HomeMy WebLinkAboutSubsoil Studyø9-29-'86 09;53 FR0M-Civil Cunstructnrs 9?0g456101H¡
HEPI,VORTFI "PÄWLAK GÊOTECHNIC.AL
T-556 Ptzlzø U_2S5
Ì1."' l\..--l.t ^r-r ád!2* r iÅ/rra¡h.\...,-; i- -
)UlU Luunrt. Road li4
Olenwco<l S'priru., Coio¡g¿lo gl ó01Ynoner 970-9,15.79ÊS
Ftr--;,97&945-845{
I c, _ - -.rÃr.¡r!Þ!&_u(À¡aï---. 1 *^ -'.--r\uvemoer ¡U, _1U05
Heim Ðesþ & Developmeut
Atm: CraigHolnr
i r-Ûü Giisnap Court, r^rrire 3û0
Glenwood Springs, Colorado gt6Ol
Job No. 105 9S7
{1-_-_!-: - ,ISSUJCUt ;
DearÀ{¡" Heln:
Su-bsoil Study for Foundation ?ul¡SO proposcd Rosidence, Lor 20,SprÍngidec II, Hidden Valley Uriui" Ga¡fiel¿ Couory, Colt u¿o
-'
As æquested, Hepworthfau¡lak oeotechaical, Inc. performed a subsoil studyfor designof founciations at the subject site. The sfudy was conducted in accord¿nce with owagreerrreut for geotechnical eegineç¡ins se¡ í"., tô '.,,.,ì! ,{:ro,l .,u,.-.'-t-- ! ¡^... ,i,! ,
dara obøured anrf ourrecommendatiori, u"**¿ or n;;;; "ï**"ur'"'*'
'"t
subsurfacc conditions encou¡tered are presented in this ,.pu*.
FrOpone¡t CqUSÊfUCti^r"- 1'È. -:¡-.-.-=r ...-..:r--^^ .-..,.,
skucrureoveran¡rr'**-;d;"íËffiîi*:"JJiTiÍ-äii"",i-ri,îffi l-"fhe exPioratory pit shown on Figure 1. Basemcnt floor will be slab-on-grad.e. c¡rt depths
T:-i*:i:u,(f rysalet'ree¡ about 3 to i2 reet. roonariù" r"ä*, arı essuner! rrr þq¿r.¡âlr.,,ç¡y i¡S¡¡i öaq. ry?¡çai oÌ iÌre proposeci type Of consürrction.
If building conditions
,or for¡¡datio'roadings are signifcantly differenr ûom tlosedescribed above, we shor¡Id be notifïed to Ã*.r{uut" the ¡eee¡rr¡¡rcn¡latii}rrs ¡rîetêñrÊr4 ;Ìì-Liüs rgport, - r- 'gvqrvue
site condftions: "rhe site wâs vaçant at tlc dme of our field exploration and is locatsdonthe we'st side of llidc.en l'lallcv D'!ve. T'rre sr¡r¡rn..r *rrf*¡c;- s-¡^+ì-.^ì--s--
sloping d,o*¡n to rhe east. The site had been ffi*;;;;#;rqlr
vu¡v ',at nno gerltlv
Subsur{ace Conditions: The subsurface conditions at ths site were cvaluated bv^L- -..-..
