HomeMy WebLinkAboutSubsoil StudyI'Iueldleston-Ilerry
lÌrr¡rirturirrlr t('l't'stittg, l-l-('
MountainVierv Construction Sen,ices. LLC
l4l3 Munro Avenue
Rit'lc, Colorado 81650
640 Whitc Avcnuc
Gland Ju¡lcliorr, CO 81.50 I
Pho¡re: 970-255-8005
Fax: 970-2-5,5-6818
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October 16,2013
Illoject#01 273-0011
Attention:
Subject:
Mr. Jerry Caves
Geotechnical Investigation
85 Green DLake
As¡ren Glen Subdivision
Garfielcl Coutttl', Colotaclo
RECEIVEÐ
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f,îf,ii,iiF.,..?#ilJ^[
Dear Mr. C{ìves,
'flris letter ¡rlesents tlre results ol'a geotechnical investigatiou conch¡ctccl by l-ludclleston-Berry
Engineering &'l'esling, f,l,C (LlBll'l') lbr 85 Green Drake in thc As¡ren Glen subclivision near
Glenrvoocl S¡l'ings, Colorarlo. 'l'he ¡lro¡losecl corrstruction is antici¡ratecl to consist of a single-
lanrily resicle¡lce. The sco¡le of our investigatiorr inclutlecl evaluatirtg tlte sr¡bsulface conclitions
at the site to aicl in cleveloping l'ounclatiorì r'ccolnmsndations fol the ¡rroposed construction.
Sitc Conrlitiorrs
At thc titnc of tlrc investigation, tlre site rvas generally open rvitlt a gentle slolle down to the rvest.
Vegctation consistccl ¡l'inrarily of liekl glasses. '[.he site rvas borulered by Golclen Stone Drive
ancl Gleen Drake to the east, by Golclerr Storte Drive to tlre trot'th, by an existing lesiclence to the
sotrlh, arrcl by att existing resiclence ancl poncl to the u¡est.
Su bsu ¡'f¡tcc Inve.stiq¡rtiolt
'fhe subsullace investigation inclucled orre tesl pit. Tlre test pit was excavated to a de¡lth of 5.0
feet belon, thc cxisting grouncl surlirce, A typed test ¡tit log is incluclecl in r\ppcrtdix A.
The test ¡lit encounterecl 1.0 foot of lean clay r.vith orgattics topsoil atrove lrrorvrt, clLy to nroist,
stiff le¿ur clay to the bottorn ol'the excavation. Groutttlrvater' lvas rtot encourrterccl in the test ¡lit
at the tinle of the invcstigatiorr.
Lallorntory Tcsting
Labolatoly testing rvas conclucteclon.sanrlrles ol'the soils ertcoutttered in the test pit. 'l'lre tcsting
ilrch¡clecl glain size analysis, AttclbcLg lirnits cletelnrirtatiort, uatural ntoisture corrterrt and density
cletermillatiolt, srvell/consoliclation testirtg, ancl ruaximum clt'y clerrsity ancl optirtruttt rnoistule
content (Ploctor) clctcrmination. The laboratoly testing results are inclucled in Appenclix B.
85 Grecn Drake
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Iluddlcston-Bcro.
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'l'he laboratoty testing results inclicate that the n&tive clay soils are slightly plastic. ln adclition,
the clay soíls rvere shorvn to be slightly collapsible, with up to approxinrately 0.7% collapse
measured in the laboratory.
F qgr,ldation Recommeqdations
Based upon the results of the subsurfbce investigation and nature of the proposed construction,
shallow foundations are recommended. Spread footings and monolithic (turndown) structural
slabs are both appropriate foundation alternatives. Flowever, as cliscussed previously, the native
clay soils are collapsible. Therefore, to limit the potential for excessive differential settlements,
it is recommended that the tbundations be constructed above a minimum of 24-inches of
structural fill.
The rrative clay soils, exchnive of topsoil, are suitable for rense as structural fill. hnported
structural fill should consist of a granular, non-expansive, non-free draining material such as
crusher fines, pit-run, or CDOT Class 6 base course. Holvever, if pit-run is used for stnrctural
fill, a minimunt of six inches of crusher fines or Class 6 base conrse shoulcl be placed on top of
the pit run to prevent large poìnt stresses on the bottoms of the footings clue to large particles in
the pit-nrn.
