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HomeMy WebLinkAboutSubsoil StudyIC'T Kumar & Assoclalm, lnc.' Geotechnical and Materials Engineers and Environmental Scientists l* Émglayæ ætrtäú Camrøsry 5020 County Road 154 Clenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 emai I : kaglenwood@kumamsa.cotr wwlv. k u rrat'usa.conr OfÏce Locations: Denver (FIQ). Parker. Colorado Springs. Fort Collins" Glenr.r,ood Springs. aud Summit County, Colorado April12,2021 Dave Cardiff Construction, Inc. Attn: Dave Cardiff 506 Mesa Verde Carbondale, Colorado 81623 davecardiffconstruction@ gmail. com Project No.2I-7-256 Subject: Subsoil Study for Foundation Design, Proposed Residence, Lot20, Ranch at Coulter Creek, Saddle Circle, Garfield County, Colorado Dear Dave: As requested, Kumar & Associates, Inc. performed a subsoil study for design of foundations at the subject site. The study was conducted in accordance with our agreement for geotechnical engineering services to you dated Marchg,202l. The data obtained and our recommendations based on the proposed construction and subsurface conditions encountered are presented in this report. Proposed Construction: Design plans for the residence have not been developed. The proposed house will be located in the area of Pits I and2 and will likely be one to two stories over a walkout basement. Ground floor will be structural over crawlspace or slab-on-grade. Cut depths are expected to range between about 4 and 10 feet. Foundation loadings for this type of construction are assumed to be relatively light and typical of the proposed type of construction. If building conditions or foundation loadings are significantly different from those described above, we should be notified to re-evaluate the recommendations presented in this report. Site Conditions: The site was vacant and the building area slopes down to the south and east at between 10 to 20 percent grade. Below the building area, the slopes steepen to about 25 percent to the east and 35 percent down to the south. Vegetation consists of sage brush and scattered pinon trees with an understory of grass and weeds. Subsurface Conditions: The subsurface conditions at the site were evaluated by excavating two exploratory pits in the building arca and two pits in the septic arca at the approximate locations shown on Figure 1. The logs of the pits are presented on Figure 2. The subsoils encountered, below about '/, to I foot of topsoil, consist of I to 3 feet of stifl sandy silty clay overlying mostly 1 whitish, medium dense to stiff, gravelly silt and sand. Basalt rocks in a sand and silt matrix were encountered in Pit 1 at a depth of 2 feet. Results of a gradation analysis performed on a sample of slightly gravelly sand and silt (minus 3-inch fraction) obtained from the site are presented on Figure 3. No free water was observed in the pits at the time of excavation and the soils were slightly moist to moist. Foundation Recommendations: Considering the subsoil conditions encounteted in the exploratory pits and the nature of the proposed construction, we recommend