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Home My WebLink AboutCT 83-04; WINDSONG SHORES PHASE 1; INTERIM REPORT OF AS BUILT GEOLOGY FIELD OBSERVATIONS AND TESTS; 1990-01-26I I I I I I I I I I I I I I I I I I I FE JJ81~4r INTERIM REPORT OF AS-BUILT GEOLOGY, FIELD OBSERVATIONS AND TESTS, PROPOaED WINDSONG SHORES PROJECT HARBOR DRIVE CARLSBAD, CALIFORNIA PREPARED FOR: Marlborough Development Corporation 28751 Rancho California Road, #208 Rancho California, California 92390 PREPARED BY: Southern California Soil & Testing, Inc. Post Office Box 20627 6280 Riverdale Street San Diego, California 92120 .. I I I I I I I I I I I I I I I I I I I SOUTHERN CALIFORNIA SOIL AND TESTING, INC. 6280 RIVERDAL.E ST. SAN DIEGO, CAL.IF. 92120 • TEL.E 280-4321 P.O. 80X 20627 SAN DIEGO, CAL.IF. 92120 678 ENTERPRISE ST. ESCONDIDO, CALIF". 92025 January 26, 1990 Marlborough Development Corporation 28751 Rancho California Road, #208 Rancho California, California 92390 SCS&T 8821027 Report No. 7 SUBJECT: Interim Report of As-Built Geology, Field Observations and Tests, Proposed Windsong Shores Project, Harbor Drive, Carlsbad, California. REFERENCE: Gentlemen: 1) "Report of Geotechnical Investigation, Windsong Shores, Carlsbad, California", by Southern California Soil & Testing, Inc., dated March 15, 1988. In accordance with your request, this report has been prepared to present a summary of our field observations and the results of relative compaction tests performed at the subject site by Southern California Soil & Testing, Inc. Our testing services were performed between October 24 and October 27, 1989. Our geologist's observations were made subsequent to the excavations for Lot 1 of the site. SITE DESCRIPTION The subject site is an approximate 10 acre parcel of land located at the southern terminus of Harbor Drive in the City of SOUTHERN CALIFORNIA SOIL AND TESTING, I N C. I I I I I I ,I I I I I I I I I I I I I SCS&T 8821027 January 26, 1990 Page 2 Carlsbad, California and a narrow strip of land located east of the proposed condominiums, parallel with AT&SF railroad right-of- way. The 10 acre condominium site is comprised of Lots 1 and 2. Only Lot 1 has been excavated at this time. Lot 2 is to be excavated in the future. As detailed in the referenced Geotechnical Report, the condominium area was lightly to heavily vegetated with both native and transplanted plants. S'oils encountered during the grading operations consisted of quaternary marine terrace deposits comprised of sands and silty sands. The narrow strip of land extending from the east side of the site northerly to Chinquapin Avenue is intended for use as an all- weather access road to the condominium site and to the'contiguous Y.M.C.A. Aquatic Facility. This area was not included in our Geotechnical Investigation for the site. Prior to grading, this area was devoid of significant vegetation. Existing soils consisted of locally derived undocumented fills and undisturbed terrace deposits. Earthwork in the area consisted primarily of filling an existing drainage channel that paralleled the AT&SF -railroad tracks. PROPOSED CONSTRUCTION It is our understanding that the site will be developed to receive a condominium complex consisting of two-story and three- story structures over single level underground parking garages. Shallow foundations as well as conventional slab-on-grade floor systems are anticipated. AVAILABLE PLANS To assist in determining the locations and elevations of our field density tests and to define the general extent of the site grading for this phase of work, we were provided with a grading I I I I I I I I I I I I I I I I I I I SCS&T 8821027 January 26, 1990 Page 3 plan prepared by Crosby Mead Benton & Associates of Carlsbad, California, dated October 3, 1989. SITE PREPARATION, ACCESS ROAD AREA Prior to the grading operations, vegetation was cleared from the area to receive fill and materials thus generated were exported from the jobsite. Soil obtained from cuts made on Lot 1 of the proposed condominium project were then placed in approximate six' to eight inch lifts, moisture conditioned to near optimum. moisture content, and compacted to a minimum of 90 percent relative compaction by means of heavy construction equipment. The existing undocumented fills were not removed prior to these operations. SITE PREPARATION, CONDOMINIUM AREA The grading operations on Lot 1 of the proposed condominium project consisted entirely of cuts to the designed finish grade elevations. The As-Built Geology section of this report pertains only to Lot 1 of the condominium site. The excavations on ~ot 2 are not complete. FIELD OBSERVATION AND TESTING Observations and field density tests were performed by a representative of Southern California Soil & Testing, Inc. during