Loading...
HomeMy WebLinkAboutCDP 2020-0017; SAREM RESIDENCE; RESPONSE TO THIRD PARTY GEOTECHNICAL REVIEW (FIRST); 2021-06-30 ENGINEERS + GEOLOGISTS + ENVIRONMENTAL SCIENTISTS Offices Strategically Positioned Throughout Southern California RIVERSIDE COUNTY OFFICE 40880 County Center Drive, Suite M, Temecula, CA 92591 T: 951.600.9271 F: 951.719.1499 For more information visit us online at www.petra-inc.com June 30, 2021 J.N. 20-155 MR. SCOTT SAREM 6684 Lemon Leaf Drive Carlsbad, California 92001 Attention: Mr. Scott Sarem Subject: Response to Third Party Geotechnical Review (First), 4005 Skyline Road, Carlsbad, California, Project ID: CDP2020-0017 References: See Attached List Dear Mr. Sarem: Petra Geosciences, Inc. (Petra) is providing the following geotechnical response to the City of Carlsbad Third Party Geotechnical Review Sheet by Hetherington Engineering, Inc. dated May 25, 2021, regarding geotechnical report dated May 11, 2020 (Petra, 2020). The paraphrased review sheet comments and our responses are included herein. Numbering is consistent with that used by the reviewer. Comment No. 1 Page 1: The consultant should provide an updated detailed description of proposed site grading, structures/improvements, foundation type, etc. Response to Comment No. 1 Based on our review of the referenced structural plans by NSSE and grading plans by Toal Engineering, we understand the proposed construction consists of a split-level two-story single-family residence with several terraces that stairstep down the hillside and support an infinity edge swimming pool/spa, appurtenant hardscape improvements, and sports court. The proposed residential structure will be of wood- framed construction founded on conventional continuous/spread foundations with slab-on-grade floors. For this type of construction, it is anticipated that relatively light foundation loads will be imposed on the subgrade soils. Grade changes will be facilitated by a series of retaining walls up to 5 feet in height. We have not been provided with structural plans for the proposed infinity edge swimming pool at this time. The infinity edge swimming pool should be designed to tolerate the settlement values provided in the referenced geotechnical evaluation. If this cannot be accomplished, then additional geotechnical recommendations will be necessary. I ~ ' ' PETRA SOLID AS A ROCK GEOSCIENCES'"c I MR. SCOTT SAREM June 30, 2021 4005 Skyline Road / Carlsbad J.N. 20-155 Page 2 Proposed grading will consist of removing all undocumented fill soils, topsoil, and weathered paralic deposits down to approved competent paralic deposits and replacing them as compacted fill up to design grades. Remedial removal depths of approximately 3 feet below design grades or existing grades, whichever is deeper, are anticipated. Exclusive of remedial grading, maximum depth of cut on the lot is anticipated to be approximately 1.75 feet below existing grades and maximum depth of fill is anticipated to be approximately 6.7 feet above existing grades. Comment No. 2 Pages 1 and 2: The consultant should provide an updated geotechnical map utilizing the current grading plan for the project to clearly show (at a minimum) a) existing site topography, b) proposed structures/improvements, c) proposed finished grades, d) geologic conditions, e) locations of the subsurface exploration, f) temporary construction slopes, g) remedial grading, etc. Response to Comment No. 2 Acknowledged. Please see the Updated Geotechnical Map utilizing the current Precise Grading and Drainage Plan by Toal Engineering, Inc., attached as Figure 1. Comment No. 3 Page 2: The consultant should provide geologic cross-sections utilizing the current grading plan to clearly show