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Home My WebLink AboutCDP 2019-0032; LOVE RESIDENCE; FINAL SOILS REPORT; 2021-05-26 May 26, 2021 Project No. 8787.1 Log No. 21450 Elite Home Construction, Inc. 2386 Ivy Road Oceanside, California 92054 Attention: Mr. Corey Love Subject: AS-GRADED GEOTECHNICAL REPORT Proposed Single-Family Residence 4615 Telescope Avenue Carlsbad, California References: Attached Dear Mr. Love: In accordance with your request, we have performed geotechnical services in conjunction with grading at the subject site. Our services consisted generally of the following:  Observation and density testing during grading.  Observation of footing excavations.  Observation and density testing of retaining wall backfill.  Laboratory testing.  Engineering and geologic analyses.  The preparation of this report, which presents the results of our testing and observations, and our conclusions and recommendations. GRADING OPERATIONS Grading was performed on February 5, 2021.Grading for the upper building pad consisted generally of 1 to 1.5 feet of removals of existing disturbed terrace deposits down to approved undisturbed terrace deposits and replacement as compacted fill in order to achieve design finish grades. The garage level was cut to design finish grade exposing undisturbed terrace deposits. The attached Plot Plan, Plate No. 1 indicates the approximate limits of grading addressed by this report. The earthwork was performed by SOIL & FOUNDATION ENGINEERING ENGINEERING GEOLOGY HYDROGEOLOGY (760) 931-1917 Fax (760) 931-0545 333 Third Stree Laguna Beach, CA 9265 (949) 715-5440 Fax (949) 715-5442 Carlsbad, CA 92008-43695365 Avenida Encinas, Suite A HETHERINGTON ENGINEERING, INC. www.hetheringtonengineering.com AS-GRADED GEOTECHNICAL REPORT Project No. 8787.1 Log No. 21450 May 26, 2021 Page 2 Elite Home Construction, Inc. utilizing grading plans prepared by Sampo Engineering, dated October 15, 2020. SITE PREPARATION Prior to grading, the site was cleared of existing surface obstructions, vegetation and debris. Within the areas of proposed construction, existing disturbed terrace deposits were removed down to approved undisturbed terrace deposits. Following removals, the exposed soils were scarified to a depth of 6 to 8-inches, brought to near optimum moisture conditions and compacted to at least 90-percent relative compaction as determined by ASTM: D 1557. SOIL TYPES The soils utilized as fill consisted of on-site soil. The on-site soil was composed generally of orange brown silty sand. FILL PLACEMENT Fill soils were placed in 6 to 8-inch thick, near horizontal lifts, moisture conditioned to near optimum moisture content, and compacted to a minimum of 90-percent relative compaction as determined by ASTM: D 1557. Compaction was achieved by mechanical means using a Cat skid steer loader. A water hose was used for moisture conditioning. FOUNDATION EXCAVATIONS Foundation excavations for the retaining walls were observed by an engineer from this office. Footings were founded in approved terrace deposits as recommended and dimensioned in accordance with the foundation plan by Cosart Engineering, dated November 26, 2019 (Reference 3). RETAINING WALLS Retaining walls were provided with backdrains consisting of 4-inch diameter, Schedule 40 perforated pipe surrounded by approximately 1-cubic-foot per lineal foot of 3/4-inch crushed rock, all wrapped in filter fabric. On-site soils were placed from the top of the backdrain to finished grade in 6 to 8-inch thick, near horizontal lifts, moisture conditioned to near optimum moisture