spread footings placed on the undisturbed natural soil designed for an allowable soil bearing pressure of 1,500 psf for support of the proposed residence. The soils tend to compress after wetting and there could be some post-construction foundation settlement. Footings should be a minimum width of 18 inches for continuous walls and2 feet for columns. Loose and disturbed soils encountered at the foundation bearing level within the excavation should be removed and the footing bearing level extended down to the undisturbed natural soils. Exterior footings should be provided with adequate cover above their bearing elevations for frost protection. Placement of footings at least 36 inches below the exterior grade is typically used in this area. Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least 12 feet. Foundation walls acting as retaining structures should be designed to resist a lateral earth pressure based on an equivalent fluid unit weight of at least 50 pcf for the on-site soil as backfill. Floor Slabs: The natural on-site soils, exclusive of topsoil, are suitable to support lightly to moderately loaded slab-on-grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 4 inch layer of free-draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2-inch aggregate with less than 50% passing the No. 4 sieve and less than2%o passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95Yo of maximum standard Proctor density at a moisture content near optimum. Required fill can consist of the on- site soils devoid of vegetation, topsoil and oversized rock. Underdrain System: Although free water was not encountered during our exploration, it has been our experience in the areathat local perched groundwater can develop during times of Kumar & Associates, lnc. @ Project No. 21-7-256 a-J- heavy precipitation or seasonal runoff. Frozen ground during spring runoffcan create a perched condition. We recommend below-grade construction, such as retaining walls, crawlspace and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain system. The drains should consist of drainpipe placed in the bottom of the wall backfill surrounded above the invert level with free-draining granular material. The drain should be placed at each level of excavation and at least I foot below lowest adjacent finish grade and sloped at a minimum 1olo to a suitable gravity outlet. Free-draining granular material used in the underdrain system should contain less than 2o/o passingthe No. 200 sieve, less than 50% passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least llzfeet deep. An impervious membrane such as 20 mil PVC should be placed beneath the drain gravel in a trough shape and attached to the foundation wall with mastic to prevent wetting of the bearing soils. Surface Drainage: The following drainage precautions should be observed during construction and maintained at all times after the residence has been completed: l) Inundation ofthe foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95o/o of the maximum standard Proctor density in pavement and slab areas and to at least 90o/o of the maximum standard Proctor density in landscape areas. Free-draining wall backfill should be capped with about 2 feet of the on-site, finer graded soils to reduce surface water infiltration. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in pavement and walkway areas. A swale may be needed uphill to direct surface runoffaround the residence. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. 5) Landscaping which requires regular heavy irrigation should be located at least 5 feet from the building. Consideration should be given to the use of xeriscape to limit potential wetting of soils below the foundation caused by irrigation. Septic Field: A USDA gradation test performed on soils from 6 to I feet deep in Profile Pit 2 indicates the soil type for septic design is Gravelly Sandy Loam which should be suitable for a conventional septic system. The septic system should be designed by a professional engineer. Kumar & Associates, lnc. o Project No. 21-7-256 4 Limitations: This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no ï/arranTy either express or implied. The conclusions and recornmendations submitted ia this report are based upon the data obtained from the exploratory pits excavated at the locations indicated on Figure I and to the depths shown on Figure ?,the proposed type of construction, and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological cont¿minants (MOBC) developing in the future. Ifthe client is concemed about MOBC, then a professional in this special field of practice should b consulted. Our fîndings include interpolation and extrapolation of the subsurface conditioas ideatified at the exploratory pits and variations in the subsurface conditions may not becorae syident uûtil excavation is performed. If conditions encountered during construction appear different frorn those described i:r this report, we should be notified at once so re-evalualioa of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We are not responsible for technical interpretations by others of our information. As tbe project evolves, we should provide continued consultation and field services during constn¡ction to review ând monitor the implementation of our recommendations, and to verify that ihe recommeadations have been appropriately inlerpreted. Significant design changes may require additional analysis or modifications to tlre recommendations presented herein. Vy'e recornmend oa-site observation of excavations a¡¡d foundatio¡ bearing strata and testing of structural fi11 by a representative of the geotechnical eagineer. If you have any questions or if we may be of further assistance, please let us kaow. Respectfully Submitted, Kumar & Associates, Daniel E. Rev. by: SLP DEFVkac attachments Figure 1 - Location of Exploratory Pits Figure 2 - Logs of Exploratory Pits Figure 3 - Legend andNotes Figure 4 - Gradation Test Results Figure 5 - USDA Gradation Test Results cc: Tim Pestot¡ik Kumar & Associates, Inc. ô otnik.ccr Project llo. 21.7.256 z LS# 286+l LO? 21 ffi 25.O' oPc 25.O' X S.1DDIÃ CINCLE ,t-- -/ BPc LS# 2S43of BPC \Ls# 2864{+* cL ./ aPc - -/LS# 2866 /g\ç * ñ \#,* *** * \ e\ñ'\¡ \*PIT Tf¡\ \ a *. \' *'\'\' Í\ * \ LOî te \ \ \ \ -ô8pc' BPC. rs# zsæJ 30 0 0 APPROXIMATE SCALE_FEET 21 -7 -256 Kumar & Associates LOCATION OF EXPLORATORY PITS Fig. 1 I P IT 7 1 446 PIT 2 EL. 7358' PROFILE PIT 1 EL. 7326' PROFILE PIT 2 EL. 7332'EL. 0 0 Fl¡Jtdl! ItFfL l¡Jô 5 I *4=6 -l -zoo=ss 5 Ft¡l l4ltL ITF TL L¡JoI GRAVEL=21 -.1 s¡¡to=¿z SILT=27 CLAY= 1 0 10 10 Fig. 2Kumar & Associates LOGS OF EXPLORATORY PITS21 -7 -256 E 4 ¡ LEGEND TOPSOIL; ORGANIC SANDY SILTY CLAY WITH ROOTS, FIRM, MOIST, DARK BROWN CLAY (cL); SILTY, SANDY, STIFF, SLIGHTLY MolST, BRowN. BASALT ROCKS; GRAVEL TO BOULDER SIZE, IN SANDY SILT MATRIX, DENSE, SLIGHTLY MOIST, WHITISH. SILT AND SAND (ML_SM); GRAVELLY, MEDIUM DENSE TO STIFF, SLIGHTLY MOIST, WHITISH t DISTURBED BULK SAMPLE. I PRACTICAL AUGER REFUSAL. NOTES.I. THE EXPLORATORY PITS WERE EXCAVATED WITH A BACKHOE ON MARCH 9, 2021 2. THE LOCATIONS OF THE EXPLORATORY PITS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. 5. THE ELEVATIONS OF THE EXPLORATORY PIÏS WERE OBTAINED BY INTERPOLAÏION BETWEEN CONTOURS ON THE SITE PLAN PROVIDED. 4. THE EXPLORATORY PIT LOCATIONS AND ELEVATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY PIT LOGS REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL. 6 GROUNDWATER WAS NOT ENCOUNTERED IN THE PITS AT THE TIME OF EXCAVATION. PITS WERE BACKFILLED SUBSEQUENT TO SAMPLING. 7. LABORATORY TEST RESULTS: WC = WATER CONTENT (%) (ASTM D 2216); +4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ISTV O +ZZ); -2OO= PERCENTAGE PASSING NO. 2OO SIEVE (ASTM D 11AO); GRAVEL = PERCENT RETAINED ON N0. 10 SIEVE; SAND = PERCENT PASSING NO. 10 SIEVE AND RETAINED 0N NO.325 SIEVE; SILT = PERCENT PASSING NO. 325 SIEVE TO PARTICLE SIZE .002MM; CLAY = PERCENT SMALLER THAN PARTICLE SIZE .002MM. 21 -7 -256 Kumar & Associates LEGEND AND NOTES Fig. 3 SIEVE ANALYSISHYDROMETER ANALYSIS TIYE RilDINOS ¿,4 HRS 7 HRS U.S. STANDARD SEiIES t1¡ ab tt6 a1a 11ı at I 3'ß' I I I øf a roo 90 80 70 60 50 ¡ao lo 20 lo o fo 20 30 Æ 50 80 70 80 90 too E .t 50 DIAMETER OF IN MI CLAY TO SILT COBBLES GRAVEL6'l SAND46 LIQUID LIMIT SAMPLE OF: Slighlly Grovelly Sond ond Silt % PLASTICITY INDEX SILT AND CLAY 46 % FROM:Pll2O4'-5' Th.t. lrtt rltull¡ opply only lo lh! somphs whlch v6rr læhd. Thr lllllng r.porl ¡holl ñol b. rcproduccd, rxc.pt ln tull, wllhoul lhc vrltlcn opprcvol of Kumor & A¡roclotct, lnc. Sl!v! onqlyrls lllllng l! Þ.rformld ln qccordoncc wllh ASTM D6913, ASTM D7928, ASTM Cl36 ond/or ASTM Dllilo. GRAVELSAND MEDIUM ICOARSE FINE COARSEFINE 21 -7 -256 Kumar & Associates GRADATION TEST RESULTS Fig. 4 ,} HYDROMETER ANALYSIS SIEVË ANALYSIS TIIVE READINGS 24t1R. 7HÊ 045 #14O #60 #35 #1A +1O .#4 3/8', 3/4" 1 3 5',6' I' 100 10 -t------t /:- -'---. , --t---- t-.,,-- I -.-- /t ;Z --t- --lr 90 20 80 30 70 ô L¡Jz. F L¡.j É. Fz L¡J É. Ld o_ 40 60 Oz. Ø U) o_ Fz.t¡lO É. L¡J o_ 50 50 60 40 70 30 80 20 90 10 '100 .001 .002 ,005 .009 .019 .045 .106 .025 .500 1.00 2.00 4.75 DIAMETER OF PARTICLES IN N/ILLIMETERS 9.5 t9.0 37.5 76.2 152 203 CLAY COBBLES GRAVEL 21 %SAND 42 %SILT 27 %CLAY 10 I" USDA SOIL WPE: Gravelly Sandy Loam FROM: Profile Pit 2 @ 6'-7' SILI 21-7-256 Kumar & Associates USDA GRADATION TEST RESULTS Fig. 5 ñ a¡Ë7458'or1'!5\Jr""-lLS# ZA6a5\¿-'-,\._*Ag*ENVELoPEB*s6-BEDROOMRESIDENCE*tL-\\\*ls*\**ìBPCd\*7446'BTlNÐINE7450.