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Home My WebLink AboutTORN RANCH - GEOTECHNICAL INVESTIGATION GEOCON E7 F I L E I N C O R P O R A T E D GEOTECHNICAL CONSULTANTS _ Project No. 20089-12-02 December 9,2002 KB Home Coastal, Incorporated 12235 El Camino Real, Suite 100 San Diego, California 92130 Attention: Mr. Gary Mingo Subject: TORN RANCH BLOCK 37 LOT NOS. 1 THROUGH 17, BLOCK 38 LOT NOS. 1 THROUGH 20, BLOCK 39 LOT NOS. 1 THROUGH 20,AND BLOCK 40 LOT NOS. 1 THROUGH 20 LAKE ELSINORE, CALIFORNIA AS-GRADED BUILDING PAD CONDITION AND FOUNDATION CATEGORIES Reference: Update Geotechnical Investigation, Torn Ranch, Lake Elsinore, California, prepared by Geocon Incorporated, dated February 15,2002 (Project No. 20089-12-01). Gentlemen: In accordance with your request, we have prepared this letter stating that it is the opinion of Geocon Incorporated, based on field and laboratory tests and observations, that the subject lots have been graded in substantial conformance with the above referenced Update Geotechnical Investigation. The purpose of this letter is to provide sufficient information to obtain building permits for the lots. Additionally, lot specific foundation recommendations that are based on the as-graded soil conditions are herein provided for the lots. A final report of grading presenting the results of our field and laboratory test results will be submitted upon completion of the grading for the remainder of the project. Grading for the subject lots began with the removal of Cofsoil and alluvium to depths recuallnenued in the field by our project geologist. The exposed surface of the over-excavations was scarified, moisture conditioned as necessary, and compacted. Compacted fill soils were then placed in layers until the design grades were achieved. The maximum depth of compacted fill for the subject lots is approximately 14 feet(Block 40, Lots 8 and 11). During the grading operation, compaction procedures were observed and in-place density tests were performed to evaluate the relative density of the soils. The in-place density tests were performed in general conformance with ASTM Test Method D2922-01 (nuclear). The results of the in-place density tests for the subject lots will be presented in our Final Report of Testing and Observation During Site Grading for Torn Ranch once grading operations are complete. Additionally, the approximate locations of the tests will be plotted along with the geologic conditions on an 4s- Graded Geologic Map, currently in progress. 43280 Business Park Drive, Suite 108 0 Temecula, California 92590-3633 0 Telephone(909)587-8169 0 Fax(909) 676-9860 Laboratory testing was performed on soil samples to evaluate moisture density relationships, optimum moisture content and maximum dry density (ASTM D1557-00). Additionally, laboratory tests were performed on samples of soil exposed at finish grade to determine the expansion potential (ASTM D4829-95) and the water-soluble sulfate content (California Test 417). The expansion index for each of the subject lots is presented in Table I. Results to the laboratory water-soluble sulfate tests for the subject lots indicate that concrete structures exposed to soils at the locations tested have a "negligible" water-soluble sulfate exposure, as defined by UBC Table 19-A-4. No special concrete deign requirements are set forth in UBC for concrete due to a "negligible" amount of sulfate exposure. The results of the laboratory testing will be presented in the final report. In general,the in-place density test results indicate that the compacted fill soils placed during grading operations for the subject lots have a relative compaction of at least 90 percent at the locations tested. The foundation recommendations for each