u r¡ne exlrìnr:t^f / -ñiî ñt +liÀ ^q-*--': - . . ...,__,., Ê¡_¡r'Ár¡ÉlvtI yL\ uv r¡¡v qppruÀllll¿üe iooaiion shown on Figrre 1. ,the
Pttlryasexcavate¿l pnor fo ouranival to the síte oï Novernber 3, 2û0S. The log ofthe p$1Spresented on Figure Z. The subsoils e¡cou:rtered, below about i foot of lopsoil, consist ofsilly sandy clay dowtr to the bofiom pit depth of 12 feet. Results of swel!-ec,ns*!i¡leri¡:ntesîing performed on relatively undisturbed samples of the clay soils,presented on Figurc3, generally indicate low to moderate conepressibility r:-nder existing moisture conditionsand light ioacting. The sarnple ûom the pit at a deptb of 5 feer showed a minor collapsepotential (afrer .we.tfitrs- Tlre san:ple frnrn +i.- *¡+ ^+ ^* P¡^¡ qr ¡/rr c( d
Irarker 303-841-?ilg r cororacio s¡:rìngs 7lg-óij-55ó2 " sir'errhorne g10-46g-rggg
û9-29-'06 69:53 FB0l{-Civil tonstructors 97094b6101 T-556 P13/2ø U-265
depth of I feet showed a mînor expansion porential after wening. No f¡ee waærwas
observed in the pit on Novernbc¡ 3, 2004 and the soils wcrc slightly moist to mojst,f .abcrafo,.ï' test i esult..i ars :rirûì:i:aized !n T+ï;.iE i,
Fo*ndation Reco¡nnendations: Considering the subsoil conditions ob.sefl¡cd iû th¿
ø<pioratorypit a¡d the nanl¡Ê of the proposed constmctio', wereçomruenel spread
footi''gs piaceci on the unrüsiurbed natural subsoils desigued fo¡ arr aitowablE soil beæing
pressì¡re of I ,500 psf for support of the proposed residence. The clay soÍls possess a
variable seftlemon/heave potentíal and thc bcaririg conditions should be ñ¡rthcr evaluated
at'the time of corrstructiou. Footings shculd þ¡e a nuni¡ni¡¡n rviddh ¿f 1 I inel:cs fc,i
continuous walls and 2 feet for columns. Loose and dign¡rbed soils encountered at the
foundatíon bearing level within the exc¿vatio¡ should be removed to expose fimn nanual
soils, and the footing bearing level should be moistened and compacted prior to
¡nr',cfrr+lir;f^^+l-*- Ë-¿--i----f-^¡- - -t -. t r r!ç-!ÈL¡ 6Ç!!iå !rrçig¿g;. .='irt-¡l'J¡ ¡uuli¡¡Bi s¡rüuiü üË piûiTüOû ftiìIi Aútrg[Aig COVgf AbOVg
their bearilg elevations fo¡ frost protecfion. Placement of footings at least j6 inchEs
bclow tho acferior glade is typicaliy used in this ¿rea. Continuous foundation walls
shor¡id be reinforced top and botto¡u 10 span local anomalies such as by assumi¡¡g ¿1
u.irs-tipponed length of ai ieast 12 iber.
S'oundatÍon anil RetaÍnfug 'W*lls: Fourrdation walls and retaining struetures whicl¿ are
laterally supponed and can tre expected to undergo euly a stight a;a,$it af d*f!*¡:1Ìnn
shot¡ld be designed for a lateral earth pressure computed on the basis of an equi.valent
fluid unit weight of at least 55 pcf for backfill consisting of tåe o¡-site soils. Cantilevered
reteining structurÊs which are sepaffite from the ¡esiclcnce ancl can be expected to deflect¡rrfF*i¡-+1-'¿^ *^L:l:-- rt- - e-ttrilu!!çrçi¡r¡-Y !1, ¡¡ruúrrlz6 ule ï'riíi ac!!!".'e eaiîn Fî€sS¡-Ìià cc¡d¡t¡.on sho.r¡d 'us rÍesig3cd for a
lateral emtù pressnre cornputed on the bæís of an equivalenr fluid unit weighiof at teast
45 pcf for backfill consistirrg of the on-sire soüs..
n l: ¿;.,,-;^+:^- ^-i -^! 'I üi ¡{}ìr¡r(¡ai¡üE a¡¡s ïsÞln¡ug siruciïrcs shouici bc riesigncri for appropriâte hydrost¿tic and
surcharge pressures such as adjacent footings, trafñc, constructíon materiais and
equiprnent' The prcssurcs recommeuded above f,ssume drained conditions bchind the
walls and a horizontal backfill surfaeê. The buildup of wate¡ trehiird a r',all oi an up.+.ard
sioping backfilt surfâce will íngease thc lateral press'oe imposed o¡ a foundafon wall or
retaitring struchffê. Ar¡ underdrain should bc proviclbd to pravent hydrostatic pæss.llÏe
buiidup behind walis.
