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Home My WebLink AboutCDP 2017-0023; SHERIDAN PLACE; FINAL SOILS REPORT; 2018-06-26Project No. FC-18-06-132 June 26, 2018 IE General Engineering Mr. Matt Parker 1440 Beaumont A venue, Suite A2-130 Beaumont, California 92233 §.lfl§ GEOTECHNICAL SOLUTIONS, INC. Consulting Geotechnical Engineers & Geologists 593 1 Sea Lion Place, Suite I 09 Carlsbad, California 920 I 0 Office: 760-602-7815 smsgeosol.inc@gmail.com Report of Geotechnical Engineering Observations And Compaction Testing, Remedial Pad Grading, Proposed Single-Family Residential Development, 3913 Sheridan Place, Carlsbad, California Submitted herewith please find the following summary report of our geotechnical engineering observations and compaction testing completed by our firm in connection with the remedial grading for the proposed new building pad at the above-referenced property. Approximate limits of the compacted fill areas at the property are delineated on the enclosed Approximate Compaction Tests Location Map (Figure 1 ), reproduced from the project available grading plan. Overall, remedial grading operations for the project new building pad development chiefly consisted of removals of the upper soft and compressible soils to the underlying dense undisturbed Terrace Deposits, but not less than 3 feet minimum, and placing back the removed soils as properly compacted fills to achieve final pad grades. Remedial pad grading operations within the designated limits were performed under engineering observations and compaction testing services provided by this office from June 6, 2018 through June 20, 2018. I. REFERENCES The following pertinent reports and documents prepared by this office were used as a basis of our engineering observations and compaction testing services. 1. "Preliminary Grading Plan, 3 913 Sheridan Place, Carlsbad, California," prepared by bHA, Inc., dated June 1, 2017. 2. "Geotechnical Investigation, Proposed Single-Family Residence, Sheridan Place, Carlsbad, California (APN 206-042-47-00)," prepared by SMSGeotechnical Solutions Inc., Project No. GI-17-02-107, dated March 27, 2017. Report of Geotechnical Engineering Observations and Compaction Testing Remedial Pad Grading, 3913 Sheridan Place, Carlsbad, California II. GEOTECHNICAL CONDITIONS June 26, 2018 Page2 Geotechnical conditions at the project property were found to be substantially the same as described in the referenced report. In general, pre-remedial grading conditions consisted of a mostly natural to locally disturbed, relatively level ground surfaces. The project property was generally underlain by a relatively shallow section ofloose and compressible undifferentiated topsoil/disturbed natural ground, on the order of 2.5 feet thick, over dense silty sandstone Terrace Deposits. III. LABORATORY TESTING Pertaining maximum dry densities and optimum moisture contents (ASTM D1557) for the onsite representative soil types were obtained from the project Geotechnical Investigation report, dated March 27, 2017. (see References). An additional maximum dry densities and optimum moisture content test was performed on a sample of minor import soils needed to complete grading and achieve final design pad grades. Pertinent test results are summarized in the enclosed Compaction Test Results sheet. IV. GROUND PREPARATION AND GRADING OPERATIONS Prior to the remedial grading operations, any surface vegetation, roots and tree stumps were removed and cleared for the project areas, as appropriate. Upper surficial soft and compressible soils within the Approximate Limits of Pad Grading areas (see attached Approximate Compaction Tests Location Map, Figure 1) encompassing the main and detached accessory building envelope plus a minimum of 3 feet outside the perimeter were then stripped and removed. Removals were extended to a minimum depth of 3 feet below rough finish pad grade, exposing the underlying dense natural Terrace Deposits throughout. All exposed bottom of removals and over-excavations were visually examined, and probed to assure competent Terrace Deposits exposures suitable for receiving new fills. Minor sandy import soil from a local export site was needed to complete grading and achieve design pad grades. Earth deposits generated from the onsite removals and remedial