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HomeMy WebLinkAboutMS 2018-0006; Breakers View Beach Homes; Site Plan Review; 2018-08-20COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS August 20, 2018 Michael Jason Ianni 2337 Catalina Ave Vista, CA 92084 Subject: SITE PLAN REVIEW Tentative Parcel Map PUD 2018-0006 Breakers View Beach Homes 3648 Carlsbad Boulevard Carlsbad, California References: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Twin Home Development 3648 Carlsbad Boulevard Carlsbad, California Prepared by Coast Geotechnical Dated February 11, 2016 REVISED CITY OF CARLSBAD RESPONSE Proposed Twin Home Development 3648 Carlsbad Boulevard Carlsbad, California Prepared by Coast Geotechnical Dated July 25, 2016 GEOTECHNICAL UPDATE REPORT 3648 Carlsbad Boulevard Carlsbad, California Prepared by Coast Geotechnical Dated May 16, 2018 Dear Mr. Ianni: As requested, we have reviewed the project site plan, Sheet 2, prepared by bHA Civil Engineering and observed that they have, in general, included the recommendations presented in our Preliminary Geotechnical Investigation Report and supplemental reports. The following comments address the plans from a geotechnical viewpoint and have generally been included in the plans. P.O. BOX 230163 * ENCINITAS, CALIFORNIA 92023 (858) 755-8622 Coast Geotechnical COMMENTS August 20, 2018 W.O. U-6541115 Page 2 of 3 1) As per our discussions with bHA Civil Engineering and addressed in our Revised City of Carlsbad Response Report, dated July 25, 2016, infiltration is feasible in the western portion and the eastern driveway area of the site. Infiltration should be directed vertically by the installation of cutoff walls as shown on the Site Plan Details Section B-B' and Permeable Paver Detail. 2) The cutoff walls should be extended a minimum of 3.0 feet below the base of the proposed footing or pavement section, whichever is greater. The cutoff walls should be a minimum of 6.0 inches thick and poured with a minimum 2-sack slurry mix and should be a continuous pour without cold joints. 3) The cutoff walls MUST be installed prior to the residential footing excavations and curbs. Contractors and workers should be notified of the subsurface walls and that any penetration of the wall will need to be adequately sealed. 4) Previous recommendations suggested that no infiltration be allowed in the narrow side yard areas. The plans include a concrete drainage swale (Section A-A') that drains away from the foundation to a narrow planter area with area drains. This approach is acceptable from a geotechnical viewpoint provided limited irrigation/infiltration occurs along the narrow planter area. Coast Geotechnical August 20, 2018 W.O. U-6541115 Page 3 of 3 5) Limited sideyard areas which include pervious pavers will include subsurface cutoff walls, as indicated on the Permeable Paver Detail on the site plans. 6) All of the recommendations of the referenced reports which are not superceded by this report remain applicable and should be implemented during the design and construction phases. If you have any questions regarding this report, please contact our office. Reference to our Job No. U-6541115 will help expedite a response to your inquiry. Respectfully submitted, ~0 BUR COAST GEOTECHNIC~1 UJ. 2◄n Mark Burwell, C.E.G v~~ Vithaya Singhanet, P.E. Engineering Geologi Geotechnical Engineer