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Home My WebLink AboutSubsoil Study for Foundation DesignPhil Castine II PO Box 32 Silt, Colorado 81652 Subject:Geotechnical Investigation 1447 Caunfy Road 321 Rifle, Colorado 2789 Riverside Parkway Grand Junction, Colorado 81501 Phone: 970-255-8005 Info@huddlestonberry. com htne2I,2022 Project#02499-0001 RËCËIVTîÜ GA[{çråÊ ti} ü{..j L¡ t-,j.ï- t, f:Otúld U NiTY UËVL: i-0Ëlt4 Ui'iT Dear Mr. Castine, This letter presents the results of a geotechnical investigation conducted by Huddleston-Berry Engineering & Testing, LLC (HBET) at 1447 County Road 321 in Rifle, Colorado. The site location is shown on Figure 1. The proposed construction is anticipated to consist of a new single-family residence. The scope of our investigation included evaluating the subsurface conditions at the site to aid in developing foundation recommendations for the proposed conskuction. Site Conditions At the time of the investigation, existing residences occupied the western and easter portions of the site. The remainder of the site rüas open and generally sloping down towards the north. Vegetation consisted primarily of weeds, grasses, and small to large bushes and trees in the northern portion of the site. The site was bordered to the north by the Colorado River, to the west and east by rural residential/agricultural properties, and to the south by County Road 321. Subsurface fnvestigat¡on The subsurface investigation included two test pits as shown on Figure 2 - Site Plan. The test pits were excavated to depths of 7.0 and 8.0 feet below the existing ground surface. Typed test pit logs are included in Appendix A. As indicated on the logs, the subsurface conditions at the site were slightly variable. Test Pit TP-l, conducted in the western portion of the investigated area, encountered 1.5 feet of topsoil above tan, moist, soft to medium stiff fat clay soils to the bottom of the excavation. Groundwater was not encountered at the time of the investigation. Test Pit TP-z, conducted in the eastern portion of the investigated area, encountered 1.0 foot of topsoil above brown, moist, soft to medium stiff silty clay soils to a depth of 3.0 feet. The silty clay soils were underlain by tan, moist, soft to medium stiff fat clay with sand soils to the bottom of the investigation. Groundwater was not encountered in the subsurface at the time of the investigation. i447 County Road 321 #02499-0001 06121/22 Laboratory Testins Laboratory testing was conducted on samples of the native soils encountered in the test pits. The testing included grain size analysis, Atterberg limits determination, natural moisture content determination, and maximum dry density and optimum moisture content (Proctor) determination. The laboratory testing results are included in Appendix B. The laboratory testing results indicated that the native silty clay soils are slightly plastic. In general, based on the Atterberg limits and our experience with similar soils in the vicinity of the subject site, the native silty clay soils are anticipated to be slightly collapsible. The native fat clay soils were indicated to be highly plastic. In general, based upon the Atterberg limits of the material, the native fat clay soils are anticipated to be moderately expansive. Foundation Recommendations Based upon the results of the subsurface investigation and nature of the proposed construction, shallow foundations are recoÍìmended. Spread footings and monolithic (turndown) structural slabs are both appropriate foundation altematives. However, as discussed previously, the native soils are anticipated to range from slightly collapsible to moderately expansive. Therefore, in order to provide a stable bearing stratum and limit the potential for excessive differential movements, it is recommended that the foundations be constructed above a minimum of 48- inches of structural fill. If a basement is proposed, HBET should be contacted to conduct additional subsurface exploration to evaluate the soil conditions below the basement foundation elevation. The native siþ clay soils, exclusive of topsoil, are suitable for reuse as structural fill. However, the native fat clay soils are not suitable for reuse. Due to the variability of the materials, any native soils proposed to be reused as structural filI should be evaluated by HBET during construction to ensure that no fat clay soils are used. Imported structural fill should consist of a granular, non-expans iv e, Wfugjg!ügg.material approved by HBET. For spread footing foundations, the footing areas may be trenched. However, for monolithic slab foundations, the structural fill should extend across the entire building pad area to a depth of 48- inches below the turndown edges. Structural fill should extend laterally beyond the edges of the foundation a distance equal to the thickness of structural fiIl. Prior to placement of structural fill, it is recommended that the bottom of the foundation excavation be scarified to a depth of 6 to 9 inches, moisture conditioned, and compacted to a minimum of 95Yo of the standard Proctor maximum dry density, within i 2yo of the optimum moisture content as determined in accordance with ASTM D698. Structural fill should be moisfure conditioned, placed in maximum 8-inch loose lifts, and compacted to a minimum of 95o/o of the standard Proctor maximum dry density for fine grained soils and 90% of the modified Proctor maximum dry density for coarse grained soils, within *. 2%o of the optimum moisfure content as determined in accordance with ASTM D698 and D1557, respectively. Structural fiIl should be extended to within O.l-feet of the bottom of the foundation. No more than O.I-feet of gravel should be placed below the footings or turndown edge as a leveling course. 2Z:VQ08 ArL PROJECTS\O2499 - Martinez Westem\02499-0001 1447 Couty Road 321U00 - Geo\02499-0001 LR062l22.doc 1447 County Road 321 #02499-0001 06/21122 For structural fill consisting of approved imported granular materials and foundation building pad preparution as recommended, a maximum allowable bearing capacity of 1,500 psf may be used. In addition, a modulus of 150 pci may be used for structural fill consisting of the native silty clay soils and a modulus of 200 pci may be used for approved imported structural fill materials. Foundations subject to frost should be at least 36-inches below the finished grade. Any stemwalls or retaining walls should be designed to resist lateral earth pressures. For backfill consisting of the native soils or imported granular, non-free draining, non-expansive material, we recommend that the walls be designed for an active equivalent fluid unit weight of 55 pcf in areas where no surcharge loads are present. An at-rest equivalent fluid unit weight of 75 pcf is recommended for braced walls. Lateral earth pressures should be increased as necessary to reflect any surcharge loading behind the walls. Water soluble sulfates