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Home My WebLink AboutRoughGrading(Feb.4,2000)_ 05/10/2BBB 14:49 9892960534 • . . LEIC~-ITON ~ ~ ~. ! ,~~ ~ ~`_~ A GTG Company \J Leighton and Associates PAC~ 02 QEOTECNNICq~ CONSUL7ANT5 ROUGH GRApING CAMPOS VERDES, '['RpC'I' 2g510 COMMF,CtCIAL A,ND PA,RK SI'I'E PADS TEMECULA RIVSxiSIDE COUN7Y, CALIFORNIA Pebruary 4, 2000 Project No. 11980289-003 Prepazed For: WOODSIDE HOMES 23121 Amonio Parkway, Suito 102 Rancho Santa Mazgarita, Caiifornia 92688 41715 Enterp~160 CIft1E N. Sulte 103, T~mOCUI~~ CA 92590•5881 (909) Z96•0530 • FAX (9~9) 286•0634'• www.leig~tongao.eom ~ 85/10/2800 14:49 909296053: LEIt~-IT~J • PA(iE 03 ` ~ ~..r~.:~:~ • • ~-~,~` Le~ghton and Associates AOTp~pa~y OEOT[CHNICqL CONSULfANT9 Fcb[vary 4, Z000 Project No. 1198Q289-003 To: Woodside Homea 23121 Antotaio Psrkway, Suite 102 Rancho San[a MazgariW, Californta 9z688 A,ttention: Mr. Naze Pugsley Snbject: Report of Rough Grading, Campos Verdes, Trac[ 28310, Commercial and Pazk Site Pads, Temecula, itiverside Counry, Califomia la accordance with your request and au[horization; Leighmn and Associates, lnc. {Leighron) Has prm'idcd geo~echnical services during cough gadtag operatioas of the Campos Verdes Commercia! and Pazk, Tract Z8510, locazed in the City of Temecula, Califocnia (See Pigure 1). The accompaayiwg report summa,rizes our observa~ious, fietd aad laborarory ceat resutu arad che geotechnacal conditions encowntered dwring the rouEh grading of the subject property. The ahe was graded to the current desigo depicted on the roferenced plaat (Roye~t Beln, William Froat Bc Associate,y (RBk~, 1999). Addit3onal eatthwork and geo~echnfcal,testioag wi11 ba neaded w t3neliu thc eubjecc buildiue pads. If you have aay questions regardiag thia report, please do uot hesitate to wntaa this of8ce, we appreciate thls opportuniry W be of service. Respactfully subnaiRed, LEICiHTON AND :~G~'"" "~ An rew T. Guatelli, PE, Q~ 5enior Project Engineer ~ ~ ~~ NO.~R.1b4t~t '~ ~ p ` Robert Riha, C~G 1921 (E ~o rs Associete GeologistlOffice EWR/AI'a/ItFR1d1m/~.a,.tyyeroeo2a9om ., ~a ~w~~w.a~ Distcibution: (6) Addreseee .... . . __.._w.._......._,...-._..,...... <171b 6nterprl9e Circle N. Sulte 703~Temacul8, CA 92590-8887 (809) 298-0530 • RAX (909) 2g6-0534 • www,lelgnlangeo~cam Z . _ 85/18/2000 14:49 9092960534 LEICaFtTON PAC~ 04 • • 11980289~003 TABLE OF CONTENTS ~,ection Paee 1.0 INTRODUCTION .................................................... ............................................ 1 2.0 SUMMARY pF ROUGH aRAQ1NG OPERA7'IONS .............................. ..................... 2 2.1 Site P~eperacion Grading ....... ........................ ........ ............................................. 2.2 Fio1Q Danalry Teating .......... . 2 . ............................................. .............. 2.3 Laborator Tcs " ................ ~ Y ttn8 ...... 2 .................................................................................... 2 3.0 ENGINEERING GEOLOGIC SUMMARY ............................... ................ 3 3.1 As-Gxadod Goologic Conditions ........................................................................... 3.Z Geologic Unita ..... . 3 . ......................................................................................... 3 3.2.1 Pauba Formatio~ (QPs) .............................................................................. 3 3.2.2 Attificial ~ill (A~ ...................................................................................... 3 3.3 Geologic Structure end Fautting ........................................................................... 3 3.4 L.andsilides end 5urficial Pailures .......................................................................... 3 3.S Ground Water ................................................................................................. 4 3,6 Expansion Testing oPFlnish Grade Soils ......:....................... .................................. 4 3.7 Soluble Sulfate Testing of Finish Grade Soils .......................................................... 4 4.0 CONCLUSIONS ................................................................................................... 5 4.1 General .......................................................................................................... 5 4.2 5ummaGy of Coaclusiona .................................................................................... S S.0 RECOMM6NDATIONS ......................................................................................... 6 5.1 Earthwork ........................:..................................................................... . 6 5.1.1 SitePreparativn ....................................................................................... 