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HomeMy WebLinkAboutPD 2018-0032; NEWBY-PUZO RESIDENCE; FINAL SOILS REPORT; 2020-02-11 Prepared For: Mr. Brent K. Newby 12253 Carmel Vista Road, Suite 103 San Diego, California 92130 AS-GRADED GEOTECHNICAL REPORT FOREST AVENUE PARCEL 3 Carlsbad, California February 11, 2020 SCST No. 190126N Report No. 2 Mr. Brent K. Newby 12253 Carmel Vista Road, Suite 103 San Diego, California 92130 Subject: AS-GRADED GEOTECHNICAL REPORT FOREST AVENUE PARCEL 3 1373 FOREST AVENUE CARLSBAD, CALIFORNIA 92008 GRADING PERMIT – GR2018-0044 APN-156-110-84-00 Dear Mr. Newby This report summarizes the results of the geotechnical observation and testing services that SCST, LLC (SCST), an Atlas company, performed during earthwork construction for the building pad at the subject project. In our opinion, the soil engineering and engineering geologic aspects of the grading are in compliance with the approved geotechnical report and the grading plan, Drawing No. 515-1A (referenced). If you have any questions, please call us at (619) 280-4321. Respectfully submitted, SCST, LLC Isaac Chun, GE 2649 Dan Ferguson Principal Engineer Geotechnical Field Supervisor PFL:IC:ds (1) Addressee via e-mail: bnewby@mccarthy.com A•• At!!. ____..,., I L } 1 :::» ----- ~c s ii SCST, LLC Corporale Headquarlers + 6280 Riverdale Street + San Diego, CA 92120 T 877.215.4321 + P 619.280.4321 + r: 619.280.4717 + w www.scst.com TABLE OF CONTENTS SECTION PAGE 1. INTRODUCTION ..................................................................................................................... 1 2. SCOPE OF WORK ................................................................................................................. 1 3. SITE DESCRIPTION ............................................................................................................... 1 4. PROJECT DESCRIPTION ...................................................................................................... 1 5. SITE PREPARATION AND GRADING .................................................................................. 1 6. AS-GRADED GEOLOGIC CONDITIONS .............................................................................. 2 7. FIELD OBSERVATIONS AND TESTING ............................................................................... 2 8. SITE IMPROVEMENTS .......................................................................................................... 2 9. FOUNDATIONS ...................................................................................................................... 2 10. CONCLUSIONS ...................................................................................................................... 3 11. LIMITATIONS ......................................................................................................................... 3 12. REFERENCES ........................................................................................................................ 4 ATTACHMENTS TABLES Table 1 .................................................................................................... Compaction Test Results Table 2 ...................................................................................................... Laboratory Test Results FIGURES Figure 1 ................................................................................................................ Site Vicinity Map Figure 2 .................................................................................................................. As-Graded Map 1 1. INTRODUCTION SCST, LLC (SCST), an Atlas company, is pleased to present the results of our geotechnical observation and testing services provided during earthwork construction for the subject project between May 15, 2019 and December 24, 2019. The purpose of our work was to observe the geotechnical conditions exposed during grading and evaluate conformance of the geotechnical aspects of earthwork construction with the project plans and geotechnical recommendations. 2. SCOPE OF WORK SCST provided observation and compaction testing services during earthwork construction to prepare the building pad for the subject development in accordance with the recommendations of the referenced geotechnical report (Reference 2). To support the field testing, representative samples of the material used for fill, backfill and pavement construction were tested in our laboratory. Field dailies were prepared at the end of each day summarizing our observations and testing. Our services did not include the supervision or direction of the actual work performed by the contractors. 