Prior to placemenl of structural Iill, il is reconlnendetl that the bottom of the founclation
çxcavation be scarifred to a depth of 6 to 8 inches, moisture conditionecl, and compacted to a
mininrum of 95o/o of the standard Ploctor maximum dry density, within *. ZYo of the optimum
moistule content as detetminecl in accordance with ASTM D698. Stnlctural fill shoukl extend
laterally beyond the edges of the founclation a distance equal to the thickness of structural fill.
Structural fill slrot¡ld be moisture conditioned, placed in maximurn f-inch loose lifts, arrd
compactecl to a ninimum of 95Yo of the standard Proctol maximum dry density for fine grained
soils ancl moclitìcd Proctor maximum chy dcnsity tbr coarsc graincd soils, lvithitt *, TYo of thc
optimum moisture content as cleterminecl in accordance with ASTM D698 aud D1557C,
respectively. Pit-run materials should be proofrolled to the Engineer's satisfàction.
For structural fill consisting of the native soils ol irnported granular materials, and foundation
building pacl preparation as recomlnended, a maxirnum allorvable bearing capacity ol 1,500 psf
may bc uscd. In uddition, n modt¡lus of subgradc rcaclion of 150 pci may bc uscd for structural
fill consisting of the native soils and a moduhls of 250 pci may be used for structural fill
consisting of crusher fines, pit-run, or base couße. Formdations subject to fìnst should be at
least 36-inches belorv the finished grade.
Water soluble sulfates are common to the soils in Western Colorado. Therefore, at a minimum,
Type I-II sulfate resistant cement is rçcornmended for construction at this site.
Any stemrvalls, basernent r.valls, or letaining rvalls shoulcl be designed to resist latelal earth
prcssrucs. For backfill consisting of thc n¿rtivc soils or irnportcd granular, non-fi'ee clraining,
non-expansive material, lve recommend that the rvalls be designecl tbr an equivalent fluid rrnit
r.reight of 50 pcf in areas where no surcharge loads are present. Lateral earth pressures should be
increased as necessary to reflect any stucharge loading behind the lvalls,
2\Y:\1003 ALl. PROTECTS O I 271 - ilouor¡¡trri€ry Conltruçtion SrßìcÉs'0 I 2 ?1.001 I 85 6r¿.n frñhel200 - Cs'O I 2 7l.0Ol I LRI 0 I6ll.doe
85 Green Drake
#01273-00t I
to/16/t3
Huddlcston.Berq'
tr;Î$iir9 I.riri. lr(
NoJ-Sf ructural Flogr: Slnþ Å$rL Exterio-r,.I,'lghvorkJtqqglnmendations
In ordel to limit the potential for excessive differenfial movemsnts of slabs-on-grade, it is
recommended that non-structural floor slabs be constructed above a minimurn of l2-inches of
structural fill with subglade pleparation and fill placement in accordance lvith the Foundalion
Recom¡nendations section of this report. It is recotruneltded that exterior flatwork be constructed
above the native soils, belorv the topsoil and/or fill, that have been scarified to a depth of 12-
inches, moistnre conditioned, and compacted to a minimum of 95% of the standard Proctor
maximum dty density, within *2% of the optimum moisture content as determined in accordance
with ASTM Ð698.
Draina ge Recommendntions
Grading and clrainage are critical to the long-term perfbrmance of foundations and slabs-on-
grade, Grading around the structnre should be designecl to cany precipitation and runoff away
fiom the structure. It is recommencled that the finished ground surface drop at least twelve
inches within the t-rrst ten feet away fiom the structure. Downspouts should empty beyond the
backfill zone, It is also recornmended that landscaping within tlrree feet of the stnrcturcs include
primarily desert plants with low lvater requircments. In acldition, it is rccommencled that
automatic inigation within ten feet of founclations be minimized.
Groundwater rvas not encountered during the subsurface investigation. Holvever, as discussecl
previously, a pond rvas observed west of the site. Therefore, although a basement is not
anticipatecl at this site, a perimeter foundation drain is recornlnencled. In general, the perirneter
fot¡ndation clrain should consist of prefabricated drain matet'ials or perforated pipe and gravel
rvith the flowline of the drain one lbot belorv the bottom of the foundation (at the highest point).