grading operations as well as the imported soils were manufactured into a uniform mixture predominantly consisting of sandy to silty sand (SM/SP) deposits ranging to very low expansion potential (Expansion Index less than 20) based on ASTM D4829 classification. Site new fills were moisture conditioned to or slightly above the optimum moisture levels, depending on the final manufactured fill mixtures, processed into uniform materials, placed in thin ( approximately 8 inches thick) horizontal lifts and mechanically compacted with heavy construction equipments, consisting of a Case 921F Wheel Loader, Ingersoll Rand DD-24 double drum roller, and a Bobcat to a minimum 90% of the corresponding laboratory maximum density per ASTM D1557. Water was provided with a fire hose. Report of Geotechnical Engineering Observations and Compaction Testing Remedial Pad Grading, 3913 Sheridan Place, Carlsbad, California June 26, 2018 Page3 Engineering observation of the grading operations and compaction testing of the fills placed within the remedial grading areas were provided by this office from June 6 through 20, 2018. Approximate limits of the remedial pad grading works and field compaction test locations, as roughly established in the field by a hand level and pacing/tap measure form staking provided by others, or relative to identifiable features located at the site and noted on the project plans are shown on the enclosed Approximate Compaction Tests Location Map, Figure 1. Field density tests establishing both the in-place dry densities and moisture contents were performed in accordance with the ASTM D 1556 (Sand Cone) and ASTM D693 8 (Nuclear Gauge) test methods, as the fill placement progressed. Test locations were placed to provide the best possible coverage. Areas oflow compaction, as indicated by the field density tests, were brought to the attention of the project contractor. These areas were reworked by the contractor and retested. Field compaction test results including pertinent bottom of over-excavation and test elevations are tabulated on the enclosed Compaction Test Result sheet. Engineering observations and compaction test results indicated that the fills within the approved areas (see Approximate Limits of Pad Grading on the enclosed Approximate Compaction Tests Location Map, Figure 1) were properly placed and compacted to at least 90% of the corresponding maximum dry density at the tested locations. Site preparations and remedial pad grading were conducted in substantial conformance with Chapter 18 (Soils and Foundations) and Appendix "J" (Grading) of the 2016 California Building Code (CBC), applicable codes, the Grading Ordinance for the city of Carlsbad and current engineering standards, as appropriate. All observations and testing were conducted by a representative from this office under direct supervision of the project geotechnical engineering. V. CONCLUSIONS AND RECOMMENDATIONS In our opinion, site excavations, remedial building pad grading operations, fill placement and compaction procedures were completed in substantial conformance with the project approved plans, city of Carlsbad grading ordinances, applicable codes and current engineering standards, and are acceptable for their intended use. All conclusions and recommendations including soil design parameters, geotechnical foundation/slab designs and improvement sections provided in the referenced Geotechnical Investigation report dated March 27, 2017 stay unchanged, as specified therein and should be considered in the final designs and implemented during the construction phase, where applicable and as appropriate. VI. ADDITIONAL GEOTECHNICAL OBSERVATIONS AND TESTING This office should be notified before any of the following operations begin in order to schedule appropriate testing and/or field observations for confirmation and approval of the completed work: Report of Geotechnical Engineering Observations and Compaction Testing Remedial Pad Grading, 3913 Sheridan Place, Carlsbad, California June 26, 2018 Page4 1. Foundations and Utility Trenches: Engineering observations or testing will also be required for the following work prior to foundation and slab concrete pours: a) Observe the plumbing and utility trenches after the pipes are laid and prior to backfilling. Backfill soils within trenches 