6 5.~.2 Removals and Rceompacdon ....................................................................... 6 5.1.3 Additional Stnictura! Fills ............................................................................6 5.1.4 Utilirylke,aclfes ........................................................................................7 5.1.5 Sluinkage and Bulking ................................................................................ 7 S.2 Temporary 51ope Stability ..................................... .............................................. 7 5.3 Surfaca Drainago anid Eroslon ................................ .:............................................. 7 S.4 Foundacioa Design .............................................. .............................................. 8 5.5 Floor Slab Desigui ............................................... ........ ............................... . ...,.. 9 5.6 Pooting Suback ....................... ........................... ............................. ... . 9 5.? Anticlpate~ Settlement .......................................... .. .... ...... ............................................. 10 5.8 Lateral Earth Pressures aad ~tesistance ..................... .......................... 10 5.9 Concrew ........................................................... ................... . ... 11 5.10 PrelLninary Pavement Deaign ................................. .... ..................................... ............................................. 11 ~ & . 1 -~ ~~ 3 05/10/2880 14:49 9092960534 LEICi{TON PAC~ 05 • • 11980289-003 TABL OF G~NTENT (cont.) d.0 GE07'ECHHICAI. REVIEW ................................................................ ... 13 6.1 Plaoa and Speclficaclons ................................................................... .... 13 .............. . Construcrion Reviaw ......................................................................................... 13 7.0 LIMITATlOIYS .............................................................................................. ..... 14 Accomo~yinp Figuree Tables Plate~ and ApQ,endiCes Fieures Figure 1- Sice Locazzon Map Reaz of Yeat ~ ,Plate i- As-C+raded Geotechnicai Map I~a Pocket p~gndices Appendix A - References Append'u B- Summaiy of fiield Density Tests ,Append'u C- Laboratory Testing Prce~ures and Test Resuits Appendix D- Oenaral FartLwork and GraAing Specificat3ons for Rougta Greding --~~ ~T ~ --_ ii - ~`~ q 85/10/2000 14:49 9892960534 LEICf{TON PA(iE 06 • • 11980269-003 1.0 INTRODUCTION In accordanee wit6 your request and authorizadon, Leigtiton aud Associazes, U~c. (I.eighton) }aas performed geotechnical obaervation aad tescing services duranQ the gradin8 operazions of the Comme~rcial and Pazk Site of Tcact 28510. 77ae site is generally located south of South Reoeral Kearny Itoad and eazt of Margsrita Road in thc C'ny of Temecula, Califonaie (See Figurc I). 'll~is report suumaarizes our geatechnical observations, field and leborazory test ~esu1[s and the geotechnical conditions encountered during the rough grading of d-e Commcrcial ~ud Pazk Site in Tracc 28510, The pra~osed grass liuad chanoet south of the subject pads and the rip-raps ro the easc of the site aze mot yec corqpleted, Ia addttioa, t6is repott provides conciusions and racommendations for the proposed cowmercial developmant of the subjecc sfce. The aLeet 10 of x2 of the 40-scale Erad'wg plan for TraM 28510 (Robert Beip, William Frost & Associates, 1949) was util'ucd as a base map to plot che geotechnicel condiUons and approx;ma[e locatioos of the fleld density tesu taken during rough grading. ~ &. -1- ~~~ 5 05/10/2008 14:49 9892960534 LEICfiTON PAGE 07 • • 1 1 9802 89-003 2.0 SUMMARY OF ROUGH-GRADIN . OP ATt('INC The ~urr~c S~redinB operazion of Trut 28510 began in April 1999. Rough gradi,ng of the subfea sice was performed by Kanmis Contractors, under the geotei.~hnical observation aod tes[ing services of I.eighcon. Ouc field techaician aad geologist wao oaRire on a TuU-time and as-aeedad bavis, respacdvelY, dur~8 ~~B oPeradons. Gradiog of the comoaazcial ped iavoivod reupvval of topsoU and alluvlum iato competeos Otder Quatemary Alluv~ium and placing of artificlal filla up to 22 foa m aeace the aesign pad devations. Grading of the pazk site pad itrvolved scarificatloa of t6e upper 18 inches of alluvial mateiials, moiature conditioning, recompaaion, and placing up ta 8 P~et of anificial fill. 2.1 Si[e Prenazation GradinQ Prior W grading, the azeas o;f proposad developme~t were stripped o~ surFace vegetatioa and debris and these materlals weca di~posed of offsite. Grading of the subJect Commercial Site was acwmplished by cempval oiFtopsoii amd upper alluvium imo co~ppeceerc Otdax Quaternary Alluvium or Alluvium materlals in aceordanrs with the recomm~dationa of the project geo[echn[ca1 report (Leigbton, 1999) and geotechnical recommendations made during the grading operations. 