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HomeMy WebLinkAboutCT 04-26; ROBERTSON RANCH EAST VILLAGE PA 16, 17, & 18; COMPACTION REPORT OF BUILDING PAD RE-CERTIFICATION PHASE 14; 2012-10-02c1O1+-2-4 1co Geotechnical. Geologic. Coastal. Environmental 4. 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 October 2, 2012 W.O. 5949-B-SC Brookfield Homes 12865 Pointe Del Mar, Suite 200 - : Del Mar, California 92014 Attention: Ms. Teri McHugh, and Mr. Greg McDonnell . Subject: Compaction Report of Building Pad Re-Certification, Phase 14 (Lots 119, .- 120, 121, 136, 137, and 138), Planning Area 16, Robertson Ranch Development, Carlsbad, San Diego County, California References: 1. "Supplemental Discussion of Slab Subgrade Pre-Wetting, Planning Area 16 of Robertson • -. Ranch, City of Carlsbad, California," W.O. 5949-C-SC, dated August 17, 2010, by '. :• , GeoSoils, Inc. - 2. "Discussion of Building Slab Subgrade Pre-Wetting, Planning Area 16 of Robertson - Ranch, City of Carlsbad, California," W.O. 5949-C-SC, dated October 8, 2009, by . GeoSoils, Inc. . . . 3: "Report of Rough Grading, Planning Area 16 of Robertson Ranch, East village (Lots 44 - ' Through 63,89 Through 99, 117 Through 140, and 160 Through 189), Carlsbad Tract 04-26, - Drawing 453-8A, Carlsbad, San Diego County, California," W.O. 5353-131-SC, dated February 16, 2009, by GeoSoils, Inc. . . . .' Dear Ms. McHugh and Mr. McDonnell: GeoSoils, Inc. (GSI) is providing this summary of our observation and testing services : during mitigative grading within Lots 119 through 121, and 136 through 138 of Planning - Area 16, at Robertson Ranch, East Village Subdivision in the. City of Carlsbad, California.: The purpose of remedial grading was to reprocess the Subject lots in accordance with; • - recommendations presented in Reference No. 2. For low expansive Lot 121, earthwork consisted of processing soils within 8 to 12 inches from pad grade, moisture conditioning to at least optimum moisture content, then compacting to a minimum relative compaction • of 90 percent per ASTM D 1557. For medium expansive Lots 119, 120, and 136 through 140, earthwork consisted of removing the upper 12 inches of existing fill soil across each .. medium expansive lot. Once removals were completed, the exposed bottom was • ' .- . processed, moisture conditioned and compacted to a depth of 12 additional inches, then - brought to grade with compacted fill, such that the upper 24 inches (medium expansive . Lots), has been reprocessed. Where tested, reprocessed and/or fill material was . compacted to at least 90 percent relative compaction, at 2 percent to 3 percent above the soils optimum moisture content per ASTM D 1557 (see Reference No. 2). Based on our ' observations and testing, the building pads appear to have been prepared in general • - ' a - accordance with the recommendations provided by this office (see Reference No. 2 and No. 3), and are Considered suitable for development from a geotechnical standpoint. Field Observation and Testing Field density tests were performed using nuclear (densometer) ASTM test method D 6938 (Procedure A). The test results taken during grading operations are, presented in the attached copies of our "Field Testing Reports" The laboratory maximum dry density and optimum moisture content for the major soil type within this construction phase were determined in general accordance with test method ASTM D 1557 The following table presents the results 4 4 SOIL TYPE MAXIMUM DENSITY (PCF) MOISTURE CONTENT (PERCENT) C - Gray Brown, Clayey SAND 120.5 - 13.0 0 -Yeiiow brown Clayey SAND 119.5 11.5 U' Field compaction testing indicates that the soils appear to meet the minimum compaction requirements previously established and adopted by the City of Carlsbad (i.e.; at léäst 90 percent relative compaction per ASTM D 1557), and recent tests indicate over optimum soil moisture content, per GSI's reports (Reference No. 1 and 2). Should a significant (i.e., three to seven days) period of time pass prior to slab construction, additional moisture conditioning and/or re-establishing consistency, as well as pad subgrade proof testing may', : be necessary, prior to placement of the underslab vapor retarder (see Reference No. 2'and -No. 3). Foundation Design/Construction Unless specifically superceded herein, the findings, conclusions, and recommendations presented in Reference No 3, are generally considered valid and applicable with respect to the construction and development of the subject building pads. Based on our review of Reference No. 3, Lot 121 is low expansive, and categorized as foundation Category IPT; • . • while the remaining Lots 119, 120, and 136-138 (medium expansive) are categorized as - foundation Category IIPT. If building code updates are adopted prior to the development: , of these pads, an additional geotechnical update report may be necessary. -. Plan Review 7. Final project plans (foundation, retaining wall, landscape, etc.) should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and + - I . - - - -- - - .