are coÍtmon to the soils in rùy'estern Colorado. Therefore, at a minimum, Type I-II sulfate resistant cement is recommended for construction at this site. Non-structural Floor Slab and Exterior Flatwork Recommendations As discussed previously, expansive soils are present in the subsurface at the site. Due to the fact thøt sløbs-on-grade do not senerate suffícíent loads to resist movement. dífferenlial movement of sløbs-on-erøde is lìkelv. However, in order to reduce the potential for excessive differential movements, it is recommended that non-structural floating floor slabs be constructed above a minimum of 30-inches of structural fill with subgrade preparation, structural fill materials, and fill placement be in accordance with the Foundation Recommendations section of this report. It is recommended that exterior flatwork be constructed above a minimum of l2-inches of structural fill. Slabs-on-grade should not be tied into or otherwise connected to the foundations in any manner. Drainage Recommendations Gradíng and drøinøge are críticøl for the long-term nerformønce of the structure and grading around the structure should be designed to carry precipitation and runoff away from the structure. It is recommended that the finished ground surface drop at least twelve inches within the fîrst ten feet away from the structure. It is also recommended that landscaping within fïve feet of the structure include primarily desert plants with low water requirements. ln addition, it is recommended that irrigation, including drip lines,'within ten feet of foundations be minimized. HBET recommends that downspout extensions be used which discharge a minimum of 15 feet from the structure or beyond the backfill zone, whichever is greater. However, if subsurface downspout drains are utilized, they should be carefully constructed of solid-wall PVC and should daylight a minimum of 15 feet from the structure. In addition, an impermeable membrane is recommended below subsurface downspout drain lines. Dry wells should not be used. In order to limit the potential for surface moisfure to adversely impact the structure, a perimeter foundation drain is recommended. In general, the perimeter foundation drain should consist of prefabricated drain materials or a perforated pipe and gravel system with the flowline of the drain at the bottom of the foundation (at the highest point). The perimeter drain should slope at a minimum of l.\Yo to daylight or to a sump with pump. The drain should also include an impermeable membrane at the base to limit the potential for moisture to infiltrate vertically down below the foundations. 2:\2008 ALL PROJECTS\02499 - Martinez Westem\0249 9-0001 1447 County Road 321V00 - Geo\02499-0001 LR062l22.doc 3 1447 Cor¡nty Road 321 #02499-0001 06l2t/22 General Notes The recommendations included above are based upon the results of the subsurface investigation and on our local experience. These conclusions and recommendations are valid only for the proposed conskuction. As discussed previously, the subsurface conditions encountered at the site were slightly variable. However, the precise nature and extent of any subsurface variability may not become evident until construction. As a result, it is recommended that HBET provide construction materials testing and engineering oversight during the entire construction process. In addition, subcontractors working on the project should be provided a copy of this report and informed of the issues associated with the presence of moisture sensitive subgrade materials at this site. It is imoortønt to note thøt the recommendøtions herein are intended to red.uce the risk of structural movement und/or dømagø to varvíng deerees, associøted with volume chønge of the nø.tive soils. Howeven HBET cannot øredíct long-term changes in suhsurføce moistute conditions und/or the precíse møgnítude or extent of volume change. lühere signifrcunt tncreases tn moísture occar due to Door sradíns.