The URL can be used to link to this page

Home My WebLink AboutCT 74-21; Carlsbad Crossroads Business Center Phase II; Soils Report; 1990-02-16American Engineering Laboratories,Inc. INTERIM AS-GRADED SOILS REPORT CARLSBAD CROSSROADS BUSINESS CENTER PHASE II, BUILDINGS F, G, H, I, J 2730 NEST LOKER AVENUE CARLSBAD, CALIFORNIA ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Carlsbad, CA92009-4859 PREPARED FOR: ROEL CONSTRUCTION COUPANY, INC. 3366 KURT2 STREET SAN DIEGO, CALIFORNIA 92138-0216 SanDiego CONWlZ4 Modesto Yucca Valley Apple Valley JOB NO.: l-l-342 FEBRUARY 16, 1990 - American Engineering Laboratories, Inc. Cormrate Office: 7Y40 Arions Dr.. Suite A. San Diem CA 92126 1619) 695-3730 350 S. tiaplr St.. Unit K. Corona.-CA 917’20 (714) 272.4230 515 Galaxy Way, Modesto. CA 95356 (209) 576.0813 5XY45 Business Center Dr. Unit A. Yucca Valley. CA 92284 (619) 22X-1754 13641 ~Johrr Gknn Rd~. Suite C. Apple Valley. CA 92307 (619) 247-X445 - / - &J.& - American Engineering Laboratories, Inc. 7940 Arjons Drive, Suite A San Diego. CA 92126 Telephone (619) 695.3730 FAX (619) 695.6712 San Diego l Corona l Modesto . Yucca Valley . Apple Valley Mr. Derek Davis ROEL CONSTRUCTION COMPANY, INC. FEBRUARY 16, 1990 3366 Kurtz Street JOB NO.: l-l-342 - San Diego, CA 92138-0216 SUBJECT: PRUJECT: REFERENCE: - - - - - Gentlemen: presents a summary of the interim as-graded conditipns for the building pad areas at the This report geotechnical proposed Carlsbad Crossroads Business Center, Phase II, Buildings F, G, B;I, and J, located Carlsbad, California. The purpose of the grading and compaction was to create finished grade elevations for the building pads within the aforementioned areas. INTERIM AS-GRADED SOILS REPORT CARISBAD CROSSROADS BUSINESS CENTER PHASE II, BUILDINGS F, G, H, I, J 2730 WEST LOKER AVENUE CARLSBAD, CALIFORNIA San Diego Geotechnical Consultants, Inc., "Foundation Investigation, Carlsbad oaks Business Center, Lots 3-6, Carlsbad, California," prepared for Five M. Develop- ment, Inc., 3456 Camino De1 Rio North, San .Di~ego, California 92108, dated November 20, 1986, Job No. 30065-00, Log No. 6-6552. Based on the results of our testing and observation of earth- work construction at the subject site, grading within the aforementioned areas has been performed in accordance with project specifications and the referenced report. This opportunity to be of continued service is sincerely appreciated. Should you have any further questions, please do not hesitate to contact the undersigned at your convenience. Respectfully submitted, AMERICAN ENGINEERING LABORATORIES, INC. TABLE OF CONTENTS - - - SECTION 1.0 2.0 3.0 4.0 5.0 6.0 -~ - - - - - 7.0 GENERAL .................................... 1 1.1 Previous Grading ................. 1 1.2 Scope of Service ................. 1 OVEREXCAVATION OF BUILDING AREA ............ 1 PREPARATION OF EXISTING GROUND ............. 2 SOIL TYPES ................................. 3 FILL PLACEWENT ............................. 3 CONCLUSIONS AND RECOWWENDATIONS ............ 3 6.1 Compaction ....................... 3 6.2 Foundation and Slab Recommendations ................ 3 6.2.1 General .......................... 3 6.2.2 Foundations ...................... 4 6.2.3 Slabs ............................ 4 6.3 Allowable Bearing Pressure ....... 4 6.4 Lateral Load Resistance .......... 4 6.5 Expected Settlement .............. 5 6.6 Drainage ......................... 5 6.7 Retaining Walls .................. 5 6.8 Trench Backfill .................. 5 6.9 Foundation Observations .......... 6 6.10 Type of Cement for Construction . . 6 6.11 Temporary Excavations ............ 6 SUMEIARY .................................... 