2.2 Field Densitv Test~e Field density testioe was performed using the nuclear gauge method (ASTM Test ]vtethods D2922 and D301'n. Tha azeas testefl met the minimum 90 percent relaUve compac~ion at near optimum moissure content. Areas that tasta! lesa than the rec~u'u~ 90 percent molsmre, were ~eworked, moLsture conditioned as aecessary aud compaaed uutil tha miuimum 90 percent was obtalned. The resulu of the field density tes~s are sum~marized in Appendix B. Approaimate Iocation of field density tests takea aze depict«i on Pla-e I. 2.3 (,~boratary Testine Labo~ratoxy mat~imum dry densky of represcmative ousite aoils were performed iin general accordance wtth ASTM Test Method b1557A1. '1'he lalmrazory test resutts and a descriptaou of the laboramry [es~ procedures are presented in Appendix C. 1 ~ 1~ _ Z _ ~1 -'_-.~ ~ - =~. L.'`~ W 85/18/2000 14:49 9092960534 LEIGFfTON PAC~ 8B ~ . • • 1198(J289-003 3.0 ENGINEERING QEO 0 ir S rn,~ A~y 3•1 G o ' C The as-gradcd cond'zcions encpuntered duzing gcading of the subjact aite wue essentially as anticipated. A summary of the goologic condhiona, Lacluding g~logic units, geologfc strucwre a~ feulting is presented below. 3.2 Geologic Unirs Tlte Beologic units encpyntered during grading ot Tract 28510, Comtnetcial and Park Site consisted of Quaternazy Ailuvium aud Oldcr Quatcrnary A,lluvium and is discuased below, 3.2.1 Ouatema~y pllyvi~m (O,~ -- ILe Quaternazy-aged altuvium encountered comaisted of orange brown, dry to moiat, loose to medium dense, porous, sUry aand. As encountered during erading, the alluvium is geaerelly loose near tbe surface, becoming moderately dense with dapth and moderately porous t6roughout. The aliuvium waa found w be 8 to t5 feet thlck. The allnviam is considered uusuitable 1br support of suucmres or addidonal fill £or siiuctura~ support and was completdy removed in the Couacaercial Site areas. Alluvium was left in placc bencath the pzopose~ park sitc. An additioual5 to S feet oP fili was placed to bring t6e park ped to the desired grade. 3.2.2 Older Alluvj~~( oat~ .. '~'tie older alluvium encoumered consisted of brown to dazk brown, moist to vetq moist, dense to very deusc siity sand. The oide~ alluvium is undetlain by the Pauba Fonmadon (I,eighton, 1999). 7Le older alluvium was exposed during the grading of the comunercial pad site and ia rnns(dered suitable for the support of additional fiU for structural support. An additional 14 w 22 feet oE fi1t was placod co bring the commercial pad m the desired grade. 3.2.3 Artificial Fi11 (Afl - qrtiflcial fill consists pf inedium bcown tn IfYht brown, silty, fine to medium sand to locatly clayey silty sand. Fill soils were ptaced under the observation and field deasiry testing by Leiglzwn represeatatives, 3.3 Geoloeic Structure and ~a ltlne Cond'ztions encountered during grading were esaentiaUy as auticipatod. Based oa our geologic observations during sice grading aad our profesaional expericnce oa adjacent sites, badding on aite is generally flat W slighdy dipping. Previous investiP.adons (Leighton, 1997 & t999) eacouotered variabte bedded units that appemr to be inclined at low angles pess than 15 degrees), No faultiag or lndicaNoas of faulting were observed duriag this pdate of grading operatirona. 3.4 ~•~~dslides ~~d ~nrfici~l Failures $ased on our review of the project geotechnucal reports (Appendlx A) and our geologic obsezvazioas during tbe cu~rent grading operazions, mere is no indicadon of landslidas or othu significant sucficial failures w;thim tha subject sice. 1 ~ - 3 - ~..t i 1 05/18l2B80 14:49 9092960534 LEI(~tTON PA~ 89 • • 11980289-003 3.5 Grouad Wate* Grouadwater was encoun~ered at a depth of appmxitna~ely 22 fea below existing ground level in the 6outhwest comer of the slta durfng ihe preliminary investigaGon (Leighton, 1999). No o[her aubsurface seepage or grouadwetet was encountered during grading, However, unfoznseen conditians may occur after the complecion of grading and establishment of site ircigation and landscapiog. If these coudipions sbould cecur, appropriate steps to mitigate aay resukinQ seepage should be made. 3.6 ~Dansion Testing of Finish rade oils Expansion iundex testa were not per£otmed on the subJect site since addalional fine grading is necessazy. Test resuits adjacent to the site and iocal experience witb similar matarials 3ndicate soils wi11 proba6ly raoga from !ow to medium aad possibly high expension potential. Expaoslon tesrs shauld be performed