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Home My WebLink AboutCT 05-13; La Costa Ridge Embankment Constraints; La Costa Ridge Embankment Constraints; 2007-02-21PACIFIC SOILS ENGINEERING 7715 CONVOY COURT, SAN DIEGO, CALIFORNIA 921 TELEPHONE: (858) 560-1713, FAX: (858) 560-0380 D.R. HORTON INC. 5790 Fleet Street, Suite 210 Carlsbad, CA 92008 INC. Initial Date February 21,2007 Work Order 401036 Attention: Subject: References: Gentlemen: Mr. Kevin Kasai, Forward Planner Embankment Constraints, La Costa Ridge Neighborhood 2.6, Carlsbad, California, See Appendix Pursuant to your request, Pacific Soils Engineering, Inc. (PSE) has prepared this letter addressing embankment constraints for the La Costa Ridge Neighborhood 2.6, Carlsbad, California. Along the eastern property line are various sewer and reclaimed water lines. These lines consist of a variety of materials, including transite, vitrified clay and ductile iron pipe. The current grading plans depict grading and the construction of superjacent slopes and/or retaining walls within four (4) to five (5) feet of these lines. To evaluate what effect the proposed development could have on these improvements, PSE has prepared cross-sections A-A' through F-F' (Plate 2) depicting the geologic contacts, existing and proposed grades and these existing buried lines. The approximate locations of these cross- sections are presented on the grading and erosion plans, prepared by David Evans and Associ- ates, Inc. (Plate 1). In preparing these cross-sections, PSE used the as-built plans of the ten- (10) inch force main and the eight- (8) inch sewer main to determine the approximate elevation of these lines. PSE did not have as-built plans for the reclaimed water line. However, we have as- sumed a "worst-case" elevation for this line of approximately nine (9) feet below grade. CORPORATE HEADQUARTERS TEL: (714) 220-0770 FAX: (714)220-9589 LOS ANGELES COUNTY TEL: (310) 325-7272 or (323) 775-6771 FAX: (714) 220-9589 RIVERSIDE COUNTY TEL: (951) 582-0170 FAX: (951) 582-0176 SOUTH ORANGE COUNTY TEL: (714) 730-2122 FAX: (714)730-5191 Work Order 40103 6 February 21,2007 Page 2 As depicted on Plate 1 and 2, PSE has determined the limits of structural influence that could conceivably affect these buried lines. This influence line is a 1 : 1 (horizontal to vertical) projec- tion from the bottom of the lines upward to existing grade. The location of this structural influ- ence line is presented in Sections A-A' through F-F (Plate 1) and on Plate 2. Accordingly, it is PSE's recommendation that the proposed design should be modified such that loading from superjacent fill slopes or retaining walls is outside of this 1 : 1 projection. Should you have any questions regarding this letter, please contact the undersigned. Respectfully submitted PACIFIC SQII/S Etf6lNEEfcINGv By:.X Y, G>2314 Services JOHN Ay HANSON, CEG 990 Vice President Dist: (3) Addressee (2) D.R. Horton, Arm: Mr. John Owen (2) David Evans and Associates, Attn: Mr. Gabriel Rodriguez JAC/JAH:bm:401036, February 21, 2007 PACIFIC SOILS ENGINEERING, INC. Work Order 401036 APPENDIX February 21,2007 REFERENCES Pacific Soils Engineering, Inc., 2007a, Updated Preliminary Geotechnical Investigation, La Costa Ridge Project, in the City of Carlsbad, California, by Pacific Soils Engineering, Inc., dated February 15, 2007 (Work Order 401036). Pacific Soils Engineering, Inc., 2007b, Preliminary Geotechnical Investigation, La Costa Ridge Project (Approximately 7+-Acre Parcel), in the City of Carlsbad, California, by Pacific Soils Engineering, Inc., dated June 2, 2005 (Work Order 401036). Pacific Soils Engineering, Inc., 2006, Suitability of Stockpile Material, La Costa Ridge 2.6-Acre Parcel, Located Southwest of Rancho Santa Fe Road and Melrose Drive, City of Carlsbad, CA, dated February 15, 2006 (Work Order 401036). Pacific Soils Engineering, Inc., 2005a, Preliminary Geotechnical Investigation, La Costa Ridge Project (Approximately 7+-Acre Parcel), in the City of Carlsbad, California, dated June 2, 2005 (Work Order 401036). Pacific Soils Engineering, Inc., 2005b, Geotechnical Summary, La Costa Ridge 2.6-Acre Parcel, Located Southwest of Rancho Santa Fe Road and Melrose Drive, City of Carlsbad, CA, dated March 29, 2005 (Work Order 401036). PACIFIC SOILS ENGINEERING, INC.