The perimeter drain should slope at a minimr¡rn of 1.5% to daylight or to a sump.
Genernl Notes
The recomrnendations included above are based upon the results of the snbsurface investigation
and on our local experience. These conclr¡sions and recomrnendations are valid orrly for the
proposecl construction.
As discussed previously, only one test pit rvas conductecl at the site. Therefore, the precise
nature and extent of any subsurface variability may not become evident until construction. As a
result, i[ is recomnrencled that a representative of HBET obsere the foundation excavation prior
to structural fill placement to verify that the subsurface conditions are consistent lvith those
describecl herein. In aclclition, it is recommendecl that a representative of HBET test compacfion
of structural fill materials.
It is important to note that the use of structtrral fill belorv slabs and fotutdations lvill reduce, bul
not eliminate, the potential for strnctnral movement as a result of collapse of the native soils.
Holvever, lvhere excess moisture is permitted to infiltrate into the subsurface clue to poor grading
ancl drainage, irrigation leak, utility leak, or other cause, significant structural movenents are
possible. While the foundation recommenclations above are consistent with generally, acceptecl
engineering practices in areas of collapsible soils, HBET cannot predict long-terrn changes in
subsutface moisture conclitions ancl/or the precise magnitucle or extent of volume change.
J\Y:\1003 ALL PROJECTS,OI 271 - trlountdnì'¡€r$ Consrrucl¡on Scwicct0l?71.00t I 65 Græn t¡rake\200 - CÐ'01??3-00I I l"Rl0lól¡.dor
85 Green Drnke
#0r273.001 I
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trVe are pleased to be of service to:|otu prôject. Please coniact us if you have anyquestions or
comments regarding the contents of this report.,
Respectfully Submitted :
eering nntl Testing, LLC
Mþhael A. Beqry, P.E.
Vice Plesident of Engineering
41y:\2008 ALL PROJECTS'o12?J - :Uountninvierv Conioçrion Sm'lc€JOl??3.001 I E5 erccî D¡¡lc$oo. G.ó'oU?1.001 ¡ LRl0ról¡.dæ
APPENDIX A
Typed Test Pit Log
g.l85 GREÊN'ovoLmo-,tC=Em7loNL\¡ölålÕl-oîÍîzo5g.tı'€oo5aô=0f\ô\O.aô\-ppã ¿ãe q:- 5;íi,;rí=ã'â=8eÞ3.*--g 6 ã^=\¿O9r;ê=æ =(F.À- /êcû¡:=-ÛokJLsql---t-c)!7o(-mo{Íoc)ız6)ıáoog,Þr)o!noLfftc)-{3tn@cìo(D(D5t'q¡xo{mØ{1t{zc=tÐrnn{TI!omorì,o¡ïr(t,rooomIEmx(}{ız3¡a{:roo?-fnxl)!¡Eomxo{ızc,oz-lfro{o7loloII¡tIIIIIIIIIôvocoI{tlrÐt-mnr-u,(f,{I'lct,{7{m0zã(Do(jÕ-mc)mg{Dr¡o3!rm{fiìoo(t3at{mnmx()Ioz{mzto.nmxC)-{ızo.?{I3tfio.ttmxo{ozc)vogzImmaozo.?{m(t{!{a,NmPoDEPTH(ft)GRAPHICLOG-.tmn(,mCI'on!:loSAMPLETYPENUMBERRECOVERY %(RAD)BLOWCOUNTS(N VALUE)POCKETPEN,(tsf)DRY UNITWT(Pcr)MOISTUREcoNTENT(%)LIOUIDUMITPLASTICLfMfTPLASTICITYINDEXFINFS CONTENTlo/o)lf., .j,- Nl -..1r¿-. ¡\-.. -t,¿¡à ;. L:'.' ¡â .l.s .'¡;.'. L'r\, ,fr_ ..! . l¿-. Ì1 , f,¿--(Dsc)çto(.It=.Cl6-tôEtloçð€-5ôac)@i+ô,a0,a9,.oarosãoFc)Ivgı{-3o,.z()oØf-b=(3*6,@(tt\tcoÀ)()@Ooo,--ãc0(¡)\¡@oo3ooo'o0,(¡ìb(}(D