3. SITE DESCRIPTION The project site is located on Forest Avenue between Pio Pico Drive and Highland Drive in Carlsbad, California. Figure 1 presents a site location map. The site is bordered by residential homes to the north, east and west, and the Las Flores Church Parking lot to the south. Prior to construction, the site elevations ranged from about 146 to 160 feet above mean sea level (MSL). After grading, site elevations ranged from about 146 to 160 feet. 4. PROJECT DESCRIPTION The project consisted of the construction of a single-family residence with a garage and associated hardscape areas with a finished floor elevation of about 153.50 feet. Surface improvements consisted of underground utilities and a driveway for site access. The new driveway connects to an existing driveway belonging to the home to the north of the site. 5. SITE PREPARATION AND GRADING Site preparation began with the removal of existing improvements, vegetation, and debris. Prior to grading, the site was underlain by residual soil and old paralic deposits. Grading consisted of excavating the residual soil beneath the building pad to expose competent old paralic deposits. Additionally, old paralic deposits within 2 feet of the deepest planned footing bottom level was over-excavated to create a relatively uniform layer of compacted fill beneath the building and reduce the potential for differential settlement. The grading contractor scarified, moisture conditioned, and compacted the surface exposed at the bottom of grading excavations. Fill was moisture conditioned and compacted until planned elevations were reached. Compaction was achieved by means of a track loader. 2 Forest Avenue Parcel 3 Carlsbad, California SCST Project No. 190126N-02 Brent K. Newby February 11, 2020 6. AS-GRADED GEOLOGIC CONDITIONS In our opinion, the geologic conditions observed at the site were generally as anticipated to those described in the project geotechnical report (Reference 2). As observed during grading, the site was underlain by residual soils and old paralic deposits. The residual soils were removed to expose dense old paralic deposits. Compacted fill was derived from on site and imported materials. The as-graded geologic conditions are depicted on Figure 2. Descriptions of the materials are presented below. Fill (Qaf): Compacted fill derived from on site and imported materials consist of silty sand were placed during grading. The fill soils have a low expansion potential. The fill overlies competent old paralic deposits. Residual Soils – Residual soils are the result of in-place weathering of the parent rock. The residual soil at the site consisted of loose silty sand. The soil extended to depths up to 3 feet below the existing ground surface. Old Paralic Deposits (Qop): The old paralic deposits consisted of dense, poorly indurated silty sandstone. Groundwater: Groundwater was not observed during grading. Future site irrigation may alter the groundwater conditions, resulting in unpredictable perched water and seepage. Groundwater conditions may also change in the future due to broken pipes or rainfall. 7. FIELD OBSERVATIONS AND TESTING A representative of SCST performed periodic field observations and compaction tests during the site improvement operations. Field density (compaction) tests were performed in accordance with ASTM D6938 and D2950 (nuclear gauge). Table 1 presents the compaction test results, and Figure 2 presents the approximate compaction test locations. Maximum dry density and optimum moisture content tests were performed on soil samples in accordance with ASTM D1557. Hveem density determinations were performed on representative samples of the asphalt concrete used in general accordance with ASTM D1560. The results of these tests were used in conjunction with the field density tests to determine the degree of relative compaction of the materials. The laboratory test results are presented in Table 2. 8. SITE IMPROVEMENTS Site improvements consist of utility trench backfill, a sewer lift station, and pavements. The sewer lift station consists of a 4 feet diameter, approximately 10 feet deep fiberglass basin with submersible pumps and guide rails located to the west of the building. The sewer lift station and utility trench backfill was observed on a periodic basis. Fills were placed in relatively thin lifts, ~ + '1 ------------ii _ ............. ,_ 3 Forest Avenue Parcel 3 Carlsbad, California SCST Project No. 190126N-02 Brent K. Newby February 11, 2020 moisture conditioned to near optimum moisture content, and compacted until field density tests indicated a minimum of 90% relative compaction. The upper 12 inches of subgrade soils beneath pavements were scarified, moisture conditioned to near optimum moisture content, and compacted until field density tests indicated a minimum of 95% relative compaction. Aggregate base was placed over the prepared subgrade and compacted using vibratory steel-drum rollers. Asphalt concrete was placed over the compacted base course using conventional paving equipment, then compacted with steel drum rollers. Tests performed by our field representative indicated relative compaction values of at least 95% relative compaction. 