BapkÍll should be placed in unifor¡n lifis and compacted to at least g0% ofthe rnaxirnum
staadard Proctor density at a moisrure content near optimum. Baskfill in pu1r**uot *áwalkway areas should be conpacted to at lesst g5% of the rnaximrun sta¡¡dard proctor
iit'-¡$¡¡t. Care siicuiki be taL(en ¡¡o'i to ovcrcoüpacr iiie baclf,iii or use iarge equipment
near the wall, since this could cause exoessive lateral pressure onthe wail. somc
vJ 20,
cå5t*"r-t
v¿ ùJ (,u er,Jó FfiUH-Urvtl tonstructors g?0g456j.üj.T-556 P1412ø U-265
s*rle¡nen¡ ofdocp foundation wall backfil
pr¿ced coriecrr y, l,¿ -""r¿,å.,n ;;i#-YH,ffiJ::f,å;;îJ' H: ffiîäfi1
-
'f'L^ l^+^-^ i .. . - :, -ri¡Ë iaÏÊiai lËslstance offoundation or retaining wall foorings will be a combination of thesliding resistanee of the fooring on the foundafion matcrialr *¿ pussiu. earth pressurea8ainsttl¡e sideof the footing. Resistûnce to slidingeTthe uo*oås of the food¡gr.ä¡,calculated baserl on a coefflcig¡ìt af ftctic,i: r;i{i.3-í- p¡ssí-.,n ,;-:",,"- ^¡: -*- - -, .
backfilt againsrthe sidcs of rhe foori:rgs ,* r," ""r""i"Ë;;rä'äiilïffiiäi,;*,weight of 300 pcf, The coefficient of Êict¡on aad passive prrrr*. values ¡ecommendcdabove assume ultim¿te soil strength. suitsble fagrårs orrurrry Jnuld be includect i:rrhe,'{¡si-ä +n !íni- +-ì.¿ a+v¿i* ,.,a.-^a ,.rr, - .a¡r'¡rËi!! LU r'j'!,'r'L u¡! ì;ü¡t¡ü ùïiû¡ "wiii uçcur ar rhe uitimate stengÍh, particglarly in the c¿secfpassivc ræistance' Fillplaced against ths sides orthe øotinls to resist laterul loadsshoulrl be cômËåded to at leustgl%of the maximun standard proctor density at amoisnre cont€nt $eã optimum.
Floor slabs; The natu¡al on-site soíIs, exclusive of mpsoÍi, are suitable to support liglrtiyloaded slab'on-grade co¡shuction. To reduce the effects of some;ñä;iffi;ää;
non-sfircnlrai floor slabs shordd bc s*pa¡atcel llr<¡rn ;¡i { he*:ìnc ì-^¡a!r.= -*.r ^^t.*" -
' -:.,-*''
exparuion joints which allow unreshaio-¿ rr"rtt""r *o,i"*J tË;rî*u""åiäi*#,
should be used to reduce dancage due to si:rinkage cracldng. The requirements for joint
::iÏf_ïl:l:l ::ïi::aent¡houta f esr3grisrred by thî ¿.rip* based on experienee.*_. ¡ a ¡¡,,*r¡¡*rlr, +
^rrvg ¡aJçr o¡ rree_ora¡ntTlg Fåvel strould bcplaced beneath ba"ceme; level slabs to facilitæe drain"g". Tb,j*, ;u,"ria sho*ld consist ofminus 2 inch aggregak wirh less than J0% passing theño. 4 sieve a,rd less t\art2%passíng the No.l00 sieve"
Alt fill matedals for supporr of floff slabs shourd be compacted fo af teæt g5% ofmaxi¡armr standard Proctor density at a moisü¡rc sonrsrr ;;.pttr""*. Roquircd fill canconsist of the on-site soils devoid of vsger¡tic,!:. tc.pç¡i! åi:d ,:v,ir,¡i"oj ¡,---.^-
underdrafn $ysteu: Although free water was not encçuntered during ow cælo¡ation, it
li-T"Ëffi ::"::::j:::î:::Yjlg:-:nøs"ounáwatøcandeveropdr¡ine
create a perchcd condition. 'We recommend below-graal const ucuon, such as retainirigwails, deep crawlspace and basement areas, be prctected ûom wetting and hydrosfatic
T;:::i::::i:l:l i1l1ïlo*" qy:'"3. shailow crawrspaces cr,ss trran +'r*t J,ue;:ii¡Lilifi¡ ¡¡'r-r ¡E'{ú¡¡e a Fcr¡iririËr uidErcirai¡ provi<ieci rne w¿ri backfill is compactedpropcrly and positive surface drainage is mainta¡nod a¡ound the house.
