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Home My WebLink AboutCT 04-01; YAMAMOTO SUBDIVSION POINSETTIA RIDGE; SUMMARY OF OBSERVATION AND TESTING; 2010-10-19Orange County I EnvironmentaD I Corporate 3185-A Airway Avenue Cona Mesa, California 92626 T. 714 549 8921 F: 714 549 1438 past + present + hsture it's in our science Engineers. Geologists October 19,20110irnonlental Scientists J.N. 155-10 Grading Permit No.: GR1O-13 Mr. Tom Tupman WARMINGTON RESIDENTIAL CALIFORNIA 3090 Pullman Street Costa Mesa, CA 92626 Subject: Summary of Observation and Testing, Reconditioning of Lots 1, 2,7 and 8 of Tract 04-01, The Points ettia Ridge Project, Southeast Corner of Black Rail Road and Songbird Avenue, City of Carlsbad, San Diego County, California References: See Attached List. Mr. Tupman: Presented herein are the results of our field observation and testing performed during reconditioning of the pad surfaces on Lots 1, 2, 7 and 8 of Tract 04-01. The purpose of this most recent grading was to restore the subject pads back to their original condition as they existed at the completion of rough grading (Reference No. F). A single-family residence is proposed on each lot. OBSERVATIONS AND TESTING A representative of this finn provided observation and testing during re-conditioning of the pad surfaces on the subject parcels and lots. In general, the work was performed in the following manner: 1. All construction debris and weeds were removed from each parcel and lot. The existing pad surfaces on each lot were scarified to depths of 4 to 6 inches, watered as necessary to achieve near optimum moisture conditions, and then recompacted in, place to a minimum relative compaction of 90 percent by wheel-rolling with a skip loader and a water truck filled to capacity. Field density tests were performed using Nuclear Test Method ASTM D 6938-08a. Test results are presented in Table I and approximate locations of the field density tests are shown on Plate 1. Field density tests were taken at regular intervals to verify adequate compaction. Maximum dry density and optimum moisture content of representative samples of the on-site soils were determined in our laboratory in accordance with Test Method ASIM D 1557-07. The results of these laboratory tests are summarized in Table H. Visual classification of earth materials in the field was the basis for determining which of the maximum density values was applicable for a given density test. One-point checks were performed to supplement visual classifications. ran er.L".Ou Saw es ou 535 01 1 WARMINGTON RESIDENTIAL CALIFORNIA October 19, 2010 Lots], 2, 7 and 8 of Tract 04-01 J.N. 155-10 Page 2 CONCLUSIONS Based on the results of our observations, on our field and laboratory tests, and on our experience and judgment, it is our opinion that the completed earthwork discussed herein has been performed in general accordance with our recommendations for processing of existing grades within the subject lots. Recompaction of the pad surfaces under the purview of this report has been completed under theobservation of and with selective testing by Petra Geotechnical, Inc., and is found to be in' compliance with the Grading Code of the City of Carlsbad, California. The completed work has been reviewed-arid is considered adequate for the construction now planned. Foundation design recommendation's provided in Reference Nos. 3 and 4 remain applicable and no further recommendations are needed at this time. REPORT LIMITATIONS A representative of Petra Geotechnical, Inc. (Petra) was present on-site on an on-call basis during post-grading operations for the purpose of providing the owner's representative with professional opinions and recommendations. These opinions and recommendatiohs were developed based on field observation and selective testing of the contractor's work. Our scope of services