at a (minimum) a) existing site topography, b) proposed structures/improvements, c) proposed finished grades, d) geologic contacts, e) geologic structure, f) locations of the subsurface exploration, g) temporary construction slopes, and h) remedial grading, etc. Response to Comment No. 3 Acknowledged. Please see the attached Geologic Cross Sections A-A’ and B-B’, Figures 2 and 3. Comment No. 4 Page 2: The consultant should provide a list of recommended geotechnical observations and testing during grading and construction. Response to Comment No. 4 The geotechnical consultant should provide geotechnical observation and testing services for the following items: a) site grading, b) foundation excavations prior to reinforcing steel placement, c) swimming pool/spa excavation, d) interior and exterior utility trench backfill, e) driveway and hardscape subgrade, and f) removal and backfill of the existing septic tank. ~PETRA ~ GEOSCIENCES"'~ SOLID AS A ROCK MR. SCOTT SAREM June 30, 2021 4005 Skyline Road / Carlsbad J.N. 20-155 Page 3 This opportunity to be of service is sincerely appreciated. If you have any additional questions or concerns, please feel free contact this office. Respectfully submitted, PETRA GEOSCIENCES, INC. 6/30/2021 Bryan M. Rall Grayson R. Walker Project Geologist Principal Engineer CEG 2729 GE 871 Attachments: References Figure 1 – Updated Geotechnical Map Figure 2 – Geologic Cross-Section A-A’ Figure 3 – Geologic Cross-Section B-B’ Distribution: Addressee (electronic) Mr. Caleb Rios, Toal Engineering (electronic) W:\2020-2025\2020\100\20-155 Scott Sarem (4005 Skyline Road, Carlsbad)\Reports\20-155 400 Response to Third-Party Geotechnical Review.docx ~PETRA ~ GEOSCIENCES"'~ SOLID AS A ROCK MR. SCOTT SAREM June 30, 2021 4005 Skyline Road / Carlsbad J.N. 20-155 Page 4 REFERENCES American Concrete Institute, 2014, Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary. Bryant, W.A., and Hart, E.W., 2007, Fault-Rupture Hazard Zones in California, Alquist-Priolo Earthquake Fault Zoning Act with Index to Earthquake Fault Zones Maps, California Geological Survey, Special Publication 42. California Department of Water Resources, 2018, Water Data Library, http://www.water.ca.gov/waterdatalibrary/ accessed September. California Geological Survey, 2010, ‘Fault Activity Map of California, Geologic Data Map No. 6, http://maps.conservation.ca.gov/cgs/fam/. ______, 2018, Earthquake Fault Zones, A Guide for Government Agencies, Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42. Google Earth™ 2020, by Google Earth, Inc., http://www.google.com/earth/index.html, accessed May. International Building Code, 2013, 2015, 2016, 2019 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2019 International Building Code, California Building Standards Commission. Jennings, C.W. and Bryant, W.A., 2010, Fault Activity Map of California: California Geological Survey, Geologic Data Map No. 6. Kennedy, M.P. and Tan, S.S, 2007, Geologic map of the Oceanside 30’ x 60’ quadrangle, California, United States Geological Survey. Macrostrat, Creative Commons Attribution 4.0, 2020, accessed May. https://macrostrat.org/map/ NSSE, 2020, Sarem Residence, 4005 Skyline Road, Carlsbad, CA 92008, Sheets S-0 through S-6, dated October 8. Petra Geosciences, Inc., 2020a, Preliminary Geotechnical Evaluation, Proposed Two-Story Residence, 4005, Skyline Road, APN-207-072-17-00, City of Carlsbad, San Diego County, California, dated May 11. , 2020b, Geotechnical Commentary on Soil Infiltration Characteristics, Proposed Two-Story Residence, 4005 Skyline Road, City of Carlsbad, San Diego County, California, dated May 28. , 2020c, Geotechnical Review of Grading and Foundation Plans, Proposed Two-Story