ímnroner stormwatet msnøsement. atilitv líne faílure. excess irrigation. or other cøase. eíther duríqg construct¡on or the result of actions of the nronertv owner. several inches of movement øre nossible. I! addition. ønv føilure to comolv with the recommendutíons ín this reoort releases Huddleston- Berw Eneineerins & Testins, LLC of ønv liøhílitv with reeard to the structure oerformønce. We are pleased to be of service to your project. Please contact us if you have any questions or comments regarding the contents of this report. Respectfully Submitted: Huddleston-Berry EngineerÍng and Testing, LLC *tË .i'."' , I . if ai Michael A. Berry, P.E. Vice President of Engineering 42:\2008 ALL pROJECTS\02499 - Marrinez Westem\02499-0001 1447 County Road 321U00 - Geo\02499-0001 LRO62122.doc FIGURES #p q Garfield County, CO : Ir*r I I i Rifle -\-... . .. -" ^.-\-*ÐÉ t MD I 971tt i' a.¡ J ' 4.r1 i_ .: , Site t .Ã l l i ! .: í!¡ 'i a a ii D ate cr e aIe d: 5 / 26 / 2Q22 Last Data Uploaded: 5/26/2O22 2:12:24 AM FIGURE 1 Site Location Map Develooed bvqþÇ i:l::':i!jÀi:l:L *,_ry q ' Garfield County, CO ::r - ' tL :r" i t_ ^;-'' ':a.-)--.' UMETCO MINERAL S CORPORAT ON R210787 217718300315 i' RIFLE crTv oF R2f0786 217718400314 ,.É J;'-,i.' ROW RoW ffiD ' ,../ L' ROW .^f ì 420654 19100133 ;,',S i- TP.I FLORES RAYMOND J ,.¡. þt r. "t,T@o'.t@fiÈs¡Bgi-" t'I;l .i !l . R924404 I :' .'2177192A0214 ", .. CARNAHAN. JUSTN P:& CARLYNN S']j'. j.: .'j-slI :;1,* N. 'Z re 'll "¿r;# ,Ð.._.-+¡ : R00s118 2177191 00499 HERNANDEZ JESSICA & JUAN MANUEL R024395 ?17719r00136 SANDOVAL MARY MARGARET & -JÕNSSON MARY MARGARET l'¡ Å¿185ft ;d 1: D ate cr e ale d: 5 I 261 2022 Last Data Uploaded: 5/26/2O22 2:12:24 AM Develouedbv$! ,-, -, ., .,,, FIGURE 2 Síte Plan APPENDIX A Typed Test Pit Logs BH COLUMNS 02499-OOO1 1447 COUNTRY RD 321.GPJ GINT US!7emo-.1zc3EmvoNà(o(oooootrmz0)5'oNão(nol\O A TJ tsT¡-¡ff-lãoÞr æãI ¡J ç*9:'Jã'9=+'øæb d o=:4"ifLno ô-wäôG^ ^Y\¿oiuræ ..< liQ;E ã'oliT.ùaþjo'!?.ÞoaFFô!nPmo{5o+ız4fDoo!7Pmo{z=mÀÀ\¡oocEI7oO)o-(¡)N){mU,{!{zc3Emn-l!I..¡!omo"Tlzo{m(nrmOXG'oôÞsÉeã-2-{=o filIIotrtmXç){ızC)ozÐ()-{o7gofaIm(t{v-1nroûrC,)NN{ıox5TDl¡)oxooo¿mc)xmUEtDoo=!ñ-tmoq(¡)t\)Nonoìrr=*ËtããHçEËËHHr9ı'-zo7oczctmIttrIızg¡ge-{man-.1!g,Nít3DEPTH(ft)GRAPHICLOG+m7f-omU,o7tl-lozSAMPLE TYPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN.(tsf)DRY UNITWT(pcÐMOISTUREcoNTENT (%)-{- -'l=m<T+tDUrmvG)FINES CONTENÏ(%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXc ..t.\-.. ))> r\: -.1/_ . {s.. l,r'ì':l:- .1-ì. t'-. lì- j--.'.'.hìt-. t\- .t.-.r\ t/,. ,\ .t/aoOJÉ.o(o0)J.c)ao-{o1'U,or-o@i:r-g)cto0)Øanoo--nÂ)orÉ.Jú)o¡=ooIvq)-f3o.(tt5+aoo3o9-c3(t4(3-G)@À()l<)N)o,f\)È\¡O)TDoo3oogtE.0):'¡ooot+ GEOTECH BH1447RD 321.GPJ GINT US!7omC)-lzc3EmvoNÀ@(oooootrmz{Â)+.oN€ogto3çANF-l å'-J äot9 æ=sÇãa'coEJ.d O=:+ øl Trro ÀwË@n^P€ö*oæ<04GE F'(> ÞËr.ùcR.Èo'ùai-rr!Fo¿-mo-{5o{ız!nPñroz=mÀè\oono0)o-(¡N)ÐD3f,{lrtU'{-o{zc=tE>m?',4 7-{qP.