6 APPENDIX A: REFERENCE WAPS APPENDIX B: RESULTS OF COWPACTION TESTS - - - - - - - - 1.0 GENERAL 1.1 Previous Grading The site previously had been rough graded under the observation and testing services of San Diego Geotechnical Consultants, Inc. The previously placed fill was reported to be properly compacted to a maximum thickness of 55 feet, and ranged in composition from silty sand, clayey silt, and clay, having generally moist and medium dense to very stiff consistency. The relevant site conditions and geotechnical engineering recommendations are addressed in their referenced report. 1.2 Scope of Services Field personnel were provided for this project to perform observations and testing of grading operations so we could develop professional opinions of the contractor's adherence to the project specifications and the referenced report's recommendations. Our services did not include supervision or direction of the actual work of the contractor, his employees or agents. Specifically, our services involved the following: 2.0 * Testing and observation of overexcavation and fill placement; * Laboratory testing to determine pertinent engineering characteristics of the fill materials; * Preparation of this report which summari- ses our field testing results during the grading within the aforementioned build- ing pads. OVEREXCAVATION OF BUILDING AREA Overexcavation was performed within the proposed building areas and to 5 feet beyond the exterior of the proposed structure. The depth of overexcavation varied at different pads. Table 1 presents the recommended site work for each building pad, as specified in Section 8.1 of the referenced report. - - - - - - - AS-GRADED GEOTECBNICAL REPORT PAGE 2 CARISBAD CROSSROADS BUSINESS CEWTER JOB NO.: l-l-342 CARISBAD, CALIFORNIA FEBRUARY 16, 1990 TABLE I RECOWWENDED SITE WORE WAXIWUWDEPTB RECOWWENDED BLDG. BEARING OF FILL ON REWEDIAL NO. WATERIAL TRANSITION LOT SITE WORE F Bedrock Cut a) Moisture condition upper 2 feet of slab subgrade G Bedrock/Fill 5 feet a) Overexcavate bedrock Transition 3 feet below lowest adjacent finished grade b) Moisture condition upper 2 feet of slab subgrade H I J Fill Bedrock Cut Bedrock/Fill Transition a) Moisture condition upper 2 feet of slab subgrade 2 feet a) Overexcavate bedrock 2 feet below adjacent finished grade b) Moisture condition upper 2 feet of slab subgrade a) Moisture condition upper 2 feet of slab subgrade 3.0 PREPARATION OF EXISTING GROUND The exposed fill and natural subgrade soil in areas to receive fill, or areas within proposed structural limits, were scarified 8-12 inches, brought to near optimum moisture condition and compacted to at least 90 percent of the labora- tory maximum density. Subgrade soils within 2 feet of slab subgrade were moisture conditioned to 5 percent above optimum moisture to decrease the expansion potential. The locations of the site, import soil and compaction tests are presented in Appendix A. - - - - - - - - - - - - - - AS-GRADED GEOTECBNICAL REPORT PAGE 3 CARISBAD CROSSROADS BUSINESS CENTER JOB NO.: l-l-342 CARLSBAD, CALIFORNIA FEBRUARY 16, 1990 4.0 SOIL TYPES Fill soils utilized at the site consisted of on-site and import materials. These soils consist of fine-grained, silty, clayey sand. Based on laboratory testing, the on-site soils exhibited a moderate expansion potential. For foundation and slab recommendations see Section 6.2. 5.0 FILL PLACEMENT Fill soils were brought to approximately 5 percent above optimum moisture content and compacted in 6-8 inch lifts to 90 percent of the laboratory maximum density. The equipment used for compaction consisted of a loaded Catepillar 623C scraper. A maximum of approximately 3 feet of compacted fill was placed during preparation of the building pads. Test method ASTM D-1556 (Sand Cone Method) was used to test the soil density. The results are outlined in Appendix B. 6.0 CONCLUSIONS AND RECORMENDATIONS 6.1 Compaction Based on the results of the observations and testing noted herein, it is this firm's opinion that the grading and com- paction were performed in general accordance with our recommendations and the requirements of the City of Carlsbad grading ordinances. 