HomeMy WebLinkAboutSubsoil Study & Perc. TestO8/O?/ÛT O8;ll FÀX S70 Ð{ı 6585 CANYON HONDA
HrpwoRrH-fiwurr< GeorEcHwlcAL, INc.slIl0 Rod 15{
Gl¡nwood Sprlngr, CÔ 8ttôl
Desclnbcr 6, 1996
f¡t 9?0 ll5-8{5{
Pho¡r î7O 915.4080
MÍkÊ Bodrogi
172 Orcbard I¡¡r
Glcnwood Springs, Colotado 81601
Subjcct: Sub¡oit Study for Foundation Designand-Porcglation Testing,,Proposcd- Residence, tot 37, Wcstbart Meea, Garficld County' Colo¡ado
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Job No. 196 584
Dcar Mr. Bodrogi:
Ae requesæd, Hq¡crotth.Pawl¡k Geotechnical, Inc, pcrformed a ¡ubsoil efi¡dy and
pËroolãtion tceiing for foundetlon end scptic disptr¡at sysfcm deeigûs a! the nrbjcct sitc.
Tte sq¡dy wrs conductd in accordance with or¡r agr€ement for gooæchnical
üUi¡ceri¡S ærviccs to yot¡ datcd Novenúer 13, 1996, Tlp data obt¿itpd ard our
rccom¡ueøetion¡ based on the proposed construct¡on end $¡bsurftce conditions
enconnærcd arc presented in thís rÊport. Assessment of potential geologie lazard
impact¡ on the eite üË beyond the scope of this sh¡dy.
hopooe¿ Coüstruction: The pfopoa€d rcsidcnpc will be a single story split hvcl
sfiücn¡re ovef s çrswlspacê lıc¡tcd on fbc siæ as drown on Fig. 1. ltlé foundation will
bc etcppcd to llmit cuß into rhe bill¡ldc. Garagc floor willbc slaÞon-grade. Cut
d.pt¡i äre expccred ûo be up to åbout l0 fcct. For¡ndation loadiqgs fo¡ this true of
corstr¡ction uc ¡¡s¡med to be reletively ligbt.
If buildfuU conditions or foundedon loadiqgs a¡c sigÃificantly different from thoee
dcscríbed ¿Uovc, sre should be notified to rccv¡luate the recommendatíons proeented in
this report.
Stte Conditlon¡: Ttc sitc wa¡ vacent ¡rd coverod with abot¡t 6 inchcs of snow at fhe
timc of our initirt field work on Novembcr 18. 1996. A tn¿lùoe h¡d to bc used to
compleæ tlre field work duc to ¡çcccs ptoblems carr¡ed by ths $now. 'fÏc ground
surficê in thc buitding a¡ca is strongty etopi¡U dowu to thc nortbe¡st at r grrde of about
3O% with ebout t5 to 20 feet of elevation diffeænce. A n¡tural drainagc about I feet
decp is locetcd tg the southc¡st of thc proposcd residênce. The ro¡d cut fof Htæbinger
Drivc locatcd along tlc northeastcrn sids of thc lot is bctween 6 atd 10 feet high.
Vcgctation consists of bruslr and æancrcdiunipcr tire¡ss ecfoss tlrc site.
Subsurfrcr Condlttons: The n¡bsurfscc conditions at the cite wcre evaluatcd by
excavating two exptoratory pit¡ in thc propod building aqga and a profile pit-in thc
se,ptie diıosal rnå ¡t ttre epproxim¡æ locatíono ohown oa Fig. t. The toge of the piæ
are presented on Fig. 2. The subsoils Ëtrcounûered, below abolt rtt tß lrâ fect of
ropsbil, consist of low dc¡uity eand and clay with scstt€rcd gravel. !,esults of swell-
coruolidatíon tcsting pcrformed on relativcly undistu¡bcd semplee of thc clay soils,
prcsented on Fþa. 3 and 4, indicatc low complescibtftry uqdcr cxisting mgisture
ãonditions and light loedi4g and a lou' to rclativoly þu;h collapse pot€ntial (scttlcmcnt
undcr constant load) when wetted. Itre samplcs showed modercæ to high
.o;8ta?/97 o8:{l FÂx s7o 9{ã 658ı CANYON HOh'DA
Mlkc Bodrogt
Dccanber 6, 1996
PageZ
comprcssibility upon additionel toâdrtrg rñer wcüing. No ftcc $r¡ter uns observed in
the pifs at thc time of exc¡v¿tion anrl the ¡oils werc slightty moist to moist.
