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BPOL2018-0051 Geotechnical Update24 73i Sudden Engineering 45090 Golf Center Parkway, Suite F, Indio, CA 92201 (760) 863-0713 Fax (760) 863-0847 6782 Stanton Avenue, 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 800 E. Florida Avenue; Hemet, CA. 92543 (951) 766-8777 Fax (951) 766-8778 May 26, 2016 Project No. 544-16138 16-05-212 Mr. Bob Safai c/o Hayer Architecture, Inc. 445 Marine View Avenue, Suite 280 Del Mar, California 92014 Subject: Geotechnical Update Project: Proposed Custom Residence 81-454 Amundson Avenue The Madison Club — Lot 19B La Quinta, California Ref: Geotechnical Investigation Report prepared by Sladden Engineering dated January 28, 2005; Project No. 544-4810, Report No. 05-01-101 Report of Testing and Observation During Rough Grading prepared by Sladden Engineering dated March 2, 2006; Project No. 522-4810; Report No. 06-02-120 As requested, we have reviewed the above referenced geotechnical reports as they relate to the design and construction of the proposed custom residence to be constructed on the site located at 81-454 Amundson Avenue within the Madison Club development in the City of La Quinta, California. It is our understanding that the proposed residential structure will be of relatively lightweight wood -frame construction and will be supported by conventional shallow spread footings and concrete slabs on grade. The subject lot was previously graded during the rough grading of the Madison Club project site. The rough grading included over -excavation and recompaction of the native surface soil along with the placement of engineered fill material to construct the building pads. The site grading is summarized in the referenced report of Testing and Observation During Rough Grading along with the compaction test results. Because the lot has been previously rough graded, the remedial grading required at this time should be minimal provided that the building area that falls within the previously assumed building envelope. The building areas should be cleared of surface vegetation, scarified and moisture conditioned prior to precise grading. The exposed surface should be compacted to a minimum of 90 percent relative compaction prior to fill placement. The previously removed soil and any fill material should be placed in thin lifts at near optimum moisture content and compacted to at least 90 percent relative compaction. Sladden Engineering wlvw.Sladdenengineering.conr 1 1. May 26, 2016 -2- Project No. 544-16138 16-05-212 The referenced reports include recommendations pertaining to the construction of residential structure foundations. The previous reports also address the potential for liquefaction, subsidence and differential settlement. Based upon our review of the referenced reports, it is our opinion that the structural values included in these reports remain applicable for the design and construction of the proposed residential structure foundations. The allowable bearing pressures recommended in the referenced Geotechnical Investigation report remain applicable. Conventional shallow spread footings should be bottomed into properly compacted fill material a minimum of 12 inches below Iowest adjacent grade. Continuous footings should be at least 12 inches wide and isolated pad footings should be at least 2 feet wide. Continuous footings and isolated pad footings should be designed utilizing allowable bearing pressures of 1500 psf and 2000 psf, respectively. Allowable increases of 300 psf for each additional I foot of width and 300 psf for each additional 6 inches of depth may be utilized, if desired. The maximum allowable bearing pressure should be 3000 psf. The recommended allowable bearing pressures may be increased by one-third for wind and seismic loading. Lateral forces may be resisted by friction along the base of the foundations and passive resistance along the sides of the footings. A friction