lot are dependent on the total depth of fill, differential fill thickness, and the expansion characteristics of the soil near finish grade within the lot. This report presents the laboratory test results and foundation recommendations as a Category I, II, or III for each of the residential buildings within the site. The design parameters for each Foundation Category are provided in the above referenced geotechnical report and the results and recommendations provided herein are considered supplemental. Due to the underlying soil conditions the geotechnical report recommended that a post-tension foundation system be used. It was also recommended that we review the foundation plans prior to construction. Table I presents a Summary of As-Graded Building Pad Conditions, and the recommended foundation category for each of the subject lots. If you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED r�pfE5S��N ;, AS` q�Fy pESS1o/yA� Keith P.Askew w No C 056416 rn David y RCE 56418 * Exp 613U105 * RCE 22527 W No 225'z� S T C W_ s E0,12 31105 KPA:DFL:dmc gTFOFCA0 CN (2) Addressee q OFcP1-� (2/del) City of Lake Elsinore Attention: Mr. Richard Hess Project No.20089-12-02 -2- December 9,2002 TABLE SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS TORN RANCH, BLOCKS 37, 38, 39, AND 40 Approximate Approximate Foundation Block— Pad Maximum Depth of Expansion Recommendation Lot No. Condition Depth of Fill Differential Fill Index (feet) (feet) Category 37- 1 Fill 13 1 1 II 37 -2 Fill 13 1 1 H 37 -3 Fill 11 1 1 H 37 -4 Fill 11 1 1 H 37-5 Fill 11 1 1 H 37 -6 Fill i 1 1 1 II 37 -7 Fill 11 1 1 II 37 - 8 Fill 10 1 1 II 37 -9 Fill 10 1 1 H 37- 10 Fill 11 1 1 H 37- 11 Fill 11 1 1 H 37 - 12 Fill 12 1 1 II 37— 13 Fill 12 1 1 II 37— 14 Fill 12 1 1 II 37— 15 Fill 11 1 1 II 37— 16 Fill 12 1 1 II 37— 17 Fill 11 1 1 H 38— 1 Fill 11 1 0 II 38-2 Fill 12 1 0 II 38—3 Fill 10 1 0 II 3 8—4 Fill 10 1 0 II 3 e -5 Fill 10 1 0 H 38—6 Fill 10 1 0 H 3 8—7 Fill 11 1 0 H 38-8 Fill 11 1 0 H 38—9 Fill 11 1 0 II 38— 10 Fill 11 1 0 II 38— 11 Fill 10 1 0 II 38— 12 Fill 10 1 0 II 38— 13 Fill 9 1 0 II 38— 14 Fill 9 1 0 II Project No.20089-12-02 December 9,2002 TABLE I (Continued) SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS TORN RANCH, BLOCKS 37, 38, 39, AND 40 Approximate Approximate Foundation Block— Pad Maximum Depth of Expansion Recommendation Lot No. Condition Depth of Fill Differential Fill Index (feet) (feet) Category 3 8— 15 Fill 8 1 0 II 3 8— 16 Fill 8 1 0 II 38— 17 Fill 8 1 0 II 38— 18 Fill 9 1 0 II 38— 19 Fill 11 1 0 II 38—20 Fill 11 1 0 II 39— 1 Fill 13 1 4 II 39—2 Fill 12 1 4 II 39—3 Fill 11 1 4 II 39—4 Fill 12 1 4 II 39—5 Fill 12 1 4 II 39—6 Fill 13 1 5 II 39—7 Fill 13 1 5 II 39—8 Fill 13 1 5 II 39—9 Fill 12 1 5 II 39—10 Fill 11 1 5 II 39— 11 Fill 11 1 4 II 39— 12 Fill 12 1 4 II 39— 13 Fill 11 1 4 II 39— 14 Fill 11 1 4 II 39— 15 Fill 10 1 4 II 39— 16 Fill 10 1 5 II 39 - 17 Fill 10 1 5 II 39— 18 Fill 10 1 5 II 39— 19 Fill 12 1 5 II 39—20 Fill 12 1 5 II 40— 1 Fill 11 1 0 II 40—2 Fill 11 1 0 II 40—3 Fill 12 1 0 II 40—4 Fill 12 1 0 II 40—5 Fill 13 1 0 II Project No.20089-12-02 December 9,2002 TABLE I (Continued) SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS TORN RANCH, BLOCKS 37, 38, 39, AND 40 Approximate Approximate Foundation Block— Pad Maximum Depth of Expansion Recommendation Lot No. Condition Depth of Fill Differential Fill Index (feet) (feet) Category 40—6 Fill 12 1 0 II 40—7 Fill 13 1 0 II 40—8 Fill 14 1 0 II 40—9 Fill 13 1 0 II 40— 10 Fill 12 1 0 II 40— 11 Fill 11 1 2 II 40— 12 Fill 13 1 2 II 40— 13 Fill 12 1 2 f H 40— 14 Fill 11 1 2 II 40— 15 Fill 11 1 2 II 40— 16 Fill 10 1 2 II 40— 17 Fill 10 1 2 II 40— 18 Fill 9 1 2 II 40— 19 Fill 10 1 2 II 40—20 Fill 11 1 2 II Project No.20089-12-02 December 9,2002