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Home My WebLink AboutCT 74-21; Carlsbad Oaks - Lots 23 & 38; Soils Report; 1997-07-09AS-GRADED GEOTECHNICAL REPORT, OF POST-GRADING OPERATIONS, PROPOSED COMMERCIAL STRUCTURE, LOTS 23 AND 38 OF CARLSBAD OAKS, CARLSBAD TRACT NO. 74-21, CARLSBAD, CALIFORNIA July 9, 1997 Project No. 4960196-003 Prepared For: WHCBO REAL ESTATE LIMITED PARTNERSHIP 30 Executive Avenue Park, Suite 100 Irvine, California 92713-9693 - 3934 MURPHY CANYON ROAD, SUITE 8205. SAN DIEGO, CA 92 123 (6 19) 292-8030 * (800) 447-2626 FAX (6 19) 292-077 I July 9, 1997 Project No. 4960196-003 To: WHCBO Real Estate Limited Partnership 30 Executive Avenue Park, Suite 100 Irvine, California 92713-9693 Attention: Mr. Jon Kelly Subject: As-Graded Geotechnical Report of Post-Grading Operations, Proposed Commercial Structure, Lots 23 and 38 of Carlsbad Oaks East, Carlsbad Tract No. 74-21, Carlsbad, California Introduction In accordance with your request and authorization, Leighton and Associates, Inc. (Leighton) has performed geotechnical observation and testing services during the post-grading operations for the proposed commercial structure on Lot 23 and 38 of Carlsbad Oaks East, Carlsbad Tract No. 74-21, Carlsbad, California. The purpose of our geotechnical observation and testing services was to document that the post-grading operations for the subject site were performed in accordance with the project geotechnical reports (Appendix A), geotechnical recommendations made during the course of grading and the City of Carlsbad requirements. This as-graded report summarizes our geotechnical observations, field and laboratoty test results, and conclusions concerning the post-grading operations at the site. Summaw of Post-Gradinn Owrations The post-grading operation were performed between December 9, 1996 and June 9, 1997 at the subject site. Post-grading operations observed andlor tested by Leighton and Associates, Inc., during the development of the site included: 1) trench excavation and backfill compaction of sewer lines beneath the proposed structure and sewer, storm drain and water utility lines in the parking areddriveways of the site; 2) observation and testing during the placement, processing, and compaction of the parking area and driveway subgrade soils and aggregate base material; 3) observation and presaturation testing of the building slab subgrade soils; and 4) observation of the foundation excavations for the building. Geotechnical observations and compaction testing were performed by representatives of our firm who were on-site as-needed during the post-grading operations. Specific observation and testing services conducted during the post-grading operations are discussed below. ?- 3934 MURPHY CANYON ROAD, SUITE 8205, SAN DIEGO, CA 921 23 (619) 292-8030 - (800) 447-2626 FAX (6 19) 292-077 I 4960196-003 Field and Laboratorv Testing Field density tests were performed during the placement and compaction of trench backfill, subgrade preparation, and placement of the aggregate base material (A.B.) during post-grading operations of the site. Density tests were performed in general accordance with the Nuclear-Gauge Method (ASTM Test Methods D2922-91 and D3017-88). The results and approximate locations of the field density tests performed are summarized in Appendix B. As indicated in Appendix B, areas in which field density tests were less than the required minimum 90 or 95 relative compaction or were observed to be nonuniform, were reworked, recompacted, and retested until the minimum 90 or 95 percent relative compaction was achieved. In accordance with the City of Carlsbad criteria, trench backfill soils were compacted to a minimum 90 percent relative compaction while subgrade soils and A.B. for the site parking areas and driveways were compacted to a minimum 95 percent of the maximum dry density (as determined by ASTM Test Method D1557-91). Representative samples of the material placed and compacted during the post-grading operations (including native soil and imported material) were tested for maximum dry density and optimum moisture content in accordance with ASTM Test Method D1557-91. The laboratory tests results are presented in Appendix C. Trench Excavations and Backfill Underground utilities, including storm drain, water and sewer were placed beneath the proposed structure and in the parking anddriveway during the development of the site. During the trench backfill operations, native and import soils where placed in 4- to 8-inch thick loose lifts, moisture- conditioned as needed to obtain a