If installed, the drains should consisr of drainpipe nlaced in the hryrorn ¡rrr..: .r,*.rr L^^r-',,r
su¡roundeci a"oove the rnvert level with frce-.lruiniig e'*.J;;;i"L ïil"*-r:;il'be placed at each levei ofexcavåtioÊ and at leasr 1 foot below lowest adjaceot finish
Jah Nc. loi9g7
c&Ftecr'
ü3-23-'ütci ûg:5s FË0r{-civir fionstructors 9209456101
-4-
T-556 Pt5/2t U-265
¡rade and sloped at a minfunum 1?ô ¡o e suitable gravi+v outler. Free-draining g¡anular
mato¡ial used in the underd.rain system shodd cont¿in icss thaû l% passing tU. fqr, ¿OoSieve, less thAn 509ó pessing the No, 4 sieve and her.,e e 1oÊxi'iuo, si:*,if 1 i¡rl-. ,,.!-.r
<irain gravel backfÌll should be at least 1!å feet d.eep.
Surface Ðrainage; Tbe follorving drainage precruiions should bo obsen¡ed du¡ins¡'nnciar¡ùl^- ^-,1 ^r-l*r-: I . !! .teuuıu id,ir,rj! ¿{¡¡u r¡l¿¡rr.¡..¡ ríçç¿ aI ail ñÈes efieÌ. thE rcsi<ic;¡c*: iias be cn compierec:1) inundarion of the for¡ndation sxcavations and underslab æËa.s should beavoiderl druing constuuction.2) Exterior bacldill should be adjusted to nÈar optinrqm moignrre nnd
cÛäiFåútËú iu at ieasl957ó of the maximr¡n standard Proctor rlensity inpâvÊmenr and sl¿b ar.eas aud to at ¡Êast g0% of the narimum standæd
Proctor density rn landscape a¡eas. Free-d.raining w¿ll bacHill should becapped with about ? fcat of the on-site cfa¡¡ *sçl!,r r-i-r redur:* $iråce ri,¡,+;.
infilrration.3) The ground su¡face surrcrunding rhe exterior of the building shouid be
sioped to drain away.ôom the fouxdation in all directions. we
icc¡¡E¡rre¡rú a ¡li¡.i¡uum siOpe Cf t; i.nChcs ui the fir-- i ^ -+_ -
areas and andnímum slop"ìr: inches inthc n¡sr t;iä'ñi:tr.l-å
*,allrvay areas4) fo?1$*,toûuts and drains should discharge wcil be-vond tle timits of sll
l,a.ulril'Ì1.
5) LandscapÍng wbich requiresregular heevy inigation, such as sod" should
. be iocated ar leasi S feet ûom the buildiug.
Limif¿1i6¡s: This study has beeu oonducted in accordance wiÏtr gcnøally acceptedgeorechaical engineeringprinciples and. praotices in this a¡ea at tlis timc. TVe make nowâr¡ânty eithar express or implied. Thc conclusions and. recornmendations submitteJinthis repori a¡e bascd upÕn ths c{aia obtai¡ecl Ln"¡m *rç e¡:n!or:at¡r-..3i+ -*^-".^-^à ^* -i -
looation indicared oo Èigor* I and to thç d*prh;;;;î;s,";äêËffiJ#
",constuctiou and our experieace in the area. our services do not incluåu á**oinir* irr"pless.ûce, prevenrion or possibility of mold or otber biological contaminants (MoBCi
.^le.r'el,'ping ìn the fut,;re. lt *Jic clici:ï is üuuucroed abourÌviûBC, *;;;;fè;*"Ii'i,
this special field of practice should be consulted, our fhdings inclurle interpotatlon arrocxtrapolation of the subsu¡facc conditÍonç ideatifiod at the exploratory pit and variarionsin tl¡e subsurface conditions may not becorne evident urr,til e,xcavatiou is perfbrme,C. [fEo¡¡üiiiu¡rs uncounrereci cÍuung construction appear differert from those ctescr;6ç¿ ¡, g¡,
report, we should be notified at onca so ¡e-evaluadon of the recommendarions may bumade.
This report has been prepared for t1re exclusive use by our client for design purposes. \1¡ea¡e oot responsible for tech¡ical interpretations by others of our infonnation. Ás the
GóreÇh
ü9-29-'tû t3:53 FËûM-civii constructors s?894s6101 T-556 PL6/2ø U-265
project evolvôsn we should prcvide oontinued consultation aad fieiC services druing
construction tô råview and moniror the implerrentation of ou'¡econurend¿tion¡, and ro
verifu that the recomme,ndations havc beæ approprÍar*ly inteçreæd. Sigificant desip
cirarrges may require additional analysis or modifications to ttre recomm'-ndations
presented he¡ein, We reoommend on-site ohsenration of e)Ceavations and foundation
beating skata and testirrg of structwal fill by a represeutative of the geotechnical
cnrvin¿æ
If you have any questions or if we may bc oifi:nhcr assisranee, piease iet us lcnow,
l1--,--^-A-lr--n r¡.rçt¡!Ërii,¿uny Þ uDmiüeü,
I{EPWORT}T - PAWI"AK INC.
