Design-build (DB) geotechnical risk mitigation is an important concern for state departments of transportation (DOT), especially they seek to accelerate project delivery schedules. The nature of the DB delivery requires that projects are awarded before a complete subsurface has been done. Hence, projects are awarded without a comprehensive geotechnical scope, nor completed geotechnical design. DOTs are responsible for how mitigate the geotechnical risk during the procurement stage. Preliminary geotechnical investigation and geotechnical requirements are included in the request for proposals (RFP), and the goal of geotechnical risk allocation is to manage these risks. Based on the DOTs’ position, design-builders’ geotechnical risk perception is affected, and is reflected in their geotechnical risk contingency at the time of bidding the project. The worst scenario is when the DOT cannot award DB projects because projects are over budget.

The purpose of this study is to identify tools to manage geotechnical risk in DB projects by analyzing what types of geotechnical information should be included in DB solicitation documents. The study found a difference in the perception of geotechnical risk between DOTs when agencies were classified based on the level of their DB experience (those who have delivered more than 10 DB projects versus those that who delivered less than 10). Based on this classification, agency approaches in managing geotechnical risk were found to be different. As a result, the study proposes mitigation tools to assist DOTs to have a better geotechnical risk approach. Furthermore, the study found 27 geotechnical risks factors. These were identified based on an importance index whose purpose was to identify those factors that are more crucial in DB projects. The study benchmarked the perception of these geotechnical factors between DOTs and DB industry. Results showed that there is a significant difference between these two perceptions. In addition to this analysis, the study also found geotechnical factors that potentially could disqualify a project from being an ideal candidate for DB delivery.

The study was based on a comprehensive literature review; surveys of U.S. DOTs; case studies where potential geotechnical factors where identified; structure interviews of DOTs and a survey of DB industry. The results make it a useful document that records the tools to manage geotechnical risk in DB projects.