duciag We fiaal grading phase of tt~e site. An appropriate foundarion desien sho~td be inc morated once re~resetnazive ~++o++vinn indire.c ha ha a~• ~, ^ 3.7 S~,luble 5ulfate Testinn of Fuch rade Soils Soluble Sulfate cescing of neat surtace aoils was not performed on the subjea site. Tes[ resulrs adjacent W the sice and loc~l exparisnce with similaz materiala indica~e soils will probably have a negligible W moderate concandtation oP soluble sulfates. An ~oDroorlate c~ncrere d~jgn chou~~ be lp.S4lg~ted into foundation pla ~ in aaordb++ce wi~h Ta61e t9 A-4 of che 1Q97 jBC onca soluble sulfate conce tration h 1 ~ ~ ^~ 4- _~ -_ ~ -l~ v 05/18/2808 14:49 4.1 deneral 9092960534 • LEIGFiTON 4.0 CONCL[ISIONS PAC~ 1 B • 1 1 9802 89-003 7Le gradiung of t6a Cottunercial and Park Site of 7~act 28510 w~v perEoima! in general ac.cq[danco with the project gootahnIwl reporis, Seote~hnical rxomme~aNona noaAe during grading end the City of Teqnecuia's rcquirwnents. It is ounr o~inion rhat the subject site is suirable tor its intended cvmmerciai use pmvidad s~iitable recommeudations from a qusiified ge~terhaical oonsuNant are incrnpoxated into the desigrt and conatruction of the wmmerciat strucaues and associated i~rovemems. 4.2 Summa[y af Concipsionc . Cieotechnlcal roadttioAS encouncered during rough erading were generally as am;cipated. . Excavatlona wera made to comp~ent materials beaeath the comimercial pad durin$ the grading operations. • 1'he proposed ,Park Sirce was graded for use as a Puk Si~e oNy. If structures are proposed, additional siw spociflc evaluation should be performed. . It is our op3nioa tha~ the s]opes are swfi),clally aad grossly s[abie (under normal irrigation/pzecipi4uion pauems) provpded che eecommendetions in thc project geotechnica! reports a[e incorporated iaw t6o eootinued grading, post-gradin$, cons[zuctioo and post- construction phases of site development. . The potenual for grouad-surface rupture on the site due to a seismic event is comsidered to ba low to xrii; however, svvn8 ground shaki.pg should be axpactad during the life of the atrucn~ras. 'I7~e standazd deaigo of suuqurea e~ imeet the seismic desig~ rec~uirements of the Uniform Building Code (IJHC~, Seismic Zone 4 wi11 be requiced. 1 ~ ~ ~ 5 !~~~'~:, ~~~`~i \ 05/10/2808 14:49 9892960534 'LEICfiTON PAC~ 11 • • 11980289-003 SA BECOMAi~NDATiONC S.1 Farth orkw Future preclse grade earthwork should be parformed in accasdance µ,;th the Q~a1 Ea~~W~,,~ ~d Grading Spaciflcations in Append'u b and t4e followimg reconwnendatio~. 1'hc racom~daaons oonrnined in Appendix D are gcnaal grading specifications provided for typical gradine Projecrs. Some of Ihe tecommeaidazioos may +wt be stnicdY aPPlicable to thia phase of the project. Tlfe specific zaomm~dadons co~inad in the omet of this repo[t su~e the general recommendations in AppeMix D. The, cv~act bet~yepv the developer and earthwprk contraz:Wr should be vrordod such thaz it is tbe responsibility of the comracwc W place any addiaonal fill propetly in accordaace wath the recomaaendatzom of this repoct aad the specificarions in APP~+~~ ~, notwitLstanding ffie teseng and obsarv~ion of rhe geoteclwical wmultem. $.1.1 S t0 Pr *ation Prior to gradi.o6, the proposed s[ruceucal improvement areas (i.e. ~11 pavements areas, struetural building, oce,) of the site should be cleared of surFace obstructions, including debris and iuterim vegetation sie<e last phaze of earthwork. Vegetation, and debris should be disposed of oFf sita, Holes resulting fzom removal of burie~ obsttvctions, which extend below the recommendad cemova~ depths described heceln or below finished site grados (whichaver is Iower) yhould be filled with~properly wmpacted soQ. 5.1.2 B~tovels and ecomn re~n~ Tde porous surface alluvial soi~a that existed on aim have been remediated in accordance ~''~' ~e Prol~ Seotectunical report (I.eighton, 1999). Future remedial wozk in the ~~nacial Pad ueas mey conaist of ra-working and moismra conditianing tha upper 0.5 W l.0 [not of existing fi11 to r~establish proper compaction aud moisture conteot of existi,ng pceviously approved fill soIls. Adl fiti, iu improved areas sbould be at or above opNmum apisture content and a minimum of 90 percent relative compaceion (ASTM DxS57). 