6.2 Foundation and Slab Recommendations 6.2.1 General The results of previous testing and observation indicate that the existing surface soils exhibit a medium to high expansion potential (see Reference). The following recom- mendations are provided for the design of footings and slabs based on the expansion potential of the soils presently at the site. Our recommendations are considered generally consistent with the Standards of Practice. The potential for favorable found- ation performance can be further enhanced by maintaining uniform moisture conditions throughout the life of the structure. - 7 - - - - - - - - - .- - AS-GRADED GEOTECBNICALREPORT PAGE 4 CARISBAD CROSSROADS BUSINESS CENTER JOB NO.: l-l-342 CARISBAD, CALIFORNIA FEBRUARY 16, 1990 The footing configurations and reinforcement recommendations herein should not be considered to preclude more restrictive criteria by the governing agencies or by structural consider- actions. A structural engineer should evaluate configurations and reinforcement requirements for structural loadings, shrinkage and temperature stresses. 6.2.2 Foundations It is anticipated that a shallow foundation system consisting of continuous or spread footings should be suitable to sup- port the proposed structure. All footings for the building should be founded entirely in recompacted fill. Footings should have a minimum depth of 24 inches below lowest adja- cent pad grade and a minimum width of 12 inches. Based on soil conditions alone, we recommend that continuous footings be reinforced with a minimum of two No. 5 bars placed one at the top of the stem wall and one at the bottom of the footing. 6.2.3 Slabs We recommend that slabs be constructed a minimum of 4 inches in actual thickness and be reinforced with at least 6x6/10-10 welded wire mesh placed at mid-height of the slab. Actual design of on-grade slabs may be based on a modulus of sub- grade reaction of 200 pcf. We recommend slabs be underlain by at least 4 inches of crushed rock or clean, washed sand as a capillary break. If a moisture membrane is used, we recommend it be overlain by at least 2 inches of sand to decrease the likelihood of curing problems. Slab subgrade should be moisture conditioned as recommended in Section 3.0. Actual reinforcement should be designed by the structural engineer. 6.3 Allowable Bearins Pressure for Footinss Footings may be designed for an allowable dead plus live load bearing pressure of 2,500 pounds per square foot with one- third increase for short-term wind or seismic loads. This bearing pressure may be increased by 500 psf and 300 psf for each additional foot of foundation depth and width. It is recommended that the maximum allowable soil bearing pressure be limited to 4,000 psf. 6.4 Lateral Load Resistance Lateral loads against buildings may be resisted by friction between the bottom of footings and the supporting soils. An allowable friction coefficient of 0.40 is recommended. - - - - - - - - - - - AS-GRADED GEOTECRNICAL REPORT PAGE 5 CARISBAD CROSSROADS BUSINESS CENTER JOB NO.: l-l-342 CARLSBAD, CALIFORNIA FEBRUARY 16, 1990 Alternatively, an allowable lateral bearing pressure equal to an equivalent fluid pressure of 300 pounds per cubic foot acting against the footings may be used, provided the foot- ings are poured tight against undisturbed soils. A maximum passive pressure of 2,000 pounds per square foot/foot (psf/ft) is recommended. 6.5 Exnected Settlement For footings supported on the properly recompacted fill and sized for the recommended bearing pressures, total and differential settlements are not expected to exceed l/2 to l/4 inch, respectively. 