near-optimum moisture content (moisture conditioning also occurred prior to fill placement), and compacted to a minimum 90 percent relative compaction (based on ASTM Test Method D1557-91). Compaction of the trench backfill soils was accomplished by hand tampers, sheepsfoot roller andor wheel-rolling with construction equipment. Testing frequency and locations were performed in general conformance with the City of Carlsbad criteria. The results and approximate location of the backfill tests are summarized in Appendix B. Structural Pavement Sections Minimum structural pavement sections were provided for the streets within the subject development based on laboratory R-value testing of representative samples of the subgrade soils (Leighton, 1997). In the southern portion of the site, import fill soils were placed in the driveway and loading dock area in order to bring this area up to the planned subgrade elevation. These soils were moisture- conditioned to a near-optimum moisture content and compacted to a minimum 90 percent relative compaction (based on ASTM Test Method 01557-91). Prior to placement of the A.B. material, the subgrade soils were scarified to a minimum depth of 12 inches, moisture-conditioned to a near- optimum moisture content and compacted to a minimum 95 percent relative compaction beneath the parking area (based on ASTM Test Method D1557-91). The A.B. material placed beneath the parking area and driveways was compacted to a minimum of 95 percent of the maximum dry density (based on ASTM Test Method D1557-91). The results and approximate location of the subgrade soil and base material density tests are summarized in Appendix B. Observation and testing of the asphalt concrete in the parking areas and driveways was not performed by Leighton. -2- 4960196-003 - Slab Subde Presaturation Prior to concrete placement, moisture presaturation tests were taken within the foundation limits of the commercial building at a depth of 18 inches. The moisture penetration tests were taken to determine whether the subgrade soils had been moisture conditioned in accordance with the recommendations outlined in the project geotechnical report (Leighton, 1996d) in order to reduce the adverse effects of expansive soils. The test results indicated that the slab subgrade soils had the minimum recommended moisture contents at the recommended depth. The foundation excavations on each of the lots were also geotechnically observed prior to concrete placement and found to be in accordance with our recommendations (Leighton, 1996c and 1996d). Summaw of Conclusions c c Geotechnical conditions encountered during post-grading were generally as anticipated. Based on our observations and testing, post-grading operations were performed in general accordance with the project geotechnical recommendations (Appendix A) and the City of Carlsbad requirements. In our professional opinion, the geotechnical aspects of the development have been evaluated and properly treated during post-grading. Field density testing indicated that the trench backfill soils and import fill soils in the southern portion of the site were compacted to a minimum 90 percent relative compaction (based on ASTM Test Method D1557-91). Field density testing also indicated that the parking area and driveway subgrade soils (i.e. the upper 12-inches of the on-site soils) and base materials were compacted to a minimum of 95 percent relative compaction (based on ASTM Test Method D1557-91). Foundation excavations for the commercial building and presaturation of the slab subgrade soils have been performed in general accordance with the project recommendations (Leighton, 1996d). t b -3- 4960196-003 If you have any questions regarding our report, please contact this ofice. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. akur Randall K. Wagner, CEG 12 (Exp. 3/31/98) .. I Project Geologist *- MichaLl R. Stew& hfG 1349 (EX~. 