1. (a)

   1. (1)

      1. (A) In a more traditional DB-B project, any geotechnical investigation and subsequent report are provided by the Arkansas Department of Transportation or an authorized representative firm prior to design to enable the department or consultant to design the project and as a resource for the contractor to construct the project.
      2. (B) In a D-B project, there are two (2) different approaches with regard to the generation of the project geotechnical information that should be considered during the project development.

   2. (2)

      1. (A) In one approach, the department would provide a complete report with all the geotechnical information for the project, including detailed analyses and recommended design parameters, to the short-list proposers in a manner similar to a DB-B project.
      2. (B) However, this approach is normally not preferred due to the potential impacts to the final design and, more importantly, the risk imputed to the department using this approach.

   3. (3)

      1. (A) The second, and preferred, approach would include the department, or an authorized representative firm, collecting samples and providing preliminary information, which may include field sampling and testing, and limited analyses depending on project risk factors.
      2. (B) The information is provided to the short-list proposers and acts as a general common base upon which general concept designs and approaches may be developed.
      3. (C) However, the department and its authorized representative firms should not provide detailed geotechnical interpretive data or analyses unless special site conditions warrant the additional risk assumed by the department performing these services and providing the information to the short-list proposers.
      4. (D) A general breakdown of the tasks and information that may be provided by the department is discussed below.

2. (b) Geotechnical investigation.

   1. (1)

      1. (A) A geotechnical investigation should be performed by the department in preparation for the preliminary design efforts and the department should release the results of the investigation to the short-list proposers as a reference to prepare their proposals.
      2. (B) The preliminary investigation would generally require a thirty percent (30%) level field investigation relative to a full PS&E level investigation required for final design.
      3. (C) The investigation conducted for any specific project may vary significantly from this target, depending on the uncertainty in the details of the preliminary design, such as:

3. (i) The potential for variations in alignments;

   1. (ii) Structure locations;

      1. (iii) Complexity of the site;

         1. (iv) The availability of preexisting subsurface information; and
         2. (v) The potential for risk.
      2. (D) The department should consider these factors when preparing the plan for the geotechnical investigation.
   2. (2) The geotechnical investigation conducted for the project should be sufficient to support the development of the preliminary design and also to provide the appropriate level of confidence for information to be released to the short-list proposers to reduce the risk of differing site condition claims by the design-builder during the implementation phase.

   3. (3) The goals of the geotechnical investigation should include, but not be limited to, the following:

      1. (A) Identify the overall vertical and horizontal distribution of soil and rock types for the preliminary design, and assess how the material properties will affect the design and construction of the project elements;

      2. (B)

         1. (i) Define the groundwater and surface water regimes for the preliminary design.
         2. (ii) It is especially important to determine the depth and seasonal and spatial variability of groundwater or surface water.
         3. (iii) The locations of confined water-bearing zones, artesian pressures, and seasonal or tidal variations should also be identified;
      3. (C) Identify and consider any impacts to adjacent facilities that could be caused by the construction of the project;
      4. (D) Identify and characterize any geological hazards that are present within or adjacent to the project limits, e.g., landslides, rockfall, debris flows, liquefaction, soft ground or otherwise unstable soils, or seismic hazards, that could affect the project as well as adjacent facilities that could be impacted by the construction of the project;

      5. (E) Assess the feasibility of the proposed alignments, including the:

         1. (i) Feasibility and schematic evaluation of retaining walls and slope angles for cuts and fills; and
         2. (ii) Effect the construction of the project could have on adjacent facilities;
      6. (F) Assess potential stormwater infiltration or detention sites with regard to their feasibility, and to gather groundwater data in accordance with stormwater regulations;
      7. (G) Identify potential suitability of on-site materials as fill and/or the usability of nearby materials sources;
      8. (H) For structures including, but not limited to, bridges, cut-and-cover tunnels, large culverts, walls, bored tunnels, or other structures or elements requiring trenchless technology, provide adequate subsurface information to assess feasibility of the preliminary design and to help quantify risks;
      9. (I) For projects that may require ground improvement to achieve the preliminary design, provide adequate information to assess feasibility and to assess the potential impacts to adjacent facilities due to the ground improvement; and
      10. (J) For projects that may include the potential for landslides, rockfall areas, and debris flows, provide adequate information to evaluate the feasibility of various stabilization or containment techniques.

