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HomeMy WebLinkAboutMS 2018-0012; THREE ON CHERRY; FINAL SOILS REPORT; 2024-08-09August 9, 2024 Danny Googin, Project Field Inspector 1635 Faraday Avenue Carlsbad, California 92008 SUBJECT: Dear ·Mr. Googin: File No. 1106E6-22 Final As Graded Report Proposed Residential Building Site 160 Cherry A venue City of Carlsbad P.O. Box 1195 Lakeside, California 92040 (619) 443-0060 In accordance with your request, our firm has inspected the grading operation and tested the removal of the existing fill soils that were replaced and compacted during the preparation of the subject side. The attached report summarizes the soil conditions encountered and the density test results obtained during the grading operation. The work was completed on June 28, 2024. This report also provides conclusions and recommendations regarding foundation and slab construction for the proposed three single family residences Our function consisted of providing the engineering services involved with determining the degree of compaction of fill placed on the site in accordance with the recommendations set forth in the Geotechnical Investigation prepared by Toro International dated September 1 7, 2021, Project No. 03-125.7. The grading was performed for the purpose of recompacting existing fill soils and to create level building pads for the three proposed single family residences. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, ?'~ Cc:f?S Chin C. Chen RPE C34442 CCC/mlj June 08, 2024 David Mezzacappa 6910 Oregon A venue La Mesa, California 91942 SUBJECT: File No. 1106E6-22 Final Paver Observation for Grading Plan, Drawing No. 530-4A, Project No. MS 2018-0012 P.O. Box 1195 Lakeside, California 92040 (619) 443-0060 Proposed Triplex Residential Building with three individual owners. 160 Cherry A venue City of Carlsbac;I Dear Mr. Mezzacappa: This letter is in accordance with your request for the Construction Change, pervious concrete to interlocking concrete pavers. During the construction of the permeable interlocking concrete pavement system (pavers) for the driveway portion, a member of our firm observed that the pavers were installed per the manufactures recommendations and to industry standards per the stormwater standards as a Best Management Practice (BMP) and Low Impact Development (LID) tool to reduce runoff and water pollution. The following items were reviewed, observed and inspected by a member of our firm, Soil Testers. • Pre-con meeting with the owner, contractor and Soil Testers staff engineer. • Excavation of the traffic area size and marking that conform to the grading plan. • All runoff is diverted away from the units and grade conforms to the grading plan. • Ensured the linear sediment barrier used" Tencate Mirafi N140". • Geotextile Installation by contractor: • Meets specifications-sediment barrier used" Tencate Mirafi N140", five inches per hour drainage/infiltration. • Placement with down slope overlap (minimum two feet) by. • Side of excavation covered with geotextile prior to placing aggregate base/rock no. 57, or subbase-Class II. 1 David Mezzacappa File No. 1106E6-22 June 08, 2024 • Within all foundation systems of the structure, a waterproof membrane was installed within the first five feet. To avoid any wicking of moisture through the soil back into the foundation system. Manufacture specification was 15 mil. Stego a vapor barrier material taped at the joints with four inches red tape. Over the vapor barrier, class II base was placed and compacted to a minimum of 90% relative compaction. • No tears, holes. • Surface tolerance of the set pavers deviate no more than +/-3/8 under a 10 ft. long straightedge or wrinkles, with a string line pulled taut and taped to the foundation or spiked. • No impermeable liner specified, and no drains or observations wells installed. • Contractor submitted the manufacturers specifications and test results meeting the Fire H20 loading to the Geotechnical Consultant. • Elevation, placement, and materials meet specifications per the approved grading plan. • Elevations, slope, laying pattern, joint widths, and placement/compaction approved by Geotechnical Consultant. • No cut paver subject to tire traffic is less than 1/3 of a whole paver. • Final Observation by the Geotechnical Consultant: • Surface swept clean. • Transitions to impervious paved areas separated with edge restraints. • Checking slope for directional drainage and looking for design ponding for infiltration. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, Chin C. Chen RPE C344Lt-2 CCC/jgr Cc, Antony K. Christensen, PE. Civil, email. File 2 May 24, 2023 David Mazzacappa 6910 Oregon A venue La Mesa, California 9194 2 Subject: Dear Mr. Geldert: File No. 1106E6-22 Report of Compacted Filled Ground Proposed Residential Building Site 160 Cherry A venue City of Carlsbad P.O. Box 1195 Lakeside, California 92040 (619) 443-0060 In accordance with your request, our firm has inspected the grading operation and tested the fill soils that were placed and compacted during the preparation of the subject side. This is to report the results of our soil tests. The work was performed during the period between April 12, 2023 and May 15, 2023. The site is located at 160 Cherry A venue, City of Carlsbad To briefly summarize the work, we found the compaction of the fill soils to conform to the recommended and approved grading specifications and current standard practices. SECTION No. 1. SCOPE Our function consisted of providing the engineering services involved with determining the degree of compaction of fill placed on the site in accordance with the recommendations set forth in the Geotechnical Investigation prepared by Toro International dated September 17, 2021, Project No. 03-125.7. The results of the field density tests are presented on Page T-1 under "Table of Test Results". The laboratory determinations of the maximum dry densities and optimum moisture contents of the fill soils are set forth on Page L-1 under "Laboratory Test Results". The approximate locations of the filled ground and the field density tests are presented on Plate No. 1 entitled "Location of Field Density Tests". 