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Home My WebLink AboutCT 77-02; HOSP GROVE UNIT 4; ENGINEERING OBSERVATIONS OF GRADING AND TESTING; 1981-06-093467 Kurtz Street Woodwafcl'Clyde Consultants San Diego, California 92110 714^224-2911 June 9, 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 WOODRIDGE PHASE II CARLSBAD TRACT 77-2, UNIT 4 LOTS 104 THROUGH 129 CARLSBAD, CALIFORNIA Gentlemen: In accordance with your request, 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 con- tractor's general adherence to plans and specifications. Consulting Engineers Geologists and Environmental Scientists Offices in Other Principal Cities Broadmoor Homes, Inc. June 9, 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 1, 1981. In our opinion, based on our observation and testing, the work performed during that period was in general conformance with the Speci- fications for Controlled Fill attached to our report entitled "Soil and Geologic Investigation for the Proposed Carlsbad Tract No. CT 77-24," dated July 19, 1979. During the grading period, fill was placed, compacted, and tested on fill Lots 104 through 107, 115 through 121, and cut-fill Lots 113, 114, and 122 through 126. Lots 110, 111, and 112, and Lot 129 were left in their natural state. Lots 108, 109, 127, and 128 are cut lots. The grading opera- tion 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 observa- tions 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. Broadmoor Homes, Inc. June 9, 1981 Project No. 592072-FC02 Page 3 dward'Clyde Consultants SUMMARY OF FINISH GRADE SOIL CONDITIONS Fill Lots and Fill Portion of Cut-Fill Lots Inspection and laboratory tests indicate that non- expansive fill was placed within two feet of rough grade on all fill lots noted herein. Cut Lots and Cut Portion of Cut-Fill Lots Not Undercut Cut Lots and cut-fill Lots 113, 114, and 122 through 126 were inspected at the completion of grading. The inspection indicated that no expansive soil is evident at rough grade surface. Nonexpansive soil is soil that swells less than three percent when compacted at 90 percent of maximum labo- ratory desnity, surcharged with 160 psf, and submerged in water. 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 plus live loads). We recommend that footings be founded at least 12 inches below finished grade and have a minimum width of 12 inches. 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 ten feet high. Fill slopes were treated by over Broadmoor Homes, Inc. June 9, 1981 Project No. 592072-FC02 Page 4 WdOdward'Clyde Consultants filling, rolling with a sheepsfoot compactor, and cut back to design grade. We recommend that structures that will not tolerate differential settlements (such as foundations, swimming pools, concrete decks, walls, etc.) not be located within eight feet of the top of a slope. We recommend that footings that are located within eight feet of the top of a slope be extended in depth until the outer bottom edge of the footing is eight feet horizontally 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 five feet or more from a building and deeper than five feet, be compacted under our observation and tested to verify compliance with the earthwork 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 adja- cent 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 particu- larly true where a substantial increase in surface water infiltration results from landscape irrigation. [nc. Broadmoor Homes^^i June 9, 1981 Project No. 592072-FC02 Page 5 dward'Clyde Consultants LIMITATIONS The elevations of compaction tests shown as finished grade (FG) tests on the attached forms correspond to the elevations shown on the "Grading Plan for Carlsbad Tract #77-2, Unit 4," 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. If you have any questions, please give us a call. Very truly yours, WOODWARD-CLYDE CONSULTANTS Steven R.E.^^577 SCH/DT/eej Attachments (4)