9. FOUNDATIONS We observed foundation excavations to evaluate conformance with the project geotechnical recommendations. The foundations consist of shallow spread footings. The foundations were excavated to the minimum recommended depth and reached suitable bearing materials consisting of compacted fill. The fill soils generally consist of silty sand. Our laboratory test results indicate that these soils generally have a low expansion potential, as anticipated in the referenced geotechnical report (Reference 2). 10. CONCLUSIONS In our opinion, the soil engineering and engineering geologic aspects of the grading are in compliance with the approved geotechnical report and the grading plan, Drawing No. 515-1A. The conclusions contained herein are based on our geotechnical observation and compaction testing services performed between the dates indicated. In general, our observations confirm that the subsurface conditions and bearing materials are in substantial conformance with the project geotechnical report. The bearing materials are considered suitable for support of the structure. No representations are made to the quality and extent of materials not observed or materials not in conformance with the project specifications or our geotechnical recommendations. 11. LIMITATIONS This report covers only the services that SCST performed between the dates indicated. Our opinions are based on our observations and the relative compaction test results and are limited by the scope of the work that we agreed to perform. As used herein, the term "observation" implies only that we observed the progress of work for which we were involved. We performed field density tests, which in conjunction with our observations, were the basis for our opinion as to whether the work was performed in substantial conformance with the project documents. Horizontal and vertical control was provided by the contractor. The accuracy of the grading limits and elevations are based on work by others. The accuracy of the test locations and elevations is a function of the accuracy of the topographic and ~ + ~ii------------- 4 Forest Avenue Parcel 3 Carlsbad, California SCST Project No. 190126N-02 Brent K. Newby February 11, 2020 lateral control provided by others. Their locations and elevations were determined by pacing and hand level methods and should be considered accurate only to the degree implied by the method used. Our work was performed in accordance with the currently accepted standard of practice and in such a manner as to provide a reasonable measure of the compliance of the grading and backfill operations with the project requirements. No warranty, express or implied, is made or intended with respect to the work that we have performed, and neither the performance of this work nor the submittal of this report should be construed as relieving the contractor of their responsibility to conform with the project requirements. Our work was generally performed on an “on-call” basis. Therefore, the in-place density tests performed by our field representative can only be construed as representative of the areas tested as shown on the attached figures. 12. REFERENCES 1. Apollo Structural (2019), Structural Foundation Details, SD1.1, January 22. 2. BWE (2019), Grading Plan for Newby-Puzo Residence (Drawing No. 515-1A). 3. SCST, LLC. (2019), Geotechnical Investigation, Proposed Residential Development – Parcel 3, Forest Avenue, Carlsbad, California, SCST No. 180318N3-1R, February 13. ~ + ~ii------------- Table 1 - Compaction Test ResultsClient:Project:Test Method: ASTM D 6938ASTM D6938 / D2950San Diego, California 92130Test #Test DateTest Type Test LocationElevation (feet)Proctor IDMoisture Content (%)In-Place Density (pcf)Relative CompactionSpecified CompactionPass/Fail1 5/16/2019GradingSoutheast area of building pad148 #1 9.2 123.5 93%90% PASS2 5/16/2019GradingSoutheast area of building pad148 #1 8.8 119.9 91%90% PASS3 5/17/2019GradingBuilding pad148 #1 7.8123.4 93%90% PASS4 5/17/2019GradingSlope, along north western edge of parcel151#1 9.2 120.7 91%90% PASS5 5/17/2019GradingSlope, along