EVALUATION OF DESIGN BUILD PROJECT DELIVERY IN THE PERFORMANCE OF BRIDGE CONSTRUCTION PROJECTS
Schieber, Miranda L.
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Since the early 1990s, state transportation agencies in the United States have been attempting to improve the transportation construction process through the use of innovative project delivery systems. These systems, which define the relationship between different contracting parties and the timing of their involvement in that relationship, have been shown to have significant impacts on the outcomes of vertical construction projects. Design build has been one of the most common innovative project delivery systems to be utilized transportation construction. Bridges are one of the most significant aspects of the United States transportation system, and the current state of bridges in the U.S. is considered by the American Society of Civil Engineers (ASCE) to be deficient. Given this, major bridge construction projects will continue to be a regular occurrence for state transportation agencies in the United States. Anecdotal accounts and analysis of case studies have led to speculation that design build could be well suited for the delivery of such bridge projects. Little research has been completed to quantitatively analyze the effect that design build delivery has on transportation construction. This study investigated the impact that design build has on performance outcomes in five different categories, including construction cost, construction schedule, change management, quality, and legal implications. This research found that bridge projects delivered by design build show significantly less construction schedule growth than those delivered by design bid build. Additionally, this research analyzed the qualitative and quantitative characteristics of bridge projects, termed project inputs for this research. This research found that bridge projects delivered by design build had a significantly higher degree of flexibility in their scope and a significantly lower degree of design completed at their time of award. It was also found that the specification sets utilized for design build projects were composed of a significantly higher degree of performance specifications, and thus a lower degree of prescriptive specification. Surprisingly, there was no difference in the level of schedule urgency demonstrated by be delivered by design build and those delivered by design bid build.