   4. (4) To accomplish these goals, the geotechnical investigation should include, but not be limited to, the following:

      1. (A) A review and compilation of historical records including previous borings, previous reports, and design plans of existing facilities;
      2. (B) A geological site reconnaissance of the project corridor focusing on all key project features and identification of potential geological and geotechnical concerns or potential hazards within and adjacent to the project corridor; and

      3. (C) A subsurface investigation consisting of an appropriate combination of:

         1. (i) Borings;
         2. (ii) Cone penetration tests;
         3. (iii) Field testing;
         4. (iv) Field instrumentation, such as piezometers or inclinometers;
         5. (v) Geophysical surveys; and
         6. (vi) Laboratory testing.
         7. (c) Geotechnical engineering.
   5. (1) The department should conduct the necessary geotechnical engineering for the project to support the development of the preliminary design and evaluate its feasibility during the procurement process.

   6. (2)

      1. (A) The focus of any geotechnical analysis or design conducted to develop a design-build project should be to evaluate feasibility, and to minimize the risk of short-list proposers including wide swings in the bids due to geotechnical issues that have not been adequately defined.
      2. (B) Issues of feasibility instead of resulting values are the most important to determine.

      3. (C)

         1. (i) For example, if shafts or piles are proposed as foundations for a bridge, the specific foundation loads will not be known accurately enough during the RFQ and RFP development to determine foundation depths and sizes.
         2. (ii) Therefore, detailed analysis of foundation skin friction and end bearing resistance would be of little use since the design-builder would have to repeat such calculations during final design.

   7. (3)

      1. (A) What is of more use is whether shaft or pile foundations are feasible to install, considering impacts to adjacent facilities and ability for equipment of sufficient size to access potential shaft or pile locations, etc.
      2. (B) Enough information must be provided to the short-list proposers so that they can determine what foundation types are feasible and what construction problems may be encountered due to difficult ground conditions such as unanticipated bedrock encountered along the project corridor.

   8. (4) Typically, geotechnical engineering in preparation of a design-build project should assess feasibility and risk associated with the preliminary design and should consist of the following activities:

      1. (A) Feasibility of proposed alignments with consideration to feasible slopes or need for walls, including applicable wall types along the project and the potential impact of those fill or cut slopes and/or walls on adjacent facilities;

      2. (B) Structure foundation feasibility, including:

         1. (i) Wall foundation types;
         2. (ii) Any associated constructability issues that could contribute to risk; and
         3. (iii) Potential impacts to adjacent facilities;
      3. (C) Seismic hazard assessment, including site-specific ground motion studies (if appropriate for the project corridor and project scope), and the potential for liquefaction and associated seismic hazards caused by liquefaction;
      4. (D) Preliminary assessment of other existing or potential geological hazards such as landslides, rockfall, debris flows, etc., as well as the feasibility of mitigation strategies;
      5. (E) Need for ground improvement to stabilize unstable ground, liquefaction, and excessive settlement, including the feasibility of various ground improvement techniques and their potential impact on adjacent facilities;
      6. (F) Whether or not on-site materials will be usable as construction materials;
      7. (G) Feasibility of site conditions present to infiltrate runoff water;
      8. (H) Need for dewatering, its feasibility, and its potential impact to adjacent facilities; and

      9. (I) Any other geotechnical design activities needed to:

         1. (i) Assess risks;
         2. (ii) Help establish baselines;
         3. (iii) Ensure feasibility of the preliminary design; and
         4. (iv) Assist the department to develop an estimate for the project.

   9. (5)

      1. (A) For soil liquefaction on the project, a preliminary assessment of the depth and extent of the liquefiable soils should be provided to the short-list proposers.
      2. (B) A preliminary assessment of the feasibility of potential mitigation schemes should be provided, as well as an assessment of the impact of liquefaction on the existing and proposed project features.

      3. (C) A complete liquefaction investigation and hazard assessment should be included in the RFP to ensure bidding consistency if one (1) or more of the following is true:

         1. (i) The potential mitigation schemes for liquefaction hazards could affect the decision on whether to widen or replace an existing bridge or similar structure; or
         2. (ii) The design assumptions and parameters needed to perform a liquefaction assessment should be provided to the short-list proposers since these values could vary significantly between short-list proposers such that the project scope could vary significantly.
      4. (D) For example, one short-list proposer assumes no stabilization is needed, while others assume that stabilization is necessary or the bridge must be replaced rather than widened.

   10. (6) Similarly, for complex site conditions and large important structures, it may be advisable to include the results of site-specific seismic ground motion or seismic hazard studies in the RFP rather than just as informational documents.

       1. (d) Preliminary geotechnical report (PGR).

