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Home My WebLink AboutPD 2022-0024; 2780 JAMES DRIVE; FINAL SOILS REPORT; 2024-12-09AS-GRADED COMPACTION REPORT 2780 JAMES DRIVE, CARLSBAD SAN DIEGO COUNTY, CALIFORNIA 92008 ASSESSOR’S PARCEL NUMBER (APN) 156-142-51-00 FOR A.C. MATTOS, INC. 3970 HIGHLAND DRIVE CARLSBAD, CALIFORNIA 92008 W.O. 8320-B/E-SC DECEMBER 9, 2024 Geotechnical ∙ Geologic ∙ Coastal ∙ Environmental 1817 Aston Ave. Suite 104, Carlsbad, CA 92008 TEL: (760) 438-3155 - FAX: (760) 931-0915 www.geosoilsinc.com December 09, 2024 W.O. 8320-B/E-SC-R A.C. Mattos, Inc. 3970 Highland Drive Carlsbad, California 92008 Attention: Ms. Ana Mattos Subject: As-Graded Compaction Report, 2780 James Drive, Carlsbad, San Diego County, California 92008, Assessor’s Parcel Number (APN) 156-142-51-00 References: 1. “Geotechnical Evaluation for Single Family Development, 2780 James Drive, Carlsbad, San Diego County, California 92008,” W.O. 8320-A, dated June 6, 2022, by GeoSoils, Inc. 2. “Response to City of Carlsbad Review Comments, 2780 James Drive, Carlsbad, California 92008, Project Issues Report PRJ-1048739,” dated January 23, 2023, by GeoSoils, Inc. 3. “Grading Plans for 2780 James Drive, Carlsbad, CA,” sheets 1 through 5, job no. PD2022- 0024, dated September 16, 2022, last revised April 30, 2022, by GAC Engineering and Land Surveying. Dear Ms. Mattos: In accordance with your request, and as required by the City, GeoSoils, Inc. (GSI) has prepared this geotechnical As-Graded compaction report of grading at the site. Observations and field compaction testing for grading occurred periodically between July 16, 2023 and September 8, 2023. Grading associated with the preparation of the two-story residence and ADU pads was observed and fill was selectively tested by a representative of GSI, on a part-time, as-needed basis. The scheduling of such was solely determined by your field representative, and GSI relied on this information to properly assess geotechnical quality assurance. Line and grade was provided by others and not GSI. Unless specifically superseded h erein, t he c onclusions a nd r ecommendations i n t he r eferenced geotechnical reports (see References 1 through 2) and plans reviewed by this firm (see Reference 3) remain valid and applicable and should be appropriately implemented during the balance of construction. A.C. Mattos, Inc W.O. 8320-B-SC 2780 James Drive, Carlsbad December 09, 2024 File:e:\wp21\pro\8300\8320b.agr Page 2 GEOTECHNICAL ENGINEERING Overexcavation Observations of overexcavation were performed by GSI. Grading appears to be in accordance with recommendations provided by GSI (see References 1 through 2). Engineered Fill Placement Engineered fill materials consisted of the onsite soils derived from the overexcavations. During grading, engineered fills were placed in approximately 6-inch lifts, moisture conditioned, mixed to achieve slightly greater than optimum moisture conditions, and mechanically compacted to a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557), where tested. Compaction Testing Field density tests on grading related to pad preparation were performed using the nuclear (densometer) ASTM test method D 6938-10 (Procedure A). The test results obtained indicate that compacted fill soils appear to meet the minimum compaction/moisture requirements recommended by this office (i.e., at least 90 percent relative compaction, and at least optimum moisture, per ASTM D 1557 [see Table 1, Field Density Test Results]), where tested. Failing test areas were reworked/removed and replaced with compacted fill. A summary of compaction tests is presented on Table 1. Approximate test locations are located on Plate 1 (Field Density Test Location Map). PURPOSE OF GRADING The primary purpose of grading was to create building pads for the said single-family home