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Home My WebLink AboutCT 04-04; LA COSTA RIDGE NEIGHEBORHOOD 2.5; INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PREFORMED DURING SITE IMPROVEMENTS; 2006-03-30C1O(4 -01- GEOCON INCORPORATED GEOTECHNICAL 'CONSULTANTS Project No. 07290-52-06 March 30, 2006 Real Estate Collateral Management Company C/0 Morrow Development Incorporated 1903 Wright Place, Suite 180 Carlsbad, California 92008 Attention: Mr. Tim O'Grady Subject: VILLAGES OF LA COSTA - THE RIDGE NEIGHBORHOOD 2.5, SITIO TORTUGA - STATION 10+00 TO 15+00 CARLSBAD, CALIFORNIA INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE IMPROVEMENTS References: 1. Update Geotechnical Investigation, Villages of La Costa - The Ridge, Carlsbad, California, prepared by Geocon Incorporated, dated August 27, 2001 (Project No. 06105-12-05). 2. Update Geotechnical Report, Villages of La Costa - The Ridge, Neighborhood 2.5, Carlsbad, California, prepared by Geocon Incorporated, dated February 1, 2006 (Project No. 07290-52-07). Gentlemen: In accordance with'your request, we have prepared this letter regarding the testing and observations services performed on an "on-call" basis during site improvements within the subject roadway at The Ridge development. The scope of our services during this phase of improvements included observing and performing in-place density tests on the storm drain, sewer main, sewer lateral, water main, and water laterals at the site. It should be noted that the subject improvements were performed by the master developer of The Ridge. We understand that the guest builder will complete the installation of dry utilities and paving of the subject roadway. A final report will be' prepared subsequent to the completion of improvements for Neighborhood 2.5 by the guest builder. During the construction of site improvements, compaction procedures were observed and in-place density tests were performed to evaluate the dry density and moisture content of the fill (trench backfill) material. In-place density tests were performed using a nuclear density gauge in accordance with ASTM Test Procedure D 2922-01. In-place density tests for asphalt concrete were performed using a nuclear gauge in accordance with ASTM Test Procedure D 2950-91. In general, the on-site materials typically consist of clayey sand with trace amounts of gravel. Using methods suggested by Woodward-Clyde, corrections were made to the laboratory maximum dry density and optimum moisture content on fill soils being tested containing rocks larger than 6960 Flanders Drive • San Diego, California 92121-2974 0 Telephone (858) 558-6900 0 Fax (858) 558-6159 GEOCON INCORPORATED 7)-LQ C. Michael C. Ertwine Shane Rodacker Senior Staff Geologist RCE 63291 MCE:SR:AS:dmc (4/del) Addressee (4) KB Homes Coastal Inc. Attention: Ms. Courtney Burnett Project No. 07290-52-06 - 2 - March 30, 2006 3/4 inch. The values of maximum dry density and optimum moisture content presented in Table I reflect the rock corrections. The results of the in-place density tests for asphalt concrete and in-place dry density and moisture content tests for fill soil are summarized in Table I. Laboratory test results are summarized on Table II. In general, the results of the in-place density tests indicate that the utility trench backfill materials, possesses a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content at the locations tested. Based on observations and test results, it is the opinion of Geocon Incorporated that the construction of site improvements, which is the subject of this report, has been performed in substantial conformance with the recommendations of the referenced geotechnical reports, pending the City of Carlsbad's review and acceptance. Any additional grading and/or improvement installation performed at the site should be accomplished in conjunction with our observation and compaction testing services. Grading plans for any future grading should be reviewed by Geocon Incorporated prior to finalizing. All trench and wall backfill and sidewalk subgrade should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. This office should be notified at least 48 hours prior to commencing additional grading or backfill operations. Adequate drainage provisions are imperative. Under no circumstances should water be allowed to pond adjacent to improvements. Finish grades should be established so that drainage water is directed away from pavements, curb and gutters, and sidewalks to controlled drainage devices. Irrigation of landscape areas adjacent to pavements should be monitored to provide just enough water to support plant life. Should you have any questions regarding this report addendum, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours TABLE SUMMARY OF FIELD DENSITY TEST RESULTS Elev. Plus Field Field Field Req'd. or 3/4" Adj. Adj, Dry Moist. Rel. Rel. