Guidelines for Managing Geotechnical Risks in Design–Build Projects (2018)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

1 The Federal Highway Administration requires a differing site conditions clause in all federal-aid projects except those delivered using design–build. Given that the contract in most design–build projects is awarded before geotechnical and subsurface investigations are complete, a situation is created in which geotechnical uncertainty is generally high and the winning design–builder is expected to conduct those investigations after it has committed itself to a firm fixed price for design and construction. Risk is a function of perception, and both owners and their industry partners agree that geotechnical risk is perceived to be high as well. Without a differing site conditions clause that allocates this risk, the study found that members of the design–build industry perceive that the risk is much higher than does the department of transportation’s geotechnical staffs. Thus, the purpose of the research was to document proven strategies and tools for managing subsurface risk in design–build projects. This document is a set of guidelines for geotechnical risk management in design–build projects and was developed through a systematic review of best practices found throughout the nation during the completion of NCHRP Project 24-44, “Guidelines for Managing Geotechnical Risks in Design–Build Projects.” The research team that produced this document completed an extensive investigation into the issue of geotechnical risk in design– build projects. A number of questions regarding this topic have been answered. The major findings are summarized as follows: • The bulk of U.S. construction case law demonstrates that owners find it challenging to win differing site conditions claims. • Nevertheless, departments of transportation continue to rely on exculpatory language to try to shed geotechnical risk in design–build projects. • The industry recognizes the risk shedding bias and perceives geotechnical risk to be much higher than do authors of department of transportation design–build requests for proposals. • The result is the inclusion of contingencies for risks that may not be realized, which must logically increase the overall cost of the project. • The solution is to align the perceptions of geotechnical risk of the department of trans- portation and the design–build team early in the process. • Progressive design–build, design–build with multiple notices to proceed, and design– build with some fixed scope validation period were identified as potential mechanisms to permit the early alignment of geotechnical risk perceptions. In other words, the surest way to effectively quantify subsurface risk is to start the digging and uncover the actual site conditions on which the project must be built as soon as practical. This can be accomplished through early contractor involvement and joint S U M M A R Y Guidelines for Managing Geotechnical Risks in Design–Build Projects

2 Guidelines for Managing Geotechnical Risks in Design–Build Projects development of the geotechnical risk profile for the design–build project. This report details proven methodologies that permit the department of transportation and its industry partner to align perceptions of geotechnical risks and perhaps their business objectives early in the delivery of a design–build transportation project both before and after contract award. The guidelines provide the following five strategies for aligning the department of trans- portation’s and its design–builder’s perception of geotechnical risk. 1. Implement early contractor design involvement through encouraging geotechnical alternative technical concepts during procurement. 2. Use the design–build process to address other subsurface issues like utility company timeliness by involving third party stakeholders as early as practical in project develop- ment and delivery. 3. Raise the visibility of geotechnical issues in design–build projects during the procure- ment process to ensure competing design–build teams understand the level of criticality on each project. 4. Avoid differing site conditions claims through enhanced contract mechanisms designed specifically for addressing geotechnical risks. 5. Promote an atmosphere of life cycle-based design and construction decision making with respect to geotechnical risk on design–build projects. The guidelines also furnish 25 geotechnical risk management tools that can be used to implement the above strategies on typical design–build projects. Each tool proved to be as effective in the field. The tools are identified in Table 1.5 and are explained in detail in Chapter 5.