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Home My WebLink AboutCT 15-04; THE GRAND MADISON; FINAL SOILS REPORT; 2019-08-22HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING • ENGIN EER ING GEOLOGY • HYDROGEOLOGY August 22, 2019 Project No. 8432.1 Log No. 20628 Grand Madison, LLC 3005 S. El Camino Real San Clemente, California 92672 Attention: Subject: Mr. Kevin Dunn FINAL GEOTECHNICAL REPORT The Grand Madison 725 Grand A venue Carlsbad, California References: Attached Dear Mr. Dunn: In accordance with your request, we have performed geotechnical services in conjunction with the construction of a multi-story, mixed use retail and residential structure at the subject site. Previous grading at the site is summarized in the "As-Graded Geotechnical Report. .. " (Reference 2) and includes density test numbers 1 through 32 performed as part of site grading. Our services during construction consisted generally of the following: • Observation of footing excavations. • Observation and testing of sidewalk subgrade. • Observation and testing of utility trench backfill. • Observation and testing of pavement sub grade, aggregate base and asphalt concrete. • Laboratory testing. • Engineering and geologic analyses. • Preparation of this report, which presents the results of our testing and observations, and our conclusions and recommendations. 5365 Avenida Encinas, Suite A• Carlsbad, CA 92008-4369 • (760) 931 -1917 • Fax (760) 931-0545 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com FINAL GEOTECHNICAL REPORT Project No. 8432.1 Log No. 20628 August 22, 2019 Page 2 GEOLOGIC CONDITIONS Subsurface conditions encountered during construction were consistent with those described in the "Geotechnical Investigation ... " (Reference 1) and "As-Graded Geotechnical Report ... " (Reference 2). No groundwater was encountered during construction. FOUNDATION EXCAVATIONS Foundation excavations for the structure were observed by a representative of this office. Footings were founded in approved compacted fill as recommended and dimensioned in accordance with the "Foundation Plan and Details ... " (Reference 4). UTILITY TRENCH BACKFILL Utility trench backfill soils were placed in approximately 6 to 8-inch thick, near horizontal lifts, moisture conditioned to near optimum moisture content and compacted by mechanical means to a minimum of 90-percent relative compaction as dete1mined by ASTM: D 1557. Density tests were performed in accordance with ASTM: D 693 8 (Nuclear Method) and D 15 56 (Sand-Cone Method). The results of the field 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 Dete1minations, Table II. PAVEMENT SUB GRADE, AGGREGATE BASE, AND ASPHALT CONCRETE The pavement subgrade and aggregate base were compacted by mechanical means to a minimum of 95-percent relative compaction as determined by ASTM: D 1557. The asphalt concrete was compacted to a minimum of 95-percent relative compaction as detemtined by Caltrans Test Method 308. Density tests were performed in accordance with ASTM: D 6938 (Nuclear Method). The results of the field 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 of soils are presented on the attached Summary of Maximum Dry Density/Optimum Moisture Content Determinations, Table II. The density of compacted HETHERINGTON