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Home My WebLink AboutCDP 16-34; THIRD PARTY REVIEW RESPONSE AND GEOTECHNICAL REPORT UPDATE; 2018-07-12EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 (619) 258-7901. Fax (619) 258-7902 Brian & Lori Lavin July 12, 2018 158 Chestnut Avenue Project No. 16-1106E6 Carlsbad, California 92008 Subject: Third Party Review Response and Geotechnical Report Update Proposed Single-Family Residence (Lavin Residence) 158 Chestnut Avenue Carlsbad, California 92008 References: See Attached Dear Mr. & Mrs. Lavin: In accordance with your request, we have prepared this report to address the third party review comments for the proposed residential development at the subject site, and provide an update of the referenced geotechnical report (Reference No. 5). Comment 1 Retaining wall design parameters were provided in the referenced geotechnical report addendum (Refere.n..e No. 3), and included back drainage recommendations. Waterproofing may consist of a 90- mil sealer fluid (Tremco 250GC or equivalent), a 10-mil plastic sheeting and a 1/2 —inch foam protection. board. Comment 2 The proposed single-family residence should be designed in accordance with seismic design requirements of the 2016 California Building Code or the Structural Engineers Association of California using the following seismic design parameters: RECEIVED AUG 22 2018 LAND DEVELOPMENT ENGINEERING Respectfully submitted, BRIAN & LOR1.LA VIN/ 158 CHES.TNUTA VENUE PROJECT NO. 16-1106E6 PARAMETER ,, 1 VALUE -- 2016 CBC and thCE 7 REFERENCES Site Class D Table 20.3-1! ASCE 7, Chapter 20 Mapped Spectral A cceleration For Short Periods, Ss 1.161a Figure 1613.3.1(1) Mapped Spectral Acceleration For a 1-Second Period, 0.445g Figure 1613.3.1(2) Site Coefficient, F,, 1,036 Table 1613.3.3(1) Site Coefficient, F 1.555 Table 1.613.3.3(2) Adjusted Max. Considered Earthquake Spectral Response Acceleration for Short Periods, SMS I .202g Equation 16-37 Adjusted Max. Considered Earthquake Spectral Response Acceleration for I-Second Period, SM1 0.692g Equation 16-38 5 Percent Damped Design Spectral Response Acceleration for Short Periods, SDS 0.802g Equation 16-39 5 Percent Damped Design Spectral Response Acceleration for i-Second Period, S11 0.461 g Equation 16-40 Comment 3 A review of the grading plan indicates that the proposed fiatwork will include sidewalks and a driveway fiom Chestnut Avenue to the residence garage with a gradient ranging between 2 and 20 percent. We recommend that concrete sidewalks be a minimum 4 inches thick and the concrete driveway a minimum 6 inches thick. The subgrade soils should be scarified to a minimum depth of 12 inches, moisture-conditioned within 2 percent over optimum and recompacted to at least 95 percent relative compaction. The concrete for the driveway should be a minimum of 3,500 psi. Placement of concrete, control/ expansion joints, and any reinforcement should be in conformance with ACI specifications and the structural engineer requirements. Finally, we have reviewed the referenced geotechnical report (Reference No. 5) and visited the site on June 11, 2018. Site conditions were found as described in the referenced geotechnical report. Therefore, the recommendations provided in the referenced geotechnical report are still valid for the proposed development. The seismic design criteria should be updated as above. If we can be of any further assistance, please do not hesitate to contact our office. Mamadou Saliou Dial to, P.E. RCE 54071, GE 2704 MSD/md IPA BRIAN & LORI LA VIN/ 158 CKESTNUTA VENUE PROJECT NO, 16-1106E6 REFERENCES "Review of Geotechnical Report, Proposed Single-Family Residence (Lavin Residence), 158 Chestnut Avenue, Carlsbad, California 92008", City Project No. CDP 16-34, GR 2018-0018, Prepared by NV5, Dated June 25, 2018. "Foundation Plan and Details Review, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1 106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated April 13, 2018. "Addendum to Limited Geotechnical Investigation, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106136, Prepared by East County Soil Consultation and Engineering, Inc., Dated April 13, 2018. "Response to City of Carlsbad Issues of Concern, Proposed Single-Family Residenëe, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated October 31, 2017. 5, "Limited Geotechnical Investigation, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated November 8, 2016. EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 920711 (619) 258-790.1. Fax (619) 258-7902 Brian & Lori Lavin April 13, 2018 158 Chestnut Avenue Project No. 16-1106E6 Carlsbad, California 92008 Subject; Addendum to Limited Geotechnical Investigation Proposed Single-Family Residence (Lavin Residence) 158 Chestnut Avenue Carlsbad, California 92008 References: 1. "Response to City of Carlsbad issues of Concern, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16- 1 106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated October 31, 2017. 