coefficient of 0.48 times the normal dead load forces is recommended for use in design. Passive resistance may be estimated using an equivalent fluid weight of 300 pcf. If used in combination with the passive resistance, the frictional resistance should be reduced by one third to 0.33 times the normal dead load forces. The bearing soil is generally non -expansive and falls within the "very low" expansion category in accordance with the 2013 (CBC) classification criteria. Pertinent 2013 CBC Seismic Design parameters are summarized on the following page. Sladden has reviewed the 2013 California Building Code (CBC) and summarized the current seismic design parameters for the proposed structure. The seismic design category for a structure may be determined in accordance with Section 1613 of the 2013 CBC or ASCE7. According to the 2013 CBC, Site Class D may be used to estimate design seismic loading for the proposed structures. The 2013 CBC Seismic Design Parameters are summarized below. Risk Category (Table 1.5-1): I/II/111 Site Class (Table 1613.32): D Ss (Figure 1613.3.1):1.516g S1 (Figure 1613.3.1): 0.711g Fa (Table 1613.3.3(1)): I.0 Fv (Table 1613.5.3(2)):1.5 Sms (Equation 16-37 fFa X Ss)): I.516g Smi (Equation 16-38 1FV X S21): 3.066g SDS (Equation 16-39 f2/3 X Sms)): 1.011g SDI (Equation 16-40 12/3 X Sm7)): 0.711g Seismic Design Category: D Sladden Engineering ivww.Sladdenengineering.com May 26, 2016 -3- Project No. 544-16138 16-05-212 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 ENGINEERING Brett L. Anderson Principal Engineer SER/clb Aft ^.cOjV No. C45389 �C c� ESP. sisoris CIVIL Copies: Q Mr. Bob Safai �� ENGINEERING =' 0, CAL ItS Sladden Engineering fvww.Sladdenengineeringcom La Quinta 14-763 06/17/14 Syll- 16 /3 /$-0S=Z/ 1773j continuity between the investigation/reporting stage and the Please verify that soils reports contain all of the above information, In addition, to ass execution siege, please us( the following checklist to verify that the conclusions and recommendations in the report cover all the required elements. Only then can we be assured that the constructions documents address all of the site soil conditions. La Quinta Geotechnical Report Checklist Does the "Conclusions and Recommendations" section of the report address each of the following criteria? "Address" means: (a) the criterion is considered significant and mitigation easu mr�e(s) no or, (b) the criterion is considered Insignificant. and explici#iyy slated, Yes No Criterion -Ef D Foundation criteria based LVj 9r, El upon bearing capacity of natural or compacted soil. D Foundation criteria to mitigate the effects of expansive soils. ❑ Foundation criteria based upon bearing capacity of natural or compacted soil. D Foundation criteria to mitigate the effects of liquefaction. ❑ Foundation criteria to mitigate the effects of seismically inducted differentia! settlement. L7 Foundation criteria to mitigate the effects of long-term differential settlement ❑ Foundation criteria to mitigate the effects of varying soil strength. ❑ Foundation criteria to mitigate expected total and differential settlement. Any "No" answers to the above checklist should be noted as specific required corrections. (W Sudden Engineering 45090 Golf Center Parkway, Suite F, Indio, CA. 92201 (760) 863-0713 Fa.� (760) 863-0847- 6782 Stanton Avenue, Suite C, Buena Park, CA 90621 (734) 523-0952 Fax (714) 523-I369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 800 E. Florida Avenue, Hemet, CA 92543 (951) 766-8777 Fax (951) 766-8778 June 6, 2016 Mr. Bob Safai c/o Hayer Architecture, Inc. 445 Marine View Avenue, Suite 280 Del Mar, California 92014 Project: Proposed Custom Residence 81-454 Amundson Avenue The Madison Club — Lot 19B La Quinta, California Subject: Soluble Sulfate Content Project No. 544-16138 16-06-223 Ref: Geotechnical Investigation Report prepared by Sladden Engineering dated January 28, 2005; Project No. 544-4810, Report