APPENDIX B
Laborntory Testing Results
l'luddleston.Berry Engineering tt Testírrg, Ll,C
640 Whitc Avcnue, tjnit B
Crand Jurrction, C() I l50l
970-255-8005
970.255.ó8 lS
GRAIN SIZE DISTRIBUTION
CLIENT MoutrlainView Cor¡slruclion Ltc PROJECT NAME 85 Gfeen Dfake
PROJECT NUMBER PROJEcT LOcATto{ qþ=lTggt sfr¡ng.s:
U.S. SIEVËOPENING IN IÑCHES I U.S. SIËVE NUMBERS HYOROMETER
112318 3 4 I 81014 20 40 I
100
95
s0
B5
80
75
70
65F.Tg60
g
útu¡ 50ztrF45z
UJB40uto-
35
30
25
20
15
10
5
0
100 10 1
GRAIN SIZE IN MILLIMETERS
0.1 0.0f 0.001
I
li
I I tf
I
)-r-I\
,1,
il
COBBLES GRAVEL SAND
SILT OR CLAYcoat$e l¡ne coarse medlum line
Specimen ldentification Classification LL PL PI Cc Cu
o TP-1, GBl 10t13 LEAN CLAY(CL)28 20 I
Specimen ldentification D100 D60 D30 Þ10 %Gravel %Sand %sitt o/oQlay
o TP-1, cB1 10/13 1,'lg 0.0 13,9 86.1
l'luddlcston-ßcrry Errgineering &'l'esting, LLC
640 \\4¡ite Avenue, ljnit B
G¡and Junction, CO 81501
970-255-8005
970-255.68t8
ATTERBERG LIMITS' RESULTS
CLIËNT MountainViewConslrucl¡on Services LLC PROJECT NAME 85 Green Drake
PROJÉCT NUMBÊR 01273.0011 PROJECT LOCATION GÍenwood Sorinos
@
P
L
A
S
T
I
c
I
T
Y
I
N
D
E
X
50
40
30
20
10 o
CL.ML @ @
0
60
LIQUID LIMIT
Specímen ldentification LL PL PI #200 Classification
a TP-1, GBl 10nt2413 28 20 I 86 LEAN CLAY(CL)
lhtddlcston-Bcrq, Enginccrirrg & Testing. LLC
640 Wlrito Avcnue, Unit B
Orartrl Juncliorr, CO II501
970-2t5.8005
970"2t5-68r8
CONSOLIDATION TEST
CLIENT MñunhlnvlÃw C¿ìnalrrôli6n LLC PROJIICI'NAME B5 Grecn Drake
PROJECT NUMBER 0I273-OO,I 1 PROJECT LOCATION Glenwood Sprinqe
0.0
0.5
1-0
1.5
2.4
2.5
s
¿
EFrñ
3.0
3.5
4,0
4.5
5.0
5.5
6.0
100 1,000
STRESS, psf
Specimen ldentification Tt MCTo
7
)
\
\
\
I I
\\
\
\
\
\
\
\
ô TP.1 3.0
Glassification
80
zut¡lcono
o
Fltrddleston-Berry Engineerilg & Ttsting, LLC
640 \\'hite Àr'enue. ljnil B
Crnnd Junction, CO 81501
970¿55.8005
970"255-6818
MOISTURE.DENSITY RELATIONSH I P
CLIENT MountainViaw C6n l¡ucl¡on ltn PROJÊCT NAME 85 Green Drake
PROJECT NUMBER 01273-0011 PROJECT TOCATION ôlanwnn¡l Sn¡i¡¡c
Sample Date:
Sample No.:
Source of Material:
Description of Material:
101112013
1
145
MA
135
130
125
124
115
110
105
100
95
TP.1
LEAN CLAY(CL)
Test Method:ASTM D698A
TEST RESULTS
Maximum Dry Density 106.0 PCF
Optimum Water Content 16.0 %
GR.AÞAT¡ON RESULTS (% PASSTNG)
#?90 #4 3t4"
86 100 100
a)
CT
ËØzl¡,cl
É,Õ
ATTERBERG LIMITS
LL Pr PI
28 2A I
Curves of 100Yo Saturation
for Specific Gravity Equal to:
2.80
2.70
2.60
90
5 150
WATER CONTENT o/o
20 30