ENGINEERING, INC. FINAL GEOTECHNICAL REPORT Project No. 8432.1 Log No. 20628 August 22, 2019 Page 3 hot mix asphalts are presented on the attached Summary of Bulk Specific Gravity/Density of Compacted Hot Mix Asphalt, Table III. SOIL TYPES The soils utilized as fill consisted of on-site soils and three import soils. The on-site soil was composed generally of red brown silty sand. Import soils varied depending on impmi source but generally consisted of sandy soils with a very low expansion potential. CONCLUSIONS AND RECOMMENDATIONS Based on our geotechnical observations and the results of our testing, it is our opinion that the geotechnical related construction at the subject site observed and tested by this office has been performed in general conformance with the recommendations contained in the referenced geotechnical report and in accordance with the requirements of the city of Carlsbad. LIMITATIONS Our services were pe1fo1med 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 rep01i. HETHERINGTON ENGINEERING, INC. REFERENCES 1) "Geotechnical Investigation, Proposed Mixed Use Building, 725 Grand Avenue, Carlsbad, California", by Hetherington Engineering, Inc., dated April 24, 201 5. 2) "As-Graded Geo technical Repmi, The Grand Madison, 725 Grand A venue, Carlsbad, California", by Hetherington Engineering, Inc., dated February 27, 201 8. 3) "Grading Plans for The Grand Madison, 725 Grand Avenue, drawing No. 489-9A" by KS Engineering, Inc., undated. 4) "Foundation Plan and Details, The Grand Madison, 725 Grand Ave, Carlsbad, California" (Sheets S 1. 0 and S3. 0), by R2H Engineering, Inc., dated October 12, 2017. HETHERINGTON ENGINEERING, INC. 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I DOOV ' ..... ~ J ) A A_/'-' '1 I 1' p}J .. + ('w') (\J) -,'-, ;u / -> I I I I • Project No. 8432.1 Log No. 20628 TABLE I SUMMARY OF FIELD DENSITY TESTS (ASTM: D 1556 and D 6938) Test No. Test Date Remarks Soil Type Elevation (feet)** Dry Density (pcf) Moisture Content (%) Relative Compaction (%) 33 3/12/2018 UT 4 -0.1 115.9 9.3 91 34 3/12/2018 UT 1 -2.0 113.8 8.8 87 (Fail) 35 retest of 34 3/12/2018 UT 4 -2.0 114.6 9.7 90 36 3/12/2018 UT 4 -2.0 110.3 10.9 86 (Fail) 37 3/12/2018 UT 4 -2.0 112.7 8.8 88 (Fail) 38 retest of 36,37 3/12/2018 UT 4 -2.0 115.8 8.1 90 39 3/12/2018 UT 4 -0.5 119.7 8.1 94 40* 3/7/2018 UT 4 46.3 100.8 10.2 79 (Fail) 41* retest of 40 3/7/2018 UT 4 46.3 124.1 10.2 97 42* 3/7/2018 UT 4 48.3 112.4 9.1 88 (Fail) 43 retest of 42 3/7/2018 UT 4 48.3 119.1 7.6 93 44 3/7/2018 UT 4 49.8 115.6 5.9 90 45 3/7/2018 UT 4 49.8 120.2 5.5 94 46 3/7/2018 UT 4 49.8 123.8 7.4 97 47 3/7/2018 UT 4 47.8 100.8 8.4 79 (Fail) 48 3/7/2018 UT 4 49.0 123.0 6.0 96 49 3/7/2018 UT 4 49.0 122.8 6.4 96 50 3/7/2018 UT 4 48.5 96.7 11.3 76 (Fail) 51 retest of 47 3/8/2018 UT 4 48.9 115.2 7.8 90 52 retest of 50 3/8/2018 UT 4 48.9 121.6 8.4 95 53 3/8/2018 UT 4 47.8 116.8 7.3 91 54 3/8/2018 UT 4 47.9 118.2 8.8 92 55 3/8/2018 UT 4 47.2 115.9 10.2 91 56* 4/24/2018 UT 4 -0.1 123.6 8.4 97 57 4/25/2018 FB 3 -0.1 114.0 10.7 91 58 4/25/2018 FB 3 -0.1 119.3 8.9 95 59 4/25/2018 FB 3 -0.1 117.4 8.7 93 60 4/2/2018 UT 4 -3.8 118.9 6.8 93 61 4/2/2018 UT 4 -1.5 116.8 6.8 91 62 4/2/2018 UT 4 -0.3 123.0 6.7 96 63 4/2/2018 FB 3 -0.1 116.9 6.9 93 64 4/2/2018 FB 4 -0.1 122.5 8.5 96 65 6/8/2018 FB 3 -1.5 