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Peer Review of Geotechnical and Geologic Hazard Investigations BSK Project G2300051 11991 Dublin Canyon Road (Hana Japan) September 6, 2024 Pleasanton, California Page 6 pavement subgrade meet a specific R-Value. Therefore, consideration should be given to increasing the depth of the pavement subgrade associated with the minimum recommended R- Value to 24 inches. 26. Geotechnical Report, Section 10.2 (Rigid Pavements): Only 4 inches of aggregate base is recommended below the Portland Cement Concrete (PCC) pavement section. A minimum of 6 inches of aggregate base is typically recommended below PCC pavements. Therefore, consideration should be given to increasing the recommended aggregate base layer thickness. 27. Geotechnical Report, Section 10.4 (Cut-Off Curbs): The cut-off curbs recommended in this section of the Geotechnical report should not be optional. In particular because the surrounding areas are sloped to drain towards this Site. Prolonged exposure of pavement subgrade to excessive moisture can reduce the pavement life by 50 percent or more. 28. Geotechnical Report, Section 12 (Limitations): Reference should be changed to Section 3 for the project description. 29. General Comment: The City should require the project Owner to retain ENGEO (the Geotechnical Engineer-of-Record for this project) to review the geotechnical/earthwork aspects of the project plans and specifications before they are finalized and issued for construction. The purpose of this review would be to allow ENGEO to confirm that the recommendations presented in the geotechnical report issued for the Site have been properly incorporated into these documents. The City should also require the project Owner to retain ENGEO during construction of the planned improvements to provide earthwork observation and testing services, including regular visits by a California Certified Engineering Geologist . We believe this approach is essential to the successful construction of this project. Limitations BSK has prepared this peer review letter for the exclusive use of the Client and members of the project design team. Our review has been limited to the review of the document(s) referenced in this letter. The intent of this letter is not to provide engineering recommendations for this project. Our input is provided for the sole purpose of consideration by the City and the design team. We did not perform any additional subsurface exploration, laboratory testing, or engineering analyses as part of our services. Our peer review specifically excludes assessment of environmental characteristics particularly those involving hazardous substances. Our review did not include checking the referenced documents for conformance with State or local government codes. Our professional opinions and conclusions are made in accordance with generally accepted engineering geologic and geotechnical engineering principles and practices that exist currently in the San Francisco Bay Area. No warranties either express or implied, are made as to the professional advice provided under the terms of BSK’s agreement with the Client and included in this report. By performing the peer review services described in this letter, BSK does not assume the role of Geotechnical Engineer-of-Record for the project.