5.1.3 AddiNnnal c~~,~ Fillc Areas to rueive suuctural ~11 snd/or other surface improvemems aUould be prepazed {n aecozdance wit6 Sectlou 5.1.2 and scazifietl to a xninimum depth of 6 incbes, brough[ ro at meaz optimum moisture concent, and recompacted to at least 90 pexcent relative compactlon (based on ASTM Test Method DI557-91). The optimum lift thiclrness to produca a uniformly compacted ~II wiU depeAd on the type and size of compaaion equipment used. Lt gcaeral, filI ahould be placed i.n uuiforp~ lilia not cxceeding 8 inches in thickness. Fill solls should be plaeed at or above the tnlnimum opt(mum mouture content, Placement and compactiaa of fitl should be perFormed in accotdaace with lpcal grading ordlnances uader the fup-time obae~vatiou and tes[Ing of the geotechuica] conaultant. xmpor[ soils ahould be observed, tested (if necesaary) and approved by the geotechnical coaaul[ant-0f-record prior to sita delivery, ~ 8i . _ -6- ~~ ~ ~~ 05/18/2800 14:49 9892960534 LEICfiTON PAGE 12 • • 11980289-003 5.1.4 IJtilitv Trenches 7'he oesice eoils may generally be sui[able as trench backfill provided rhey are acreened of rocks over 6 inchea ia diameta~ and arganic mauer. Trench bac-~11 should be compacted in uniform Iifts (not ezceeding 8 inc,hes in compactad thickpess) by mechanlcal meaas to at leaat 90 pe~rcent rela~ive compaction (ASTM Tesc Method D1557-91). Excavation of utillty tcea4hes should be performed in accordauce with the project plans, specificatJons aad all applicable OSH'A r¢quiremencs. 7Le conuaaor should be tesponaible for providing the "competent person" raquired by OSHA standards. Con~actors should be advlsed t6at sand'y soils (such as the onsite alluvium) can make excavations particulazly uasafe if aU safety precautions are aot taken. In addition, excavations at or aear the toe of slopea ead/or parapel to slopea may be higlily unsteble dua w the incceased driviog force and load on the aench waiL 5poi1 pi~es duc to the excavation and consa~uctlon equipment should be kept away &om the sides of rhe uenche,c, 5.1.5 Sl~j~~lcaee and Bulkina The votume change of e~ccavated onsite materials upon recompaction is expecced to vary wicd mazeriala, densiry, ias;nr rooisture coatent, location end compaction effort. 'I'he ia- place and compacced densitiea o£ ao;l materiaLs vazy amd accurate overali determination of stuinkage and bulicing caonot be made. There£ore, we recommend site grading include, if posaible, a bafance azea or ability w adjust import quentities tA accommodate some variation. $aaed on results of 1a~ratory testing and our experience wi[h simlter wsteria(s, the followiog values are provided as guidelines: Alluvium 10 to 15 percent shridcage ~~~~5 ~~1~ S perceat shrinkage to 5 percem bulkfng 5.2 Ter~por~y~IQ~e St~ah~_;,,lirY Durua$ ranswction of the underground facilities, tempprazy excava[ion should have side slopes no steeper than I:1 (horizontal W vertical}. Excavations should be performed in accordaace with O.S.H.A. guideliaes. 'I'he use of sLoring ahould be lmplemented if ezcavation is [o zamain open. 5.3 Surface brainage and Eroxian Wa recommead that measures be taken to propedy finish grade each buildieg azea, such thaz drainage water ~rom the building area is d'uecteii away from bui~ding foundations (2 percent minimum grade oa soil or sod tor a distance of 5;eet). Ponding of watec should not 6e permitted, and installarion of roof gutters which audet inco a drainage aystem ia considaed prudent. Plandng are~ at grades elzould 6e provided wirn positive drainaga directed away from buildings. Drainage aad subdraiaage design for theae facilities should be providai by tha design civil eng~neer aadlor landscape azchitect. •~~, ~G .~ _ ~ ~~'"y~i~ ~~ 05/iB/2080 14:49 9092960534 LEIGFfTON PAGE 13 . . • • 11980289-003 5.4 ~'oun ation Desinn We artticipate t6at the commercial site sttucnues wi11 be supported on a combination of conventlonal interior and exteNor isotated~pread footings aad continuous perimeter footings. Foundaaon deaign recouuneudations aze based oe ~e assumption that the underlying compaded fill soila will be dertved from onsite aoil or impcin yo~ls wich similer ang[neerang characteristics. TLe following xecommeadatious are based on c6ie asaumptions thac the proposed suucture foomagy wilt be uiadutaln by a miniwum of 3 faet of Qroperiy compaae~ flll soila with a low to me~iAUm expension potent[al (90 or lesa per U9C 18-I-B). The following Tabie suromarizes our foundation design parametecs. Fouadation for appurtea~nce,y withiin the Park Sue may be preliminarily drsigned usiiag the same criteria and recommendatious. Seismic P meteS,g Seismic sheking a~ rhe subjecc sice can be mitigatea by adhering to ~Ge 1997 Upiform Building Code NBC) end state-of-thepractice seismic d~ign parameta~y of tLe Swcwre Engin~KS Associazion of California. 3eismic design paramecazs in eccoXdaq~e with the 1997 UBC provided below: Sefsmic Zone = 4 Seismic Source = H Near Source Faccor, N~ = 13 Neaz Source Factoe, N~ = 1.6 3oii Profile Type = 5n Horizonta! Peak Ground Accetaratiou = 0.54e (10% P[obability ia 50 yeary) . ~ & 1 8 ~-1~ r~~. ~2 All reinforcement should be in accocdance with the structurat enginieer's requiremenu. Incexior wiuma foodngs should be stn,cturally isoiateA From floor s~abs, Tb,e srcu~tuces should also be Aesiigned for tLe aaticipa[ed seulameat (See Seaion 5.7). 