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BRES2018-0195Sladden Engineering 45090 Golf Center Parkway, Suite F, India, CA 92201(760) 863-0713 Fax (760) 863-0847 6782 Stanton Avenue, Suite C, Buena Park, CA 9(1621(714) 523-0952 Fax (714) 523-I369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Boo L. Florida Avenue, Hemet, CA 92543 (95I) 766-8777 Fax (951) 766-8778 March 23, 2018 Project No. 544-18088 18-03-129 Hobbs Br Carr Development Corporation One Park Plaza, 61h Floor Irvine, California 92614 Project: Proposed Custom Residence 53095 Via Vicenze The Hideaway - Lot 181 La Quinta, California C. TY OF LA QUINTA BUILDING DIVISION REVIEWED FOR CODE COMPLIANCE Subject: Geotechnical Update Ref: Geotechnical Engineering Report prepared by Earth Systems Southwest (ESSW) dated September 22, 2000; File No. 07117-10, Report No. 00-09-772 Report of Testing and Observation During Rough Grading prepared by ESS dated August 28, 2002 File No. 07117-11, Report No. 01-07-718 Report of Testing and Observation During Rough Grading prepared by Sladden Engineering dated October 12, 2003; Project No.544-2199 Report No. 03-10-647 As requested, we have reviewed the above referenced geotechnical reports as they relate to the design and construction of titre proposed custom residence. The project site is located at 53095 Via Vicenze within the Hideaway Golf Club development in the City of La Quinta, California. It is our understanding that the proposed residence will be a relatively lightweight wood -frame structure supported by conventional shallow spread footings and concrete slabs on grade. The subject lot was previously gs•aded during the rough grading of the Hideaway project site and was subsequently regraded. Tile rough grading included over -excavation of the native surface soil along with the placement of engineered fill soil to construct the building pads. The regrading included processing the surface soil along with minor cuts and fills to construct the individual building pads to the current configurations. Some additional over -excavation was performed in areas where the building envelopes were reconfigured. The supplemental site grading is summarized in the referenced Report of Testing and Observations During Rough Grading prepared by Sladden Engineering along with the compaction test results. The referenced reports include recommendations pertaining to the construction of residential structure foundations. Based upon our review of the referenced reports, it is our opinion that the structural values included in the referenced grading report prepared by Sladden Engineering remain applicable for the design and construction of the proposed residential structure foundations. Slutlden Engineering ivtvrv.Sladrlettetrgitteeritrg. can March 23, 2018 -2- Project No. 544-18088 18-03-129 Because the lot has been previously rough graded, the remedial grading required at this time should be minimal provided that the building falls within the previously established building envelope. The building area 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 is attained prior to fill placement. Any fill material should be placed in thin lifts at near optimum moisture content and compacted to at feast 90 percent relative compaction. The allowable bearing pressures recommended in the referenced grading report prepared by Sladden Engineering remain applicable. Conventional shallow spread footings should be bottomed into properly compacted fiII material a minimum of 12 inches below lowest 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 Dearing pressures of 1500 psf and 2000 psf, respectively. Allowable increases of 300 psf for each additional 1 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 0.50 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 non -expansive and falls within the "very low" expansion category in accordance with 2016 California Building Code (CBC) classification criteria. Slab thickness and reinforcement should be determined by the structural engineer. We recommend a minimum floor slab thickness of 4.0 inches. All slab reinforcement should be supported on concrete chairs to ensure that reinforcement is placed at slab mid -height. Slabs with moisture sensitive surfaces should be underlain with a moisture vapor .retarder consisting of a polyvinyl chloride membrane such as 10-mil Visqueen, or equivalent. All laps within the membrane should be sealed and at least 2 inches of clean sand should be placed over the membrane to promote uniform curing of the concrete. To reduce the potential for punctures, the membrane should be placed on a pad surface that has been graded smooth without any sharp protrusions. If a smooth surface can not be achieved by grading, consideration should be given to placing a 1-inch thick leveling course of sand across the pad surface prior to placement of the membrane. Sladden Engineering svwiv.Sladrle►tetigitteerittg. coot March 23, 2018 -3- Project No. 544-18088 I 8-03-129 The seismic design category for a structure may be determined in accordance with Section 1613 of the 2016 CBC or ASCE7. According to the 2016 CBC, Site Class D may be used to estimate design seismic loading for the proposed structures. The 2016 CBC Seismic Design Parameters are summarized below. Risk Category (Table 1.5-1):I/111111 Site Class (Table 1613.32): D Ss (Figure 1613.3.1): 1.500g Si (Figure 1613.3.1): 0.651 g Fa (Table 1613.3.3(1)):1.0 Fv (Table 1613.5.3(2)):1.5 Sms (Equation 16-37 {Fa X Ss)):1.500g Sml (Equation 16-38 (Fv X Si)): 0.976g SDS (Equation 16-3912/3 X Srns)):1.0009 SD1 (Equation 16-40 12/3 X Smi1): 0.651g Seismic Design Category: D In addition, we have sampled the surface soil on the subject lot to determine the soluble sulfate content as it relates to selecting appropriate concrete mix designs. The testing indicated soluble sulfate content of 340 ppm (0.034 percent) that corresponds with the "negligible" exposure category in accordance with ACI 318-08, Table 3. Based upon this, the use of sulfate resistant concrete mixes should not be required. If you have questions regarding this letter or the referenced reports, please contact the undersigned. Respectfully submitted, SLADDEN ENGINEERING Brett L. Anderson e iteTT L Principal Engineer v, Q. Cs5339 m t7 FOP 9l��liB SER/gvm ■ v= GiNEErING 1 Copies: 4 / Addressee Sladden Engineering wivrc .Sladdenengineering. COM Please verify that soils reports contain all of the above information. In addition, to assure continuity between the Investigationlreporting stage and the execution stage, please use tha following checklist to verify that the conclusions and recommendations in the report cover all the required elements. Only then can we be 2SSured that the construction documents address all of the site soil c❑nditions. 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 measure(s) noted, -or, (b) the criterion is considered insighi€icant and explicitly so stateri. VOS WO CrI erion ® Foundation criteria based upon bearing capacity of natural or compacted sail. Q Foundation criteria to mitigate the effects of expansive soils. © Foundation criteria based upon bearing capacity of natural or compacted soil- ® Foundation criteria to mitigate the effects of liquefactlon. EJ Foundation criteria to mitigate the effects of selsmically induced differential settlement. ® 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 "too" answers to the -above checklist should be rioted as specific required catrections_ aR�-rT L- C �8S M VIL OF laden Engineering 6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 45090 Golf 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) 845-8863 Date: March 23, 2018 Account No.: 544-18088 Customer: Hobbs & Carr Location: The Hideaway, Lot 181, 53095 Via Vicenze, La Quinta Sulfate Series Analytical Report Soluble Sulfates per CA 417 ppm 340 Soluble Chloride per CA 422 PPm 140 Sulfate 544-18088 032318 TABLE 19-A-2—REQUIREMENTS FOR SPECIAL EXPOSURE COMMONS MINIMUM %', MAXIMUM NORMAL -WEIGHT AND WATER-CEMENTIllOUS LIGHTWEIGHT AGGREGATE CONCRETE, MATERIALS RATIO, BY pal WEIGHT, NORMAL -WEIGHT x 0.00609 for MPa EXPOSURE CONDITION AGGREGATE CONCRETE Concrete intended to have low permeability when exposed to water 0.50 4,000 Concrete exposed to freezing and thawing in a moist condition or to deicing chemicals 0.45 4,500 For corrosion protection for reinforced concrete exposed to chlorides from deicing chemicals, salts or brackish water, or spray from these sources 0.40 5,000 TABLE 19-A-3—REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE -CONTAINING SOLUTIONS LIGHTWEIGHT ,1 } NORMAL -WEIGHT AGGREGATE AGGREGATE CONCRETE MaxtmumWeter- cementltlous Motedels RatID, by welght• Normal -Weight Aggregate concrateI rNormaf- YIghl and Llghtwefghl Aggregate Concrete, psis SULFATE EXPOSURE WATER-SOLUBLE SULFATE IS041 IN SOIL, PERCENTAGE BY WEIGHT SULFATE (SO411N WATER, ppm CEMENTTYPE x 0.00b09lor MPa Negligibfe 0.00-0.10 0-150 — — — Moderate2 0.10-0.20 150-1,500 II, IP(MS), IS OSO 4.000 (MS) Severn 0.20-2.00 1,500-10.000 V 0.45 4.500 Very severe Over 2.00 Over 10.000 V plus pDrsolan3 0-45 4,500 'A lower wafer{cment_i60u i materials satin or bighcr strength may be required for low permeability or for protection against corrosion of embedded items or freezing and thawing (Table 19=R-2)- 2Seawater. 3Pozzolan that has been determined by test or service record to improve sulfate resistance when used inconcrete con- taining Type V cement. 2 264 Sladden Engineering 45090 Golf Center Purkway, Suite F, Indio, CA 92201 (760) 963-0713 Fax (760) 863-0847 6782 Stanton Avenue, Suite C, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 945-8863 800 E. Florida Avenue, Hemet, CA 92543 (951) 766-8777 Fax (951) 766-8778 June 26, 2018 Project No. 544-18088 18-04-162 Hobbs & Carr Development Corporation One Park Plaza, 60, Floor Irvine, California 92614 Project: Proposed Custom Residence 53095 Via Vicenze The Hideaway - Lot 181 La Quinta, California Subject: Foundation and Precise Grading Plan Review Ref: Geotechnical Update prepared by Sladden Engineering dated March 23, 2018; Project No. 544-18088, Report No.18-03-129 In accordance with your request, we have reviewed the Foundation Plans and Details prepared by ESI/FME, Inc. along with the Precise Grading Plans prepared by Essi Engineering- The plans reviewed were prepared for the proposed custom residence to be constructed on Lot 181 located at 53095 Via Vicenze within the Hideaway Golf Club development in the City of La Quinta, California. Based on our review, it is our opinion that the recommendations provided in the above referenced Geotechnical Update as well as the previous geotechnical reports have been properly incorporated into these plans. If you have questions regarding this memo or the referenced report, please contact the undersigned. Respectfully submitted, F�SSrO SLADDEN ENGINEERING REiT L. y f F LA QUINT Au°rR5° No. BUILDING DIVISION �OIlB � i Brett L. Anderson CNIt REVIEWED FOR Principal Engineer Ar F_NGlt4EEft1Nr CODE C MPLIANC Letter/gvm OF - Is B"Z- rN Copies: 4 / Hobbs & Carr Development Corporation Sladden Engineering wtvlv.Slnddeiteitgbteering. cone 14