The URL can be used to link to this page

BRES2015-0086 Geotechnical Update=f Sladden Engineering 45090 Golf Center Parkway, Suite F, Indio, CA 92201 (760) 863-0713 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) 845-8863 800 E. Florida Avenue, Hemet, CA. 92543 (951) 766-8777 Fax (951) 766-8778 January 27, 2015 Project No. 544-15019 15-01-044 Mr. Mark McClure c/o Hayer Architecture 445 Marine View Avenue, Suite 280 Del Mar, California 92014 R""'ECEV " ELE","- Subject: Geotechnical Update MAR 13 2015 Project: Proposed Custom Residence 53-713 Ross Avenue CITY OF LA QUINTA The Madison Club COMMUNITY DEVELOPMENT La Quinta, California Ref: Geotechriical 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. 5 U-46.10-epor o. 06-02-120 CITY - - CITY OF LA QUANTA As requested, we have reviewed the above referenced geot chjSiji&&sErt®die design and construction of the proposed custom residence to be to APP - Ross Avenue within the Madison Club development in the City of Li3Tour understanding that the proposed residential structure will be of rel ively lig weigh wood - frame construction and will be supported by conventional s 6ff t' a concrete slabs on grade. The subject lot was previously graded during the rough grading of the Madison Club project site. The rough grading included 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 January 27, 2015 -2- Project No. 544-15019 15-01-044 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 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 bearing 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 0.48 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/II1 Site Class (Table 1613.3.2): D Ss (Figure 1613.3.1): 1.511g S1 (Figure 1613.3.1):0.710g Fa (Table 1613.3.3(1)): 1.0 Fv (Table 1613.5.3(2)): 1.5 Sms (Equation 16-37 (Fa X Ss)): 1.5118 Smi (Equation 16-38 (Fv X Si)): 1.065g SDS (Equation 16-39 (2/3 X Sms)):1.007g SDI (Equation 16-40 (2/3 X Sm1)): 0.710g Seismic Design Category: D Sladden Engineering o January 27, 2015 -3- Project No. 544-15019 15-01-044 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. Testing indicates that the site soil is generally considered non- corrosive with respect to concrete. The testing indicated soluble sulfate content of 250 ppm (0.025 percent) that corresponds with the "negligible" exposure category in accordance with ACI 318-08, Table 3. Based upon this, the use of sulfate resistance concrete mixes is not required. 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 undersi€ned. Respectfully submitted, SLADDEN ENGINEEF Brett L. Anderson Principal Engineer SER/gvm ` BRE7T ANDERSON G Ll Exp. 9/30/16F A r CIVIL ENGINEERING OF CAU,F Copies: 4/ Mr. Mark McClure Sladden Engineering 5 y1-/ -- I S"019 �Sol•ayy LA QUINTA Please verify that soils reports contain all of the above information. In addition, to assure continuity between'the investigation/reporting stage and the execution stage, please use 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 construction 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 Griterion is considered significant and mitigation measure(s) noted, or; (b) the criterion is considered insignificant and expiicitly.so stated. Ye. s No Criterion ® Foundation criteria to mitigate the effects of expansive soils. ® Foundation criteria based upon bearing capacity -of natural er--compacted soil. ® Foundation. criteria to mitigate the effects of liquefaction. ® Foundation criteria. to mitigate the effects of seismically induced differential settlement. ® Foundation criteria to mitigate the effects.of long-term differential settlement. ® Foundation criteria to mitigate the effects.of.varying soil .strength. . Ct Foundation criteria to mitigate expected total and differential settlement. Any "No" answers to the above checklist should be noted as specific required coFTections. �OQROFESS�� # # # �� A SRE77 L. 912 RSON �) °. 4.5389 Ex . 9/30/16 m CIVIL ' G ' � 9 '�- CALF . Sladden Engineering 6782 Stanton Ave., Suite C, 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) 363-0847 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Date: January 30, 2015 Account No.: 544-15019 Customer: Mark McClure Location: Madison Club, 53-713 Ross Avenue, La Quinta Sulfate Series Analytical Report Soluble Sulfates Soluble Chloride per CA 417 per CA 422 ppm ppm 250 60 -3ulfate 544-15019 013015 TABLE 19-A-2—REQUIREMENTS FOR SPECIAL EXPOSURE r mmnmnWz TABLE 19-A-3—REQUIREMENTS• FOR CONCRETE FYPnRFnTn Ctit FhTFJ`n/iTArinlrn:c-nr.r—.— ",N7 AND .WATER CEMENTrrLOUS HT,MATERIAf:S' RATIO;BY. ; AGCRETF,.WEIGHT;NbRMAL'-WEIGHT•EXPOSURE QA CONDITION AGGREGATE CONCRETE MPa Conqretc 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, orspraY•from these 'sources' 0.40 5,000 TABLE 19-A-3—REQUIREMENTS• FOR CONCRETE FYPnRFnTn Ctit FhTFJ`n/iTArinlrn:c-nr.r—.— Alowerwater-ccrDcnLidousmaterialsratioorhr erst req pertraeability•orforproteetion' F� trn$dt may be , aired for low 2 agaimt corrosion *of embedded items or freezing and thawing ('Table 19-A-2). Scawater- ?Pozzolan that has been determined by test or service record to improve sulfate resistance when used in concrete con- taitiing 7Ia V cement. 2-26-4 UGHTW EIGHT NORMAL WEIGHT :AGGREGATE AGGREGATE -.CONCRETE Mwdmurri Water- 11"Normat- WATER-SOLUBLE Camandtfous •Vfatght-and SULFATE MdtertalaaRatlo;bi'. WhtwElght' (so IN SOIL, WHggh4 •i -Aggrbgate• . SULFATE PERCENTAGE BY SULFATE (SOS) IN Noimal-Welglit Concrete; pill EXPOSURE WEIGHT WATER m CEMENT TYPE Aogn_yatl ' � PP Concrete x a.0D689'►or MPs Negligible 0.00-0.10 0-150 — Moderate2• 0.10-0.20 150-1,500 II, TP(MS), is OSO 4,000 (MS) Severe 0.20-2.00 t,500-1-0,000 V 0.45r 4,500 Very severe Over 2.00 Over 10,000 ' V plus 0.45 q,500 • . pozzolan3 . I ' Alowerwater-ccrDcnLidousmaterialsratioorhr erst req pertraeability•orforproteetion' F� trn$dt may be , aired for low 2 agaimt corrosion *of embedded items or freezing and thawing ('Table 19-A-2). Scawater- ?Pozzolan that has been determined by test or service record to improve sulfate resistance when used in concrete con- taitiing 7Ia V cement. 2-26-4 UGHTW EIGHT NORMAL WEIGHT :AGGREGATE AGGREGATE -.CONCRETE Mwdmurri Water- 11"Normat- WATER-SOLUBLE Camandtfous •Vfatght-and SULFATE MdtertalaaRatlo;bi'. WhtwElght' (so IN SOIL, WHggh4 •i -Aggrbgate• . SULFATE PERCENTAGE BY SULFATE (SOS) IN Noimal-Welglit Concrete; pill EXPOSURE WEIGHT WATER m CEMENT TYPE Aogn_yatl ' � PP Concrete x a.0D689'►or MPs Negligible 0.00-0.10 0-150 — Moderate2• 0.10-0.20 150-1,500 II, TP(MS), is OSO 4,000 (MS) Severe 0.20-2.00 t,500-1-0,000 V 0.45r 4,500 Very severe Over 2.00 Over