This study compares the performance of design/bid/build and design/build to see if one project delivery method is superior in regards to time and cost. Similar military buildings were used to identify two samples of projects delivered with each of the two delivery methods. These projects provide a meaningful comparison because they include buildings of the same typology (i.e., U.S. Navy Bachelor Enlisted Quarters) delivered using similar design models. Project duration, project duration per bed, project time growth, cost growth and cost per bed were statistically compared. Upon completion of the analysis, the hypothesis that design/build projects are superior to design/bid/build projects in regards to time and cost was tested. Design/build projects were proven superior in performance in almost every measure. Other findings, including recommendations to practitioners and researchers, will be provided as well.

This study compares and analyzes the relationship of design-build (DB) and design-bid-build (DBB) project delivery methods with performance metrics of large highway projects ( >$50 million ). Project performance is measured in cost, schedule, and change orders on these two types of highway projects. This study also investigates associations between project characteristics (input variables) and project performance (output variables) of large highway projects. The performance comparison methodology used here is derived from work done on a Texas Department of Transportation study of the State Highway 130 Project. The study results show that the construction speed and project delivery speed per lane mile (or lane kilometer) of DB projects were significantly faster than that of DBB projects for this sample. The study also showed that out of 21 inputs analyzed, 14 inputs have statistically significant associations with one or more outputs of these projects.

In 2012, 775 fatalities were recorded, and many more were injured at construction sites in the United States. Of these, 415 fatalities (54%) were due to fall, slips, and trips as well as being struck by falling objects. In order to decrease fatalities at construction sites to these types of events, the Occupational Safety and Health Administration (OSHA) provides Fall Prevention and OSHA-10 trainings to construction workers. Moreover, safety personnel monitor whether the workers use personal protective equipment (PPE) properly. Data shows that construction fatalities have decreased by 2% annually since 1994; however, the owners still are not satisfied with this result. Various studies have shown that fall is the biggest contributor for construction fatalities. One study showed that half of the fall fatalities were because the workers either had not used PPEs or had not used them properly. In addition, studies showed that, with proper use of hard hats, the fatalities due to fall, slips, trips, and being struck by falling objects could be reduced. This study developed and tested a hard-hat detection tool that uses image-processing techniques to identify whether workers are wearing hard hats. The tool dispatches warning messages if the workers do not use hard hats.

In an economy with an unsure market and scarce work for construction projects, public owners across the United States, especially universities, are using alternative project delivery methods to complete their projects within cost and schedule. As an alternate delivery method to design-bid-build (DBB), public universities across the United States are beginning to use design-build (DB) to construct their facilities. In order to analyze and compare DB and DBB projects, this study used 77 building projects built by planning and construction divisions of United States public universities. Statistical tests were conducted to determine if metrics related to cost, schedule, and change orders were significantly different from each other in these two types of projects. Results showed that DB projects significantly outperformed DBB projects in terms of schedule saving. The study also found that the number of construction change orders was significantly lower in DB projects than in DBB projects. The primary c...

This study analyzed 363 Clark County Department of Public Works (CCDPW) projects to determine construction cost and schedule overruns in various types and sizes of the projects. The sample projects were constructed from 1991 to 2008, with a total construction cost of $1.85 billion, equivalent to 2012 cost. A one-factor ANOVA test was conducted to determine whether construction cost and schedule overruns significantly varied based on types and sizes of the projects. The study showed that large, long-duration projects had significantly higher cost and schedule overruns than smaller, short-duration projects.