\ilrÍ 1a\74427440'*¡7438 '\\****trfv(\\**\\d\*\**#***hê*d**\\*,\STA^ô(/THE LOCATION OF PROPOSED IMPNOT THE RESULT OF A PROPERTYARE APPROXIMAIE. IT IS THE HOMENSURE ALL CONSTRUCTION ANDARE ACCURATE. PROPERTY LINESSHOULD BE CONFIRMED PRIOR TCFOR PRINTING ON 1I" X 17" PAPER,\ar\\iltÍ teTY LINE\\\\t1w2.0SITE PLAN\BPCLSt 28€4.:tL3LSt 28643 ## OPEætlrV/ ûJ # #k # BUILDING EIVVEL \ J \ DROOM DENCE I 00' 7438.5' \ \ - .rtü¡,,#1n¡\'- 4'' DIA SDR-35 SEWER PIPE WITH CLEANOUT MIN 2% FALL TO TANK R OO-GALLON, TWO-COM PARTM ENT SEPTIC TANK WITH EFFLUENT SCREEN(J \ \ \ # x DISTRIBUTION BOX WITH ACCESS AT GRADE 4" DIA SDR-35 PVC SEWER LINE (MrN. 1% FALL TO D-BOX) # # .sl¡¡,,ffi # #$# # $'4# sk 4'DIA SDR-35 SEWER LINE TO EACH Tf (MrN. 1% SLOPE TO TRENCH) ### #4" DIA SDR-35 INSPECTION PORT, BEGINNING AND END OF EACH TR 'QUICK-4' CHAMBER TRENCHES, 5 TRENCHES WITH 14 CHAMBERS PE FOR A TOTAL OF 70 CHAMBERS AND B4O SF. K -,$ì12.æ'-l,fi$\# \ # 5B \tWzus, n^_ 3'IIIIIIIIIIIIIIIIIITFILTRATOR'ID PLATER-35 INSPECTIONBEGINNING ANDACH TRENCH4'maxLLIMIT OFEXCAVATIONSCARIFYGRAVELLESS 'QUICK-4'CHAMBER (4'x 3')4AT GRADE4'DIA SDR-35EFFLUENT PIPE FROMSEPTIC TANK14 CHAMBERS PER TRENCHUNDISTUSOIL'm¡4" DIA SDR-35 DISTRIBUTIONLINE TO EACH TRENCH(MlN. 1% SLOPE TO TRENCH)4" DIA SDR-35 SEWER LINE(MrN 2% SLOPE TO TANK,MlN. 1% TO STA)SCREENED ROCKOR SAND FORBEDDINGCOMPACTBASE TO SUPPORTBOXUSE HOLE SAW TOCUT THRU TOP OFEND PLATEPES PLACED INTOP PORT OFCHAMBER ENDPLATESINOTE: TRENCHES MAY BESÏAGGERED TO AVOID TREESNOTE: THETRENCHESMUST BE INSÏALLED JUSTBELOW THE TOPSOILHORIZON4" DIA SDR.35INSPECTIONPORTGRAVELLESS 'QUICK-4'CHAMBER (4'x 3')2'minl IENCEJS/BEDROOM x 3 BEDROOMS + 225 cPD (4TH, sTH, ANDW = 675 GPD;TWO-COMPARTMENT CONCRETE SEPTIC TANKIREA (STA):)TANCE RATE (LTAR) = 0.6 GALi SF= Q/LTAR = 675 10.6 = 1125 SFiS = 1 125 SF X 1.0 = 1125 SFSF X 0.7 = 788 SF I 12 SF / CHAMBER = 66 CHAMBERSCHAMBER TRENCHES}ERS IN EACH TRENCHCHAMBERS)UGHT TO GRADEBAFFLE ORANGLED PIPETO BE USEDAT INLETA DISTRIBUÏON BOX DETAILOWTS COMPONENTS ANDPHYSICAL FEATURESHOUSE TO SEPTIC TANKSEPTIC TANK TO WELLSEPTIC TANK TO WATER COURSESTA TO HOUSESTA TO WELLSTA TO WATER COURSESLIP-ON PVCDO NOT GLUEINSULATED COPTRACER WIRE4'DIA SSEWER LINEMINIMUM REQUIREDSETBACK5'20'100'50'TO TANKFINISHED GRADETO HOUSEAPPROXII!SI50'50'A CLEAN OUT DETAIL/\CIOCICIOUTLETS\.7r{ol 10 sc^lr\7rcTrcru æqmtffifuJtel* Garfield County, CO 0 CARBONDALE SOPRIS CLASSICS LLC 501 WEST BROADWAY, SU ITE to25 SAN DIEGO CA921O7 2019 Total Actual Value Overview Legend fi Parcels Roads Parcel/Account Numbers Highways - Limited Access * Highway * Major Road * Local Road * Minor Road ' OtherRoad . Ramp -* Ferry Pedestrian Way Owner Name I Lakes&Rivers * County Boundary Line $L71,300 Last2Sales Date Price 4/21/2021 $282,000 4/26/2018 $O Account RO4I281 Number Parcel 2397O7\O7O2O Number Acres 6 Land SqFt 