and accompanying ADU. LABORATORY TESTING Maximum Density Testing The laboratory maximum dry density and optimum moisture content for the major soil type encountered during grading and initial investigation were evaluated in general accordance with test method ASTM D 1557. The following table presents the results: A.C. Mattos, Inc W.O. 8320-B-SC 2780 James Drive, Carlsbad December 09, 2024 File:e:\wp21\pro\8300\8320b.agr Page 3 SOIL TYPE MAXIMUM DENSITY (PCF) MOISTURE CONTENT (PERCENT) A - Reddish Brown Silty Sand 133.7 7.7 Expansion Index A representative sample of the onsite earth materials was evaluated for expansion potential. Expansion Index (E.I.) testing and expansion potential classification were performed in general accordance with ASTM Standard D 4829. The results of the expansion index testing are presented in the following table: SAMPLE LOCATION AND DEPTH (FT) EXPANSION INDEX EXPANSION POTENTIAL ADU Location @ Pad Surface 5 Very Low E.I. = 0 to 20 - Very Low Expansion Potential. Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides Testing was performed on a representative sample of the onsite earth materials for general evaluations of soil corrosivity and soluble sulfates, and chlorides. More specifically, the testing included evaluations of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are presented in the following table: SAMPLE LOCATION AND DEPTH (FT) pH SATURATED RESISTIVITY (ohm-cm) SOLUBLE SULFATES (% by weight) SOLUBLE CHLORIDES (ppm) ADU Location @ Pad Surface 7.9 2,300 0.004 32 Corrosion Summary Laboratory testing indicates that the tested sample of the onsite soils is slightly alkaline with respect to soil acidity/alkalinity; is moderately corrosive to exposed, buried metals when moist; presents negligible sulfate exposure to concrete (Exposure Class S0 per Table A.C. Mattos, Inc W.O. 8320-B-SC 2780 James Drive, Carlsbad December 09, 2024 File:e:\wp21\pro\8300\8320b.agr Page 4 19.3.1.1 of ACI 318-14 [ACI, 2014]); and contains concentrations of soluble chlorides that are below action levels. GSI does not consult in the field of corrosion engineering. Therefore, additional comments and recommendations may be obtained from a qualified corrosion engineer based on the level of corrosion protection required for the project, as determined by the project architect, civil engineer, and structural engineer. Conclusions The work performed to date is in conformance with the preliminary recommendations contained in References 1 through 2, GSI field recommendations, Appendix Chapter J of the 2022 California Building Code, and with the grading guidelines of the City, from a geotechnical standpoint. Field testing indicates that fills placed under the purview of this report have been compacted to at least 90 percent of the laboratory standard (ASTM D 1557), where tested. Based on the observation and compaction testing performed, GSI concludes that the building pads are suitable for their intended use. REGULATORY COMPLIANCE The soil engineering and engineering geologic aspects of the construction are in compliance with the approved geotechnical reports and geotechnical aspects of the construction. Furthermore, with respect to the grading plans, GSI will certify1 that the soil engineering and engineering geologic aspects of the building pads are in compliance with the approved geotechnical reports (see References 1 through 2) and the grading site plan 539-5A (Reference 3). LIMITATIONS The conclusions and recommendations presented herein are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. The term “Certify” is used herein as defined in Division 3, Chapter 7, Article 3, § 6735.5 of the California Business and Professions Code (2023). A.C. Mattos, Inc W.O. 8320-B-SC 2780 James Drive, Carlsbad December 09, 2024 File:e:\wp21\pro\8300\8320b.agr Page 5 If you have any