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Home My WebLink AboutCT 77-02; HOSP GROVE UNIT 3; GRADING AND TESTING; 1981-06-053467 Kurtz Street San Diego. California 92110 714-224-2911 Woodward-Clyde Consultants June 5, 1981 Project No. 592072-FC02 Broadmoor Homes, Inc. 3911 Sorrento Valley Boulevard San Diego, California 92126 Attention: Mr. James Carter FINAL REPORT OF ENGINEERING OBSERVATION OF GRADING AND TESTING OF COMPACTED FILL WOODWRIDGE PHASE II CARLSBAD TRACT 77-2, UNIT 3 LOTS 70 THROUGH 103 CARLSBAD, CALIFORNIA Gentlemen: In accordance with your reguest, and our proposal dated January 22, 1981, we have provided engineering services in conjunction with the grading of the subject site. SCOPE OF WORK Our services included: ° Providing engineering observation of the grading operation, ° Providing engineering and geologic observation of alluvial removal, ° Performing field density tests in the placed and compacted fill, ° Performing laboratory tests on representative samples of the material used for fill, and ° Providing professional opinions regarding the contractor's general adherence to plans and specifications. ^ RECEIVED Consulting Engineers, Geologists and Environmental Scientists Offices in Otner Principal Cities riTY OF CARLSBAD Engineering Ueo^ • Broadmoor Homes, Inc. June 5, 1981 Project No. 592072-FC02 Page 2 Woodward'Clyde Consultants SUMMARY OF GENERAL EARTHWORK AND TESTING Site preparation, compaction, and testing were done between December 22, 1980 and May 8, 1981. In our opinion, based on our observation and testing, the work performed during that period was in general conformance with the Specifications for Controlled Fill attached to our report entitled "Soil and Geologic Investigation for the Proposed Carlsbad Tract No. CT 77-2," dated July 19, 1979. During the grading period, fill was placed, compacted, and tested on fill Lots 70 through 72 and cut-fill Lots 73, 81 through 84, 99 and 100. Lots 102 and 103 have been left in their natural state. Lots 74 through 80, 85 through 98, and Lot 101 are cut lots. The grading operation generally consisted of removing alluvial and loose surface soils, scarifying, watering, and compacting areas to receive fill and making cuts and fills to design grade. During the grading operation, compaction procedures were observed, and field density tests were made to help evaluate the relative compaction of the placed fill. Field observations and results of field density tests indicate that the fill has been generally compacted to 90 percent or more of maximum laboratory dry density as determined in accordance with ASTM Test Method No. D1557-70. For reference, the approximate locations of field density tests and the limits of compacted fill have been recorded on a copy of the grading plan. The results of field density tests, expressed as a percent of laboratory dry density (relative compaction), are given on the attached forms. Laboratory tests were made on representative samples of the materials used for fill. The tests were performed to evaluate moisture density relationships, maximum dry density, optimum moisture content, grain size distribution, plasticity and swell characteristics. The results of laboratory tests are attached. SUMMARY OF FINISH GRADE SOIL CONDITIONS Fill Lots and Fill Portion of Cut-Fill Lots Inifipection and laboratory tests indicate that nonexpansive fill was 5^1 aced within two feet of rough grade on all fill lots noted herein. Broadmoor Homes, Inc. June 5, 1981 Project No. 592072-FC02 Page 3 Woodward'Clyde Consultants Cut Lots and Cut Portion of Cut-Fill Lots Cut lots and cut-fill lots were inspected at the completion of grading. The inspection indicated tJiat no expansive soil is evident at rough grade surface. Nonexpansive soil is soil which swells less than three percent when compacted to 90 percent of the maximum laboratory compaction density at optimun water content under a surcharge of 160 psi. RECOMMENDATIONS Foundations for Structures on Nonexpansive Soils We recommend that foundations for single- or two-story, multi- dwelling, residential structures placed on nonexpansive, undisturbed soil or on nonexpansive, properly compacted fill be designed for a bearing pressure not exceeding 2,000 psf (dead plH^.,.a4l^ loads). We rppommend that footihfs Bef founded at •^SmlsiSi 1*!'