0 TaxArea 011 2019 Mill Levy 75.5380 Physical Address Owner Address 81623 Date crealed:9/4/2027 Lâst Data Uploaded: 9/4/2027 2:03:37 AM De ve ro ped rr Ét *åg"t""^dgl 9t2t2021 qPublic.net - Garfield County, CO - Property Record Card: R041281 #qPtrrbfuc.læt'* Garfield County, CO Summary Account Parcel Property Address Legal Description Acres Land SqFt Tax Area Mill Levy 5ubdlvision R041281 239707701020 ,CARBONDALE,CO 87623 Sect¡on: 7 Township: 7 Range: 87 Subdivision: RANCH AT COULTER CREEK PUD Lot: 20 As PER FIRST AMENDED FINAL PLAT RECEPTION NUMBER 889891 5.91ó ACRES 5.975 o 1"1" 75.5380 RANCH AT COULTER CREEK PUD View M3p Owner SOPRIS CLASSICS LLC 5Ol WEST BROADWAY SUITE 1025 SAN DIEGO CA 92101 Land UnitType VACANT RES LOTS-0100(VACANT LAND) Square Feet 0 Actual Values Assessed Year Land Actual I mprovement Actual Total Actual Assessed Values Assessed Year Land Assessed I mprovement Assessed Totâl Assessed Tax History 2020 çr,432.20 2021 $171,300.00 $o.oo $171,300.00 2027 $49,ó80.00 $o.oo $49,ó80.00 2019 $1,392.32 2020 $ó5,380.00 $o.oo $ó5,380.00 2020 $18,9óO.00 $o.oo $18,9ó0.00 20L8 $2,476.8O 20t9 $ó3,000.00 $o.oo $ó3,000.00 2079 $18,270.00 $o.oo $18,270.00 2077 $2,367.48 Tax Year ïaxes Billed Click here to view the taLiUlq¡EÂ!.jg!-þLlilEpårcelo,ì the G¿rñe site Transfers Sale Date DeedType Reception Number 4/2r/212r SPECIALWARRANTYDEED 95+793 4/26/2018 DECLARATION 906379 3/7/2077 Plat 889891 8/1/2016 RESOLUTION 880478 8/3t/2OOs WARRANTYDEED 68\73? 6/7/2004 DEED 653779 qi4iel5/6/2004 AGREEMENT s/6/2OO4 DEED 653777 3/L5/2OO4 DECLARATION 653776 3/75/2004 DECLARATTON 6531f5 3/\5/2004 COVENANTS 653774 3/I5/2OO4 AGREEMENT 653773 3/I5/2OO4 DEED 653772 3/I5/2OO4 DEED 653771 3/r5/2o14 DEED 6537JO 3/I5/2OO4 DEED 653769 3/rs/2004 suBDrvrsroN IMPRoVEMENTS 653167 2/2/2004 RESoLUTION 646147 2/2/ZOO4 RESOLUTTON 646L46 Book - Page L724-727 1595-798 159ó-838 1595-18r t595-778 t595-775 1595-746 t595-744 1595-740 r595-13? 15?5-138 1-595-737 L595-7L9 155?-435 15s?-42r Sâle Price $282,000 $o $o $o $28o,ooo $o $o $o $o $o $o $o $o $o $o $o $o $o $o https://qpublic.schneidercorp.com/Application.aspx?ApplD=1038&LayerlD=22381 &PageTypelD=4&PagelD=9447&KeyValue=R041 281 1t2 9t212021'qPubl¡6.net - Gar{ield-êounty- GO - Froper.ty. Reoord Card;-R,04-1'2&1 6/76/2003 7/28/2002 7/75/2002 It15/20'02 L/t5/2002 t/L5/2002 tl1.5/2002 6/7/7998 6/7/L998 4/72/1994 8/29t7984 1/7/7900 6297A9 59ó800 v60356 595426 595825 se582+ 595823 7462-663 7326-247 RESOLUTION SPECIAL WARRANry DEED BARGAIN AND SALE DEED WARRANWDEED PERSONAL REP DEED BARGATN AND sALr oE¡o PERSONAL REP DEED EASEMENT EASEMENT DEATH CERTIFICATE Deeds Deeds $4,ooo,ooo $4,ooo,0oo $o $o $o $o $o 1321.-704 L32t-702 r327-696 1327-69s 1070-0089 1070-0081 094ó-0803 0655-0987 0346-OO42 $o $o $o $o $o No data available for the following modules: Buildings, Photos, Sketches. cår'not lte EU^riIi9,:11 User Privaçy Policy GDP&ùû¿çy,No{ce !=es!-Qa!a!plsêd::l?læã*-!2.!8fg&1 r/e¡sion 2 3.1'14 lle,relcped l¡y Ctffi^4çr https://qpublic.schneidercorp.com/Applicâtion.aspx?ApplD=1038&LayerlD=22381&PageTypelD=4&PagelD=9447&KeyValue=R041281 2t2