12/31/97) Director of Geology RKwms Attachments: Appendix A - References Appendix B - Summary of Field Density Tests Appendix C - Laboratory Testing Procedures and Test Results Distribution: (6) Addressee (2) Reno Contracting Attention: Mr. Craig Hueners -4- 4960 196-003 APPENDIX A REFERENCES International Conference of Building Officials (ICBO), 1994, Uniform Building Code, Volume 1- Administrative, Fire- and Life-Safety, and Field Inspection Provision; Volume 11-Structural Engineering Design Provisions; and Volume 111-Material, Testing and Installation Provisions" ICBO. Kahr and Associates, 1996, Grading Plans for Lots 23 and 38, Carlsbad Tract 74-21, Lincoln Property Company, Drawing No. 350-2A, 4 Sheets. Leighton and Associates, Inc., 1996a, Geotechnical Investigation, Proposed Of€ice/Manufacturing/Warehouse Facility, Carlsbad Oaks East, Lots 23 and 28, Northeast Comer of El Fuerte Street and Palomar Airport Road, Carlsbad, California, Project No. 4960196-001, dated August 2, 1996. , 1996b, Grading Recommendations, Lots 23 and 28, Carlsbad Oaks East, Carlsbad, California, Project No. 4960196-001, dated September 26, 1996. , 1996c, Report Addendum, Proposed Building, Carlsbad Oaks East, Lots 23 and 38, El Fuerte and Palomar Airport Road, Carlsbad, California, Project No. 4960196-001, dated October 28, 1996. ,1996d, As-Graded Report of Fine-Grading Operations, Proposed Commercial Structure, Lots 23 and 38 of Carlsbad Oaks, Carlsbad Tract No. 74-21, Carlsbad, California, Job No. 4960196-003, dated December 4, 1996. ,1997, Pavement Design Recommendations, Lots 23 and 38 of Carlsbad Oaks East, Carlsbad Tract No. 74-21, Carlsbad, California, Project No. 4960196-003, dated January 9, 1997. San Diego Geotechnical Consultants (SDGC), Inc., 1987, As-Graded Geotechnical Report, Final Report of Mass Grading, Carlsbad Oaks Business Center, Carlsbad Tract 74-21, Carlsbad, California, Job No. 05-1079-002-00-10, dated February 19, 1987. Ware. and Malcomb, Architects, Inc., Site Plan for the Proposed Lincoln Property Warehouse Facility, Untitled and Undated. A- 1 4960196-003 APPENDIX B EXPLANATION OF SUMMARY OF FIELD DENSITY TESTS Test of GRADING Natural Ground Original Ground Existing Fill Compacted Fill Slope Face Finish Grade SEWER STORM DRAIN AREA DRAIN DOMESTIC WATER RECLAIMED WATER SUBDRAIN GAS ELECTRICAL TELEPHONE JOINT UTILITY IRRIGATION Bedding Material Shading Sand Main Lateral Crossing Manhole Hydrant Lateral Catch Basin Riser Inlet ~ RETAINING WALL :RIB WALL LOFFELL WALL STRUCT FOOTING Footing Bottom Backfill Wall Cell Test of Abbreviations NG OG EF CF SF FG B S M L X MH HL CB R I ~ F B C Test of SUBGRADE AGGREGATE BASE CEMENT TRFATED BASE PROCESSED BASE ASPHALT CONCRETE Curb Gutter Curb and Gutter Cross Gutter Street Sidewalk Driveway Driveway Approach Parking Lot Electric Box Pad Compacted Fill PRESATURATION Moisture Content INTERIOR TRENCH Plumbing Backfill Electrical Backfill Test of Abbreviations C G CG XG ST sw D DA P EB CF M P E N represents nuclear gauge tests that were performed in general accordance with most recent version of ASTM Test Methods D2922 and D3017. S represents sand cone tests that were performed in general accordance with mast recent version of ASTM Test Method D1556. 15A represents first retest of Test No. 15 15B represents second retest of Test No. I5 "0" io Test Elevation Column represents test was taken at the ground surface (e& finish grade or suhgrade) '"-1" in Test Elevation Column represents test was taken one foot below the ground surface B-1 t 5 3 CCC 333 CCrrr 32233 YYYYY 00000 iiiij i Y = rr+rrt 333333 YYYLYL 000000 m c m Y c * v) z w 0 z Y 0 2 YYYYYLY 0000000 ... ZZZ v) + ul W C > v) 2 Y 0 0 L t w z Y OL UUm OOOOOOOOOOOOOOONNNNNN u- COI ..................... I NNNNNNNNNNNNNNNUUUU*U I 000000000000000~00000 02 , c Y c-* 000000000000000 - ????9?????9???? v) -, 31 &.I P V)v I Y> I CY I --la P 2 Y Yl Y Y - 0 0000000000000000000000000 ... ddddddddddddddddddddddooo 4960196-003 Sample Number 1 2 3 4 5 APPENDIX C Maximum Dry Optimum Moisture Sample Description Density (pcf) Content (YO) Light-brown silty sand 115.5 14.0 ............................................................................................................................................................................................................................................. Light-brown clayey to silty sand 108.0 20.0 .............................................................................................................................................................................................................................................. Orange to light-brown cobbly sand 128.0 9.0 Class I1 Base 136.0 8.0 Class 11 Base 140.0 6.0 .............................................................................................................................................................................................................................................. .............................................................................................................................................................................................................................................. Laboratow Testing Procedures and Test Results c- 1