- - Brookfield Homes • W.O. 5949-B-SC -. PA-1.6, Phase 14, Robertson Ranch • October 2, 2012- . File e \wpl2\5900\5949b phl4 cr0 GeOSoils, Inc. Page 2 - • U David W. Skelly Civil Engineer, RCE 4 recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical evaluations may be warranted. Closure The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to contact our office. Respectfully submitted GeoSoils, Inc. No. 1934 # i ' CertUled Engjneerng /-V:5~ Robert G. Crisman' pGooIogstist Engineering Geolog4j RCG/DWS/JPF/jh Attachment: "Field Testing Reports" Distribution: (1) Addressee (via mail and email) Brookfield Homes W.O. 5949-B-SC PA-16, Phase 14, Robertson Ranch October 2, 2012 FHe:e:\wp12\5900\5949b.phl4.cro GeOSoils, Inc. Page 3 FIELD TESTING REPORT ..________ DATE 17 I NAME HOURS t- - CLIENT _____________________-TRACT _P / LOCATION_(L-&flO SUPT. 1j-E? i1 CONTRACTOR C/L L.cIEr EQUIPMENT ~J6 S ELEV. DEPTH OR hW!.kiiIU MOISTURE 4. DRY DENSITY .7. RELATIVE - .!I-J!W._. =2 WWWOM 11 VNIZA - WN9 =1 __- PAGE This field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should be informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our firm will not be responsible for job or site safety on this project. FIELD TESTING REPORT N1-Bx DATE NAME_____________ HOURS - CLIENT XfrFIE-O TRACT P3 1(1" LOCATION______________________ SUPT-69E6 /1") CONTRACTOR 4i1. Ccif5T EQUIPMENT OR I • MOI STURE CONTENT DRY DENSITY '. RELATIVE .Iifif.1• £oJ Mimi= '510I)TIM 99NOWAMAN! OWN W --I -a rm 0 M 6 AM, r, W M Warm"i x Sm COMMENTS: BY:G2 _ / PAGE _: OF] This field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should be informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our firm will not be responsible for job or site safety on this project. FIELD TESTING REPORT CLIENT -TRACT LOCATIONY-1 EiuiL.CONTRACTOR G-JtUl~/ EQUIPMENT TEST NO. ELEV. OR DEPTH MOISTURE CONTENT % DRY DENSITY P.C.F. % 7 RELATIVE COMPACTION ME Me W Wif H "r -14 W, 170011 r st EM, I I nw- 1%, will MR Tiff, % J W) 071 NNA COMMENTS: J1fl1 1 This field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should be informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our firm will not be responsible for job or site safety on this project. FIELD TESTING REPORT w.o.S&jC DATE a NAME_____________ HOURS 7 - CLIENT _______________________TRACT I CO LOCATION_______________________ CONTRACTOR CPiC. Liçr SUP EQUIPMENT D cl wzo (*I)( Wiàirir II CONTENT E LE DEPTH MOISTURE % DRY DENSITY P.C.F. % RELATIVE COMPACTION E 'loom , mm I - -- --j-_-- I 0J Mtllu W-71MR21 IR I me I mv, MHAZ d %= MIA (14 -I -- - a COMMENTS: _2- BY: PAGE L OF This field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should be informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our-firm will not be responsible for job or site safety on this project. p . ,f4jJ S - TRACT _hI.YU[.1øT?$7 CLIENT SUPT EQUIPMENT FIELD TESTING REPORT ELEV. OR DEPTH MOISTURE CONTENT % DRY DENSITY P.C.F. % RELATIVE COMPACTION ri_,rd WE W, INS ri..&IMME -_ riff., YOM V ffrol"'s W oil I Win 1"r go, M6 41, f "k, LO fit "I M. L W_V on"M WINE,= COMMENTS: PAGE OF This field field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should be informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our-firm will not be responsible for job or site safety on this project. FIELD TESTING REPORT DATE 91? I/7 NAME_____________ HOURS - I. PA% r FA I W01 ELEV. OR DEPTH MOISTURE CONTENT % DRY DENSITY P.C.F. % RELATIVE COMPACTION - fm PRO= =11111 ra; 0=01 all ZZE-No .0.13W.m. 9 "'a J 01 ME 1 -- -- -t COMMENTS: BY: /fó j/VV PAGE OF This field report presents a summary of observations and testing by Geosoils, Inc. personnel only where the tests were performed. Our work does not include supervision or direction of the actual work of the contractor, his employees, or agents. The Contractor should The informed that neither the presence of our field representative, nor the observation and testing by our firm, shall excuse him in any way for defects discovered in his work. It is understood that our firm will not be responsible for job or site safety on this project.