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C-1 Appendix C: Details of Geotechnical Risk Management Tools This appendix provides a detailed description of each tool. Table C. 1 is a list of the geotechnical risk management tools found to be effective by having been successfully employed in the field. Table C. 1 â Tools for Managing/Mitigating Geotechnical Risks 1. Flexible footprint for NEPA clearance: This tool depends on the agency selecting DB project delivery much early enough to influence the final form of the NEPA clearance. In essence, this tool seeks to provide as much flexibility in the final permit as practical to avoid the potential # Tool 1 Flexible footprint for NEPA clearance 2 Develop and furnish GBR in RFP 3 Geotechnical conditions database 4 Site conditions history from property owners during ROW acquisition 5 Prescriptive geotechnical design 6 Performance specifications for post-construction performance (subsidence, etc.) 7 Include differing site conditions clause 8 Progressive DB 9 Request of geotechnical and/or utilities ATCs 10 Define no-go zones for geotechnical ATCs 11 Competitor designated boring locations 12 Competitors permitted to conduct supplementary borings at own expense 13 Unit prices for contaminated material, over-excavation, etc. 14 Weight geotechnical evaluation criteria 15 Include life cycle criteria in best value award scheme 16 Scope validation period 17 Multiple NTPs with one designated for geotechnical investigation, design, and a second specifically to commence excavations, utility work, etc. 18 Contractor produced GBR-C 19 Negotiated GBR interpretation 20 Differing site conditions allowance 21 Contaminated material allowance 22 Unforeseen utilities allowance 23 Assign design-builder responsibility for utility coordination 24 Validate proposed life cycle elements during design 25 Encourage life cycle related value engineering proposals from subcontractors
C-2 that attractive geotechnical design solutions are not unintentionally disallowed by commitments made to obtain the permit in a timely manner. 2. Furnish geotechnical baseline report (GBR): developed by the owner, who collects all the relevant data from similar previous projects and the test results for the current project and assembles the information into what will serve as the geotechnical baseline for bidders for the purpose of decreasing geotechnical uncertainty during procurement, which can make proposals received more competitive. 3. Geotechnical conditions database: The advancement of computing power and the reduction in data storage costs has made it feasible for agencies to create corridor-level geotechnical databases consisting of all the data gathered in past projects. The database can then be mined to furnish information on site conditions for upcoming projects. 4. Site conditions history from property owners during ROW acquisition: Property owners will often have knowledge of a given parcelâs history and may be able to provide information with regard to previous utilities and structures. Additionally, they may also have knowledge of the presence of buried material such as demolition materials from previous structures, as well as provide potential warning that contaminated material may be present. The tool merely adds these questions to the ROW acquisition process and may trigger the need to conduct sampling during preliminary engineering. 5. Prescriptive geotechnical design: DB project delivery is by definition performance-based in that the contract is awarded before the design is complete. However, since geotechnical issues are often on the critical path, this tool involves the agency prescribing a geotechnical design approach with which it is comfortable and stating in the DB RFP that no deviations will be permitted. The result saves time during initial design reviews of subsurface features of work, which potentially allows those design packages to be released for construction as early as practical if desired. 6. Performance specifications for post-construction performance (subsidence, etc.): to mitigate potential geotechnical-related failures in the operation phase of the project, an owner might include a requirement for specific geotechnical-related performance warranties by the contractor. 7. Include differing site conditions (DSC) clause: Much of the geotechnical claim generally falls under changes due to Differing Site Conditions (DSC). The typical DSC clause provides broad relief to a contractor for site conditions that differ materially from what is expected according to the contract documents. The FHWA does not have a DSC mandate for DB projects. Nevertheless, many state DOTs use a DSC clause in their DB contracts. 8. Progressive Design-Build (PDB): PDBâs attraction in the geotechnical risk management realm is the ability to negotiate the geotechnical risk after award and after the geotechnical investigation has been completed rather than depending on the DSC clause to allocate the subsurface risk. With PDB, the first design and construction package released for construction could commence the subsurface investigation and conduct selected excavation on the project site to identify where the geotechnical issues will be encountered and their magnitude. Thus, a fair and equitable amount for the realized subsurface risk can be established. This eliminates the need for adding unnecessary contingencies in the price, as the uncertainty of the subsurface conditions is eliminated early in the project. 9. Request of geotechnical alternative technical concepts (ATCs): ATCs allow proposers to submit alternative solutions to potential subsurface problems before the contract is awarded; request ATCs (which the agency will hold confidential and preapprove if applicable) to