^^®^ belbw fihished grade ahd havfe a minimum width df 12' inaii&s. In our opinion, this bearing pressure can be increased by no more than one-third for loads that include wind or seismic forces. Slopes Fill slopes at the site have varying inclinations of approximately 1-1/2:1 to 2:1 (horizontal to vertical), and are approximately 10 feet high. Fill slopes were treated by over filling, rolling with a sheepsfoot compactor and cutting back to design grade. . recoBttiend that structures that will not tolerate ^il itittr^ foundations, swiramihg pools, concrete decks, walls, etc.) not be located within eight feet of 1;he top of a slope. We recommend that footings that are located within eight feet of the top of a slope be extended in deptliL uhtil the outer bottom edge of the footing is eight feet horiz6litally from -the outside face of the slope. Additional Fill and Utility Trenches This report discusses the fill placement observed by personnel from our firm during the period specified. We recommend that any additional fill placed, as well as backfill placed in utility trenches located within five feet of a building and deeper than 12 inches, or backfill placed in any trench located Broadmoor Homes, Inc. June 5, 1981 Project No. 592072-FC02 Page 4 Woodward'Clyde Consultants five feet or more from a building and deeper than five feet, be compacted under our observation and tested to verify compliance with the eartJiwork specifications for the project. We should be contacted at least 24 hours prior to backfilling operations. Drainage We recommend that positive measures be taken to properly finish grade each lot after structures and other improvements are in place, so that drainage waters from the lot and adjacent properties are directed off the lot and away from foundations, floor slabs, and slope tops. Even when these measures are taken, a shallow ground water or surface water condition can and may develop in areas where no such water condition existed prior to site development; this is particularly true where a substantial increase in surface water infiltration results from landscape irrigation. LIMITATIONS The elevations of compaction tests shown as finished grade (FG) tests on the attached forms correspond to tJie elevations shown on the "Grading Plan for Carlsbad Tract #77-2, Unit 3," dated February 14, 1980, prepared by Roy L. Klema Engineers, Inc. Elevations and locations used in this report were based on field surveys done by others. The soil conditions described in this report are based on observations and periodic testing. This office should be notified of any indications that soil conditions are not as described herein. We will inspect foundation excavations for each lot if we are requested to do so. For this report, rough lot grade is defined as that grade set in the field by the grade checker from reference stakes established by the surveyor, and represents rough grade at the time we were inspecting the grading operation. The conclusions and opinions drawn from the test results and site inspections apply only to our work with respect to grading, and represent conditions at the date of our final inspection. We will accept no responsibility for any subse- quent changes made to this site by others, or by uncontrolled action of water, or by failure of others to properly repair damages by uncontrolled action of water. Broadmoor Homes, Inc. June 5, 1981 Project No. 592072-FC02 Page 5 Woodward'Clyde Consultants If you have any questions, please give us a call. Very truly yours, WOODWARD-CLYDE CONSULTANTS Steven C. Haley R.E. 18577 SCH/DT/rs Attachments (4) COMPACTION TEST RESULTS JOil NAME WOODRIDGE PHASE II, UNIT 3 DATE REPORTED 6/5/81 JOB NUMBER 592072-FCO2 DATES COVERED JANUARY 19, 1981 THROUGH MAY 8, 1981 PACE 2. or 1 DATl n •T nrrcsT LOCATION ELEVATION OF TEST HOimiMI eOMTCPIT % mmrwt. PltLS MMSITT LA»0«ATOKV KKLATIVK MMSITT COMPACTION rcr % or LAB. DIM*. JAN 19 1 LOT 71 180 13.0 111.5 121.0 92 2 II 70 184' 13.6 110.1 121.0 91 3 II 72 188 ' 13.0 117.8 128.C 92 JAN 20 4 LOT 71 186' 12.3 117.2 128.0 91 5 " 72 192' 13.0 114.0 123.0 92 6 It 73 194' 12.3 112.6 123.0 96 JAN 21 7 LOT 70 194' 11.1 114.0 123.0 92 8 II 84 190' 13.0 114.2 121.0 94 9 II 82 192 ' 11.7 111.0 121.0 91 JAN 22 10 LOT 99 196' 11.7 110.8 121.0 91 11 II 100 198' 12. 