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Home My WebLink AboutCDP 15-35; JAMES RESIDENCE; AS GRADED GEOTECHNICAL REPORT; 2000-11-28AS-GRADED GEOTECHNICAL REPORT Martinet Property 4111 Park Drive, Parcel 2 Carlsbad, California RECEIVED DEC 10 2015 CITY OF CARLSBAD BUILDING DIVISION Fi HETHERINGTON ENGINE4NG, INC. C215•q3 HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING ENGINEERING GEOLOGY' HYDROGE.OLOGY November 28, 2000 Project 3720.1 Log, No. 7150 Mr. Ed Martinet 2380 Camino Vida Roble, Suite F .1: Carlsbad, CA 92009 Subject: AS-GRADED GEOTECHNICAL REPORT 41ll Park Drive, Parcel 2 Carlsbad, California References: Attached Dear Mr. Martinet: In accordance with your request, we have performed geotechmcal services in conjunction with grading of the subject site Our services consisted of observation and testing during grading laboratory testing, and the preparation of this report which presents the results of our testing and observations, and our conclusions and recommendations. GRADING OPERATIONS Grading was performed during the period August 24 through September 7, 2000. Grading consisted generally of over-excavating existing unsuitable topsoil and colluvium, and placement - of compacted fill to design site grades. Removals ranged from approximately 3 to 8 feet. The attached Plot Plan, Figure 1 indicates the approximate limits of removals, thickness of fill and locations of density tests. The earthwork was performed by Southwestern Heavy Equipment utilizing plans prepared by Sea Crest Engineering, Inc. (Reference 4). SITE PREPARATION Prior to grading, the site was cleared of surface obstructions, vegetation and debris. Following removal of unsuitable topsoil and colluvium, the exposed soils were scarified to a depth of 6 to 8 inches, brought to near optimum moisture conditions and recompacted to at least 90 percent - relative compaction as determined by ASTM: D 1557-91A. SOIL TYPES The soils utilized as fill consisted of on-site materials composed of dark brown to red brown silty F fine to medium sand and orange brown silty fine to medium sand. 5205 Avenida Encinas, Suite A a Carlsbad, CA 92008-4369. (760) 931-1917 ® Fax (760) 931-0545 32242 Paseo Adelanto, Suite C 9 San Juan Capistrano, CA 92675-3610 (949) 487-9060 • Fax (949) 487-9116 .. . : ...• AS-GRADED GEOTEC}ThTCAL REPORT Project No. 3720.1 November 28, 2000 Page 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 1557-91A. Compaction was achieved by track walking with a Caterpillar 975 loader and a Caterpillar D10 bulldozer in general accordance with the geotechnical guidelines presented in the referenced 'Preliminary Geotechnical Investigation..." (Reference 1). The approximate limits and thickness of compacted fill placement are shown on the attached Plot Plan, Figure 1. Density tests were performed in accordance with ASTM: D 1556 (Sand-Cone Method) and ASTM: D 2922 (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, Figure 1. Maximum dry density/optimum moisture content determinations are presented on the attached Summary of Maximum Dry Density/Optimum Moisture Content Determinations, Table II. Expansion and sulfate content test results are presented on the attached Tables III and IV. CONCLUSIONS AND RECOMMENDATIONS 1. General Based on our observations and the results of our testing, it our opinion that the subject grading has been performed in general conformance with the recommendations contained in the "Preliminary Geotechnical Investigation..." (Reference 1), and the requirements of the City of Carlsbad, California. Should future construction be planned for the areas outside of the limits of removals, additional geotechnical work will be necessary since unsuitable topsoil/colluvium remains in these areas. -. 