south edge of parcel150 #1 9.1 123.2 93%90% PASS6 5/21/2019GradingSouthern portion of building pad150 Imp#1 6.5 108.9 98%90% PASS7 5/17/2019GradingNorthwest of building pad149 #19.2 121.292%90%PASS8 5/17/2019GradingAdjacent to garage pad147 #1 9.1 122.893%90%PASS9 5/21/2019GradingGarage pad150 Imp#1 10.0 106.5 96%90% PASS10 5/31/2019 Other, See Location Details Sewer lift station backfill143 #1 9.2 119.5 90%90% PASS11 5/31/2019 Other, See Location Details Sewer lift station backfill145 #1 12.9 119.7 90%90% PASS12 5/31/2019 Other, See Location Details Sewer lift station backfill147 #1 9.2 118.5 90%90% PASS13 5/31/2019 Other, See Location Details Sewer lift station backfill149 #1 9.2 119.3 90%90% PASS14 5/31/2019 Other, See Location Details Sewer lift station backfill151 #1 9.0 121.9 92%90% PASS15 5/31/2019 Other, See Location Details Sewer lift station backfill151 #1 9.1 124.1 94%90% PASS16 5/31/2019 Other, See Location Details Sewer lift station backfill145 #1 9.2 120.3 91%90% PASS17 6/6/2019 Utility Trench Backfill: Sewer Service/Lateral North of garage pad151 Imp#1 9.4 100.2 90%90% PASS18 6/17/2019 Utility Trench Backfill: Sewer Service/Lateral Driveway, approximately 30 feet from Forest Avenue156 #1 5.6 123.7 93%90% PASS19 6/17/2019 Utility Trench Backfill: Sewer Service/Lateral Driveway, adjacent to garage of existing home155 #1 7.3 119.190%90%PASS20 6/13/2019 Utility Trench Backfill: Sewer Main 10 feet south of point of connection159 #1 9.9121.7 92%90% PASS21 6/13/2019 Utility Trench Backfill: Sewer Main 5 feet south of point of connection159 #1 10.2118.8 90%90% PASS22 7/26/2019Subgrade: PavementForest Avenue, utility trenchSG#1 8.6 125.2 95%95% PASS23 11/15/2019Subgrade: PavementUtility crossing on Forest AvenueSG#1 9.0 126.0 95%95% PASS24 11/15/2019Base: RoadwayUtility crossing on Forest AvenueABB-1 8.8 119.5 98%95% PASS25 12/11/2019Base: RoadwayDriveway, south approachAB B-18.5 117.596%95%PASS26 12/11/2019Base: RoadwayDriveway, north approachAB B-17.6 116.796%95%PASS27 12/24/2019Base: RoadwayDriveway, north endAB B-111.6 116.095%95%PASS28 12/24/2019Base: RoadwayDriveway, south endAB B-111.3 116.996%95%PASS29 11/18/2019Subgrade: PavementPaver areaSG #1 8.4 125.695%95%PASS30 11/18/2019Subgrade: PavementPaver areaSG #1 7.7 125.395%95%PASSAC1 7/26/2019Asphalt Base CourseForest Avenue, utility trenchAC AC1 - 140.0 98%95% PASSAC2 11/15/2019Asphalt Base CourseUtility trench crossing at Forest AvenueAC AC1 -142.0 99%95% PASSAC3 11/15/2019Asphalt Wear CourseUtility trench crossing at Forest AvenueAC AC2 -140.9 96%95% PASSAC4 11/19/2019Asphalt Wear CourseSouth driveway approachAC AC2 -138.7 95%95% PASSAC5 11/20/2019Asphalt Wear CourseNorth driveway approachAC AC2 - 139.3 95%95% PASSSCST LCC - San DiegoLEA: 47, Exp: 04/25/20216280 Riverdale StreetSan Diego, Ca 92120Phone: (619 ) 280-4321 / Fax: (619) 280-4717Brent K Newby12253 Carmel Vista RoadSuite 103190126N-2Forest Avenue Parel 3Carlsbad, CaliforniaTABLE 1Ill -- Table 2 - Laboratory Test ResultsClient:Brent K Newby12253 Carmel Vista RoadSuite 103Carlsbad, CaliforniaSan Diego, California 92130143.2AC1 (48931)Utility Trench CrossingAC2 (48945)3/4" Type III B31/2" Type III C2 Utility Trench Crossing146.7Test #B-1 (49118)Maximum Density and Optimum Moisture Summary (ASTM D1557)Test #Material Description Sample Location / Representative Area Unit Weight, pcfSoil DescriptionSCST LLC - San DiegoLEA: 47, Exp: 04/25/20216280 Riverdale StreetSan Diego, Ca 92120Phone: (619 ) 280-4321 / Fax: (619) 280-4717Hveem - Maximum Bulk Specific Gravity (Cal 308)Imp#1 (41182)111.4#1 (41526)132.3121.9SILTY SANDSILTY SANDRecycled Aggregate BaseMaximum Density, pcfProject:190126N-2Forest Avenue Parcel 3Optimum Moisture (%)8.17.29.6TABLE 2~~ -:~g PROJECT SITE©2019 OpenStreet Map1SITE VICINITY MAPForest Avenue Parcel 3Carlsbad, CaliforniaDate:Job No.:By:February, 2020190126N-2PFLSCST, LLCFigure:SCALE (feet)N7501,5000~ l :2 I ~, c, ~· 0 Buena Vista Lagoon Buena Vista way Knowles Avenue r· .................... -Cl Cynthia Lane ~ j Knowles Avenue ~ E Buena Vista wa1 0 °' ~\ <:i'~ "{' (ll '"'~~ PJ' "~ I:? .,~ Carlsbad High Schoof SCST, LLCFigure:2AS-GRADED MAPForest Avenue Parcel 3Carlsbad, CaliforniaDate:Job No.:By:February, 2020190126N-2PFLSCST LEGEND:Reference:BWE (2019), Newby-Puzo Residence, Grading Plan, Sheet 5.SCALE (feet)N35 700Note: All locations are approximateApproximate Bottom Elevation(Mean Sea Level)26Approximate Location of In-PlaceDensity TestsApproximate Limits of Grading146514614614414414651465123456798101112131415161718192021222423AC2AC3AC1AC5AC4252627282930-I PARCEL I / A11411., / I F I I I I -,-1 I" I / / <=-!&-l 11.?Jn I PAF/CEL 2 Aj(3S91 ' D •