questions or comments regarding this letter, please do not hesitate to contact the undersigned. Respectfully submitted, GeoSoils, Inc. John P. Franklin Stephen J. Coover Engineering Geologist, CEG 1340 Geotechnical Engineer, GE 2057 JWJ/DRE/JPF/SJC/sh/th Attachments: Table 1 - Field Density Test Results (B) Plate 1 - Field Density Test Location Map (B) Table 2 – Field Density Test Results (E) Plate 2 – Field Density Test Location Map (E) Distribution: (1) Addressee (PDF via email) Table 1 FIELD DENSITY TEST RESULTS TEST DATE TEST LOCATION TRACT ELEVATION DRY RELATIVE TEST SOIL NO.OR DEPTH DENSITY COMPACTION TYPE TYPE(ft)(pcf)(%) GRADING 1 9/2/23 Main Residence 2780 James Drive -2.0 121.5 90.9 ND A 2 9/2/23 Main Residence 2780 James Drive -2.0 122.8 91.8 ND A 3 9/5/23 Main Residence 2780 James Drive -1.0 123.4 92.3 ND A 4 9/5/23 Main Residence 2780 James Drive -1.0 121.7 91.0 ND A 5 9/5/23 Main Residence 2780 James Drive -1.0 122.6 91.7 ND A 6 9/7/23 Main Residence 2780 James Drive FG 123.9 92.7 ND A 7 9/7/23 Guest House/ADU 2780 James Drive -1.5 122.8 91.8 ND A 8 9/7/23 Guest House/ADU 2780 James Drive -1.5 126.8 94.8 ND A 9FG 9/8/23 Main Residence 2780 James Drive FG 120.5 90.1 ND A 10FG 9/8/23 Guest House/ADU 2780 James Drive FG 120.8 90.4 ND A 11FG 9/8/23 Main Residence 2780 James Drive FG 122.4 91.5 ND A LEGEND FG = Finish Grade ND = Nuclear Densometer Test A.C. Mattos, Inc. 2780 James Drive, Carlsbad File: C:\excel\tables\8300\8320b.tbl1 GeoSoils, Inc. W.O. 8320-B-SC October 2023 Page 1 Plate 1 See Bar Scale DATE: 10/23 W.O. 8320-B-SC ALL LOCATIONS ARE APPROXIMATE This document or e-file is not part of the Construction Documents and should not be relied upon as being an accurate depiction of design. FIELD DENSITY TEST LOCATION MAP GSI LEGEND X-11 NOT A PART OF THIS STUDY N.A.P. N.A.P. N.A.P. N.A.P. 15 30 45 1” = 15 N.A.P. APPROXIMATE LIMMITS OF FILL PLACED UNDER THE PURVIEW OF THIS REPORT APPROXIMATE LOCATION OF FIELD DENISTY TEST X-3 X-2 X-1 X-5 X-4 X-7 X-6 X-8 X-10 X-9 X-11 Table 2 FIELD DENSITY TEST RESULTS W.O. 8320-E Print Date: 12/9/2024 TEST UTILITY DATE TEST LOCATION TRACT ELEV MOISTURE DRY REL TEST SOIL NO.TYPE NO.OR CONTENT DENSITY COMP METHOD TYPE DEPTH (ft)(%)(pcf)(%) SG1 7/16/24 Curb and Gutter 2780 James Dr BG/SG 12.9 118.6 96.6 ND C SG2 7/16/24 Curb and Gutter 2780 James Dr BG/SG 13.4 117.2 95.4 ND C SG3 7/16/24 Curb and Gutter 2780 James Dr BG/SG 12.7 117.9 96.0 ND C SG4 7/17/24 City Sidewalk 2780 James Dr BG/SG 12.9 115.5 94.1 ND C SG5 7/17/24 City Sidewalk 2780 James Dr BG/SG 13.4 114.8 93.5 ND C SG6 7/17/24 City Sidewalk 2780 James Dr BG/SG 11.5 117.7 95.8 ND C SG7 7/25/24 Driveway 2780 James Dr BG/SG 11.5 116.6 95.0 ND C SG8 7/25/24 Driveway 2780 James Dr BG/SG 11.8 115.4 94.0 ND C SG9 7/25/34 Driveway 2780 James Dr BG/SG 10.5 116.9 95.2 ND C 1 AC 8/6/24 James St 2780 2780 James Dr FG-4"8.3 127.3 95.1 ND A 2 AC 8/6/24 James St 2780 2780 James Dr FG-4"9.1 130.8 97.8 ND A 3 AC 8/6/24 James St 2780 2780 James Dr FG-2"x 143.3 96.3 ND AC 4 AC 8/6/24 James St 2780 2780 James Dr FG-2"x 142.1 95.5 ND AC 5 AC 8/6/24 James St 2780 2780 James Dr FG x 142.9 96.1 ND AC 6 AC 8/6/24 James St 2780 2780 James Dr FG x 141.4 95.2 ND AC LEGEND: ND =Nulcear Densometer BG =Base Grade SG =Subgrade FG =Finish Grade Ms. Anna Mattos 2780 James Drive, Carlsbad File: C:\excel\tables\8300\8320.tbl1 GeoSoils, Inc. W.O. 8320-E-SC December 2024 Page 1 Plate 2 See Bar Scale DATE: 11/24 W.O. 8320-B-SC ALL LOCATIONS ARE APPROXIMATE This document or e-file is not part of the Construction Documents and should not be relied upon as being an accurate depiction of design. FIELD DENSITY TEST LOCATION MAP GSI LEGEND SG-15 10 20 30 1” = 10’ APPROXIMATE LOCATION OF FIELD DENISTY TEST SG-4 SG-9 AC-6 AC-5 AC-3 AC-4 SG-8 SG-1 SG-7 SG-6 SG-3 SG-2 AC-1 AC-2 SG-5 AC-6 APPROXIMATE LOCATION OF FIELD DENISTY TEST