C-3 identify geotechnical issues and enhance innovation in geotechnical design and subsurface construction means and methods. 10. Define no-go zones for geotechnical ATCs: ATC No-go zones are those areas of the geotechnical baseline design that MAY NOT be proposed for change during the DB procurement. 11. Competitor designated boring locations: to reduce geotechnical risk by conducting subsurface explorations (borings) at strategic locations to help provide reasonable geotechnical parameters to the bidders; additional borings are made available to all competitors, but sometimes the agency performs more borings to avoid giving away the location requested by a proposer so the competitive advantage is retained; an important element for the success of the project during the procurement phase is to have sufficient geotechnical information that allows competitors to price the project without excessive contingencies. 12. Competitors permitted to conduct supplementary borings at own expense: allow competing design-builders to conduct their own pre-bid geotechnical investigations before developing their proposals to reduce geotechnical uncertainty; an important element for the success of the project during the procurement phase is to have sufficient geotechnical information that allows competitors to price the project without excessive contingencies. 13. Unit prices for contaminated material, over-excavation, etc.: a formalized geotechnical risk allocation technique to draft the contract provision that uses selective unit pricing, which provides an effective means for managing geotechnical quantity uncertainty. 14. Weight geotechnical evaluation criteria: tailor relative geotechnical weight for the contractor selection process in each DB project. 15. Include life cycle criteria in best value award scheme: since design is where the quality standards for construction are established, it is important that agency expectations for post- construction life cycle performance be articulated in the solicitation; used to identify successful approaches for managing geotechnical risks across the DB projectâs life cycle as well as discuss those practices that did not adequately address the geotechnical requirements and cause the agency to hold geotechnical liability that it had hopes to shed. 16. Scope Validation Period: a period of time incorporated in the contract to allow the contractor to discover any site conditions that differ with owner-furnished information early in the project. After the end of the scope validation period, the design-builderâs claim rights are waived for items not previously raised. This approach allows for an early resolution of geotechnical- related issues and establishes a limit for the ownerâs liability by assigning a specific timeframe for differing site conditions claims. 17. Multiple Notices to Proceed (NTPs): Using multiple NTPs allows the owner to reduce the risk of differing site conditions by issuing an NTP only for the contractorâs subsurface exploration and underground work before releasing the entire scope of work. This way, there is a prioritization in removing the uncertainty of the subsurface conditions early in the project so any differing site condition is addressed before advancing to the next stages of the project. 18. Design-builder produced geotechnical baseline report for construction (GBR-C): developed for the purpose of baselining geotechnical conditions for a project to allocate geotechnical risk encountered during construction; the owner collects all the relevant data from similar previous projects and the test results for the current project (geotechnical data report - GDR). Based on the data collected and test results the owner prepares a GBR for Bidding (GBR-B). The bidder uses the GBR-B and augments it with its approach and design to develop a new version: the GBR for Construction (GBR-C). It will incorporate the contractorsâ interpretation and
C-4 approach and its proposed means and methods. The owner should review the GBR-Cs prepared by bidders and seek clarification on any issues as needed. Based on this review, the owner will have the opportunity to seek adjustment of contract price if appropriate. After the bidder is selected, its GBR-C will be incorporated into the DB contract documents and forms the basis for risk allocation during the design-construction phase. 19. Negotiated GBR interpretation: This tool generally involves the use of a GBR-C as described above and a GBR-B (the ownerâs GBR used during bidding). After award of the DB contract and the subsequent completion of the GBR-C, the owner and the design-builder compare the two GBRs and agree on how to interpret a final GBR (GBR-F) during construction with respect to the contractâs DSC clause. The aim is to mutually agree on what constitutes a âmaterial differenceâ and in doing so share the DSC risk on a project-specific basis. 20. Differing site conditions allowance: including a specified dollar amount (allowance) in the RFP Agreement for differing site conditions to mitigate this commonly misallocated geotechnical risk. 21. Contaminated material allowance: including a specified dollar amount (allowance) in the RFP Agreement for testing and handling of hazardous materials to mitigate this commonly misallocated geotechnical risk. 22. Validate proposed life cycle elements during design: DB procurements often include both design and evaluation criteria that seek to encourage life cycle design decision-making by the competing proposers. This tool consists of conducting the subsequent life cycle cost analysis to validate that the winning proposalâs betterments indeed reduce the projectâs projected life cycle cost from that of the baseline design. 23. Encourage life cycle related value engineering proposals from subcontractors: Subcontractors are technical specialists in their particular areas of expertise. This is particularly true in areas like jet grouting, seismic retrofits, soil nails, and other geotechnical specialties. As such they are normally up to date with the state of technology and should be asked to review their scopes of work for potential improvements that would reduce life cycle cost.