Evaluating the Influence of Differing Geotechnical Risk Perceptions on Design-Build Highway Projects

Abstract

Managing geotechnical risk in design-build (DB) projects is complicated because the contract is awarded before a thorough subsurface investigation is conducted, making geotechnical uncertainty high during bid preparation. Typically, owners allocate geotechnical risk between themselves and competing design-builders in the DB project’s request of proposals (RFP), and the perceived RFP risk profile is reflected in the bid prices proposed by competing DB teams. The level of perceived geotechnical uncertainty is exacerbated when the RFP’s geotechnical content is either inadequate or ambiguous, a condition that may not have been recognized by the RFP’s authors. Hence, the purpose of this paper is to understand the influence of differing perceptions on the DB project’s pricing. The paper analyzes the difference in perceived DB geotechnical risk for 27 common geotechnical risk factors identified in a survey of state department of transportation (DOT) geotechnical engineers and professionals of the DB industry. Those geotechnical risk factors were rated on the basis of frequency and impact by 46 DOT and industry practitioners, and the results are synthesized using importance index theory. The study finds a statistically significant difference in the perceptions of importance of geotechnical risk factors between public agencies and the DB industry. The average perceived difference in the rated factors is nearly 12%. This paper recommends that the perceptions of geotechnical risk be aligned before the contract award using progressive DB procurement or after the award using a scope validation period to provide an opportunity to share the geotechnical risks.