3 117.8 128.0 92 FEB 4 12 LOT 81 UPPER FG 193.5' 13.0 112.6 123.0 91 13 II 82 FG 193.2' 11.7 112.3 123.0 91 14 tl 83 FG 193.2' 13.0 112.9 123.0 91 15 II 84 FG 192.8 12. 3 111.5 123.0 90 FEB 5 16 LOT 73 FG 195.3' 13.6 118.4 128.0 92 17 II 7-: FG 195.3' 10.5 116.4 128.0 90 FEB 6 18 LOT 71 LOWER FG 187.0' 11.7 116.1 128.0 90 19 11 70 FG 187.0' 11.7 116.5 128.0 91 FEB 24 20 LOT •70 UPPER FG 196.0' 12.3 118.4 128.0 92 21 II 71 FG 196.0 12. 3 118.1 128.0 92 MAY 8 22 LOT 99 FG 199.6-12.3 117.0 128.0 91 23 II 100 FG 199.e 13.0 118.2 128.0 92 Wpodward'CtydeCon«ultaiits ^ PLASTICITY CHARACTERISTICS 1 2 3 Liquid Limit, % 32 22 24 Plasticity Index, % 16 3 12 Classification by Unified Soil Classification System SC SM SC 150 ZERO AIR VOIDS CURVES -2.80 SG 2.70 SG 2.60 SG 2.50 SG 110 COBBLES GRAVEL SAND c 1 f c| m 1 f SILT 4 CLAY 100 100 80 60 40 20 0 V \ Y 3 V \\ 1 • 2 V _J— 1 J 1 1 11 -i 1 1000 100 10 1.0 0.1 0.01 0.001 GRAIN SIZE, mm MECHANICAL ANALYSIS DIRECT SHEAR TEST DATA 1 2 3 Dry Density, pcf Initial Water Content, % --- Final Water Content, % --- Apparent Cohesion, psf — — — Apparent Friction Angle, degrees -- SWELL TEST DATA 1 2 3 Initial Dry Density, pcf --118 Initial Water Content, % — _ 11 Final Dry Density, pcf --116 Final Water Content, % --15 Load, psf --160 Swell, percent --1.5 SAMPLE LOCATION 1 LOT 130, CANYON BOTTOM 2 CUT LOTS 123-128 3 CUT LOTS 90-98 10 20 30 LABORATORY COMPACTION TEST LABORATORY COMPACTION TEST METHOD: ^S™ ^ " ^57 70 A FILL SUITABILITY TESTS WOODRIDGE PHASE II, UNIT 2 DRAWN BY: ch 1 CHECKED By:JV\(aft.PROJECT NO: 592072-FCO2 | DATE: 4/13/81 1 FIGURE NO: 1 WT 3/30/81 WOODWARD-CLYDE CONSULTANTS PLASTICITY CHARACTERISTICS 4 5 6 Liquid Limit, % -44 34 Plasticity Index, % NP 27 18 Classification by Unified Soil Classification System SM SC SC 150 ZERO AIR VOIDS CURVES -2.80 SG 2.70 SG 2.60 SG 2.50 SG COBBLES GRAVEL SAND SILT t CLAY COBBLES c 1 f c m 1 f SILT t CLAY 100 1000 100 10 1.0 0.1 0.01 0.001 GRAIN SIZE, mm MECHANICAL ANALYSIS DIRECT SHEAR TEST DATA 4 5 6 Dry Density, pcf -- Initial Water Content, % --- Final Water Content, % --- Apparent Cohesion, psf --- Apparent Friction Angle, degrees --Mfc 1 SWELL TEST DATA 4 5 6 Initial Dry Density, pcf 109 111 114 Initial Water Content, % 11 11 10 Final Dry Density, pcf 109 108 112 Final Water Content, % 15 18 16 Load, psf 160 160 160 Swell, percent .01 3.1 1.5 SAMPLE LOCATION 4 CUT LOTS 36-39 5 LOTS 42 & 43 6 BUTTRESS CUT W. OF 10 20 30 LABORATORY COMPACTION TEST LOTS 130-139 40 LABORATORY COMPACTION , TESTMFTHOn- ^STM b^lSl 70 A FILL SUITABILITY TESTS WOODRIDGE PHASE II, UNIT 2 ch I CHECKED BY: iVWH PROJECT NO: 592072-FCO2 | DATE: 4/13/81 | FIGURE NO; 2 DRAWN BY: WT 3/30/81 WOODWARD-CLYDE CONSULTANTS PLASTICITY CHARACTERISTICS 7 Liquid Limit, % - Plasticity Index, % NP Classification by Unified Soil Classification System SM 150 140 130 120 110 100 ZERO AIR VOIDS CURVES -2.80 SG 2.70 SG 2.60 SG 2.50 SG COBBLES GRAVEL SAND c f c| m 1 f SILT 4 CLAY 1000 100 10 1.0 0.1 0.01 0.001 GRAIN SIZE, mm MECHANICAL ANALYSIS DIRECT SHEAR TEST DATA 7 Dry Density, pcf - Initial Water Content, % - Final Water Content, % - Apparent Cohesion, psf - Apparent Friction Angle, degrees - SWELL TEST DATA 7 Initial Dry Density, pcf 115 Initial Water Content, % 9 Final Dry Density, pcf 115 Final Water Content, % 14 Load, psf 160 Swell, percent 0.4 SAMPLE LOCATION 7 BUTTRESS LOTS 130-139 10 20 30 LABORATORY COMPACTION TEST LABORATORY COMPACTION TEST METHOD: ASTM D 1557 70 A FILL SUITABILITY TESTS WOODRIDGE PHASE II, UNIT 2 DRAWN BY: 1 CHECKED BY: ,(y|C4l|-PROJECT NO: 592072-FCO2 | DATE: 4/13/81 1 FIGURE NO: 3 WT 3/30/81 WOODWARD-CLYDE CONSULTANTS