Residence, 4005 Skyline Road, City of Carlsbad, San Diego County, California, dated October 20. San Diego County Regional Standards Committee, 2108, Regional Standard Drawing Book, 2018 Edition. http://www.regional-stds.com/home/book/drawings SEAOC & OSHPD Seismic Design Maps Web Application – https://seismicmaps.org/ Tan, S. S., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, Relative Landslide Susceptibility and Landslide Distribution Map, Plate A, California Division of Mines and Geology Open-File Report 95-04. ~PETRA ~ GEOSCIENCES'"' SOLID AS A ROCK MR. SCOTT SAREM June 30, 2021 4005 Skyline Road / Carlsbad J.N. 20-155 Page 5 REFERENCES Tan, S.S., and Kennedy, M.P., 1996, Geologic maps of the northwestern part of San Diego County, California: California Division of Mines and Geology, Open File Report 96-02. Toal Engineering, Inc., 2020, Grading and Drainage Plan, Sheets C-1, C-2, and A1.0, dated August 21. United States Geological Survey (USGS), 2014, Unified Hazard Tool v4.0x, https://earthquake.usgs.gov/hazards/interactive/ ~PETRA ~ GEOSCIENCES"'~ SOLID AS A ROCK TP-4TP-2TP-1TP-3AA'B'BAfu(Qvop)Afu(Qvop)T.D.=6'T.D.=4'T.D.=5.2'T.D.=3.5'LEGENDApproximate location of Test PitT.D.=Total DepthGeologic Cross-SectionArtificial Fill-UndocumentedVery Old Paralic Deposits-Bracketed Where BuriedUPDATED GEOTECHNICAL MAP4005 Skyline RoadCarlsbad, CaliforniaFIGURE 1DATE: JUNE 2021J.N: 20-155PETRA GEOSCIENCES, INC.500 La Terraza Blvd. Suite 150Escondido, California 92025PHONE: (951) 253-4458COSTA MESA TEMECULA VALENCIA PALM DESERT CORONA SAN DIEGOSCALE: 1"=20'TP-1T.D.=5.2'A A'Afu(Qvop)' \ I I I I I I I N:\200xx\20036\Drowings \ Civil\20036-gp-02.dwg 06/23/2021 09:30 DEEPENED CONC. EDGE POOL BY OTHERS {PER SEPARATE PLAN AND PERMIT) □ ( I \ CONSTRUCTION NOTES \ I I I \ I I \ 0-CONSTRUCT CONCRETE DRWEWAY /HARDSCAPE. SEE DETAIL ON SHEET 5. CD-CONSTRUCT TURF BLOCK DRIVEWAY. SEE LANDSCAPE PLANS. G)-1NSTALL 4" PVC SCH40 OR SDR35 PIPE DRAIN SYSTEM. ©-INSTALL 6" PVC SCH40 OR SDR35 PIPE DRAIN SYSTEM. ©-INSTALL 8" PVC SCH40 OR SDR35 PIPE DRAIN SYSTEM. @-INSTALL 6" DECK DRAIN NOS 918B W/ RISER & ADAPTOR, OR EQUAL. @-INSTALL 6" ATRIUM DRAIN NOS 90 W/ RISER & ADAPTOR, OR EQUAL @-INSTALL 12" ATRIUM DRAIN, NOS 1280 W/ RISER & ADAPTOR OR EQUAL. ©-INSTALL 24" CONC. CATCH BASIN (BROOKS CB-2424 OR EQUAL). @-INSTALL BIOFILTRATION SYSTEM (423 S.F. MIN. AREA). SEE DETAIL ON SHEET 5. @-coNSTRUCT STORM WATER STORAGE VAULT. SEE DETAIL ON SHEET 4. @-CONSTRUCT DRAINAGE SPREADER. SEE DETAIL ON SHEET 5. @-INSTALL 5" CHANNEL DRAIN W/ LIGHT TRAFFIC GRATE (NOS B64GMTL OR EQUAL.) @-CONSTRUCT 12" WIDE CONCRETE V-DITCH. SEE DETAIL ON SHEET 5. @-INSTALL 1" WATER METER AND SERVICE W/ SPRINKLER PER CITY STD. DWG. NO. W-3A. @-INSTALL PERVIOUS PAVING ON WALKWAYS/PATIOS AS SHOWN (SEE LANDSCAPE PLAN). @-INSTALL SUBDRAIN PER SOILS REPORT. SEE DETAIL ON SHEET 5. @-DOWNSPOUT {PER ROOFING CONTRACTOR). SEE DETAIL ON SHEET 5. NOTICE TO CONTRACTOR REQUIRED CERTIFICATIONS/ APPROVALS In addition to any certifications required by the agencies having jurisdiction over this project, the following approvals from the Civil engineer of record are required: 1. Foundation forms for improvemen1s on or abutting property lines is required prior to concrete pour. 2. Location, size, and depth of all drain lines prior to backfill. TOAL ENGINEERING, INC. , I E '9 I I I r I I r I I ~ j' 1 I H ' y LI< I : \ I 'i;JJl¾l /298.17 1W FS '6 g/1~ 92.17TF -t.J1 I ADDITIONAL NOTES 1. ALL ROOFS SHALL BE GUillRED & DOWNSPOUTS CONNECTED TO STORM DRAIN SYSTEM. 2. PAO ELEVATIONS ARE BASED ON 4' CONCRITT SLAB OVER 10-MIL VAPOR BARRIER OVER 4" of CLEAN AGGREGATE BASE PER FOUNDATION PLAN (NEAL SHAH STRUCTURAL ENGINEERING DATED 2/26/2021). CONTRACTOR SHALL VERIFY ALL PAO ELEVATIONS W/ SOILS ENGINEER AND STRUCTURAL ENGINEER PRIOR TO GRADING. 