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. Test No. Date Location No. (°"O) (pci) (%) (pci) SD 1 01/10/06 Sitio Tortuga 17+60 -2 - 13 0 127.1 10.1 118.3 11.3 93 90 SD 2 01/10/06 Sitio Tortuga 17+15 - -2 13 0 127.1 10.1 119.3 10.8 . 94 90 Project No. 07290-52-06 .' .. . . March 30, 2006 Test No. Date Location SL 1 01/06/06 Lot 3; Sitio Tortuga SL 2 01/06/06 Lot 1; Sitio Tortuga SL 3 01/06/06 Lot 12; Sitio Tortuga SL 4 01/06/06 Lot 5; Sitio Tortuga SL 5 01/06/06 Lot 7; Sitio Tortuga SL 6 01/06/06 Lot 9; Sitio Tortuga SL 7 01/06/06 Lot 11; Sitio Tortuga TABLE SUMMARY OF FIELD DENSITY TEST RESULTS Elev. Plus Field Field Field Reqd. or 3/4 Adj. Adj. Dry Moist. .Rel. Re!. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. (ft) No. (%) (pcf) (%) (pcI) (%) (%) (%) -2 13 20 131.9 8.3 118.3 11.2 90 90 -2 13 20 131.9 8.3 . 119.9 9.2 91 90 -2 13 20 131.9 8.3 121.0 8.4 92 90 -2 13 20 1319 8.3 121.8 8.1 92 90 -2 13 20 131.9 8.3 122.0 8.2 92 90 -2 13 20 131.9 8.3 123.4 8.0 94 90 -2 13 20 131.9 8.3 123.3 8.0 93 90 Project No. 07290-52-06 March 30, 2006 I F- TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. Plus - Field Field Field Req'd. - - or 3/4" Adj. Adj. Dry Moist. Rel. Rel. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. Test No Date Location (t) No (%) (pcf) (%) (pet) (%) (%) (%) SM 1 01/06/06 Sitio Tortuga 18+55 2 13 20 131.9 83 1 18 1 105 90 90 SM 2 01/09/05 Sitio Tortuga 18+00 - -2 13 20 131.9 8.3 118.6 10.1 90 90 SM 3 01/10/05 Sitio Tortuga 17+55 2 13 20 1319 83 1212 88 92 90 SM 4 01/10/05 Sitio Tortuga 19+50 2 13 20 1319 83 1183 102 90 90 SM 5 01/10/05 SitioTortuga19+00 2 13 20 1319 83 1200 87 91 90 SM 6 01/10/05 Sitio Tortuga 20+00 2 13 20 1319 83 1189 100 90 90 SM 7 01/10/05 Sitio Tortuga 20+50 2 13 20 1319 83 1230 80 93 90 SM 8 01/10/05 Sitio Tortuga 21+35 2 13 20 1319 83 1227 82 93 90 1 Project No. 07290-52-06 March 30, 2006 - . . '. Project No. 07290-52-06 . • • • March 30, 2006 TABLE I VIARY OF FIELD DENSITY TEST RESULTS Elev. Plus Field Field Field Req'd. or 3/4" Adj. Adj. Dry Moist. Rel. Re!. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. ;(ft) No. (%) (pet) (%) (pcf) -1 13 10 129.5 9.2 118.5 12.1 92 90 -1 13 10 129.5 9.2 118.9 8.9 92 90 -1 13 10 129.5 9.2 121.6 11.6 94 90 -1 13 10 129.5 9.2 119.3 10.0 92 90 - TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. - Plus Field Field Field Reqd. or 3/4" Adj. Adj. Dry Moist. Rel. Rel. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. Test No. Date Location t) No. (%) (pcf) (%) (pcf) WM 1 01/11/06 ConnitaSt; Water Tie-in -2 13 0 127.1 10.1 118.2 10.3 93 90 WM 2 01/20/06 Sitio Tortuga 21+90 -2 13 0 127.1 10.1 121.3 10.0 95 90 WM 3 01/23/06 Sitio Tortuga 21+10 . -1 13 10 129.5 9.2 118.9 11.3 92 90 WM 4 01/23/06 Sitio Tortuga 20+60 I -1 13 10 129.5 9.2 118.4 10.0 91 90 WIvI 5 01/23/06 Sitio Tortuga 19+95 -1 13 10 129.5 9.2 119.0 8.9 92 90 WM 6 . 01/23/06 Sitio Tortuga 19+24 -1, 13 10 129.5 9.2 121.6 8.4 94 90 WM 7 01/23/06 Sitio Tortuga 18+40 -1 13 10 129.5 9.2 121.0 12.0 93 90 WM 8 01/23/06 Sitio Tortuga 17+55 -1 13 10 129.5 9.2 118.9 11.1 92 90 Project No. 07290-52-06 March 30, 2006 TABLE I EXPLANATION OF CODED TERMS -TEST SUFFIX A, B, C.... Retest of previous density test failure, following moisture conditioning and/or recompaction. -STRIKE-OUT Fill in area of density test failure was removed and replaced with properly compacted fill soil. - PREFIX CODE DESIGNATION FOR TEST NUMBERS SL - STORM DRAIN • - - SL -SEWER LATERAL SM -SEWER MAIN WL - WATER LATERAL WM - WATER MAIN -CURVE NO. Corresponds to curve numbers listed in the summary of laboratory maximum dry density and optimum moisture content test results table for selected fill soil samples encountered during testing and observation. - ROCK CORRECTION For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum • moisture content were adjusted for rock content. For tests with rock cntent equal to zero, laboratory maximum dry density and optimum moisture content values are unadjusted. - TYPE OFTEST - • -. SC: Sand Cone Test (ASTM D1556) . • NU: Nuclear Density Test (ASTM D2922) OT: Other - ELEVATION/DEPTH • S Test elevations/depths have been rounded to the nearest whole foot. • - Project No. 07290-52-06 - • • March 30, 2006 I TABLE II SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557-00 Sample Maximum S Optimum No Description Dry Density Moisture Content (pci) (% dry weight) 13 Dark brown, Clayey SAND with trace gravel 127.1 10.1 Project Project No. 07290-52-06 March 30, 2006