Managing Geotechnical Risks in Design–Build Projects (2018) / Chapter Skim
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From page 16... ...
16 Chapter 2: Research Approach 2.1 Research Framework The research framework springs directly from the NCHRP 24-44 RFP and is divided into two phases: • Phase 1 – Benchmark the state of the practice in geotechnical risk management • Phase 2 – Quantify the costs and benefits and Develop the proposed Guidelines for Managing Geotechnical Risk on Design-Build Projects. Hereafter referred to as the "Guidelines." The outcome of the research is a set of guidelines, an interim research report, which was submitted in January 2017 and approved by the NCHRP panel in April 2017, and this final research report based on a rigorous analysis of a state-of-the-practice review.
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17 A directed survey of DOT (22 responses) and industry experts (24 responses)
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18 Figure 2.2 Phase 2 Research Work Plan 2.1.1 Phase 1: Benchmark the State of the Practice in Geotechnical Risk Phase 1 evaluated current applications of geotechnical risk in traditional low bid DBB transportation projects, while maintaining a keen focus on how DOTs have modified the traditional NCHRP 24-44: Guidelines for Managing Geotechnical Risks in Design-Build Projects Research Framework Phase 2: Tasks 5, 6, and 7 Ph as e 2: D ev el op a nd V et P ro po se d Gu id el in es PRODUCE GEOTECHNICAL RISK MANAGEMENT GUIDELINES Develop Risk Analysis Plan Conduct Geotechnical Risk Simulation – Evaluate Output Data – Quantify Geotechnical Risk Task 7 Final Research Report & Recommended Guidelines NCHRP Panel Review Project Complete Industry Advisory Panel Review Draft Guideline Vetting Plan Literature Review Output Case Study Project Output Survey Output Task 5 Quantitative Risk Analysis Task 6 Prepare Geotechnical Risk Management Guidelines Develop 1st Draft Guidelines Document Content Analysis Output Assemble Risk Analysis Input Data Generic Geotechnical Risk Register Geotechnical Risk Model Draft Geotechnical Risk Management Guidelines Develop Guideline Vetting Plan Conduct DOT Vetting Workshops Final Draft Geotechnical Risk Management Guidelines Industry Advisory Panel Review From Phase 1 Revise Guidelines as required
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19 process to accommodate alternative project delivery. It evaluated the state of the practice with respect to alternative project delivery selection and the way it is applied on a variety of project types.
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20 risk survey as a starting point, and modified it to include the cogent findings of the Synthesis 455 ATC survey. The survey for this study was industry-wide, so the team could compare highway agency practices with those of other agencies and private sector firms.
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21 with ten or more DB projects worth of experienced was tested statistically against the respondent that reported experience with less than ten DB projects using the Pearson Chi-Square Test and found to be statistically significant. Details on this are found in Chapter 3.
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22 The first step was to assemble the possible case studies identified in Task 1 and pass them through a filter to ensure that the case study population covered the full spectrum of the research interest. The goal was to have a set of possible case study projects that furnish these attributes: Range of project types – roads, bridges, tunnels, ITS, etc.
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23 The key step in Task 3a is the first one: develop a case study protocol for the case study interviews and data collection plan. The protocol (See Appendix C)
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24 Financial and schedule progress data available Design consultant and construction contractor available for interviews Agency information – construction volume, outsourcing of design, seasonal issues, and so forth Alternative project delivery experience data – number, type, cost/schedule performance, project-specific legal issues, claims, protests, and so forth The case study data collection plan included the procedures for assembling the necessary input data to calculate metrics that quantify the geotechnical risk management cost and benefits for use in Task 5, the quantitative risk analysis. During each case study interview, the DOT was asked to furnish quantitative data on the case study project as well as other past projects that had significant geotechnical issues.
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25 Task 3b. Summary of the state of the practice for managing highway transportation project geotechnical risk on DB projects The state-of-the-practice summary was devoted to the system-level and detailed effective practices for managing geotechnical risk on DB projects.
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26 work plan in detail. The Phase 2 work plan included the steps necessary to advance the panelapproved draft Guidelines outline and Final Research Report.
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27 used it to represent a "correlation factor" (Hong et al.
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29 schedule demands and other non-technical considerations. Therefore, a formal risk analysis to identify and quantify major geotechnical risk factors becomes critical to setting the DB project up for success.
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30 This involves the development of an index, like a benefit-cost ratio or other more appropriate parameter, that will provide a quantified value for risk reduction as the investment in early subsurface investigation is increased. This analysis used data collected in Task 3a for the case study projects.
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31 rationally determine a well-understood financial measurement such as return on investment or benefit-cost ratio that can be applied to each case study project. The result is a means to determine whether the resources needed to reduce geotechnical risk for each case study project provided a measurable outcome that justified their expenditure.
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32 A highly structured approach was taken to author the Guidelines. First, the team revised the Task 3 annotated outline, as reviewed by NCHRP panel as required to comply with panel comments.
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33 travel. Generally, there are multiple people within an organization who will be impacted by the contents of a guidebook; therefore it is wise to include all of these people in the vetting.
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35 involves presenting the group's findings to all the workshop participants and coordinate each topical area's feedback with all other areas. The day after the workshop, a meeting with the DOT representatives will be held to assess the previous day's results and separate the feedback that applies only to the given DOT and that content which has broader application.
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36 Table 3.18. This ranking is based on responses from 22 DOT employees and 24 contractors.
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37 Figure 2. 4 Risk Quantification Approaches 2.2.1.1 Qualitative Risk Assessment The qualitative approach is quite subjective and based on the perception of the project development team regarding the type of risks to be encountered and their impact on project.
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38 The results of the NCHRP 24-44 survey was used to validate that geotechnical risk assessment is performed as part of the overall project risk assessment by most DOTs. In other words, no independent formal geotechnical risk assessment is conducted.
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39 Figure 2. 5 The Proposed Two-step Procedure for Estimating Project Risk Score The zones of high, medium, and low risk in the matrix shown are based a synthesis DOT risk management documentation and published research (WSDOT 2014; Clayton 2001)
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40 The method adds the "Effort to mitigate risk" as the third factor for rating a major risk factor. This came from Missouri DOT practice.
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41 it might be necessary to conduct a more detailed quantitative geotechnical risk assessment. The next section describes this process.
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42 2007; Von Winterfeldt and Edwards 1986)
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43 simulation options for calculating the total impact of risk also. A detailed discussion of these computational methods is beyond the scope of this discussion.
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44 R IS K A SS E SS M E N T R IS K R E SP O N SE P ro ba bi lit y Im pa ct P ro ba bi lit y *
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45 Fi gu re 2 .
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46 2.2.1.4 Risk Mitigation and Monitoring The last phase of risk management exercise is risk mitigation and monitoring. In the design-build approach, the owner's control is somewhat limited compared to the traditional DBB or construction manager/general contractor (CMGC)
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47 The DOT survey found that the owners usually do not often require the contractor to maintain a risk register and to implement and monitor the owner's risk management program. The premise that optimizing the exposure to geotechnical risk demands that the owner involve the DB Contractor, resulting in a joint post-award formal risk assessment and implement the mitigation efforts will benefit both the owner and the contractor.
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48 Accepting the risk: finally, this strategy can be used by the owner to deal with risks that are relatively rare and/or have limited impact. The owner usually accepts some risks by establishing a contingency budget.
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