3. WHERE EXTERIOR/INTERIOR UTIL/TY TRENCHES ARE PROPCSED IN A DIRECTION THAT PARALLELS ANY BUILDING FOOTING, THE BOTTOM OF THE TRENCHES SHALL NOT EXTEND BELOW A 1 :1 PLANE PROJECTED DOWNWARD FROM THE BOTTOM EDGE OF FOOTING. WHERE THIS OCCURS, ADJACENT FOOTING SHALL BE DEEPENED OR UTIL/TY CONSTRUCTED AND BACKFILLED PRIOR TO BUILDING CONSTRUCTION. 4. FOR BUILDING FOOTING AND FOUNDATION DESIGN SEE STRUCTURAL PLANS. 5. ALL RECOMMENDATIONS WITHIN THE SOILS REPORT FOR THIS PROJECT PREPARED BY PETRA GEOSCIENCES, IN REPCRT NO. 20-155 DATED MAY 1 1. 2020, AND ALL ADDENDA THERETO, ARE CONSIDERED A PART OF THIS 6. ALL ORAN LINES SHALL HAVE A MINIMUM SLOPE OF 1 % TOWARDS ounm. WALL NOTES 1. WALLS SHOWN HEREON FOR INFORMATION ONLY AND ARE TO BE CONSTRUCTED PER SEPARATE PLAN/PERMIT. TE~□ VERIFY •1t CL 1.-f.T P.L {If NOT, CO ;fl. cPNSRUCJ\ NEW CL P.L. PER Cr()' STAN NOTE: ON-strr SEW SYSTEM IS NOT IN EASEMENT NOTES ALL EASEMENTS LISTED HEREON ARE PER A PRELIMINARY TITLE REPORT PREPARED BY FIRST AMERICAN TITLE COMPANY, FILE NO.OIV-6066955 DATED OCTOBER 4, 2019 UNLESS NOTED OTHERWISE. NO SEWER, TOBER 13, COUNTY. M RECORD 30" JI' ,JI!·" 0 0 10 ~ I SOM. 16 "AS BUIL T11 2. ALL PROPOSED WALLS ARE ANTICIPATED TO BE CMU UNLESS OTHERWISE NOTED; SEE SITE WALL PLANS FOR DESIGN INFORMATION. RCE ___ EXP. ___ _ 3. NO WAI.LS OR FENCES ARE TO EXCEED 6' IN HEIGHT MEASURED FROM LOWEST ADJACENT GRADE ANO NOT T ~ PETRA f-----------i EXCEED 42" WITHIN THE REQUIRED FRONT YARD SETBACK. HEIGHT SHALL INCLUDE ANY REQUIRED SAFETY ~ GEOSCIENCES'"' REVIEVED BY· I r r 20 I DATE I r ,-----,--,---_.:~=========~==~=~=~~=~~~=-1::1~N~SP~E~C~T~□R~~~~====~D~A~TE~d I SH2EET I CITY OF CARLSBAD I SHE8ETS I CALEB RIOS R.C.E. 575B7 DATE· 1-----+--+-----------------t---t----t-----il-----t ENGINEERING DEPARTMENT t----+----lt----------------i----i---;----;---, GRADING PL.ANS FOR: SAREM RESIDENCE (4005 SKYIJNE ROAD) GR2021-0016 PRECISE GRADING PLAN APPROVED: JASON S. GELDERT GRADING SUBMITTAL NO. 1 Existing Grade CROSS SECTION A-A' 4006 Skyline Road Carlsbad, California FIGURE 2 DATE: JUNE 2021 J.N: 20-155 PETRA GEOSCIENCES, INC. 500 La Terraza Blvd. Suite 150 Escondido, California 92025 PHONE: (951) 253-4458 COSTA MESA TEMECULA VALENCIA PALM DESERT CORONA SAN DIEGO SCALE: 1"=20' A 300 280 320 310 290 270 A' 300 280 320 310 290 270 TP-2 (Proj. 35' South) Proposed Grade Skyline Rd. CLPL TP-3 (Proj. 10' North) Approximate Removals PL Proposed WallApproximate Limits of Proposed Sports Court Approximate Limits of Proposed Infinity Edge Swimming Pool Approximate Limits of Proposed Patio Approximate Limits of Proposed Residence Approximate Limits of Existing Residence Approximate Limits of Proposed Driveway Afu ?????????? ??? ? TP-1 (Proj. 19' South) Approximate Removals Approximate RemovalsAfu Afu (Qvop) Afu N84W N86W 0 20 40 I I I !r - _ _i - PETRA GEOSCIENCES'"' B 300 280 320 310 290 B' 300 280 320 310 290 PLPL ? Afu ?????? ? (Qvop) Proposed Wall Approximate Limits of Existing Residence Existing Grade Approximate Limits of Proposed Residence Proposed Grade Approximate Limits of Proposed Entry Way Approximate Limits of Existing Residence Approximate Limits of Proposed Residence Proposed Wall Approximate Limits of Existing Residence Approximate Limits of Existing Structure Afu TP-2 (Proj. 15' East) CROSS SECTION B-B' 4006 Skyline Road Carlsbad, California FIGURE 3DATE: JUNE 2021 J.N: 20-155 PETRA GEOSCIENCES, INC. Approximate Removals 500 La Terraza Blvd. Suite 150 Escondido, California 92025 PHONE: (951) 253-4458 COSTA MESA TEMECULA VALENCIA PALM DESERT CORONA SAN DIEGO N06W SCALE: 1"=20' 0 20 40 -~ -~ - ----\----t PETRA ,______ _ ___, GEOSCIENCES""