Geotechnical Requirements in the Design–Build Selection Process

Abstract

Geotechnical uncertainty is always high before a comprehensive site investigation is completed. In many design–build (DB) projects, the contract is awarded with the geotechnical investigation included as part of the required design deliverables. To ensure the necessary geotechnical design and construction quality, the agency must include appropriate factors in the best-value (BV) selection process. This paper describes an investigation of specific design–builder selection decisions involved in the procurement phase of a DB project and the ways in which the geotechnical requirements are incorporated into the selection decision in state departments of transportation (DOTs). The results are presented from the study of four independent sources of information, which were obtained through a review of the literature on geotechnical requirements in procurement documents, a survey of 42 state DOTs, a content analysis of procurement documents from 26 states, and the findings from 11 structured interviews with design–builders whose markets encompassed more than 30 states. The study results led to the conclusion that geotechnical designer qualifications and the experience of companies with geotechnical projects were key in achieving quality in DB projects. The weight of geotechnical factors in requests for qualifications and requests for proposals (RFPs) should be assigned proportionately with respect to the other factors that define DB project success. Experienced DOTs were seen to tailor the amount of geotechnical information that they included in the DB RFP to the specific requirements of a given project. Interactivity during the proposal preparation period offered an agency the opportunity to understand how competing design–builders perceived the geotechnical risk and to adjust the procurement plan accordingly. Alternative technical concepts also were presented as a viable approach to reduce perceived geotechnical risks.