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Home My WebLink AboutCT 06-25; ROBERTSON RANCH EAST VILLAGE PA 21; COMPACTION REPORTS OF BUILDING PAD RECERTIFICATION; 2013-01-21GJC. Geotechnical. Geologic . Coastal • Environmental, 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 • www.geosoilsinc.com January 21, 2013 W.O. 6332-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 12 (Lots 28, 29, and 30) of Planning Area 21 ("Sago at the Foothills"), Robertson Ranch Development, Carlsbad, San Diego County, California References: 1. "Geotechnical Update for Planning Area 21, Robertson Ranch, East Village, City of Carlsbad, San Diego County, California," W.O. 5981-B-SC, dated May 25, 2011, by GeoSoils, Inc. "Discussion of Building Slab Subgrade Pre-Wetting, Planning Area 21 of Robertson Ranch, City of Carlsbad, California," W.O. 5981-C-SC, dated January 21, 2010, by GeoSoils, Inc. "Report of Rough Grading, Planning Area 21 of Robertson Ranch, East Village Carlsbad, San Diego County, California," W.O. 5953-131-SC, dated November 24, 2008, 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 Phase 12 (Lots 28, 29, and 30) of Planning Area 21 (Sago at the Foothills), 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. Earthwork consisted of re-processing surficial soils to a depth of approximately 8 to 12 inches, moisture conditioning, and compaction of soil to a minimum relative compaction of 90 percent per ASTM D 1557 (see Reference No. 2). Based on our observations and testing, the building pads appear to have been reconditioned in general accordance with the recommendations provided by this office (see Reference No. 2 and No. 3), and are considered suitable for their intended use. Field Observation and Testing Field density tests were performed using nuclear (densometer) ASTM test methods D 2922 and D 3017. The test results taken during grading operations are presented in the attached copy of our "Field Testing Report." 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: SOIL TYPE MAXIMUM DENSITY (PCF) MOISTURE CONTENT .. (PERCENT). IX - Dark Brown Silty SAND ---77 131.5 I 9.0 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 least 90 percent relative compaction per ASTM D 1557), and recent tests indicate at least optimum soil moisture content (see attached field testing reports). Should a significant (i.e., three to seven days) period of time pass priorto 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. 1 and No. 2). Foundation Design/Construction Unless specifically superceded herein, the findings, conclusions, and recommendations presented in Reference No. 1, and 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, the subject lots are very low to low expansive. However, due to maximum fill depths beneath the lots, Lots 28 and 29 are assigned to foundation Category Ill, while Lot 30 is assigned to Category II. If new building code updates are adopted prior to the development of these pads, an additional geotechnical update report/revised foundation recommendations, may be necessary. Plan Review Any revisions to 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 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 Brookfield Homes W.O. 6332-13-SC PA-21, Robertson Ranch January 21, 2013 File: e:\wpl2\6300\6332b.phl2.cro GeoSoils, Inc. Page 2 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 ônsite, 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 su GeoSoils, Inc. cL i'!o. 1934 GertNiod \ Enoineering Geotogist ,:• Robert G. Crisman "ThF à' Engineering Geologist, 1340 RCG/ATG/JPF/jh Attachment: "Field Testing Report" Distribution: (3) Addressee (via mail and email) OESS, CO fc f< No. 0E2329 -I * Exp._f1-/1j13J * DA 'Andrew T. Guatelli Geotechnical Engineer, GE 2320 Brookfield Homes W.O. 6332-13-SC PA-21, Robertson Ranch January 21, 2013 GeoSoils File:e:\wpl2\6300\6332b.phl2.cro , Inc. Page 3 FIELD TESTING REPORT W.O. DATE _______ flftiH NAME HOURS_____________ CLIENT _______________________TRACT 1 LOCATION______________________ SUPT. _T CONTRACTOR (P&__tiSr EL .7 OR DEPTH MOISTURE CONTENT 0/ DRY DENSITY P.C.F. % RELATIVE COMPACTION uciai W-UNK100101 iiui Imam 11010110101101 1101 11010110101101 1101 ME ME 1101MINIM101 1101 ME 1101 Own Mmxt- "to NMI SWIVINVVE11"2111 I ~ "01 wilk" 1101 EEM COMMENTS: 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. C 0 N S U L T A N T S Civil Engineering a Surveying January 23, 2013 J.N.: 08-1245--04 City of Carlsbad Building Department 1635 Faraday Avenue Carlsbad, CA 92008 RE: Robertson Ranch PA 21, Grading Plan Drawing No. 461-6A Pad Certification Units 28-30 Dear Sirs: Based on our field survey of January 23, 2013, the rough grading of the pads for Units 28 through 30 of Grading Plan 461-6A have been substantially completed in accordance with the approved grading plan to the approximate final elevation The final elevations are certified to a tolerance of plus Or minus 0.1 feet and the horizontal location is certified for approximate location. Very truly yours,. O'DAY CONSULTANTS, INC. 224" /(23 s TC/ps Tim Carroll Project Manager TMOflfya\\\ * CARo )) 77UO 1*11 ¼9CALO!i/ N:\081245\1130123_PadCert-PA21 - Units 28-30.doc O'Day Consultants Inc. E-mail: oday@odayconsultants.com 2710 Loker Avenue West, Suite 100 Website: www.odayconsultants.com Carlsbad, California 92010-6600 Tel: 760.9317700 Fax: 760.931.8680 J9f99 &IJ 4? 