I'ound¡tlon Recommend¡tlons: The nan¡ral eoils are relatively low densíty ard
moderately to highly coppressible under light load¡ng when wetted. Consklering tlte
zubsoil conditions errc¡ounûer€d in thc cxploratory pits and tlp naturc of the Þroposed
construction, qread footi4gs plaocd on the undieturbed ¡atr¡¡el eoil can be used for
s¡pport of the proposed rcsidence with some risk of post-corsruction ¡ettlement and
distress to tho buildigg. Thc magninde of settlement will depend on tlp depth and
extent of any wettiqg bclow the foundetion ¡nd could be on tlp ordcr of I to 2 fu¡ches.
$pread footings should bc desigræd for an alloweble soil bcaring precsurc of I,000 psf
end have e minimum width of 20 inchcs for contiuuou¡ wells and 2 fæt for columns.
Loose anrl disturbcd eolls cncounrcrod at the foundation bcsring level ¡ho¡¡ld be
¡emoved ard the exposed subgrade moistenod ond compacted. Extcrior footiqgs should
bc providcd wiih adequarc cover abovc their bca¡ing clevations for froet proûection.
Plicement of footings at least 36 incåes below the exterior grade is tlpically usêd in this
o¡ea. Continuous found¡tion walle should be heavily reinforced top and bonom to limit
the effects of poæntiel diffsrentiel settlement and to span local anomelie¡ euch as by
asnrming an unzupportod lenglh of et leest 14 fæt. Tbe foundetion úould be
consüucted in a 'box-[ike' configuration rather then with isoleted pads ûo ñrther help
lirtrit thc effects of differential ættlement. Foundation walls acti¡lg as rctâin¡ng
strußüres should be designed to resist a leteral eartb pressrrre baeed on an eqrrivalent
ftuid unit weigbt of at least 50 pcf for tlre on-site soil as backf¡ll.
Floor Slebg: The netural on-site eoils, exch¡sive of ûopsoil, erc suiteble to $rpport
liebily loeded etab-on-grrdc constructiotr" Tlte low de¡sity soils encountcred tend to
cotlapse when wetted, which could result in slsb distress. To reduce the eftbcrs of some
rlifferential movÊment, floor slabs should bc separated ftom dl bearing walls atd
colurnns wÍth expansion joÍnts wbich ellow uûresEainÊd vertical movement. Floor slab
control joints drould be used ¡o rduce damege dræ to shrinkrgs cf¡gliry. '¡Tê,
requircments for joint spaciug ¡nd slab rcinforcement should be cstablisheci . -* the
deÀigner bascd on cxpcrience ånd tbe irtended sleb usê. A minimum 4 Ínch iayer of
frce-¿ra¡nirU gravel should be placcd beûeâth cl¡bs ùo facilitatc draÍnage. This msterial
should con¡ietof minrs 2 insh eggregste with less thm 50%' passíng the No. 4 sieve
and less thsr-Z# passing the No. 200 sieve.
A¡ filt mrrerials for ¡mpgort of floor slabs ¡hor¡ld be cornpactd to at least 95* of
maximum stardard hoc"tor density ¡t a moish¡re contcnt rËar optimum. Requ¡red ftlt
c¡n consist of ttre on-eitc soils devoid of vcgctation, topsoil ¡nd oversizcd rock.
Underdrrln Slstem: Although free weter l[r¡s Dot encountered during our exploration,
it has been 6r¡r experience in the aree that local perched grourdweter may develop
drrring times of lrearry precipitåtion or season¡l runoff. Ffozen ground during epring
runoff can üeffe a perched crrdition. We recommend below-grade constnrction, such
@o¡
H-P GEOÎECH
rO!,¡O7.rO7 08!11 FrX O?O gl8 8585 CTNT'ON HONDÀ
Mlkê Bodrogi
Dccembe¡ 6, lW6
Page 3
âs r€t¡ining srålls ¡nd creu,lspace eltts, be protectd fiom wettiqg and [ydrostrtic
presstre htildup by rnundednln system.