1 David Mazzacappa File No. l 106E6-22 May 24, 2023 The grading was performed for the purpose of recompacting existing fill soils and to create level building pads for the three proposed single family residences. SECTION No. 2. SOIL CONDITIONS Soils used in the fill were those generated from the on-site excavation. EARTHWORK Preparation: Prior to placement of fill, the areas to receive fill were scarified, watered and compacted to 90 percent. Natural ground to receive fill was tested to determine its relative compaction. Native soils having a relative compaction of less than 85 percent were removed, replaced and compacted to 90 percent. Placing and compacting fill: Fill soil was placed, watered and mechanically densified in the areas indicated on attached Plate No. 1. During grading, any fill found to have a relative compaction of less than 90 percent was reworked until the proper density of 90 percent had been achieved. Field density test results: To verify compaction, field density tests·were performed in accordance with applicable American Society of Testing and Materials (ASTM) test methods. Test method ASTM D1556-82 was used at the indicated locations. SECTION No. 3. SUMMARY AND RECOMMENDATIONS Based on the work and tests described hereinbefore and work description set forth in Section 1, 'Scope', we conclude: 1. The filled ground has been compacted to 90%. 2. The placement of fill has been accomplished in accordance with the grading specifications and with current standard practices. 3. Spread footings will have a minimum allowable bearing value of at least 1750 pounds per square foot. The allowable bearing value will be considerably more for footings larger than 12 inches wide and/or 12 inches deep. If loads heavier than 17500 pounds per square foot for continuous footings are anticipated, we should be contacted for an increased bearing value. 4. Detrimentally expansive soils were not encountered. The following foundation depth is a recommendation based on the previously referenced report. 2 David Mazzacappa File No. 1106E6-22 May 24, 2023 ■ Use continuous exterior perimeter foundations (including door openings). They should be founded a minimum of 24 inches below lowest adjacent grade. ■ Interior footing depth should exceed 18 inches below top of slab or 18 inches below lowest adjacent grade for raised floor construction. ■ Reinforce continuous concrete foundations as a beam with at least one #5 bar positioned 3 inches above the bottom of footing and one #5 bar positioned at least 1 inch below top of foundation or top of finish floor. 5. Concrete Slab-On-Grade should be designed by the project's structural engineer based on anticipated loading conditions. Please see the previously referenced report for additional information. We also recommend that a moisture barrier be provided by a membrane, visqueen 10 mils in minimum thickness or equivalent, be placed at top of well compacted Class II Aggregate Base, between 4 inches of moist clean sand. Floor slabs, as a minimum, should be 5 inches thick with #3 reinforcing steel at 18" on-center each way. Reinforcement should be placed at mid-height of the slab. The final slab thickness and reinforcement should be determined by the structural design engineer. Control joints should be provided in accordance with the recommendations of the structural design engineer. SITE EROSION CONTROL During the construction, surface water should be controlled via berms, gravel bags and/or sandbags, silt fence, straw wattles, siltation basins, while maintaining positive surface grades or other methods to avoid damage to the finish work or adjoining properties. All site entrances and exits must have coarse gravel or steel shaker plates to minimize offsite sediment tracking. Best management Practices (BMP's) must be used to protect storm drains and minimize pollution. The contractor should take measures to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. After completion of grading, all excavated surfaces should exhibit positive drainage and eliminate areas where water might pond. 3 David Mazzacappa File No. 1106E6-22 May 24, 2023 SITE AND SURFACE DRAINAGE Drainage at the site should be directed away from foundations, collected and tight lined to appropriate discharge points. Consideration may be given to collecting roof drainage by eave gutters and directing it away from foundations via non-erosive devices. Water, either natural or from irrigation, should not be permitted to pond, saturate the surface soils or flow towards the foundation. Landscaping requiring a heavy irrigation schedule should not be planted adjacent to foundations or paved areas. The type of drainage issues found within the project and materials specified and used should be determined by the Engineer of Record. GROUNDWATER AND SURFACE WATERS There was no indication of a near-surface groundwater table within our exploratory trench or perched groundwater. Although groundwater is not expected to be a significant constraint to the proposed development, our experience indicates that near-surface groundwater conditions can develop in areas where no such groundwater conditions previously existed, especially in areas where a substantial increase in surface water infiltration results from landscape irrigation or unusually heavy precipitation. It is anticipated