,T$sr¡a. T l¡*alf D¡¿wr u¡ !- ¡u¡!,{. a
Reviewed by;
-\// t\ /\ 4""\^
Daniel Ë. Ha¡din" P
'I l !¿ ,|.'crrt¿ ltv ¡w tv
a$ac}rrnents Figure 1* Location of Ëxploratory pit
Figure 2 - Log of Exploratory Fit
Figue 3 * Swell-Consolidation Tesi Rasults
Table I - Summary of Laboratory Tûst Results
t.
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105 987
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f?r1-90-. âa àn , Ë4 r.-¡¿'i-¿i- uû ir';5¡ ¡i{¡ri-tivii rlonstructors 97054561t1
APPROXIMA]E SÇAIE
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pti 1
0 0
5 WC= 10.6
ÐD-94
.a,go-sz
WC-9,1
DD-114
10
ïOPSOlk stighfly sândy s[V clay, ftrm, rnoist, dark brown, organic.
CLAY (CL); eilty, sandy, mediurn stiff, msist ts Ëlightly moist wÍth depth, brown to dãik brown, calcdreous
wirh deprh.
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LEGEND:
þ 2r' Diameter hånd drivÊn finer sample,
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NOTES:
ì. ihe expioraiory pii wãs ûbservecj Õn Novemþer 3, A0tS.
2- The location of exploratory pit was mmsured by pacins frsm feåtrres shown on the site plan provided.
3. ThB exploratory pit elevâtion was not rneasured and lrg of e)eloratory pit is dreÌ'n to dgpth.
I ftr¡ ¿.,.!,r¡,,É¡'..,..ii 1,.,$¡i^- -h^.,¡¡ l- ----:i--¡¡t' i I iä tÅí.¡i|-;i.jiurlg' ãiii iiii'äuai Ì 5aÐu!û :-î.+ ctilSiüg{Ét AûCU|åî$ Crliy i+ ihe iegree impíieCi by ihe rnethOd iSed,
5. The llnes between rnalerlâls Bhown on the exploratory plr bg rsprs€ent the approx¡mate boundaries betwÊen måtêri¡typos and transitions måy be graduat.
6' No hee water was gneountered in the pit at ihe lime of axcar¡ating- Fluctustion in'¡¡atcr le.¡el mav cccr ¡i wiih +imç
7. Labontory Testing Results:
WC - Water Content ("/o)
0D - Dry Densily (¡.rc0
-200 = Percerf pâsEing N0. 200 sieva
105 987 æ¿
FIGURE 3
øS-?9-'06 tg;84 FROFI-tivit Constructors 9?ø34561ø1
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APPLIËD PBESSURË. ksf
0
10
Moisture Content = 9.1
Dry Denslty * 114
Sampteof: SandyClay
From: Pit 1 at Ê Feet
T-556 Pt9/2ø U_265
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Mô¡sture content : 10,6
Dry Ðensity = 94
Sample r¡f: San4¡ Ctay
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From: Pit 1 at S Feet
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HÊpwoRT¡tpAWLAK GECITËGHFflcAL, I NC., TABLElSUMT,IARY OF LABQR.ATORY TEST RESULTS,lc,b No. {05 S*7Samly clrrySaudy cûtye3IF.J(3GÞg)G](J)iir*.ts¡l:f.,c'J..ICì¡l.rc)ıItvt-r'=CIt+oIln(¡*¡F(arsLllct,,ÁEFr*:tI{JtLficÐ'ÉFJ€N]tsIr.atÐ(J1stlrl.ITT'EFr-Astt0llltlExttNcoHfiNtrocoàÊpRESS|'VÊ.sTrËt{clFtl'lßlUEUIDuHtlPERCENTPASB}NGNO. ¿00stÈvË92(eflsA|¡f)NATU.IALMOISTURECONTENTNATURÀLORYÐENSITYf,¿¡GRAVEI.94tL4t0.59.1{fr'lDfFTH5ISAilo.PITl