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Home My WebLink AboutTract Map 9833-3 Lot 3 Geotechnical Update � � . �'��33r� � � �°� 3 Sladden Engineering 77-725 Enfield Lane, Suite 100, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895 6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 15438 Cholame Road, Suite A, Victorville, CA 92392 (760)962-1868 Fax (760) 962-1878 May 15, 2007 Project No. 644-07059 07-05-046 Benson Design and Build, Inc 29281 Mammoth Pl Canyon Lake, C a 92587 Subject: Geotechnical Update Project: 43599 Calle De Valerdo Temecula, California Ref: Grading Report prepared by Sladden Engineering dated November 30, 2005, Project No. 644-5125, Report No. 05-11-1131. ` As requested, we have reviewed the referenced geotechnical report as it relates to the design and construction of the proposed single family residence. The property is located at 43599 Calle De Valerdo in the City of Temecula, California. The referenced geotechnical report includes recommendations for the design and construction of residential building foundations. Based upon our review of the referenced report and our recent site observations, it is our opinion that the recommendations included in the above referenced report remain applicable for the proposed residence. Footings should extend at least 12 inches beneath lowest adjacent grade. Isolated square or rectangular footings should be at least two feet square and continuous footings should be at least _ 12 inches wide. Continuous footings may be designed using an allowable bearing value of 1500 pounds per square foot (psf) and isolated pad footings may be designed using an allowable bearing pressure of 1800 psf. Allowable increases of 200 psf for each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be utilized if desired. The maximum allowable bearing pressure should be 2500 psf. The allowable bearing pressures are applicable to dead and frequently applied live loads. The allowable bearing pressures may be increased by 1/3 to resist wind and seismic loading. Care should be taken to see that bearing or subgrade soil is not allowed to become saturated from the ponding of rainwater or irrigation. Drainage from the building area should be rapid and complete. .- May 15, 2007 � -2- � Project No 644-07059 07-05-046 The recommendations made in the preceding paragraph are based on the assun:ption that all footings will be supported upon a uniform mat of properly compacted soil. All grading shall be performed under the testing and inspection of the Soil Engineer or his representative. Prior to the placement of concrete, we recommend that the footing excavations be inspected in order to verify that they extend into properly compacted soil and are free and loose and disturbed materials. Settlements may result from the anticipated foundation loads. These estimated ultimate settlements are calculated to be a maximum of 1 inch when using the recommended bearing values. As a practical matter, differential settlements between footings can be assumed as one- half of the total settlement. Resistance to lateral loads may be provided by a combination of friction acting at the base of the slabs or foundations and passive earth pressure along the sides of the foundations. A coefficient of friction of 0.40 between soil and concrete may be used for dead load forces only. A passive earth pressure of 250 pounds per square foot, per foot of depth, may be used along the sides of footings which are poured against properly compacted native or non expansive approved import soil. Passive earth pressure should be ignored within the upper 1 foot except where confined (such as beneath a floor slab) Retaining walls is necessary cantilever retaining walls may be designed using "active" pressures. The "active" pressures may be estimated utilizing and equivalent fluid weight of 35 pounds per square foot (pcf) for drained level native backfill soil. For restrained walls "at rest" pressures should be utilized in design. The equivalent fluid weight should be increased to 55 pcf for restrained wall with drained level native backfill soil. The site was previously partially leveled. It is our assumption that the subject lot was rough graded during the initial grading of the adjacent residential lots north and south of the site. The building areas should be cleared of vegetation, debris, and other unsuitable materials that should be removed from the site. In order to provide for firm and uniform foundation bearing conditions, the artificial fill soil and any loose native soil within the primary foundation bearing zones should be removed and recompacted. Removals should extend to competent native soil or to a minimum depth of 3 feet below pad� grade, whichever is deeper. Based upon our preliminary observations,.removal depths of 2 to 3 feet should be expected in most areas. The exposed surface should be scarified, moisture conditioned and recompacted to at least 90 percent relative compaction. Once unsuitable materials are removed, .the excavated material may be replaced as controlled compacted fill. Overexcavation should be observed and compaction should be verified by testing. Overexcavatoin should extend a minimum distance of 5 feet beyond the building limits. Sladden Engineering . �- ' � � � � May 15, 2007 -3- Project No 644-07059 07-05-046 It should be noted that the site is located within a seismically active area of Soutizern California and it is likely that the proposed structures will experience strong ground shaking as a result of an earthquake event along one of the faults in the region during the expected life of the development. As a minimum, structures should be designed based upon Seismic Zone 4 design criteria included in the Uniform Building Code (UBC). The potential for liquefaction or other geologic/seismic hazards occurring at the site is considered to be negligible. We appreciate the opportunity to provide service to you on this project, if you have any questions regarding this letter or the referenced reports please contact the undersigned. Respectfully submitted, � `''- SLADDEN ENGI EERI�'QG ��QROFESSrp,� w �.�� ,�� , Atyp�� F �r - p � o. C 453�9� � Brett L. Anderson �x�. 9 l3fil�;� � Principal Engineer ` s C/ a j }'�� CF�LVFb�� SER/Mr "�"""�.°"..� f . Copies: 4 Benson Design and Build, LLC Sladden Engineering r ,.. . . • . May 15, 2007 � -4- � Project No 644-07059 07-05-046 2001 CALIFORNIA BUILDING CODE SEISMIC DESIGN INFORMATION The California Code of Regulations, Title 24 (2001 California Building Code) and 1997 Uniform Building Code, Chapter 16 of this code, contain substantial revisions and additions to earthquake engineering design criteri�. Concepts contained in the code that will be relevant to construction of the proposed structures are summarized below. Ground shaking is expected to be the primary hazard most likely to affect the site, based upon proximity to significant faults capable of generating large earthquakes. Major fault zones considered to be most likely to create strong ground shaking at the site are listed below. Approximate Distance Fault Type Fault Zone From Site (1997 UBC) Elsinore (Temecula) 2.1 km B Elsinore (Julian)_ 15.8 km A Based on our field observations and understanding of local geologic conditions, the soil profile type judged applicable to this site is So, generally described as stiff or dense soil. The site is located within UBC Seismic Zone 4. The following table presents additional coefficients and factors relevant to seismic mitigation for new construction. Near-Source Near=Source Seismic Seismic Seismic Acceleration Velocity Coefficient Coefficient Source Factor, N� Factor, N� Ca C� Elsinore (Temecula) 1.3 1.6 0.44 N. 0.64 1V. Elsinore (Julian) 1.0 1.0 0.44 Na 0.64 N.. Sladden Engineering