The draÍ¡u rhor¡ld consist of draÍnpipe placed in thc bonom of the w¿ll b¡cldrll
surmurded above thc invcrt level with free-draining gra¡ulrr mstêrial. The drain
drould be pl¡ced at each level of exc¡vafion a¡d at least I foot below lowest adjacent
finish gnde rud eloped at â minimuml* to a suiable ggavity outlet. Freedreining
granrlar måteriel useil in tlp underdrain s¡rsæm should contain less th¡n 2% paesing the
No. Zfi) sicve, le¡s than 50% passiqg thc No. 4 sieve and have e maximum size of
2 incbcs. The dr¡ín gravel baclfill should be ¡t leas llt fødeep. An ir4pervious
membrano such ss ã) mil PVC cbould bc placd bencaü ûe dra¡n gravel in a troug
shape and ¡ttachcd to the foundetion w¡ll with m¡stic to prevent wefiiog of tbe beari¡g
soils.
Su¡face Dralnege: The followiqg drainrgo prpcaution¡ should be obscrvcd during
congtructíon and meintainsd at all tines after the residence has been completed:f) Inundr$on of the foundetion excradons end undersl¿b ereâs should be
evoided dt¡rÍng constnrction.2,) Exærior beclfill should be ¡djusted to rner optimum moisture ¡nd
compacted to at least 95% of thc marimum smnd¿rd Proctor density in
Davcrncn¡ and stab a¡cas and to at le¿st 90% of the m¡xim¡¡m standard
Proctor dÊns¡ty in landscepe are¡c. Frec-draining wall baclf,¡ll ehould be
coppÊd with about 2fiæi of ths on-sile, finsr graded ¡oile to reúrce
er¡rface $rater infilü¡tion.3) fire ground n¡rfacc zunouding the exterior of the building should be
eloped to dn¡n awey from the foundation ín ¡ll dircctiors. Wc
recommend ¡ rninirRum slope of 12 inches in the ftrst l0 foet in unpaved
areas ad e minimr¡m elope of 3 ine.hs in tho f¡rst l0 feet inpayement
and walkway arç¡rs. A ¡wale will be ffidd uphill to dircct ¡urfacc
runoff ¡rourd the residercc. . .4) Roof dorrmrpouts and dmins slrould díschargc well boyond the limits of
¡ll bacltr¡ll.5) taulecaping whic.h rcquircs regular hcary irrigation should bc loc¡tcd at
leest 10 feet from thc buildirU. Conskþretion should be given to thÊ use
of xericc¡pc to hÊÞ lin¡t tbÊ risk of wetti4¡thc bcering soils.
pcrcol¡don Teslngl The ¡esultÊ of percolstion te*¡ conducæd at the site are presented
in Table n. fhe æit locations are sho\rrn on Fig. I and the log of ths profile pit is
shoum on Fig. 2. A percota,tion ¡ate of about 9 to t0 minr¡tes per inch was mÊasured.
Brsgd on our fi¡di¡gs and acoordi4g to thÊ ¡oil¡ eocountcred, üe testÊd are¡ should be
suit¡ble for a convention¡l infrlüNtioû seÞtie disposal systcm. The meast¡rod percoletion
rate ¡ppeers higher than grpically fomd in frnp-g¡ti¡Êd soils ¡nd ¡ ¡lower flte should
probeUty be unpd for design. The desi¡n shor¡ld considcr thc stcêply elopi¡U ærrain.
