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Home My WebLink AboutCT 74-04; Quail Ridge Phase 4; Soils Report; 1983-03-09- CT 74-G l Ph 4 ase - INCORPORATED ENGINEERS ANDGEOLOGISTS l CONSULTANTSINTMEAPPLIEDEARTM SCIENCES - - - - - - - - File No. D-0684-MO2 March 9, 1983 Standard Pacific of San Diego 7290 Clairemont Mesa Boulevard San Diego, California 92111 Attention: Mr. Sam Thompson Subject: Quail Ridge Carlsbad, California Pad Drainage Criteria Gentlemen: In accordance with your request we have reviewed the "Grading Plan and Plot Plan for Carlsbad Tract No. 74-4, Quail Ridge" prepared by Rick Engineering Company and dated June 8, 1981. The purpose of this review is to evaluate the locations of the drainage swales on the finished building pads and to comment on the conformance of the plans to the requirements of the City of Carlsbad Engineering Department. The City of Carlsbad drawing entitled "Typical Lot Grading" Supplemental Standard No. GS-15 indicates that drainage wales should be a minimum of five (5) feet away from buildings. Our review of the plans indicates that several loots will have drainage swales between four (4) feet and five (S) feet away from the buildings, In our opinion, the placement of the drainage wales at a minimum of four (4) feet from the building is acceptable from a geotechnical standpoint and should not cause a detrimental effect on the building pads. Alllots should be finish graded after the structures and other improvements are in place so that drainage waters from the lots and adjacent properties are directed off the lots and to the streets away from building foundations, floor slabs and slope tops. - If you have questions or desire additional information, please contact the undersigned. Very truly yours, GEOCON, INCORPORATED - &w pb aI@ ]a4 RCE 28188 - - MRR:pr (4) addressee 53 PI l n 9530 DOWDY DRIVE l SAN DIEGO, CALIFORNIA 92126 l PHONE (714) 695.2880 I’ - GEOCON INCORPORATED ENGINEERSANDGEOLOGISTS l CONSULTANTSINTHEAPPLIEDEARTM SCIENCES - - - .- - - - - - File No. D-0684-MO2 March 8, 1983 Standard Pacific of San Diego 7290 Clairemont Mesa Boulevard San Diego, California 92111 Attention: Mr. Sam Thompson Subject: QUAIL RIDGE LOTS 215 THROUGH 219 (MODEL LOTS) CARLSBAD, CALIFORNIA TESTING AND OBSERVATION SERVICES DURING GRADING OPERATIONS; PARTIAL FINAL REPORT OF GRADING Gentlemen: In accordance with your request and our proposal dated November 24, 1982, we have provided engineering observation and testing services during grading of the subject lots as part of our engineering services during grading of the Quail Ridge subdivision. Our services included: . observing the grading operation including the removal and/or processing of loose topsoil and uncompacted fill soils; . performing in-place density tests in the placed and compacted fill; . performing laboratory tests on representative samples of the material used for fill; and . providing professional opinions in regard to the contractor's general adherence to the plans and specifications. Locations and elevations presented herein are based on the "Grading Plan for Carlsbad Tract No. 74-4, Quail Ridge" prepared by Rick Engineering Company and dated June 8, 1981 and stakes set by the contractor's grade checker. n 9530 DOWDY DRIVE . SAN DIEGO, CALIFORNIA 92126 l PHONE (714) 695-2880 - - - - - .- - -. - - - - - File No. D-0684-MO2 March 8, 1983 As part of the grading, the site was cleared of organics and other surface debris. Grading of the lots consisted of excavating loose topsoils, preparing the areas to be filled and making cuts and fills to design grade. The subject lots are design cut-fill transition lots. During grading, the cut portion of the lots were undercut 2 feet and the material was moisture conditioned and then properly recompacted. In-place density tests were performed during grading to help evaluate the relative compaction of the placed fill. Field observations and the results of the in-place field density tests indicate that the fill has generally been compacted to at least 90 percent of maximum laboratory density as determined in accordance with ASTM D1557-70. Laboratory tests were made on representative samples of the material used for fill. Tests were performed to evaluate moisture-density relationships and maximum dry density and optimum moisture content. The results of the laboratory tests are shown on Table I. The results of the in-place density tests are shown on Table II. The in-place density test results have been extracted from the tests from the ongoing site grading and no attempt has been made to renumber these tests. The approximate locations of the in- place density tests have been recorded on a copy of the grading plans for reference. Our visual inspection indicates that the material within 2 feet of rough lot grade can be classified as nonexpansive to slightly expansive. CONCLUSIONS AND RRCOMMF.NDATIONS 1. Based on our observations, it is our opinion that the subject lots have been satisfactorily graded in accordance with the recommendations contained in our "Soil and Geologic Investigation, Quail Ridge, Carlsbad, California" dated November 5, 1976 and our addendum letters dated December 15, 1982 and January 6, 1983. 