No. 05-01-101 Report of Testing and Observation During Rough Grading prepared by Sladden Engineering dated March 2, 2006; Project No. 522-4810; Report No. 06-02-120 As requested, we have reviewed the geotechnical update report prepared for the subject property located at 81-454 Amundson Avenue, Lot 19B located within the Madison Club residential development with respect to soluble sulfate content as it relates to selecting appropriate concrete mix designs. Laboratory testing indicated soluble sulfate content of 2400 ppm (024 percent) that corresponds with the "severe" exposure category in accordance with Table 3 of ACi 318-08 Chapter 9. In accordance with ACI 3I8-08, special sulfate resistant concrete mix designs wiU be required for structural concrete on this project. Structural concrete in contact with soil should have a minimum compressive strength of 4500 psi and maximum water/cement content of 0.45. A copy of the laboratory test results is attached. If you have questions regarding this letter or the referenced report, please contact the undersigned. Respectfully submitted, SLADDEN ENGINEERIN Brett L. Anderson - Principal Engineer Letter/clb ES V( No. Ca5339 j Exp.9/30i16 r - CIVIL *\ ENGINEERING11r Copies: 4 / Mr. Bob Safai C_ ,AZ Sladden Engineering 6782 Stanton Ave., Suite A. Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 45090 Goff Center Pkwy, Suite F, Indio, CA 92201 (760) 863-0713 Fax (760) 863-0847 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 84&8863 Date: June 6, 2016 Account No.: 544-16138 Customer: Mr. Bob Safai c/o Hayer Architecture, Inc Location: Amundson Way, Lot 19B, La Quinta Sulfate Series Analytical Report Soluble Sulfates per CA 417 ppm 2400 Soluble Chloride per CA 422 ppm •11 2�1 Sulfate 544-16138 060616 -TA13LE 19--A-2—REOUIREMEfFI-S FOR SPECIAL EXPOSURE CQNDM0hjS' HOA7dAL II AAiM 1.tAX11.tUM - . WATER-Z0.16P7Ti jOtrS ; �HT. - ' bi{1TFJitA'�'^' RA�7o-','8Y- ,.- AGGflEG111'EEORCA� - -• EXPOSURE CONDITION �GhEGAT = AGGREGATE CORCREIE • ..tAL'-YtREM - intended to have low perrneibility when Ebrmackiih x •1'crliPa _ o water QSQ1000 ; exposed to'fizccing and thawing in a moist or to deicing chemicals Q_d5 - ion prolecdon for reinforced concrete 4500 - chlorides from deicing chernica.ls, salts or i+atcr, or•sprayfrom th='zcunxs 0_40 SAG TABLE 19-A-3--REMAREME &FOR COPICl3ETE EXPOSED TO TO SULFATE COALTAINWG-SOLUTIONS , - AGGREGATE : Cxi31CRETE _ . Maxi lmlwatnr- WATER- SOLUBLE Camu[tttlosu ' M tiarmat- .1am-and _ SULFATE r,[atnrIatc'Rattart :. SULFATE SOIL,W PROMSOIL, ffdr - �0a' SUA( H (So.,) ggmgeteEXP7SUAE WDGy_, ^t�CEREA7TYPE Coate - +:P x TarldPs ' Negligible 0_00-0.I(y Mod rat 4.10-Q2Q ISO-1.500 ir.H,(MS),IS -050• 4.000 CMS} 5cvcre Q 20-Z00 1500-iD,Q00 - iV 0 4i 4,50Q Very Seven Over2.00 Over IQ,00Q Yplus 4.45 4,g{l0 - - pozxolart3 _ t lower Water-ccr= tious macr[Ws ratio orhighcr sq=gt ma b�qn� for tDw Pcrnara a g Lmsc rorrosion'of cmbcddcd items or firing and rhswii�g (-able 24-�12}. M ��m Scaw =- 1FoaoLart tftat has boon detrsmiaed by rest or_ suvjce rccord to oe - V ecmertL improve sulfate resister when nsgd is eto con- _ 2 264 REINFORCEMENT— REFER TO FOUNDATION PLAN TURN DOWN SLAB REINF. 01" INTO FOOTING 4" CONCRETE 5LA5 2 SAND OVER 10 MIL II VAPOR RETARDER \ ,�\ o i 2—#5 TOP AND 50TTOM U.N.O. REFER TO CONT. FTC. SCHEDULE 6 FND. PLAN 0 O WEEP SCREEP LOCATION. REFER TO ARCHITECTURALS FOR COMPLIANCE. WITH: 2015 C5C 2512.12 2015 CRC R'705.6.2.1 5H=ARYVALL PER PLAN t- I SILL PLATE WITH 5/8"cP AB AT 4'—O" o% U.N.O. REFER TO FOUNDATION PLAN AND SHEAR WALL SCHEDULE "X" = 6" FOR RESIDENTIAL. AS PER IRC R51i.1 "X" = 5" FOR COMMERCIAL E.N. AS PER 15C 2504.112.2 FOUNDATION DETAIL 4B-3,2 4" CONCRETE SLAB REINFORCEMENT— REFER TO FOUNDATION PLAN TURN DOWN SLAB REINF. ct" INTO FOOTING 2" 5AN12 OVER 10 MIL VAPOR RETARDER ADDITIONA GREATERI "D" = A5 P: FIN15H A5 F REINFORCE TO FOUNDA TURN DOWN 9" INTO FOc 4" GONGRE 2° SAND VAPOR' 2—#5 TC U.N.O. K 5CHEDU