05l10/2088 14:49 9092960534 ~LEIGFffON PAGE 14 • • 11980289-003 5.5 Floor Slab cisn A1l slabs should have a minimwn thiclmegs of 5 io~ches and be ceinforc~ at slab midheight wifh 6X6 6/6WWP and in acwrdance widh aRnc~ual ~~io~er's recommendations. Coxuid~ing the iuherent d'~1`~~Y ~ p~~ welded-wiro meslz ec sleb midhelght we offer an altema[e reinEorcement of No. 3 rebars at 18 ieches on ceo0er (eecL way) or No. 4 rebars at 24 inches ceWer (each way). Addidonal reinfrn'cemera andlor conaeto thicln~eas oo acconwodaza speclfic volumni, machinery or equlpr~zem loading conditions or anticipated settlemeo[ should be waluated by the srruca~ral engineer based on a modulus of subgrada reacdoa of t001b/ia'/in and ~fhe amicipaoed aeW~~ts oudmed in 5ectioa 5.7. We emphasize that it ia the respons~ltity oF the contractor W ereure tbei the slab reL~forcemenn is placed az midheight of tha slab by use of "chairs" oc ot6er suppon. Lelghton doea r~ support the mwhod Imnwn as hooking in order to poeition sred az slab mid4elgLt. Slabs in a„eas of nqisn~re s~si~lve goor cover(og or smrage area~ foc matc.~ials sensi4ve ro moisnue should be underlairt by a 2-lnch lay~ of clean sand (SE great~ than 3p) to aid i~ ~~cr~ ~~, wblch is undetisin by a 10-mll (ot bexvier) moish~te bacraer, which ~S, in Nm. undalaio by a 2-inch lay~ oP Cleen saud f0 aCt 3s a Capillary breek. All penettaHona m~d I~s in the molsture barrie,t should ~ aPW'oP~~1Y 6ealed. Oue expe~l~ce iadicates that rhe use of reinforcement in sla6s and foundations wiU generally reduce the potenqal Eor dryin8 ~d ~Be aadcing. However, soma cracldng should be expecoed av the concreta c~aes. Minor uackjng Lt coa5idered noraual; howevcx, it is M1ea dggravated by a high cemem rauo, hi~ concrete t~r~ure at the rime of plscemem, ~mall nomina! aggreBare aize aud rapM moisdtte looae due ro ha. M'~ md/or wiady weather co~diaons duriAg placement snd nu'io8. Cracking due do temperature and moistwe fluctuations can also be expected. 'ibe use of 1Dw sluu~ ooncrete (noc p~cee~~ q~;~~ ~~e p~ of placemen[) can reduce tGe poteotlalfarshrLilregecxac)dog. Moi~ture barriers can reta~d~ but not aliiniaato m~i~hue vapor ~vement from the underlying soils up thr0ugh the slab. We reoommend t6at the floor covering iastaller tes[ the ~isture vapor tlux rate prior ro anampting applicazion of the Rooiing. "BZeathable" floor cove~ings ahould be considered, if c6e vapor flua rat~ are b1~. A alip~heet ahould be usad if c:ack sensitive Qoor coverings aze plazined. 5.6 Foc~ting e~rh~~r We recommend a minimum horizomal s~back dlstaece fi'om the ~aca of slopes for all sauaural footinga md seulement-aensitive suucWrea (i.e. fences, walls, signs, etc.). This distance is measured from the outside edga of rhe faoting, 6oriwarally tu the slope face (or to the face of a retaining wall), Slope I#eight Aecom¢~ended Foo[ing Satback <5 feet S fee~ minimum 5-15 feez 7 feet minimum > 15 feet Hl2, where H is the slope hefght, aot to exceed 10 fee[ for 2:1 stopes 9- ~ & ~ 1~__~~ ~-_ ~t~ ~ ~~ 05/10l2800 14:49 9092960534 ~ ~ • ~ LEIGFfTON PAGE 15 • 11980289-003 We should ~te thaz the soiis withiu a slope s~back area posaess poor loug eazm lateral stability, and improvements (suc6 as eetainiog wall. sidewaUis, Fencas. Pavemeu[~ uaderground utilities, etc.) cons~uaed within t}ais setbeck area may be ~bJec[ fo latenl mov~ens end/or di~t'ereutial seWemeat. 5.7 A.ntlcioated Sehlemcnt Settlemopt of uuremoved alluvlel matttial and pioperiy compaaed fi11 soils is expected to occur due. W rha applicazion of structural loads (elastic sealemeat), tha majority of whtch typically occwa during and slighdy after consaucaon. Mosc of the sealemeuc wid,ia alluvial so~ls uader the loading of compacted fill embankments ia also expected to occur duxing or shortly after cousuuatoa. Sased oa resul~s of consolldafiou and col~apse tasts, hydrocnnaolidatiou of compacted fill or underlying dense older alluviuno is wnsidcred co be typicat for similaz bulldings in this vicintty. Total and differential settlementlat the subject building pada should mt exceed 1 inch and ~h inch within 30 feet (Augulaz distpztion, 1/72~, respectively. 5.