that site development will include appropriate drainage provisions for control and discharge of surface water runoff. The type of drainage issues found within the project and materials specified and used should be determined by the Civil Engineer. The type of plants and soil specified along with proper irrigation used should be determined by the Landscape Architect. SECTION No. 4. LIMITATIONS UNIFORMITY OF SOIL CONDITIONS: The values presented in this report are based on our evaluation of the observed, exposed soil conditions. We have assumed that the soil conditions in the remaining portions of the site can be interpolated without significant deviation in physical properties. We have made a conscientious effort to select representative test locations and to provide enough tests for a statistically adequate population in excess of current standard practices. However, parameter values may be substantially different in other areas due to unforeseeable variations in the soils. Also, the parameters are affected in time by the moisture-expansion (volume)-pressure changes that seriously affect the tested values. ENGINEERING INTERPRETATION: We are available for consultation and should be made aware of any pertinent condition or problem. Our conclusions will be re-evaluated and any problem or potential problem solved with a minimum effort and cost before it gets out-of-hand. 4 David Mazzacappa File No. l 106E6-22 May 24, 2023 TIME LIMITS: This report presents conclusions and findings that are valid as of this date. Changes on this site and adjacent property including grading, improvements, drainage, erosion, etc. may directly affect th~ findings, conclusions and recommendations presented herein. Subsequent alterations or conditions may invalidate these recommendations and values. The values in this report will probably remain applicable for one year provided the site conditions remain unaltered. After this period, we should be contacted to inspect the site and review this report so that we may verify its validity. WARRANTY: Certain risks are involved with geotechnical and soil engineering work, which should be recognized by those involved. We have performed our services in accordance with current standard practices and procedures. These practices and procedures are those presently utilized by members of our profession in this region. We do not express or imply a warranty or guarantee regarding these services. OUTSIDE RESPONSIBILITY: It is the responsibility of the client (firm or person to whom this report is submitted) to ensure that the information presented herein is made available to the concerned parties. In addition, it is the client's responsibility to make certain that any construction reflects any applicable requirements and conforms with the current codes of jurisdictive governmental agencies. PROJECT CONCEPT: We should be notified of any changes in the proposed structures, construction, or site grading, or project concept so that any addendum or modifications to this report may be provided as necessary. SOIL TEST METHODS: Summary of the GRADING SPECIFICATIONS USED for Proposed Residential Building Site 160 Cherry A venue City of Carlsbad Maximum Density & Opt Moisture Density of Soil In-Place ASTM D1557-78 ASTM D1556-82 Soil Expansion Shear Strength Gradation & Grain Size 5 UBC STANDARD 29-2 ASTM D3080-72 ASTM Dl 140-71 David Mazzacappa Capillary Moisture Tension LIMITING SOIL CONDITIONS: Minimum Compaction Expansive Soils Insufficient Fines Oversized Particles PREPARATION FOR FILL: File No. 1106E6-22 ASTM D2325-68 90% for "disturbed" soils. (Existing fill, newly placed fill, plowed ground, etc.) 85% for natural, undisturbed soils. May 24, 2023 95% for pavement subgrade within 2' of finish grade and pavement base course. Expansion index exceeding 20 Less than 40% passing the #4 sieve. Rocks over 10" in diameter. Brush, trash, debris and detrimental soils were cleared from the area to receive fill. Detrimental soil was removed to competent soil. Slopes exceeding 20% were stepped with benches 1 O' or greater in width. The area to be filled was scarified to a 6" depth and compacted. FILL MATERIAL: Contained sufficient fines and did not contain oversized particles or excessive organics. Special attention was given to the disposition of any oversized rock, organic soils and expansive soils. Please read this report carefully. If you have any questions, please contact our office. This opportunity to be of service is sincerely appreciated. Page L-1, Page T-1 and Plate No. I are parts of this report. Respectfully submitted, CCC/mlj 6 David Mazzacappa File No. 1106E6-22 May 24, 2023 Page L-1 LABORATORY TEST RESULTS The maximum dry densities and optimum moisture contents of the fill materials as determined by the A.S.T.M., Dl557-07, Method A, which uses 25 blows of a 10 pound rammer falling from a height of 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot compaction cylinder, are presented as follows: Soil Type 1 Brown, Fine SAND Maximum Dry Density lb./cu.ft. 123.5 Optimum Moisture Content dry wt. 10.5 David Mazzacappa Page T-1 DEPTH OFFILL TEST SOIL ATTEST NO. TYPE IN FEET 1 1 +2 2 1 +2 3 1 +2 4 1 +2 5 1 +3 6 1 +3 7 1 f.g. 8 1 f.g. 9 1 f.g. 10 1 +2 11 1 f.g. f.g. = finish grade File No. 1106E6-22 TABLE OF TEST RESULTS A.S. T .M., D 1556-82 FIELD DRY MOISTURE DENSITY % P.C.F. 8.2 121.9 9.7 118.8 8.4 120.5 7.4 119.9 8.1 119.6 6.5 117.1 6.9 116.4 7.5 116.8 7.0 117.4 5.2 118.5 5.6 114.9 May 24, 2023 MAXIMUM DRY DENSITY PERCENT P.C.F. COMPACTION 123.5 98.7 123.5 96.2 123.5 97.6 123.5 97.1 123.5 96.8 123.5 94.8 123.5 94.3 123.5 94.6 123.5 95.1 123.5 96.0 123.5 91.1 LOCATION OF FIELD DENSITY TESTS NO SCALE e FIELD DENSITY TEST COMPACTED FILL PLATE I 5-23-23 P.O. BOX 1195 LAKESIDE, CA 92040