Agmt17 AECOM Technical Services, Inc.

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• Select and implement the most appropriate Best Management Practices (BMPs) to be used at each exploratory boring location in order to minimize impact to the environment and the public. • Drill up to 30 exploratory borings (depths ranging from 30 to 100 feet) at the proposed foundation locations for the bridge structures, and retaining walls. • Drill up to 25 borings to maximum depths of about 8 feet to explore the subgrade of new structural pavement. • Obtain representative soil samples, and gathering other site-specific subsurface data including groundwater levels when feasible. • Conduct geotechnical laboratory testing on representative soil samples. • Perform geotechnical engineering analyses in order to develop recommendations for the final design of foundations of the proposed bridge structures and retaining walls, three overhead sign structures (two along northbound off ramp. one along southbound off ramp, sections for new pavement, and mitigation of geologic hazards; specific engineering analyses will include: • Update seismic design parameters in accordance with Seismic Design Criteria, version 1.7 and Guidelines for Structures Foundation Reports (version 2.0, updated December 2009), based on supplemental geotechnical and geological data • Recommend and develop foundation type, depth and capacity for compression, tension and lateral resistance • Develop the lateral earth pressures for retaining wall design including dynamic earth pressures due to seismic loading • Recommend foundations for retaining walls, including evaluation of sliding, overturning and bearing capacity • Develop construction considerations for installation of foundations, such as pile driving, CIDH installation, dewatering, footing excavations and shoring requirements • Evaluate slope stability of new embankment fills and MSE walls • Evaluate embankment settlement with stage construction considerations • Document all findings and presenting recommendations in the geotechnical reports (Tasks 2.6.4, 2.6.5, & 2.6.6). Borings will be sampled as the drilling progresses with the Standard Penetration Test, modified California, and/or Shelby tube samplers, at 5 feet intervals (or closer if changes in material type are observed). Below a depth of 50 feet, sampling may be increased to 10 -foot intervals. All sampling and logging of the soils will be in accordance with Caltrans' Soil & Rock Logging Classification, and Presentation Manual. Traffic control pursuant to Caltrans standards will be provided during the drilling of all exploration sites. Clearance of underground utilities will be based on USA and private utility locate services where appropriate. All soil cuttings generated during the drilling of the borings will be placed in drums or roll -off bins, sampled for possible contamination, and disposed of off-site following reception of the analytical testing results and acceptance of the materials for disposal at a nearby Class 2 landfill. A photo ionizing detector (PID) will be on-site during the exploration program to test the air around the bore hole and samples for possible volatile organic contamination. If analytical results Page 18 of 73 REV: 07-18-17 PR ATTY/AGR.2017.166/AECOM 101/84 PS&E