6.6 Drainase To enhance future site performance, it is recommended that all pad drainage be collected and directed away from proposed structures to disposal areas. For soils areas, as well as heavily landscaped areas, we recommend that a minimum gradi- ent of 5 percent be maintained. For paved areas, a minimum gradient of 2 percent should be maintained away from the structure for a minimum distance of 10 feet. Overall site drainage should be at least 2 percent to allow proper drain- age. Planters should be constructed so moisture is not allowed to seep into foundation areas or beneath slabs or pavements. Property owners should be made aware that altering drainage patterns, landscaping, the addition of patios, planters and other improvements, as well as irrigation and variations in seasonal rainfall, all affect subsurface moisture conditions. 6.7 Retainins Walls Retaining walls should be designed in accordance with the recommendations of the Geotechnical Investigation by San Diego Geotechnical Consultants, Inc., November 20, 1986. 6.8 Trench Backfill It is our opinion that utility trench and/or wall backfill consisting of the on-site material types could be best placed by mechnical compaction to a minimum of 90 percent of the laboratory maximum density. - - - - - _- - - - -. - - - -~ AS-GRADED GEOTECHNICAL REPORT PAGE 6 CARISBAD CROSSROADS BUSINESS CENTER JOB NO.: l-l-342 CARISBAD, CALIFORNIA FEBRUARY 16, 1990 6.9 Foundation All excavations should be observed by the soils engineer prior to placement of forms, reinforcement or concrete for verification of conformance with the intent of these recom- mendations. All excavations should be trimmed neat, level, and square. All loose or sloughed material should be removed prior to the placement of concrete. Materials from footing excavations should not be spread in slab-on-grade areas unless compacted to a minimum relative compaction of 90 percent. 6.10 Tvne of Cement for Construction Based on our experience with similar soil types, ordinary Type I or Type II Portland cement may be used for concrete structures in contact with the on-site soils. 6.11 Temnorarv Excavations Temporary construction excavations may be made vertically without shoring to a depth of 5 feet below the adjacent surrounding grade. For deeper cuts, the slopes should be properly shored or sloped back at least 1:l (horizontal: vertical) or flatter. The exposed slope face should be kept moist (but not saturated) during construction to reduce local sloughing. No surcharge loads should be permitted within a horizontal distance equal to the height of cut from the toe of the excavation unless the cut is properly shored. Excavations that extend below an imaginary plane inclined at 45 degrees below the edge of any nearby adjacent existing site facilities~ should be properly shored to maintain founda- tions support of the adjacent structure. All excavations and shoring systems should meet the minimal requirements given in Article 6 of the State of California Occupational Safety and Health Standards. 7.0 SUNNARY Our description of grading operations, as well as observa- tions and testing services herein, have been limited to those grading operations performed between January 23 and February 15, 1990. No representations are made as to the quality or extent of materials not observed, or for any subsequent changes made to this site. - - - - - - - - - - - - - - AS-GRADED GEOTECBNICAL REPORT PAGE 7 CARISBAD CROSSROADS BUSINESS CENTER JOB NO.: l-l-342 CARISBAD, CALIFORNIA FEBRUARY 16, 1990 Elevations and test locations noted in the attached Table I are estimated from field surveys done by others. Based on our observations and testing, it is our opinion, as aforemen- tioned, that the work performed has been accomplished in accordance with our