5CP ODC C/IS X 1 ; PAD-P1421 22.15J 4 A AD-PA21 22154 8176 PAD-P421 22155 +8186 22158 PAD-PA2/ 8182 \ 3O PAD-PA21 157 - • AD-P,421 22159 PAD-P,421 +JpA21 22160 22161 4 8199 not PAD-P421 PAL)-PA2 2.2162 or F, aw "10.2 PAO-PA21 +&W At mov 22165 C1o((.1 5741 Palmer Way Carlsbad, California 92010 (760) 438-3155 FAX (760) 931-0915 www.geosoilsinc.com November 3, 2011. W.O. 6332-B-SC Brookfield Homes 12865 Pointe Del Mar, Suite 200 Del Mar, California 92014 Attention: Mr. Greg McDonnell Subject: Compaction Report of Building Pad Re-Certification, Model Lots 25, 26, and 27 of Planning Area 21, Robertson Ranch Development, Carlsbad, San Diego County, California References: 1. "Geotechnical Update for Planning Area 21 Robertson Ranch, East Village, City of Carlsbad, San Diego County, California," W.O. 5981-B-SC, dated May 25, 2011, by GeoSoils, Inc. "Discussion of Building Slab Subgrade Pre-Wetting, Planning Area 21 of Robertson Ranch, City of Carlsbad, California," W.O. 5949-C-SC, dated January 21, 2010, by GeoSoils, Inc. "Report of Rough Grading, Planning Area 21 of Robertson Ranch, East Village Carlsbad, San Diego County, California," W.O. 5953-131-SC, dated November 24, 2008, by GeoSoils, Inc. Dear Mr. McDonnell: GeoSoils, Inc. (GSI) is providing this summary of our observation and testing services during mitigative grading within Lots 25, 26, and 27 of Planning Area 21, at Robertson Ranch, East Village Subdivision in the City of Carlsbad, California. The purpose ol remedial grading was to reprocess lots in accordance with recommendations presented in Reference No. 2, for the planned model lots. Earthwork consisted of re-processing surficial soils to a depth of approximately 8 to 12 inches, moisture conditioning, and compaction of soil to a minimum relative compaction of 90 percent per ASTM D 1557 (see Reference No. 2). Based on our observations and testing, the building pads appear to have been prepared in general accordance with the recommendations provided by this office (see Reference No. 2 and No. 3), and are considered suitable for their intended use. Field Observation and Testing Field density tests were performed using nuclear (densometer) ASTM test methods D 2922 and D 3017. The test results taken during grading operations are presented in the attached copy of our "Field Testing Report." 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: MAXliVIUM MOISTURE CONTENT - SOILTYPE DENSITY(PcF - (PERCENT). [x - Gray Brown, Clayey SAND I 131.5 I 9.0 I 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 least 90 percent relative compaction per ASTM D 1557), and recent tests indicate over optimum soil moisture content, per GSl's reports (References 1 and 2). Should a significant (i.e., 3 to 7 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. 1 and No. 2). Foundation Design/Construction Unless specifically superceded herein, the findings, conclusions, and recommendations presented in Reference No. 1, and 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, the subject lots are low expansive, and categorized as foundation Category Ill, due to maximum fill depths beneath the lots. If building code updates are adopted prior to the development of these pads, an additional geotechnical update report may be necessary. 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 Brookfield Homes W.O. 6332-B-SC Model Lots 25, 26, & 27, PA-21, Robertson Ranch November 3, 2011 Fi1e:e:\wp12\6300\6332b.cro Page 2 GeOSGIRS, Resrr1-fi iII, i ihrn GeoSoHs, Inc. ( Robert G. CrismE Engineering Geo 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. Geotechnical Engineer, GE 2320 RCG/ATG/JPF/jh Attachment: "Field Testing Report" Distribution: (1) Addressee (via email) (1) Brookfield Homes, Attention: Ms. Terri McHugh (via email) Brookfield Homes W.O. 6332-B-SC Model Lots 25, 26, & 27, PA-21 Robertson Ranch November 3, 2011 FiIe:e:\wp1263OO\6332b.cro Page 3 GecXelfs, Inc. w.O.$52-4q•5 DATE.JA-- /1 NAME HOURS CLIENT TRACT_R42J,2s-2) LOCATIONS— /- 4&2 SUPT. 'T CONTRACTOR EQUIPMENT ./- , / 10-14-9-11 TEST NO. LOCATION ELEV. OR DEPTH MOISTURE CONTENT % DRY DENSITY P.C.F. % RELATIVE COMPACTION TEST TYPE SOIL TYPE / / _25 J 1. 5 /1 / 2 ) ii q, 5, 3 a27 2. ) Tox COMMENTS: BY: I I PAGE / OF - E:/wp/Iorrns/flel I/