12-inches or more in depth shall be compacted by mechanical means to a minimum of 90% of the corresponding maximum dry density, unless otherwise specified. Jetting or flooding of the backfill is not allowed. Care should be taken not to crush the utilities or pipes during the compaction of the trench backfill. b) Test the plumbing trenches beneath the floor slabs for minimum compaction requirements prior to sand and moisture barrier placement. c) Observe the bottom of the footing trenches for proper compaction levels, and design minimum footing widths and embedment. e) Confirm footing reinforcement size and placement, slab thickness and reinforcing, sand thickness and moisture barrier placement. 2. Fine Grading and Improvements: a) Observe placement and perform compaction testing for fills placed under any conditions 12 inches or more in depth, to include: • Pad perimeter contour grading for establishing positive (minimum 2%) drainage away from the building. • Utility and storm trench backfills. 0 Retaining wall back drainage and backfills compaction testing. Minimum 90% compaction levels are also required for wall backfills. 0 Spreading or placement of soil obtained from any excavation (spoils from footings, underground utilities, etc.). b) Observation and testing of subgrade (and base layer, if any required) in the access driveway areas, perimeter side yards and beneath patios, sidewalks, etc., prior to placement of finish paving or concrete surface. c) Any operation not included herein which requires our testing, observation, or conformation for submittal to the appropriate agencies. Report of Geotechnical Engineering Observations and Compaction Testing Remedial Pad Grading, 3913 Sheridan Place, Carlsbad, California VII. DRAINAGE June 26, 2018 Page 5 The owner/developer is responsible for insuring adequate measures are taken to properly finish grade the building pad after the structures and other improvements are in-place so that the drainage waters from the graded pad and improved sites as well as adjacent properties are directed away from the new building foundations. Stormwater and swface run off water should not be allowed to impact or saturate natural and graded ground surfaces, fills and backfills, foundation bearing and sub grade soils. Only the amount of water to sustain vegetation life should be provided. A minimum of 2% gradient should be maintained away from all foundations. Roof gutters and downspouts should be installed and all discharge from downspouts should be led away from the foundations and slab to a suitable location. Install area drains in the yards for collection and disposal of surface water. Planter areas adjacent to foundations should not to allowed. Site retaining walls should be provided a well-constructed back drainage. Planting large trees behind site retaining walls and near the building foundations should be avoided. It should be noted that shallow groundwater conditions may develop in areas where no such conditions existed prior to site development. This can be contributed to by substantial increases of surface water infiltration resulting from landscape irrigation which was not present prior to the site development. It is almost impossible to absolutely prevent the possibility of shallow water conditions developed from excessive landscape irrigation over the entire site, and onsite drainage facilities. Therefore, we recommend that shallow water conditions, if developed, be immediately remedied by implementing appropriate measure, which may include the installation of sub-drain(s) consisting of a 4-inch diameter perforated pipe (SDR 35) surrounded in ¾-inch rocks all wrapped in filter fabric. The property owner(s) should be made aware that altering drainage patterns, landscaping, the addition of patios, planters, and other improvements, as well as over-irrigation and variations in seasonal rainfall, all affect subsurface moisture conditions, which in turn affect structural and overall slope performance. VIII. LIMITATIONS Our description of the remedial grading operations, as well as observations and testing services described herein, are limited to the work performed by this office during the period from June 6, 2018 through June 20, 2018. The recommendations provided herein have been based on our field observations