Managing Geotechnical Uncertainty Using Design Build Methodology: A Case Study

This paper discusses the use of Design-Build (DB) project delivery as a means to address geotechnical uncertainty in transportation projects. This paper reviews four public agencies’ approaches to using DB project delivery as a means to address geotechnical uncertainty. Four case studies were selected for inclusion to highlight specific geotechnical issues that were addressed by using DB project delivery. The first case study highlights the use of a Geotechnical Baseline Report (GBR) as a means to allocate subsurface condition risk for an urban elevated guideway project in the City and County of Honolulu, Hawaii. The second case study is a rockfall mitigation project in Montana that highlights the use of unit price pay items for the uncertain features of the scope. The third case study is the Hastings bridge in Minnesota. This case study highlights the agency’s interactivity with competing design-builders during DB proposal preparation through confidential one-on-one meetings. The last case study is a slide repair project in Missouri that highlights the use of DB project delivery to shorten the time the roadway is out of commission and to encourage innovative methods to lessen the cost of slope repair projects. The paper concludes that the use of DB project delivery is an effective means for managing geotechnical uncertainty in transportation projects.