recommendations as well as the require- ments of the regulating agencies. This report should be considered subject to review by the controlling authorities. Professsional judgements represented in this report are based partly on our evaluations of the technical information gath- ered, our understanding of the proposed construction, and our general experience in the geotechnical field. Our engineering work and judgements rendered meet or exceed the standard of care of our profession at this time. No other warranty, expressed or implied, is made as to the conclusions and pro- fessional advice included in this report. This opportunity to be of service is appreciated. Should you have any questions regarding this report, or require further assistance, please do not hesitate to contact this office. AMERICAN ENGINEERING LABORATORIES, IN&, Bradlev. RG Geotechnical Department Manager Eric Iscan, RCE #26243 Director of Engineerint- SNB/EI/vr/RlO - - - - - - - - - - - - APPENDIX A REFERENCEMAPS - .- - - - - - - - - - - .- - - American Engineering Laboratories SITE LOCATION MAP (SUBJECT SITE) JOB NO. 1-,-.342Dm. 1990 FIG 1 - - American Engineering i&oratories - .- - - - ---- - - - EXPORT SITE -. - - - I I - - SITE LOCATION MAP (MATERIAL EXPORT SITE) JOB NO. I-,-st&%i. wgo( FIG- 2 - - - - - APPENDIX B DENSITY TEST RESULTS - - TABLE I RESULTS OF COMPACTION TESTS - - - - - - - - - - - - Dfj NO*: l-1-342 NAME: Carlsbad Crokroads Phase II DATE: February 1990 I I DEPTH/ MOlSTUtIE UNIT DRY nwimw .EVAT,ON COWFNT D$,N_s!rY COMt’A_~TION “IL TYPE EST NO. OATE ,; 11, 1* l/24/90 t366.5’ 18.5 2* l/24/90 t366.5’ 18.5 3* l/25/90 t367.0’ 14.0 4* l/25/90 t367.0’ 19.0 5* l/25/90 t367.0’ 20.0 6* l/25/90 t369.1’ 11.0 7* l/25/90 +367.5' 18.0 8* l/25/90 t367.5’ 18.0 9” l/26/90 +369.5’ 16.0 lo* l/26/90 t369.0’ 15.0 11* 2/36/90 t367.5 19.0 12* l/26/90 t370.0’ 19.0 13* l/26/90 t367.5 22.0 14* l/26/90 t368.5’ 19.0 15* l/26/90 t369.1’ 21.0 16* l/26/90 t370.5’ 21.0 17* l/26/90 i-367.9’ 19.0 18* l/26/90 +369.0’ 19.0 19* l/29/90 +371.01 19.0 20* l/29/90 t371.5’ 22.0 21* l/29/90 t369.6’ 22.0 22" l/30/90 t370.0’ 20.0 23* l/30/90 +370.5 71-n \T”V, 96.5 101.3 90.5 101.3 114.0 111.0 100.0 100.0 103.0 105.0 102.0 104.0 105.0 105.0 113.0 113.0 103.0 110.0 102.0 103.0 118.0 105.0 1-1 86.7 91.0 81.0 91.0 93.4 91.0 90.0 90.0 92.5 94.3 91.6 93.4 94.3 94.3 92.6 92.6 92.5 90.0 91.6 92.5 96.7 94.3 m-l 7 J- 1 1 1 1 2 2 1 1 1 1 1 1 1 \: 1 2 2 1 2 1 1 2 1 See Test #2 Retest of #l See Test #5 Retest of #3 SEE PLAN FOR TEST LOCATIONS ‘SAND-CONE TEST. ALL OTHER8 NUCLEAll DEN8ltY tE8fS ‘TEST FAILED. SEE RETEST 0, . ..CL...... C..-...-.....m I .n.h~a-l.-r~rwre. AMlSllbAN IZNtilNUtllNU LAISUHA I UHIC3 - - - - - - - - - - TABLE I RESULTS OF COMPACTION TESTS os NO.: l-l-342 NAME: Carlsbad Croisroads Phase II ,AT,February 1990 MOISTURE UNIT DRY RELATIVE ‘EST NO. DATE EL;;pA!$;N COW;“’ “E&J;;:Y COMMOTION “IL TYPE 24” l/30/90 t370.5’ 19.0 105.0 94.3 1 25* z/7/90 t371.5' 18.0 115.0 94.3 2 26” z/13/90 i-371.1’ 18.0 109.0 90.0 2 27* z/13/90 t371.1’ 19.0 114.7 94.0 2 28* 2/13/90 t371.1’ 19.0 105.0 94.3 1 29* z/13/90 t371.1’ 18.0 106.0 95.2 1 30* 2/ 13190 t371.5’ 18.0 117.0 97.1 3 31* 2/14/90 t371.5’ 20.0 111.0 92.1 3 32* 2/14/90 t370.0’ 18.0 100.0 90.0 1 33* z/14/90 t370.0’ 18.0 100.0 90.0 1 34* 2/15/90 t368.9’ 18.0 118.0 96.7 2 1. 35* 2/15/90 t368.9’ 18.0 110.0 90.2 2 SEE PLAN FOR TEST LOCATIONS *SAND-CONE TEST, ALL OTHERS NUCLEAtl DENSITY TESTS *TEST FAILED. SEE RETEST I, AMERICAN ENGINEERING LABORATOlUES - - - - - - - - - TABLE II LABORATORY TEST RESULTS OS NO.: l-1-342 NAME: Carlsbad Crossroads Phase II DATE: February 1990 SOIL CLASSIFICATION MAXIMUM OPTIMUM TYPE DENSITY (PCF) M°KYE 1 Light gray sandy CLAY 111.3 15.6 2 Yellow sandy SILT 122.0 12.2 3 Brown clayey well-graded SAND with some gravel 120.5 13.2 I, A@33icAN ENGWEEFUNG LABORATORIES