Eùo,t
H+ G¡EOÍÉCH
.O8/O7/57 08¡{1 FitX 9?û 9{5 8ô85 CANYON IIONDA
Mite Bodrogi
Dcccmber 6, 1996
Page 4
Ilmlt¡don¡: This rspoft ha¡ beenprep¡rcd in accord¡nce with genenlly ecoept€d
geotechnicel erçineerir¡g principlæ and practices in thi¡ arç¡ et tbi6 tirne. ïVe make rrc
other warrenty eithererçrcsecd or implied. fin conclusions fld recom¡ne¡dation¡
zubmitted in üis report are basd upon the daÞ obtåincd ftom the eraloratory pits
excav¡ted ¡t the loc¡tions indicatod on Fig. I, lhe propoced type of constn¡ction, ånd
or e¡perieræe in ttre e¡ea. Our findings include inærpolation and exnrpolstion of the
zub¡urface co¡ditions üentifrd rt ahÊ cxploratory pite ¡od v¡riatíons in the subs¡rface
conditions Eey Dot become evident until excavation is performed. If condition¡
cûcqr¡ntêr€d durlqg construction cpgesr differe¡t fro'¡r thosc deecribcd in thts rÊport, we
strould be notified at once eo rc+vrlu¡tion of the recommêndåtions mry be made. Thc
site Ís underlein by the E¡gte Valley Evrporiæ whiÞh is prone to developing volds sod
sínkholes. Eveluation of the potent¡¿l for ñ¡n¡re zubsidencc due to dissolution of the
bcdroct is beyond the ecopc of this sa¡dy.
This report hes beenpreparod for the exclusive use by our client for design purposes.
tr/e are not responsible for technicel in¡erprcaüons by othcrs of otx inform¡tion. As
tbe project evolves, we should províde contin¡cd consultstion and field scrvicce duritg
eonstnrction to revþn¡ end monitor the implernentation of our recontmend¡tíons, a¡rd to
veriff th¡t tho ¡cconme¡dotions hsve been appropriately interpreted. Sign¡fiomt desi¿n
chaqges måy roquire additionrl an¡lysie or modificetions to the recommendåtions
presenæ¿ herein. We recommend on+iæ obeervetion of excav¡tions ¡nd fo¡utd¡tion
bearing stmta md te.sting of structural fitl by e repe3entative of the geotec,hnical
cnglnccr,
If you bave any questione or if we måy be of ñrtber assiotance, please call our offrcc.
Sincedy,
. PAIPI.AK INC.
fi
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Jordy Ir.. P 29'TA7 F
By
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Sæven L. Pawlak,P.E.
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cc: Gierd Homes, Inc. - Atttr Icff G¡ard
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F{EPI'VORTH. PAWI.AK
GËOTECHNICAL INC,
tocAlþil oF ExPl.oi¡lronv Plls
ANO PERCOLATIOI{ 1E31 H(r€S Ftr. I
ot/o7/g? 08:{l FAX 9?0 9{5 658ı CANTON ¡IONDA 0ùoz
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TOFSOI¡ ctayry t'¡tty sârid. o$sn¡cô. loossto modium dcnse, mo¡¡ù dark reddl¡h brorrn-
clÁy AND SAND (cL-sch siltv, Scattered gfevst. oocaslonal eobblt, ¡tlff, loo¡e to mcdium densô'
slighrly mo¡3t tight reddish blown ¡liohüy poroüs and a¡lc¡roose. tngu¡8r silt$tone/sand¡tonc
ü¡agmenæ.
CiLAy(CU; cllty, candv, stiff. sli¡htly rno¡st" r€ddish brown, sl¡ghtlyto mod€rstoly porout,
slightly to modgr¡têÌy GôlcsËdls.
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DD - Dry Density þcfl -200 - Percent pæsing No' 200 8íd'â'
LEGEND:
n
L:D¡strrbod bulk eamPle-? Diametor hsnd ddwn liner sample.
NOTES:
I . E¡rplotôtory plþ w6re o(Garatd on Norrombcr f I and 21, tgg6 wlth a brckhoe'
2- Locations of oetorstory plæ $r€16 measurêd approximrt€V by pacing hom foaturcs shown on
the site plan Provided.
3. Elerrationô of ãplorìrtory pfrc r¡ræra obtatnâd by lntelpolation bèñt Ëon contouns on the site plan provided.- ;t d ¿úlrc¿ Un¡nstãme¡rt iq1rtt. Logs of o<pior¡tory plts are druwn to depth'
¡r. Thc exploretory pit locetione ¡nd ela¿tlons slrould bc consftlelsd eccurâtc only to üo dtgree
implied bythe mdtmd usad.
6. The linee bctlr,gen m¡tedats show'r on the orplontoryplt logs rep¡¡eent the tpp?oximete
bound¡ñes btttÆ¡ fnãtodal tïtpss tnd tf¡ltsltions mry þe 0ndurl.