the site grading operations. The density tests were taken according to A.S.T.M. Test 1556-74 and the results of those tests are shown on the attached Plate No.2. The accuracy of the in- place density tests locations and elevations is a function of the accuracy of the survey control provided by other than Southern California Soil & Testing, Inc. representatives. Unless otherwise noted, their locations and elevations were determined I I I I I I I I I I I I I I I I I I I SCS&T 8821027 January 26, 1990 Page 4 by pacing and hand level methods and should be considered accurate only to the degree implied by the method used. As used herein, the term "observation" implies only that we observed the progress of work we agreed to be involved with, and performed tests, on which, together, we based our opinion as to whether the work essentially complies with the job requirements, local grading ordinances and the Uniform Building Code. LABORATORY TEST A maximum dry density determination was performed on a representative sample of the soils used in the compacted fills according to A.S.T.M. Test 1557-78, Method A. This method specifies that a four inch diameter cylindrical mold of 1/30 cubic foot volume be used and that soil tested be placed in five equal layers with each layer compacted by twenty-five blows of a 10-pound hammer with an 18-inch drop. The result of this test, as presented on Plate No.2, were used in conjunction with the field density tests to determine the degree of relative compaction of the compacted fill. AS-BUILT GEOLOGY Based on the results of on-site observation by a member of our engineering geology staff, the following conclusions pertaining to the excavations made on Lot 1 of the proposed condominium project are presented: 1) The geologic conditions exposed during the grading operations at the site are similar to those anticipated and described in the referenced report. I I I I I I I I I I I I I I I I I I I SCS&T 8821027 January 26, 1990 Page 5 2) Cut slopes have been observed and, in our opinion, found to be free of geologic conditions which may lead to significant instability problems. 3) All adverse geologic conditions found to exist on the site were corrected and it is our opinion that the site is geologically suitable and safe for construction. CONCLUSIONS Based upon our field observations, it is our opinion that the soils on the condominium site are as anticipated in the referenced "Report of Geotechnical Investigation", and the recommendations contained therein remain applicable. LIMITATIONS This report covers only the services performed between October 24 and October 27, 1989. As limited by the scope of the services which we agreed to perform, our opinions presented herein are based on our observations and the relative comp-action test results. Our services were performed in accordance w~th the currently accepted standard of practice and in such a manner as to provide a reasonable measure of the compliance of the grading operations with the job requirements. No warranty, express or implied, is given or intended with respect to the services which we have performed, and neither the performance of those services nor the submittal of this report should be construed as relieving the grading contractor of his responsibility to conform with the job requirements. If you should have any questions after reviewing this rep.ort, please do not hesitate to contact this office. I I I I I I I I I I' I I I I I I I I I SCS&T 8821027 January 26, 1990 This opportunity to be of professional appreciated. Respectfully submitted, SOUTHERN CALIFORNIA SOIL & TESTING, INC. DBA/DH/MH/rr cc: (4) Submitted (1) SCS&T, Escondido . Page 6 service is sincerely I I JOB NAME: Windsong Shores JOB NO: 8821027 PLATE NO: 2 I I I I I I I I I I I I I I I I I TEST DATE NO. LOCATION ELEVATION MOISTURE DRY DEN. SOIL ~EL.CbMP. (percent) (p.c.f.) TYPE (percent) 1 2 3 4 5 6 7 8 9 10 10-24-89 Access Road 22.0 8.7 125.3 1 Station 14+50 10-24-89 Access Road 21.0 11.1 120.9 1 Station 12+00 10-25-89 Access Road 26.0 10.5 125.2 1 Station 12+90 10-25-89 Access Road 24.5 10.5 127.1 1 Station 16+00 10-25-89 _ Access Road 27.0 9.9 124.7 1 Station 15+00 10-25-89 Access Road 28.0 12.4 125.5 1 Station 14+50 10-2-6-89 Access Road 28.0 11.7 126.3 1 Station 11+00 10-26-89 Access Road 27.5 12.4 125.2 1 Station 15+50 10-27-89 Access Road 30.5 11.1 123.6 1 Station 13+50 10-27-89 Access Road 36.5 11.7 120.4 1 Station 14+10 MAXIMUM DENSITY AND OPTIMUM MOISTURE DETERMINATIONS, ASTM 1557-78 ----------------------------------------------------------------- SOIL TYPE 1 METHOD DESCRIPTON OPTIMUM MOISTURE (percent) A Reddish/Brown, Fine to 8.8 to Medium Grained Sand -- MAXIMUM D~NSITY (pcf) 132.0 94.9 91.6 94.8 96.3 -94.5 95.1 95.7 94.8 93.:6 91.2