content, and HETHERINGTON ENGINEERING, INC. AS-GRADED GEOTECHNICAL REPORT Project No. 8787.1 Log No. 21450 May 26, 2021 Page 3 compacted by mechanical means to a minimum of 90-percent relative compaction as determined by ASTM: D1557. Density tests were performed in accordance with ASTM: D 6938 (Nuclear Method). The results of the density tests are presented on the attached Summary of Field Density Tests, Table I. The approximate locations of the field density tests are indicated on the accompanying Plot Plan, Plate 1. Maximum dry density/optimum moisture content determinations are presented on the attached Summary of Maximum Dry Density/Optimum Moisture Content Determinations, Table II. CONCLUSIONS AND RECOMMENDATIONS Based on our observations and the results of our testing, it is our opinion that the grading of the site has been performed in general conformance with our recommendations and the requirements of the city of Carlsbad. The portion of the site addressed by this report is considered suitable for the intended use. The recommendations for the proposed construction provided in the “Geotechnical Investigation…” (Reference 1) remain applicable. LIMITATIONS Our services were performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, HETHERINGTON ENGINEERING, INC. Mark D. Hetherington Edwin R. Cunningham Civil Engineer 30488 Civil Engineer 81687 Geotechnical Engineer 397 (expires 3/31/22) (expires 3/31/22) HETHERINGTON ENGINEERING, INC. AS-GRADED GEOTECHNICAL REPORT Project No. 8787.1 Log No. 21450 May 26, 2021 Page 4 Jose Pimentel Engineer In Training Attachments: Plot Plan Plate No. 1 Summary of Field Density Tests Table I Summary of Maximum Dry Density/ Table II Optimum Moisture Content Determinations Distribution: 3-Addressee 1-Via e-mail (elitehomeconstruction@yahoo.com) HETHERINGTON ENGINEERING, INC. REFERENCES Project No. 8787.1 Log No. 21450 1. “Geotechnical Investigation, Proposed Single-Family Residence, 4615 Telescope Avenue, Carlsbad, California”, by Hetherington Engineering, Inc., dated March 11, 2019. 2. “Grading Plan for Love Residence, Carlsbad, CA”, prepared by Sampo Engineering, dated October 15, 2020 3. “ Foundation Plan, 4615 Telescope Avenue, Carlsbad, CA”, prepared by Cosart Engineering, dated November 26, 2019. HETHERINGTON ENGINEERING, INC. FG: Finish Grade Project No. 8787.1 RW: Retaining wall Log No. 21450 TABLE I SUMMARY OF FIELD DENSITY TESTS (ASTM: D 6938) Test No. Test Date Remarks Soil Type Elevation (feet) Dry Density (pcf) Moisture Content (%) Relative Compaction (%) 1 2/5/21 FG 1 298.3 114.6 13.6 90 2 2/5/21 FG 1 298.3 115.4 11.2 91 3 2/5/21 FG 1 298.3 116.5 11.9 91 4 2/5/21 FG 1 298.3 125.6 8.6 98 5 2/5/21 FG 1 298.3 121.8 10.0 96 6 2/5/21 FG 1 298.3 118.4 9.2 93 7 2/5/21 FG 1 298.3 116.0 9.0 91 8 5/25/21 RW 1 298.0 114.8 8.6 90 9 5/25/21 RW 1 298.0 116.0 11.7 91 10 5/25/21 RW 1 296.0 115.5 8.1 91 11 5/25/21 RW 1 294.0 115.3 9.8 90 FG: Finish Grade Project No. 8787.1 RW: Retaining wall Log No. 21450 TABLE II SUMMARY OF MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT DETERMINATIONS (ASTM: D 1557) Soil Type Description Maximum Dry Density (pcf) Optimum Moisture Content (%) 1 Orange brown silty sand 127.5 10.0 N PLOT PLAN GEOTECHNICAL CONSULTANTS HETHERINGTON ENGINEERING,INC. PROJECT NO. PLATE NO. 012 5 1015200 SC A L E : 1 " = 1 0 ' LEGEND 8787.1 4615 Telescope AvenueCarlsbad, California 1 APPROXIMATE LOCATION OF DENSITY TEST APPROXIMATE ELEVATION OF CLEANOUT BOTTOM (FEET) 11 297.0 297.0 297.0 297.3 6 10 5 7 8 11 1 4 3 2 9 APPROXIMATE LIMITS OF GRADING APPROXIMATE LIMITS OF GRADING