2. Foundation and Slab Recommendations The proposed structure may be supported on conventional continuous footings founded in compacted fill. Footings should extend to a minimum depth of 18 inches. Footings located on or adjacent to slopes should be extended to sufficient depth to provide at least 10 feet of horizontal distance between the footings and the face of the slope. Footings located adjacent to utility trenches should extend below a 1:1 plane projected upward from the I I inside bottom corner of the trench. All footings should be reinforced with a minimum of two #4 bars, one top and one bottom. HETHENGTON ENGINEERING, INC. AS-GRADED GEOTECHNICAL REPORT Project No. 3720.1 November 28, 2000 Page 3 Footings bearing as recommended may be designed for a dead plus live load bearing value - of 2000 pounds per square foot. This value may be increased by one-third for loads including wind or seismic forces. A lateral bearing value of 250 pounds per square foot per foot of depth and a coefficient of friction between foundation soil and concrete of 0.4 may -: be assumed. These values assume that footings will be poured neat against the foundation soils. Footing excavations should be observed by the Geotechnical Engineer to ensure that they are founded in suitable bearing materials. Floor slabs should have a minimum thickness of 4-inches (actual) and should be reinforced with #3 bars spaced at 18-inches, center-to-center, in two directions, and supported on chairs so that the reinforcement is at mid-height in the slab. In areas where moisture sensitive floor coverings are planned, slabs should be underlain by at least 2-inches of clean sand over a 6-mil visqueen moisture barrier. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. 3. Retaining Walls Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 30 pounds per cubic foot, equivalent fluid pressure, assuming level backfill consisting of on-site soils. Walls restrained from movement at the top should be designed for an - additional uniform soils pressure of 8xH pounds per square foot where H is the height of the wall in feet Any additional surcharge pressure behind the wall should be added to these values. Retaining wall footings should be designed in accordance with the previous building foundation recommendations. Retaining walls should be provided with adequate drainage to prevent buildup of hydrostatic pressure and should be adequately waterproofed. A. Trench and Retaining Wall Backfill All trench and retaining wall backfill should be compacted to at 1ea.t 90 percent relative compaction and tested by the Geotechnical Engineer. 5. Flatwork Concrete flatwork should be at least 4-inches thick (actual) and reinforced with No. 3 bars placed at 18-inches on center (two directions) and placed on chairs so that the reinforcement is in the center of the slab. Slab subgrade should be thoroughly moistened prior to a placement of concrete. Contraction joints should be provided at 10 feet spacings (maximum). HETHERINGTOIU ENGINEERING INC. AS-GRADED GEOTECHNTCAL REPORT Project No. 3720.1 November 28, 2000 Page 4 6. Site Drainage The on-site soils are sandy in nature and susceptible to erosion. The following recommendations are intended to minimize the potential adverse effects of water on the structure and appurtenances. Consideration should be given to providing the structure with roof gutters and - downspouts. All site drainage should be directed away from the structure and not allowed to flow over slopes. C. No landscaping should be allowed against foundations. Moisture accumulation or watering adjacent to foundations can result in deterioration of wood/stucco and may effect foundation performance. d. Irrigated areas should not be over-watered. Irrigation should be limited to that required to maintain the vegetation. Additionally, automatic systems should be seasonally adjusted to minimize over-saturation potential particularly in the winter (rainy) season. C. All slope, yard, and roof drains should be periodically checked to verify they are not blocked and flow properly. This may be accomplished either visually or, in the case of subsurface drains, placing a hose at the inlet and checking the outlet for flow. 7. Recommended Observation and Testing During Construction The following testing and/or observations by the Geotecimical Consultant are recommended during construction: Footing excavations prior to placement of reinforcing steel. Interior (undersiab) utility trench backfill. a) Exterior utility trench backfills. r b) Retaining wall backfill. HETHERINGTON ENGINEERING, INCA AS-GRADED GEOTECHNTCAL REPORT Project No. 3720.1 November 28, 2000 Page 5 Type Cement for Construction Based on the results of sulfate tests, special provisions are not required for concrete in contact with on-site soils. Seismic Parameters for Structural Design The following seismic parameters are for use in the design of structural elements for the project. The basis for the following parameters is the geotechnical data that was previously presented in. our "Preliminary Geotechnical