2. We recommend that footings founded in nonexpansive to slightly expansive, properly compacted fill soils be designed for an allowable soil bearing pressure of 2000 psf when founded at 12 inches below lowest adjacent grade. Footings should have minimum widths of 12 inches. This pressure may be increased by up to one-third for transient loads such as wind or seismic forces. 3. Continuous footings should be reinforced with two No. 4 reinforcing bars, one placed near the top of the footing and one placed near the bottom. -2- GEOCON INCORPORATED - - - - .- - .- - File No. D-0684-MO2 March 8, 1983 4. Concrete slabs-on-grade should have a nominal thickness of 4 inches and should be reinforced with 6x6-10/10 welded wire mesh placed at the slab midpoint. The slabs should be underlain by 4 inches of clean concrete sand. Where moisture sensitive floor coverings are planned, a visqueen moisture barrier with a 2-inch sand covering should also be employed. 5. The recommended reinforcement presented above is based on soil condf- tions only and is not intended to be in lieu of reinforcement necessary to satisfy structural loadings. 6. Footings should not be located within 8 feet of the top of slopes. Footings that must be located in this zone should be extended in depth until the outside bottom edge of the footing is at least 8 feet from the face of the slope. LIMITATIONS Each lot should be finish graded after the structures and other improve- ments are in place so that drainage waters from the lots and adjacent properties are directed off the lots and away from building foundations, floor slabs, and slope tops. Even when such drainage is provided, a shallow or near-surface ground-water condition can, and may, develop in areas where no such ground-water condition existed prior to site develop- ment. This is particularly true in residential developments where a substantial increase in surface water infiltration results from landscape irrigation. We will accept no responsibility for any subsequent changes made to the site by others or by the uncontrolled action of water or by the failure of others to properly repair damages caused by the uncontrolled action of water. The conclusions and recommendations contained herein apply only to our work with respect to grading, and are based on conditions at the conclusion of our fulltime observation. Any subsequent grading should be done under our observation and testing. Subsurface conditions and the accuracy of tests used to measure such conditions can vary greatly at any time. Therefore, our opinion means only that we performed our services in such a manner as to have reasonable certainty that the work essentially complies with the job specifications. We make no warranty, expressed or implied, except that our services were performed in accordance with engineering principles generally accepted at this time and location. -3- GEDCON rNCORPOR*TED - - - - - - - - - - - File No. D-0684-MO2 March 8; 1983 If you have any questions, please contact the undersigned. Very truly yours, GEOCON, INCORPORATED RCE 28188 MRR:MWR:lm (4) addressee -4- GJ3OCON INCORPORATED - File No. D-0684-MO2 March 8, 1983 TABLE I Sumnary of Laboratory Compaction Test Results Soil Max. Dry Density Optimum Moisture iTYkE Source & Description pcf % dry wt. 10 Tan, Clayey SAND 127.9 9.4 11 Red-b?qm, Clayey SAND 126.0 10.2 - - Date Tcrist - WNo. 314 91 - 92 93 - - 315 94 95 96 - 97 90 - 99 100 - 317, 101 102 103 - 104 105 - 318 106 107 - 108 109 - 110 TABLE II Summary of Field Density Test Results Dry Dens. Moisture Rel Comp. Soil Type Location & Elevation pcf % dry wt. x of max. & Remarks Lots 2171218 293 122.4 10.4 96 10 Lots 2151216 298 123.2 8.5 96 10 Lots 218/219 293 123.0 9.4 96 10 Lots 216/217 300 119.0 12.4 93 10 Lots 2151216 301 122.2 12.7 95 10 Lot 218 297 122.6 12.2 97 11 Lot 217 301 119.7 10.4 95 11 Lot 216 303 124.0 10.7 97 10 Lot 215 304 120.8 10.0 95 11 Lot 215 FG 306 117.1 12.1 91 10 Lot 216 Slope 301 118.4 11.7 94 11 Lot 216 FG 308.8 120.9 12.4 95 11 Lot 217 FG 302.5 i21.6 11.3 95 10 Lot 218 FG 299.4 120.5 13.3 94 10 Lot 219 FG 296 119.5 11.7 93 10 Lot 215 305 120.1 11.7 94 10 Lot 216 304 117.6 10.5 92 10 Lot 217 302 118.9 10.5 94 11 Lot 218 299 120.5 9.4 94 10 Lot 219 295 119.3 10.7 93 10 GEDCON INCORPORATEO