment method for reuse is proposed to facilitate benefit maximization. Applying this 10-step method, the costs related to building replacement and sustainable reuse are compared using two case histories and a theoretical building. A clear correlation is shown with the potential for savings as a function of project size.