$ Later I Fan prgg r c anA A~gj anro ~m6edded st~uctural walls or canti~ever reraiuing wa11s a6~uld be designed for latera! eanh pzesaures exetted o~a rham. The magnitude of these pxessures depends on the amouac of deformation ffiat thc wall caa yield under load. !f the watl caa yleld enough co mvbilize the full shear strength pf the soil, h caa be designed for "active" pressure. If t6e wall cannot yield undec the applied load, the shear saength of the soil capnoc be mobitizcA aad che earth pressure will be higher. Such walls should be designed for "at rest" conditious. If a structure moves tawazd the soils, ~e resulting resistance developed by the soit is the "passive" resistance. For design purposes, tha recommended equivalent tluid pressure fo~ each case for walls founded above the static ground wata~ table and bacl~illed with very low to low expanssiou potential soils is providod below. Dotermi~ation of which condicaon, active or at-rest, is appropria[e fOr design will depeud on tha flexibility of the wall. T6e epPect of any yurcharge (dcad of live load) should be added to tha following lateral eanh pcessurac. Based on our investigation, the aendier onsite aod impozt soila may provide low w vezy lvw expaneive poten[ial backfill mate~rial. Alt backfiJl soils should have aa expansion potential of Iesa than 30 (per UBC 18-1-H). 'I'be passive pressures provided below assume that the setback reconomenAaNons in Saction 5,6 ere adhered to. Equivatent Fluid Weight (pcfl Cond'-tioa Levd 2:1 Slope acuve qp ~ At-lteyt 60 70 Passive 250 (Maximum of~3 ks~ 150 7'he lazeral eanh p~ressurea s6ould be inareuai to reflect the incremem of additionul pressure caused by the design earrhquake. pccordinglY, an inaemmc of laceral pressure equal to 16.4 H', whe~e kI is the hcighc of the wall, should be apptied at a distance oF 0.6k1 above the toe of the wall. Under the ~ & ~ - - 10 - ="-` ~~~ a~ ~~ 05/10/2880 14:49 9092968534 LEICfiTON PAC~ 16 • • 1 1 9 802 89-003 ~°°tbin°d effaMS °f ~tic ead eatth9uake toads on ihe waU a factor of safety between 1. a a~ui 1.2 i~ acceptabie when eveluating t6e stability (sllding, ovenuroing) of the wall (NAVFAC DM 7.2). All retaining waU amicturea ahould be provlded widi aPP~P~~ ~'~ge and waterproofing. Typical dreinege de6igu is iUustrated in Appepdix D. As sn altanadve, an appcoved drainage bostd sysceua iastallod 'm accordauce wit4 the maaufacauers' recommendazioos may be usod. Wali backfill should be compacted by mechanical methods w at ]east 90 p¢rcent relative compaction (based on ASTM Test Method D1537). Surcharges fzom adjaceat a4vcwzes, traffic, forklifts or ofha loada adjacem W retaioing walts should bc considered i~u the design, Wall fvoting dasiyos shautd be iw accadanca wNh the previous fouadation design recottunendations a~ rain~Forced in acsordance witb, shu~tural coo,siderations. Soil resislance developed against lamrai s~+~cduel'm~~ut can be obtained from the p~sive pressure va-ue provided above. Funher, for alid3ng r~istance, e iniaion coefficiem of 0.35 may bc used ac the co~uxete and soil in[erFace. T'hese valuas may be increasod by onethitd when c~nsidering loads vf sho~t durarion including wlnd or seismic loads. 'Ihe total resistance tnay be take~~~as the aum of d~e frictianal ar~d p3qsivc resistamce provided that the pasalve po-tion does not e~cceed two-thirds of the rocel resistance. 5.9 Concrete Laboratory tests indicate a negligible [o moderate concentracion of aoluble aulFatea in onai[e and proposed iAnpott soils (~ess than ISO ppm) fo[ tested representariva samples (Appendix D). AccordinglY, typical Type IN cement may be uaed for ooncr~s !q mntaa with onsite soUs [n accordanco with Table 19-p~ of the 1997 UBC: 3.10 ~eliminarv Pavement Desi¢n $acm~sa of the variability oF inaterlals on aite and unknown iumpon source~ it is not po5sible to hww whicb soils will be placed ar acpased at pavanetu sub~ade. In order to provide the following ~recommwdationa, we Mave uhiliud $ value cest resulb performed on repr~entazive Bamples from the adjacem projects with similaz soils (R~25 for onsite surface alluvium and R=50 for sandy Pauba Formadon mateitats). The fullowiu~g pavmnent saxions are provided for the e,otry and Sn~erior driveways and parlting areas. Based oo the City~of Tanecula nvniocwm pavement sec[ions ~d R- value~ of 25 and S0, we Provtle the followiog preliminary sections for planning P~uposes. Pavemetrt seceous were det~uiiaed using thie Calaar~s mahotl tor d~igu of 8euible pavemenrs. ~'raffic indices udlized in this method of design are based on esfimated equiva-eM axle loada over a perbd of 20 Y~rs. u is xecommended that ~ive semples of actual subgrade tnazeclals be obtaiaed md tested as the basis for the final paveu,ent desigu. . tS~dard Dutv~kin~Are~ ('~'ra~c Inde~ S ni R-Value = 25: 3" AC / 6.5" ,AB R-Value = S0: 3" AC / 6^ AB . Entrv and Inrerior Drlvewgy4 fTraffi • i,~ T~ a 7 p~ R-Value = 25: 4" AC 1 10.5" AB R-Value = 40: 4" AC / 6" A,B ~ & .. •11- ~` r ~~ 05/10/2808 14:49 9092960534 ` ~ • ~LEIGHTON . PAGE 17 • 11980289-003 Class 2 aggtegate beee (AB) ahould coaform to Section 26 of the State of Califorpia, Depaztment