2. "Limited Geotechnical Investigation, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6, Prepared by East County Soil Consultation and Engineering, Inc.. Dated November 8, 2016. Dear Mr. & Mrs. Lavin: In accordance with your request, we have prepared this addendum to address the new foundation and slabs, and the retaining walls for the proposed single-family residence at the subject site. It is our understanding that the proposed construction has been changed to a two-story over basement. Therefore, the following recommendations should be implemented in the design and construction. FOUNDATIONS AND SLABS Continuous footings should be at least 24 inches deep and 18 inches wide for the proposed two- story over basement structure. Interior concrete slabs-on-grade should be a minimum 4 inches thick. Reinforcement should consist of 93 bars placed at 16 inches on center each way within the middle third of the slabs, The remaining foundation and slab recommendations provided in the referenced geotechnical report (Reference No. 2) are still valid for the new proposed development. BRIAN & LOP] LA ViN/ 158 CHESTNUT A VENUE PROJECT NO. 16-1106E6 RETAINING WALLS Cantilevered retaining walls should be designed for an "active" lateral earth pressure of 35 psf/ft (35 pcf EFP) for approved granular and level backfill conditions. Where the walls support 2:1 (hor: vert) sloping backfill, the equivalent active fluid pressure should be increased to 45 pcf. Walls subject to uniform surcharge loads should be designed for an additional uniform lateral pressure equal to one- third (1/3) the anticipated surcharge pressure. This pressure is based on the backfill soils being free draining and non-expansive. Restrained walls such as basement 'alls should be designed utilizing an "at-rest" earth pressure of 60 psf/ft (60 pcf EFP) for approved granular and level backfill conditions. Restrained walls subject to uniform surcharge loads should be designed for an additional uniform lateral pressure equal to one- half (1/2) the anticipated surcharge. Other additional lateral earth pressures due to earthquake motions of 26 and 39 pcf (EFP) for unrestrained and restrained conditions respectively may be applied using an inverted triangular distribution if required. Soil design criteria, such as bearing capacity, passive earth pressure and sliding resistance as recommended under the Foundation and Slab recommendations section of the referenced geotechnical report (Reference No. 2) may be incorporated into the retaining wall design.. Footings should be reinforced as recommended by the structural engineer and appropriate back drainage provided to avoid excessive hydrostatic wall pressures. As a minimum, we recommend a fabric-wrapped crushed rock and perforated pipe system. At least 2 cubic feet per linear foot of free- drainage crushed rock should be provided. If we can be of any further assistance, please do not hesitate to contact our office. Respectfully submitted, Mamadou Saliou Diallo, P.E. RCE 54071, GE 2704 MSD/md EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. :10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 (619) 258-790.1. Fax 258-7902 Brian & Lori Lavin 158 Chestnut Avenue Carlsbad, California 92008 Subject: Foundation Plan and Details Review Proposed Single-Family Residence (Lavin Residence) 1.58 Chestnut Avenue Carlsbad, California 92008 References: See Attached Dear Mr. & Mrs. .Lavin: April 13, 2018 Project No. 16-1106E6 In accordance with your request, we have reviewed the foundation plan and details prepared respectively by Brooks Design and PcSD Engineering, both of Carlsbad, California for the proposed single-family residence at the subject site. The foundation plan and details were found to be in accordance with the recommendations provided in the referenced geotechnica1 report and addendum (References No. 1 and No. 3). Our firm should observe the foundation excavations for proper size and embedment into competent bearing soils. If we can be of further assistance, please do not hesitate to contact our office. 2OFES8/Th ous1 GE 2704 6Vrn EXP!j Ix, Mamadou Saliou Diallo, P.E. RCE 54071, GE 2704 MSD/rnd BRIAN & LORI LA VIN/ 158 CHESTNUT VENUE PROJECT NO. 16-1106E6 REFERENCES 1, "Addendum to Limited Geotechnical Investigation, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6. Prepared by East County Soil Consultation and Engineering, Inc., Dated April 13, 2018. "RespOnse to City of Carlsbad Issues of Concern, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated October 31, 2017. 3. "Limited Geotechnical Investigation, Proposed Single-Family Residence, 158 Chestnut Avenue, Carlsbad, California 92008", Project No. 16-1106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated November 8, 2016. EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD SUITE I SANTEE CALIFORNIA 92071 619 258-7901 fax 6:19 258-7902 Brian & Lori Lavin October 31, 2017 158 Chestnut Avenue Project No. 16-1106E6 Carlsbad, California 92008 Subject: Response to City of Carlsbad Issues of Concern Proposed Single-Family Residence (Lavin Residence) 158 Chestnut Avenue Carlsbad, California 92008 Reference: "Limited Geotechnical Investigation, Proposed Single-Family Residence (Lavin Residence), 158 Chestnut Avenue, 158 Chestnut Avenue 92008", Project No. 16- 1106E6, Prepared by East County Soil Consultation and Engineering, Inc., Dated November 8, 2016. Dear M. & Mrs. Lavin: In accordance with your request, we have reviewed the grading plan prepared by Coastal Land Solutions, Inc. of Encinitas. California to address the City of Carlsbad issues of concern in their review of documents dated September 2, 2017 for the proposed single-family residence at the subject site. Due to the site limitations to the east and •west, the 2 percent drainage gradient on hardscape areas adjacent to the structure will be sufficient provided the proposed vegetated swales adjacent to the retaining walls are changed to concrete swales with a minimum gradient of 1 percent. In order to protect adjacent structures or pavement from erosion, the proposed bioretention basin may be lined with a Mirafi FW 400 geotextile or equivalent. If we can be of further assistance, please do not hesitate to contact our office. Respectfully submitted, (OFESSIO ØuT ( GE 2704 k EXP. -ti I' * -.------ I OJtr'L IA AL1Y'' Mamadou Sa o iallo, P.E. R.CE 54071. GE 2704 MSD\md