during this project did not include supervision or direction of the contractor, his personnel or his subcontractors. As documented in this report, our observations and testing did not reveal any obvious deviations from the recommendations provided in the referenced geotechnical reports by our firm; however, Petra does not in any way guarantee the contractor's work, nor do our services relieve the contractor (or any subcontractors) of their liability should any defects subsequently be discovered in their work product. Based on our findings, this report was prepared in conformance with generally accepted professional engineering practices, and no further warranty is implied nor made. This report is subject to review by the controlling authorities for the project. Should you have any questions, please do not hesitate to call. Respectfully submitted, PETRA GEOTEC ,04 6Oi2 rM Siamak Jafroudi, P 2W3W' Principal. Senior Principal /o/LOffQ SM/S Jfkg OF c 0 W:\2010\100\155-10 Warmingion Rcsidcrniaj Coliforni 3OO\Rcccrflcaiioo Lrttcr(Lots 1,27,8 ofTrO4-OI)doc WARMINGTON RESIDENTIAL CALIFORNIA October 19, 2010 Lots 1, 2; 7 and 8 of Tract 04-01 J.N. 155-10 Page 3 REFERENCES Christian Wheeler Engineering, Report of Field Observation and Relative Compaction Testing, Grading and Site Improvements, Black Rail 16-Lot Development, Black Rail Road and Songbird Ave., Carlsbad, California: prepared for Watkins Landmark Construction, dated January 4, 2007 (CWE 2050489.05). Geotechnical Commentary on Design and Construction of Post-Tensioned Slabs On-grade for Lots 1 through 16 Carlsbad Tract No. 04-01, The Poinsettia Ridge Project, Southeast Corner of Black Rail Road and Songbird Avenue, City of Carlsbad, San Diego County, California, letter by Petra Geotechnical, Inc., dated April 1, 2010. Geotechnical Review of Precise Grading Plans and Updated Foundation Design Recommendations, Lots I through 16 Carlsbad Tract No. 04-01, The Poinsettia Ridge Project, Southeast Corner of Black Rail Road and Songbird Avenue, City of Carlsbad, San Diego County, California, letter by Petra Geotechnical, Inc., dated April 13, 2010. Response to City of Carlsbad Review Sheet and Review of Precise Grading and Foundation Plans, Lots 1 through 16, Carsbad Tract No. 04-01, The Pointsettia RidgeProject, Southeast Corner of Black Rail Road and Songbird Avenue, City of Carlsbad, San Diego County, California, letter by Petra Geotechnical, Inc., dated July 14, 2010. WAIRMINGTON RESIDENTIAL CALIFORNIA October 19, 2010 Lots 1, 2, 7 and 8 of Tract 04-01 J.N. 155-10 Page 4 TABLE! FIELD DENSITY TEST SUMMARY Date of Test Test No. Parcel Number Depth * (ft.) Moist. (%) Unit Wt. libsicu.ft. % Re). Comp. Soil Type 10/4/2010 1 Lot#1 FG 11.9 116.3 92 A 10/14/2010 2 Lot#2 FG 12.4 117.3 93 A 10/14/2010 3 Lot #7 FG 12.6 117.2 93 A 10/14/2010 4. Lot #8 FO 12.1 116.2 92 A FO - Finish Grade * - Depth Below Finish Grade TABLE II Soil Type Optimum Moisture (%) Maximum Dry Density (pct) A - Silty Sand (SM) 10.0 126.0 i4 All Wlow3o ' 36 '1 s o - L1• - ; -4_ F'°• LII 7W Rh 491-4 F43063 Ste . . •0.6 - F',,745 - 's30315.030.45 TT 's.3i' 17 — -.-_--_.''!• •I R t0 4 1 'iiiiJ /LH5 :6 t. '5 — 'ft W. I — FF3363036 F ;1Lt4 ..L '°" 4i °" / I 20-'---JL. I41.3 • . . /6!! CJ 11/ . 7iI IIDQ$7 qf,35055" ff -- No If I 11146 16W f - 530k . 95 / H 97.3 . I i. 40ZL5-090-95 ®' / I I'I\' 6 / ) 138T750f5 \ . 56.17 •, . (.13001 I _13 afooff 1 1 ° V Ds. . V I L3310 I 7033 Ile 'I &0 0 4 .6 %5#7' •'33 I 0116213.040-41 I - — lluoa ,. . .0 • — -- II q •J • . -. - -r x' - ) Co.30.3'Rs5.WdI -.__ .;--- • * _ / /D5s01. 147.49 dF01h,9f,HI70FI - - -- - !I L. ,H' "'I O.d2j, 366-ti'r L\'u L1 Evuseffferit Now -H F.. o EXPLANATION : -, PETRA GEOTECHNICAL. INC. - 'roctha Fidge' GRAPHIC °—' fit Approximate Limits of This Report -j J.N. 155-10 OCT 2010 - P7T/. PLATE I Section X —4 Approximate Location of Density Test -L