of 'ftaospo~ctation, Sta~rdazd Speci$catioos. Conczete croas guttets ahot~d be teinfacced at a ml~imum with 6x6-lU/10 wdded•wire mesh at slab midheight. Aspbalt Concrete, PorNand Cement Concreta, anid base materials ahouid conform w and be placrd in accordance wirh the 1997 Edicion of the "Greenbaot", 5tandazd Speciticatioos for Public Warks Consuuc[[on. 73e uppar 6 inchea of subgzade soils should be moisture co~xiitioned aud compacted to at least 95 petcent reladve compaction based pn ASTM Test Mahod D1557 Qrior ro placement of road basa. The base layer should be compacted to at -east 95 percout rela[ive compaction as deteimined by AS7M Test Method DI557-91. If pavement ateas are adJacent to heavity watered landacape areas, some deterioration aE rhe subgrade load bearing capacity may resuit. W6 recommeuel some measuxes of moisNre wnttol (such as deepened curb8 or other moisture barrier mazerials) be provided to prevenc the subgrade soils fxom becoming saturated. . -iZ- ~ & ~ ~~~'~r: Y~ B5/18/2800 14:49 9092968534 ~LEIGHTON PAC~ 18 . . • • 11980289-003 bA GEOTErHWICe[. R_EVIEW Geotechnlcal review is oP pecamount importance im.engiaeering pcgctice. TAe ,poor perforroance of meny foundatlion aad eartdwork projacts dave bcea 6ttributed to ~adequacc cooavuction review. We raommead that L,eightoa and Assocauea be pxovided~ the opporNnity to review t6e following iteau. 6.1 P~g and~pecificatio e The gaotaLnical angineer ahould review rhe project plans snd specifications praor to release for bldding and eonstruction, Syeh review ;n neceasary cn decermine wherher che geotechnical recommendationa have bew effectively implemented. Review fl,~dings shou-d be repoRed in writing by the geotechnical enginex. 6.Z Consuvction Revicw Observatlon and test;ng should be performad by Leighcon and Associates represen[ativea during conc[ructioa. It should be auticipazad thac rhe. subspata ezposed during consauct;on may vary from that encounterad in the tcat borines or ~enches. Reasoaably continuous consavction obaervatton and review during sitc Ecading and foundation installauon aliows for evaluation of the aetual soil conditlons aad the abiliry to provfde appropriate revisio~as where required during consbruction. Slte prepazatioa, removal o~ unsuitabie soila, approval of imponed earth materials, fill placement, foundadon iastatlation aud otha 'site geotechnleally-related operations ahould ba observed and tested. ~ & +`~~, - -13- ~` r. `~ 05/18/2008 14:49 9092968534 ` ' • ~LEICfiTON 7.0 ~.imitetionc PA6E 19 • 11980289-0~3 This r~ort was prepared for Woodside Homes, based on Woodside Homes nee~s, dicectiona and requirements at tbe titne. T'b,9s repon was necessarily baned in part upon data, obtaiined from a limited nunaber of obsecvances, site visits, soil and/or samples, testa, aaalysea, hisao~es of occurrences, space~ subsurface axplorations and limited inPocmatioa oa hisrodcal eveata aad observations. S~ch intormatiou is nuossazily incomplete. The nawre o£ many sttea is such that differing c6aracteristics can be ezperienced within sma11 distauces and under various dimatic condiflons. Changes im subaurface coaditions can and do occw~ over time, Tho preseace of our 5eld reprosentuive et tha aita was incended w provido the owner with professiona- advlce, opinions, end recommendatipns based on obsezvations of the rnnusctor'a work. Altbough the obeervations did Aot reveal ob~'ious deftCiencies or devistions from projecc 6pacifications, we do not guazantee the contractor's wozk, ~r do our servicea ielieve the convacWr or 6is subcontractor's work, nor do ouc setvices relleve tha contraaor or his subcontractora of their respousibllity lf defects are subsequendy discovered in their work. Our responsibilfdes dld not include any supervisiou or direc[lon of the ud~al work proceduces of the coutractor, his peraonnel, or subconuactors. The conclusions io this report are basod on tcst reaults ~ and obsarvatio~ o~ the grading and earthwork procedures used end represcnt our enEineering opinlon as to ihe compliaace of the results with t6e projeet specificatioas. This repozt is not aurhor)zed for use by, and is not to ba celied upon by any party except, Woods,ide Homes, trs suceesaors eod assigns as ownec of the'property, hs teaants aed its lenders with whom Leighwn contracted for the work. Use o£ or celiance on this report by eny MtAer party is at that party's risk. Unauthoziized use of or reliana on this Re~ort conaUmtes an agree~oeat W defemd and indemnify Leighton & Associatas from and against any liability which may arise as a result of such use or ~relienee, regardless of any faulc, eegligence, or strict Ilabil;ty of Leighmn and Associates. ~ & -.. - 14 - ~~-.~~ '' ~t~ ~ `~