Investigation..." (Reference 1) as well as the data and guidelines presented in References 5 and 6. Seismic considerations that should be used for structural design at the site include the following: Ground Motions-- The proposed structure should be designed and constructed to resist the effects of seismic ground motions as provided in Chapter 16, Division IV-Earthquake Design of the 1997 Uniform Building Code. The basis for the design is dependant on and considers seismic zoning, site characteristics, occupancy, configuration, structural system and building height. Soil Profile Type - In accordance with Section 1629.3.1, Table 16-J, and the underlying geologic conditions, a site Soil Profile of Type S is considered appropriate for the subject property, C. Seismic Zone = In accordance with Section 1629.4.1 and Figure 16-2, the subject site is situated within Seismic Zone 4. Seismic Zone Factor (z) - A Seismic Zone Factor of 0.40 is assigned based on Table 16-I. Since the.site is within Seismic Zone 4, Section 1629.4.2 requires a Seismic Source Type and Near Source Factor. Near Source Factor (N3 and NL— Based on the known active faults in the region and distance of the faults from the site, a Seismic Source Type of B per Table 16- U, and Near Source Factors of N3 = 1.0 per Table 16-S and N,= 1.2 per Table 16- T are provided. Seismic Coefficients (C and C)_— Using the Soil Profile Type and Seismic Zone r Factor along with Tables 16-Q and 16-R, the Seismic Coefficients C3 = 0.40(Na) . and C = 0.56 (NJ are provided, or Ca = 0.40 and C. = 0.67. HETHPIIGTOJ ENGINEERING, INC. AS-GRADED GEOTECIThICAL REPORT Project No. 3720.1 November 28, 2000 Page 6 LIMITATIONS Our services were performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Soils Engineers and Geologists 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 appreciated. If you have any questions, please call our office. Sincerely, HETHENGTONE$ERING, INC. Civil Engineer 3048 Geotechnical En (expire 3/31/04) ( MDHJDC/ dkw Danny Cohen Civil Engineer 41 NO. 234 HETHERINGTON ENGINEERING, INC .- REFERENCES "Preliminary Geotechnical Investigation, Martinet Property, Proposed Parcel 2, 4111 Park Drive, Carlsbad, California," by Hetherington Engineering, Inc., dated April 25, 1991. "Grading Plan Review, Martinet Property, Parcel 2, MS8 12, Southeast End of James Drive, Carlsbad, California," by Hetherington Engineering, Inc., dated December 9, 1993. "Geotechnical Update, Martinet Property, Parcel 2, MS8 12, Southeast End of James Drive, Carlsbad, California," by Hetherington Engineering, Inc., dated June 22, 1995. "Grading Plans For: Ed Martinet, M.S. 812," by Sea Crest Engineering, Inc, dated November 28, 1995. "Probilistic Seismic Hazard Assessment for the State of California," DMG Open-File Report 96-08 and USGS Open-File 96-706, dated 1996. "1997 Uniform Building Code, Volume II, Structural Engineering Design Provisions," by lntetñational Conference of Building Officials, dated April 1997. HETHERUUGTON ENGINEERING, INC. TABLE I SUMMARY OF FIELD DENSITY TESTS Test Location ___ Test Date Soil Type Elevation (feet) _______ Dry Density (pci) Moisture Content (%) Relative Compac tion (%) * 8-24-00 2 132.5 105 12.9 82 2 ** 8-24-00 2 132.5 117 7.9 91 RT#1 3 ** 8-25-00 1 138 124 8.7 95 71 4 ** 8-25-00 1 141 126 7.8 97 5 ** 8-25-00 1 127 128 7.8 98 6 8-25-00 j_ 129 123 8.1 94 7 ** 8-25-00 1 130 119 6.8 92 8 ** 8-25-00 1 132.5 121 7.9 93 9 ** 9-8-00 2 FG 127 3.8 98 10 ** 9-8-00 2 FG 124 4.1 95 * ASTM: D 15,)6 (Sand-Cone Method) ASTM: D 2922 (Nuclear Method) TABLE 11 SUMMARY OF MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTFT DETERMINATIONS (ASTM: D 1557-91A) Optimum Maximum Dry Moisture Density Content Soil Type Description (pct) (%) 1 Dark brown to red brown silty sand 129 9.0 2 Orange brown silty sand 130 9.0 TABLE III EXPANSION TEST RESULTS (ASTM: D 4829) Soil Initial Compacted Final Expansion Expansion Type Moisture Dry Moisture Index Potential (%) Density (%) (pci) 1 7.8 118 13.3 0 Very Low TABLE IV SULFATE TEST RESULTS (EPA 9038) Soil Type Soluble Sulfate in Soil (%) 1 0.0058 Project No. 3720.1 Loa No. 7150 p LEGEND O APPROXIMATE LOCATION OF DENSITY TEST 125.00 APPROXIMATE BOTTOM ELEVATION OF REMOVALS APPROXIMATE LIMITS OF REMOVALS 0. 1 2 o io 20 30 40 g 1ypicgL C HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS Martinet Lot Grading PROJECT NO. 3720.1 I FIGURE NO. 1 - --•••- I I