and testing, as noted. No representations are made as to the quality or extent of materials not observed and tested. Report of Geotechnical Engineering Observations and Compaction Testing Remedial Pad Grading, 3913 Sheridan Place, Carlsbad, California June 26, 2018 Page 6 All geotechnical information, test location and mapping on the enclosed Approximate Compaction Tests Location Map are based on rough field measurements for the purpose of geotechnical presentations only. This report is issued with the understanding that the owner or his representative is responsible for ensuring that the information and recommendations are provided to the project architect/structural engineer and respective contractors so that they can be incorporated into the plans and implemented at the site. Necessary steps shall be taken to ensure that the project general contractor and subcontractors carry out such recommendations during construction. The project geotechnical engineer should also be provided the opportunity to field verify the foundation trenching, and foundations/slab steel reinforcement prior to placing concrete. If the project geotechnical engineer is not provided the opportunity of making these reviews and observations, he can assume no responsibility for misinterpretation of his recommendations. This report should be considered valid for permit purposes for a period of six months and is subject to review by our firm following that time. IF ANY CHANGES ARE MADE IN THE FINAL PAD SIZE, LINES AND GRADES, BUILDING LOCATION, ELEVATIONS, ETC., PRIOR TO THE CONSTRUCTION, THIS REPORT WILL BECOME INVALID AND FURTHER ENGINEERING AND RECOMMENDATIONS WILL BECOME NECESSARY. If you have any questions or need clarification, please contact this office at your convenience. Reference to our Project No. GI-18-06-132 will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. §1'.I§ Geotechnical Solutions, Inc. Distribution: Addressee (3, e-mail) Attachments: Approximate Compaction Tests Location Map, Figure 1 Compaction Test Results Sheet 61'16 GEOTECHNICAL SOLUTIONS, INC. PROJECT NO: PROJECT NAME: PROJECT LOCATION: COMPACTION TEST RESULTS FC-18-06-132 Sheridan Place Single-Family Residence 3913 Sheridan Place, Carlsbad LABORATORY MAXIMUM DRY DENSITY/ OPTIMUM MOISTURE CONTENT TEST RESULTS (ASTM 01557): Soil Type (2): Tan to Red-Brown Silty Sand. Soil Type (3): Medium Brown Silty Sand (Import). Maximum Dry Density: 129 .0 pcf Maximum Dry Density: 119 .0 pcf Optimum Moisture: 10% Optimum Moisture: 9% Note: Also see the project Geotechnical Investigation Report dated March 27, 2017 for different Soil Types. FIELD COMPACTION TEST RESULTS, ASTM D1556 (SAND CONE) AND ASTM D6938 (NUCLEAR GAUGE) TEST METHODS: Approximate Approximate Field Field Max. Relative Test Test Dry Soil Dry Date No. Test Elevation (MSL) Moisture Density Type Density Compaction Comments Location (ft) (%) (pct) (pct) (%) 06/06/2018 1 Northerly Pad/Building Areas 48.00'± 11 117.8 2 129.0 91 Bottom ofover-ex. @47.00'± 06/06/2018 2 Northerly, Garage Areas 48.00'± 11 116.8 2 129.0 91 06/07/2018 3 Southeasterly Pad Areas 48.00'± 11 116.5 2 129.0 90 Bottom of over-ex. @47.00'± 06/07/2018 4 Central, Building Areas 48.00'± 9 117.2 2 129.0 91 06/07/2018 5 Southwesterly, Spa Areas 48.00'± 8 116.6 2 129.0 90 06/20/2018 6 Northeasterly, Garage Areas Finish Pad Grade 8 117.8 2 129.0 91 06/20/2018 7 Northerly, Building Areas Finish Pad Grade 8 117.9 2 129.0 91 06/20/2018 8 Northwesterly, Accessory Finish Pad Grade 8 117.1 2 129.0 91 Building Areas 06/20/2018 9 Westerly Pad Areas Finish Pad Grade 9 118.1 2 129.0 92 06/20/2018 10 Southeasterly Building Areas Finish Pad Grade 10 116.l 2 129.0 90 06/20/2018 11 Central Building Areas Finish Pad Grade 8 108.8 3 119.0 91 §M§ GEOTECHNICAL SOLUTIONS, INC. 49.0J FS 48.27 IE 4" PVC/J" REDUCER 48.JJ IE )6-042-26 / I 0.5 " ' -I 6.250' . Bott. of over-ex. @ 47 .00'+ MAIN BUILDING _/,<:) .... . -~-,, LOT 16 50.50 FF ! 5D.00 PAO. __ ,,,,,, --- / 0. X LANDSCAPING 0 •~ N2839'00"W 61.69' MAP NO. 4751 LOT 15 L EXISTING BUILDING I 1.0 I '; / EXISTING FENCE TO BE REM0\1£D 8' PUBLIC UTILITY EASEMENT PER MAP NO. 4751 I C C.l i ; ~x1s!J ;~LiJ i> I 2+59.5J 49.78 FS 4' PVC SEWER LA TERA! \ I I FIGURE 1 GEOTECHNICAL LEGEND ,.--., i i t,_,J @] ApproL Limits of Pad Grading ApproL Compaction Test Location