   11. (1) The department may prepare and release a preliminary geotechnical report (PGR) for the project that will:

       1. (A) Document and summarize the data gathered;
       2. (B) Include preliminary analyses; and
       3. (C) Form the common basis for the short-list proposers’ preliminary design and cost estimates.

   12. (2)

       1. (A) The PGR should contain all the relevant factual geotechnical data gathered for the project and should be included in the RID released with the RFP.

       2. (B) The PGR should contain the following information:

          1. (i) A summary of the site reconnaissance and description of the geological and geotechnical conditions that are anticipated to impact design and construction of the project;
          2. (ii) A description of the geotechnical site exploration program, including any explanatory information needed to understand the boring logs and in-situ field test logs;
          3. (iii) The logs of all borings, test pits, and other site investigations, including any existing subsurface geotechnical data;
          4. (iv) Groundwater measurements;
          5. (v) A description of the geological and seismic setting for the project corridor at a regional level;
          6. (vi) Results of all field tests conducted;
          7. (vii) Installation details, logs, measurements, and results of all geotechnical field instrumentation installed for the project or existing geotechnical instrumentation and measurements and results which are relevant for the project; and
          8. (viii) A description of all laboratory tests conducted and the test results, as well as any previous geotechnical laboratory test results that are relevant for the project.

   13. (3)

       1. (A) In addition to presenting the data collected, the PGR can also serve as an interpretive geotechnical document used to establish a common understanding between the short-list proposer and the department of the subsurface conditions, their potential impacts, and effect of risk on the design and construction of the project.
       2. (B) The PGR should be considered to be the primary interpretation of the project geotechnical subsurface conditions and their potential effect on design and construction of the project as presented in the RFP.

   14. (4)

       1. (A) The PGR should establish the geotechnical baseline regarding subsurface conditions present within the project, but specifically focused on the preliminary design as presented in the RFP.
       2. (B) The geotechnical baseline should be primarily focused on conditions that affect construction risk, or possibly provide some guidance on how certain geological conditions are normally interpreted in this geographical region which, for final design purposes, may affect project cost.
       3. (C) The geotechnical baseline should clearly define the specific geotechnical conditions the short-list proposer should consider as the basis for developing the proposal.
       4. (D) The geotechnical baseline is also used to allocate risk between the department and the design-builder.
       5. (E) The geotechnical baseline is not intended to be used directly in the final design.
       6. (F) The selected short-list proposer, the design-builder, will conduct the final geotechnical investigations and will develop the final geotechnical report for use in the final design of the project.

   15. (5)

       1. (A) When establishing the geotechnical baseline in the PGR, it must be recognized that subsurface conditions are inherently variable, and that variability can translate to design and construction risk.
       2. (B) The geotechnical baseline, however, must be as clear and concise as possible, conveying to short-list proposers the content and variability in the conditions being addressed.
       3. (C) The geotechnical baseline represents engineering interpretations or assumptions about geotechnical conditions that can affect the design of a project feature or its constructability, expressed as contractual representations of anticipated geotechnical conditions.
       4. (D) Since the information represents judgment or conclusions based on data collected and, as such, is interpretive by nature, the PGR should generally not be included or drawn into the contract but be provided to the short-list proposers for information only and included in the RID.

4. (e) Preliminary geotechnical information.

   1. (1)

      1. (A) The department should release to the short-list proposers all available geotechnical reference documents, including borings, test results, and any PGR prepared for the project, but also any existing documents that include interpretive or recorded information on the geological and geotechnical conditions along the project corridor.
      2. (B) The collection of such documents is generally referred to as the preliminary geotechnical information (PGI) which should be included in the RID released with the RFP.

      3. (C) These documents could include, but are not limited to, the following:

         1. (i) Geotechnical interpretive reports, which may include a formal PGR, containing results of preliminary geotechnical engineering used to establish the feasibility of the preliminary design and to help quantify geotechnical risks;
         2. (ii) Interpretive geotechnical background information that was used to assess the feasibility of the preliminary design or which could be used by the design-builder as background information in support of the geotechnical design activities, e.g., geological stratigraphy;
         3. (iii) As-built information for existing facilities within or adjacent to the project corridor that may or may not be directly affected by the project;
         4. (iv) Detailed design plans and construction records for existing facilities within or adjacent to the project corridor; and
         5. (v) Historical information about the project corridor.
   2. (2) Based on the size and location of the project, project budget, and level of effort the department determines is appropriate, the volume of information included in the PGI can vary greatly, but it is intended that all relevant representative information be provided to the short-list proposers in an effort to reduce the risk for both the proposer and the department throughout the project.

Codification Notes: “PS&E” means plans, specifications, and estimates.