0. No frco ¡rator $fas cncouritef.d ln ttrs pite ü üo tftne of exCafitng.
Fluctr¡adons ¡n utatar lÊìtol mw occ¡¡rwith tlme'
7. t¡bo¡story Testlttg ResulF:
WC: WatcrContcnt(%l
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Fls. 2LOGS OF É(PLORATORYPITS}.IEFt'VORÎH. PAWLAK
GEOTECI{N|GAL. lNC.196684
O3/O7/57 08:ll FAI 970 Ð15 6585 CANI'ON UONDA Boo
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Molst¡re Content - 1Ol percont
DryUnhìlllcight = 95 Pcf
SampÞsf: SandySihyClrv
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DryUnttìltreight = gl pcf
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196684 HEP1,\/ORTH. PAWLAK
GEOTECHNICAL INC.
Fig. 4$,I'E[I-. CIONSOUDANON TES}T RESULTS
HEPWORTH-PAWLAK GEOTECHIIICAL, n¡c.TABLE ISUMMARY OF IABORATORY TEST RESULTSJoB No. 196 584è-gtc\¡aÞ{o!î!t.r,n€{êorb(¡a(rlÞ(rlozozozÞFc¡sandy sw claystndy siky claysendy ¡ilty claysand and clrysand and claylotctæf ?TtttmolñrEq*HvttÎËmsr¡rt¡¡ßFqü¡llrfn¡ilrrrrr.urDI.TTl*ta24367ræElÎ2tûtrEþ.2ClãEttþfit¡ftfi¡rE*DßÎü9092Io95mrtElto5glftåÎñt4.18.58310.15.9t¡Îtßlmm¡*qrlãrfi't024to 41h7r1!tüm2Itr;lÊþûffinÈ1IIIIIIITIIIIIIII
. .O8/O7IA7 0E141 FÂX S?0 0{5 85tı CANTON trOhÐA 6rr
I{EPWORTI{-PAWIAK OEOTECI{NICAL, INC.
TABLE II
PERCOTATIO]II ÎEST BESULÎS JOB ¡{O. 196 684
percolillon ¡¡t hob¡ wore h¡nd dug in tlrc bottðm of brckhoc Þltr ¡tìd rorked on Nornmblr 21. te08. Tsrt holsr
w6rt oovstêd to Êrotect agålnct frcc¡lng ovêtnlght. Pcrcol¡tlm ta¡t$ wcfÊ cor¡dust¡d on lrtov¡mb¡t 22, 19e6.
a
HôLÊ tlo.¡IOL¡ DEPTII
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I 81n 1112
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HEHiÍORTH-PAWLAK GEOTECHNICAL, ¡Hc.TABLE ISUMMARY OF TABORATORY TEST RESULTSèÊtc{to{ê3r¡Tl'/l€{a,È(rlo)Ê¡loatJOB No. 196 584oÞzozC>z17Ecsand and claysandy sW claytot cæctfir:send and claysrndy siltV claysandy siþ claytmffiÊoo;ß¡úttfHmF'i.úræFqft¡lìrtffit[rtrûrDr.ffi(¡t824367fæglln¡¡arBþ-æwÊ$mtflt*lGrvt"*o fs91909592TA|Ißotro5slffco8310.15.94.18.5t¡Tttffisfttrcüíftrt*ùIDpnlÍrr!4to 4'!L71122Ëlt$TTCþGÍfilIIIIIIIIIIIIrIIIIIIIIIIIIIIII
a A8/A7/57 08:ll FAI 970 9{5 6ı85 CANI'ON IONDA Boa
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Mol¡t¡re Content r lo.l pôfccnt
DryUnhWaight = 95 pcl
Samplc sf; $ndv Sltty Clrv
From: Plt t at 7 foat
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196684 HEFI^/ORTH - PAW.AK
GEOTECHNICAL, INC.
S,I,EIL . @NSOLIDATION TEST RESUL11S Fls. 3
Ag/O?tS? O8:{1 FAX 070 915 6585 CANYO¡i HONDA @os
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0.1 t.0 t0 100
APPLIED PßESSURE.K¡f
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DyUnitWeþht - 9l Þc{
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ts684 HEFV\'ORTH.PAWIÁK
GEOTECHNICAL. INC.
$,I'E[T- - CONSOUDATION TEST RESULTS FiO. 4