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HomeMy WebLinkAbout106-Attachment E.pdf(L"7T \ ' C m /1\ A 13777 FRUITVALE AVENUE • SARATOGA, CALIFORNIA 95070 (408) 867 -3435 MEMORANDUM TO: Iveta Harvaiicik, Associate Engineer DATE: July 6, 2006 FROM: City Geotechnical Consultant SUBJECT: Supplemental Geotechnical Peer Review (S0076B) RE: Hall, DR -06 -307 - Grading for Private Road Wardell Road We have completed a supplemental geotechnical peer review of the subject application using: • Geotechnical Peer Review Response (letter), prepared by Terrasearch, Inc., datad June 27,2006; • Slope Stability of New Road (letter- report), prepared by Terrasearch, Inc., dated June 5, 2006; • Response to Geotechnical Peer Review (letter), prepared by Terrasearch, Inc., dated May 10, 2006; • Geotechnical /Geologic Assessment (report), prepared by Terrasearch, Inc., dated March 20, 2006; and • Grading and Drainage Plan (4 sheets, various scales), prepared by TS Civil Engineering, dated March 15, 2006. In addition, we have reviewed pertinent technical documents from our office files and been in communication with the Project Geotechnical Consultant. DISCUSSION The applicant is proposing construction of a new private access road. We understand that this roadway would serve three (presently) undeveloped properties intended for future residential development. The referenced plans indicate that cuts are proposed for retaining walls up to 5 feet in height, and 2:7 cut slopes are proposed up to 10 feet in height. Proposed earthwork will include an estimated 629 cubic yards of cut and 66 cubic yards of fill. In our previous peer review report (dated June 16, 2006), we indicated that the Project Geotechnical Consultant should perform additional evaluations to address the stability of slopes near the proposed Iveta Harvancik Page 2 July 6, 2006 S0076B roadway segment from station 10 +00 to 13 +00. We were primarily concerned that appropriate site specific strength data may not have been utilized in slope stability calculations. CONCLUSIONS AND RECOMMENDED ACTION The referenced Terrasearch letter of rune 27, 2006, indicates that additional subsurface exploration is not warranted because completed borings identified generally similar subsurface conditions (including relatively granular Santa Clara Formation bedrock). The consultant has clarified that correlations with collected site SPT data were utilized to check earth material strength values, and that site specific data supports higher strengths than utilized in slope stability calculations. We understand that triaxial strength testing procedures may be inappropriate based on the generally granular nature of site bedrock materials. Given the above, we find the that consultant has adequately addressed the issues of our previous peer review, and we recommend Project Geotechnical Clearance with the following conditions: 1. Geotechnical Plan Review - The Project Geotechnical Engineer shall review and approve all geotechnical aspects of the final project construction plans (i.e., site preparation and grading, site drainage improvements, pavement design, and design parameters for retaining walls) to ensure that their recommendations have been properly incorporated. The results of the plan review shall be summarized by the Project Geotechnical Engineer in a letter and submitted to the City Engineer for review prior to issuance of grading permits. 2. Geotechnical Field Inspection - The Project Geotechnical Engineer shall inspect, test (as needed), and approve all geotechnical aspects of the project construction. The inspection shall include, but not necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and excavations for retaining walls prior to the placement of steel and concrete. The results of these inspections and the as -built conditions of the project shall be described by the Project Geotechnical Engineer in a letter and submitted to the City Engineer for review prior to final project approval. Iveta Harvancik Page 3 July 6, 2006 S0076B This peer review has been performed to provide technical advice to assist the City of Saratoga in its discretionary permit decisions. Our services have been limited to review of the documents previously identified, and a visual review of the property. Our opinions and conclusions are made in accordance with generally accepted principles and practices of the geotechnical profession. This warranty is in lieu of all other warranties, either expressed or implied. MEMORANDUM TO: Suzanne Thomas CC: Terrence Szewczyk - Applicant FROM: Iveta Harvancik, Associate Engineer SUBJECT: Geotechnical Conditions for 06 -307, Wardell Road DATE: July 7, 2006 1. The Project Geotechnical Engineer shall review and approve all geotechnical aspects of the final project construction plans (i.e., site preparation and grading, site drainage improvements, pavement design, and design parameters for retaining walls) to ensure that their recommendations have been properly incorporated. The results of the plan review shall be summarized by the Project Geotechnical Engineer in a letter and submitted to the City Engineer for review prior to issuance of the grading permit. 2. The Project Geotechnical Engineer shall inspect, test (as needed), and approve all geotechnical aspects of the project construction. The inspection shall include, but not necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and excavations for retaining walls prior to the placement of steel and concrete. The results of these inspections and the as -built conditions of the project shall be described by the Project Geotechnical Engineer in a letter and submitted to the City Engineer for review prior to final project approval. 3. The owner (applicant) shall pay any outstanding fees associated with the City Geotechnical Consultant's review of the project prior to Zone Clearance. -I - 4. The owner (applicant) shall enter into agreement holding the City of Saratoga harmless from any claims or liabilities caused by or arising out of soil or slope instability, slides, slope failure or other soil related and/or erosion related conditions. -2-