À)zo{mant-ooontoE{olflxoÞ{ız=mTotrtmxo{ız0Þ'-tmg,{n-1mo01(¡)t\)Noo2{zoo7Ioormoxm0@@-.1ñoxF0)oFoooo=!rfn-tm0(¡l(¡)N)NIm7mxoIız-{mzoo-nílxoÞızo¡o7o>=ro#ãotr'n ¡JXEËtrfhızoao7oCzofilrmIızman-{!LNmccDEPTH(ft)GRAPHICLOGImnt¡-trmU,o7-o-.1ozSAMPLE TYPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN(tsf)DRY UNITWT(pcÐMOISTURECoNTENT (%)--.{r --l=mS¡l@(/)mvoFINES CONTENT(Y")LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXhl. ¿. l\-_' t,rþ-. .ls. ¡;-...1s;i\ . t/_. J\ . -tl,Ø.c)0)É.o(o0):loa,-toItØIt-c)TD:Ìr-0¡(taÂ)aØ.3ooa.or-ot-r:r-ctoÉ-f3o6',j*aoo3oec3(nÊ-2\s^ou,Nr\)-.!l\)o-.¡co-.¡.Tl0)ot-É.3U'fl)fo-c¡ìr-0)-J39.of+(to+ô3oqE3U'=tDoo3ooø9.0)çþo(Do APPENDIX B Laboratory Testing Results U>l N oú. úÞz:) o N ooooo No Huddleston-Berry Engineering & Tasting, LLC 2789 Riverside Parkway G¡and Junction, CO 81501 970-255-8005 GRAIN SIZE DISTRIBUTION CLIENT Ìúartìnez Western PROJECT NAME 1447 Countrv Road 321 PROJECT NUMBER o2¿99-0nol PRO'ECT LOCATION U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS HYDROMETER 1 3t4 J 6 14 100 90 85 80 t--"I(, u.l =dl É. uJz TL t--z IUoÉlufL 70 65 60 55 50 45 40 30 20 l5 10 5 0 100 10 1 GRAIN SIZE IN MILLIMETERS 0.00'l t-\I I\I \ \ COBBLES GRAVEL SAND SILT OR CLAY coarse fine coarse medium fine Specimen ldentification Classification LL PL PI Cc Cu o TP-1, GB-l 5/31 FAT CLAYw¡th SAND(CH)50 26 24 a TP.2, cB-1 5131 srLTY CLAY(GL-ML)27 20 7 Specimen ldentification D100 D60 D30 D10 o/oGravel % Sand %silr o/oClay o TP-1, cB-1 5/31 9.5 0.3 24.2 75.5 tr TP-2, GB-1 5/31 2 0.0 12.9 87.1 Huddleston-Berry Engineering & Testing LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005 ATTERBERG LIMITS' RESULTS CLIENT Ma¡linez Westcrn PROJECT NAME 1,147 Countrv Road 321 PROJECT NUMBER 02499-OOO1 PROJECT LOCATION Pifle lìô @ P L A S T I c I T I N D E X 4 3 20 10 CL-ML @ @ 0 60 LIQUID LIMIT 80 100 Specimen ldentification LL PL PI #200 Classification a TP.I, GB.1 5131 50 26 24 76 FATGLAYw¡th SAND(CH) x TP-2, GB.I 5131 27 20 7 87 srlwGLAY(GL-ML) NN oq @ ts + Iooo No af- J t-z6 Àq N od. t¡-zf F ooóo No zotr Àã (J Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005 MOISTU RE-DENSITY RELAT¡ONSH IP PROJECT NAME 1,147 Country Road 321 PRo.JECT LOCATION Riflc CC)PROJECT NUMBER 02499-OOO1 CLIENT Martinez Westem )l \ \ 't \ \ \ \ \ \ \ \ \ ,/\ 7 / V Sample Date: Sample No.: Source of Material: Description of Material: 513112022 22{507 145 TP.I GB.I FAT CLAYw¡th SAND(CH) Test Method (manual)ASTM D6984 140 135 TEST RESULTS Maximum Dry Density 95.5 PCF Optimum Water Content 25'O % 130 125 GRADATTON RESULTS (% PASSING) #200 #4 314" 76 100 100 () cl.tF-6zluo É.o ATTERBERG LIMITS 1 20 LL PL PI 50 26 A 115 Curves of 1OO% Saturation for Specific Gravity Equalto: 110 2.80 2.70 2.60 105 100 95 90 5 15 WATER CONTENT, % 0 10 20 25 30 dt-z:) o F + oooôo Noz tro & Huddleston-Berry Engineering & Testing LLC 2789 Riverside Parkway Grand Junction, CO 81501 970-255-8005 MOISTU RE.DENSITY RELATIONSH I P PROJECT NAME 1447 Country Road 321 PROJECT LOCATION Rifle. COPR(}'ECTNUMBER 02499-OOO,I CLIENT Martinez Westem ,Ul \ \ \ \ \ \ \ \ \ \ \ \ /\ 7 // ,t/ Sample Date: Sample No.: Source of Material: Description of Material 513112022 508 145 TP.2.GB.I srLTY CLAY(CL-ML) Test Method (manual):ASTM D6984 140 135 TEST RESULTS Maximum Dry Density 109'5 PCF Optimum Water Content 14.0 % 130 125 GRADATTON RESULTS (% PASSTNG) #200 #4 314" 87 100 100 ocltl-ızt¡lo ú^o ATTERBERG LIMITS 120 115 110 105 100 95 LL PL PI 27 20 7 Curves of 100o/o Saturation for Specific Gravity Equalto: 2.80 2.70 2.60 90 5 15 WATER CONTENT, % 0 10 20 25 30