113.4 10.2 90 Project No. 8432.1 Log No. 20628 TABLE I SUMMARY OF FIELD DENSITY TESTS (ASTM: D 1556 and D 6938) Test No. Test Date Remarks Soil Type Elevation (feet)** Dry Density (pcf) Moisture Content (%) Relative Compaction (%) 66 6/8/2018 FB 3 -1.5 110.6 13.3 88 (Fail) 67 retest of 66 6/8/2018 FB 3 -1.5 117.5 12.5 94 68 6/8/2018 FB 3 -0.1 120.4 6.1 96 69 6/8/2018 FB 3 -0.1 120.3 11.1 96 70 7/18/2018 UT 4 -1.5 123.4 9.3 96 71 7/18/2018 UT 4 FG 122.2 8.8 96 72 7/18/2018 UT 4 -1.0 117.8 8.9 92 73 7/18/2018 UT 4 FG 118.6 9.1 93 (Fail) 74 retest of 73 7/18/2018 UT 4 FG 121.6 9.9 95 75 7/19/2018 B 5 -0.3 131.1 4.5 96 76 7/19/2018 B 5 -0.3 133.7 7.1 98 77 7/20/2018 UT 4 FG 122.2 9.4 96 78 7/23/2018 UT 4 FG 124.0 11.0 97 79 7/25/2018 B 6 -0.3 128.9 4.8 96 80 7/25/2018 B 6 -0.3 128.5 5.2 96 81 7/25/2018 B 6 -0.3 127.9 4.5 95 82 7/31/2018 UT 3 45.0 129.2 11.9 92 83 7/31/2018 UT 3 47.0 113.8 11.7 91 84 7/31/2018 UT 3 FG 124.5 9.0 99 85 7/31/2018 UT 3 45.0 111.5 12.7 89 (Fail) 86 retest of 85 7/31/2018 UT 3 45.0 115.8 11.8 92 87 7/31/2018 UT 3 46.0 118.8 11.8 95 88 7/31/2018 UT 3 FG 123.6 7.3 99 89 8/1/2018 B 6 -0.3 128.4 5.0 96 90 8/1/2018 UT 6 -0.3 128.2 5.9 96 91 8/1/2018 AC 8 FG 141.7 - 97 92 8/1/2018 AC 8 FG 146.0 - 100 93 8/1/2018 AC 8 FG 132.9 - 91 (Fail) 94 retest of 93 8/1/2018 AC 8 FG 139.8 - 96 95 8/1/2018 UT 3 -0.5 123.9 7.5 99 96 8/1/2018 UT 3 -0.5 119.5 10.8 95 97 2/13/2019 B 7 -0.3 133.4 5.4 98 98 2/13/2019 B 7 -0.3 135.6 5.9 100 Project No. 8432.1 Log No. 20628 TABLE I SUMMARY OF FIELD DENSITY TESTS (ASTM: D 1556 and D 6938) Test No. Test Date Remarks Soil Type Elevation (feet)** Dry Density (pcf) Moisture Content (%) Relative Compaction (%) 99 2/13/2019 AC 8 FG 140.7 - 96 100 2/13/2019 AC 8 FG 139.6 - 96 101 2/13/2019 AC 8 FG 139.5 - 95 102 2/13/2019 AC 8 FG 139.8 - 96 103 2/19/2019 UT 3 -1.3 110.3 15.3 88 (Fail) 104 retest of 103 2/19/2019 UT 3 -1.3 115.1 10.9 92 105 2/19/2019 UT 3 -0.8 116.8 9.0 93 106 3/19/2019 SW 3 FG 126.0 7.7 100 107 3/19/2019 SW 3 FG 112.5 8.4 90 108 3/19/2019 SW 3 FG 126.8 7.6 100 109 3/19/2019 SW 3 FG 125.5 10.3 100 110 3/19/2019 SW 3 FG 122.4 9.6 98 111 3/19/2019 SW 3 FG 125.8 6.1 100 112 3/27/2019 SW 3 FG 121.4 5.7 97 113 3/27/2019 SW 3 FG 113.0 10.7 90 114 3/27/2019 SW 3 FG 115.4 13.2 92 115 3/27/2019 SW 3 FG 116.9 7.9 93 * Indicates Sand Cone Method ASTM: D 1556, all others Nuclear Density Method ASTM: D 6938 **Negative sign followed by number indicates depth below existing grade AC: Asphalt Concrete B: Aggregate Base FB: Footing backfill FG: Finish Grade UT: Utility trench backfill SW: Sidewalk subgrade Project No. 8432.1 Log No. 20628 TABLE II SUMMARY OF MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT DETERMINATIONS (ASTM: D 1557A) Soil Type Description Maximum Dry Density (pcf) Optimum Moisture Content (%) 1 Red brown silty sand 131.0 9.0 2 Aggregate base (import)123.5 12.5 3 Red brown silty sand (import) 125.5 11.0 4 Green gray slightly silty sand (import) 128.5 10.0 5 Aggregate base (import)137.0 8.0 6 Aggregate base (import)134.0 7.0 7 Aggregate base (import)136.0 6.0 TABLE III SUMMARY OF BULK SPECIFIC GRAVITY/DENSITY OF COMPACTED HOT MIX ASPHALT (Caltrans Test Method 308) Asphalt Concrete Type Description HMA Density (pcf) Optimum Moisture Content (%) 8 203 3B3 PG64-10 Asphalt Concrete 146.0 ----