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Home My WebLink AboutGeotechnical Investigation 09.26.2018I{uddleston-Berry 640 White Avenue Grancl Junction, Colorado 81501 Phone: 970-255-8005 Fax: 970-255-6818 Inf'o@hucldlestonbeny.com Iinginerring rt Testing, LLC September 26,2018 Project# 01842-0001 Shane Wacle PO Box 425 Silt, Colorado 81652 Subject Geotechnical Investigation 46 High Point Drive Glenwood Springs, Colorado Dear Mr.'Wade, This letter presents the results of a geotechnical investigation conducted by Huddleston-Berry Engineering & Testing, LLC (HBET) 46 High Point Drive in Glenwood Springs, Colorado. The site location is shown on Figure l. The proposed construction is anticipated to consist of a single family residence. The scope of our investigation included evaluating the subsurface conditions at the site to aid in developing founclation recoÌnmendations for the proposecl construction. Site Conditions At the time of the investigation, the site was open with a slight slope down to the west. Vegetation consisted primarily of grasses and weeds with scattered brush. The site was bordered to the north, south, and east by a vacant lots, and to the west by High Point Drive. Subsurface Investisation The subsurface investigation included two test pits as shown on Figure 2 - Site Plan. Test Pits TP-l and TP-2 were excar.ated to depths of 8.0 and 6.0 feet below the existing ground surface, respectively. Typed test pit logs are included in Appendix A. As indicated on the logs, the subsurface conditions at the site were fairly consistent. The test pits encounterecl 1.0 fbrot of topsoil above red, moist, medium stiff to soft sandy silt soils to the bottoms of the excavations. However,inTP-Z, cobbles and boulders were observed in the silt soils. Groundwater was not encountered in the subsurface at the time of the investigation. Laboratorv 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, water soluble sulfates content determination, ancl maximum dry density and optimum moisture content (Proctor) determination. The laboratory testing results are included in Appendix B. 46 High Point Drive #0 r 842-000 I 09126/18 The laboratory resting results indicate that native silt soils are slightly to moderately plastic' Based upôn our experience wilh sirnilar suils in the viciiity of thc subject sitc, thc nativc silt soils are anticipated to be slightly collapsible. 'Water soluble sulfates were detected in the site soils in a ooncentration of 0.016%. Foundation Recommendations Based upon the results of the subsurface investigation and nature of the proposed construction, shallow founclations are recommended. Spread footings and monolithic (turndown) structural slabs are both appropriate foundation alternatives. However, as discussed previously, the native soils are anticipated to be slightly collapsible. Therefore, in order to lirnit the potential for excessive differential movements, it is recommended that the foundations be constructed above a minimum of 24-inches of structural fill. The native silt soils, exclusive of topsoil. are suitable for reuse as structural fill; provided particles in excess of 3-inches in diameter are removed. Irnported structural fill should consist of à granular, non-expansive, &@@g. material such as crusher fines or CDOT Class 6 base course. Unless it can be demonstrated that the materials are not free-draining, pit-ruu materials should not be used as structural fill. 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 24- inches þelow the turndown edges. Structural fill should extend laterally beyond the edges of the foundations a distance equal to the thickness of stntctural fill for both foundation types. 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 conrpacted to a minimum of 95o/o of the stanclard Proctor maximurn dry density, within + 2yo of the optimum moisture content as determined in accordance with ASTM D698. Structural fill should be moisture conditioned, placed in maximum S-inch loose lifts. and compacted to a minimum of 95o/o of the standard Proctor maximum dry density for fine grained soils and modified Proctor maxirnum dry density for coarse grained soils, within + 2o/o of the optimurn moisture content as determined in accordance with ASTM D698 and D1557, respectively. Structural f,rll should be placed to within 0.1-foot of the bottom of foundation elevation. Clean gravel in excess of 0.l-foot in thickness below foundations will not be acceptable. For structural till consisting of the uative soils o¡ imported granular materials and foundation building pad preparation as recommended,a maximum allowable of may be used. In addition, a tnodulus of reaction ¡:f pci may he rrsed fnr stnrcfilral fill consisting of the native silt soils and a modulus of 250 pci may be used for structural fill consisting of crusher fines or base coutse. Foundations subject to fÌost should be at least 36- inches below the finished gradeæ Huddlcsron-Bcrr:' ¡ h¡h.dri'¡L ¡i{1Ì!. Li.( 2x:u008 ALL pRoJECTS\01 842 - Shane Wule\o1842-0001 46 Hig¡ Poirt Drv00 - Geo\o1 842{001 LR09ló l8.doc 46 High Point Drive #0 r 842-000 I 09126/18 Any stemwalls or retaining walls should be designed to resist lateral earth pressttres. For backfill consisting of the native soils or imported granular, non-free draining, non-expansive material, we recommend that the walls be desigrred for an active equivalent f'luid unit weight of 45 pcf in areas where no surcharge loads are present. An at-rest equivalent fluid unit weiglrt of 65 pcf may be used for braced walls. Lateral earth pressut'es should be increased as neçessary to reflect any surcharge loading behind the walls. As discussed previously, water soluble sulfates were cletected in the site soils in a concentration of 0.016%. This concentration of sulfates represeuts a negligible degree of potential sulfate attack on concrete. However, water soluble sulfate concentrations calt vary widely in Western Colorado. Therefore. at a minimum, Type I-II sulfate resistant cernent is recommended for collstl'Llction at this site. Non-Structural Floor Slab and Exterior Flatrvork Recommendations In order to reduce the potential for excessive differential movenettts, it is recotnmended tliat non-structural floating floor slabs be constructed above a minimum of l8-inches of structural fill with subgrade preparation, structnral fill rxaterials, and fill placement be in accordance with the Fo1ndation RecommendcLtions sectíon of this report. It is recotnmended that exterior flatwork be oonstructed above a minimum of l2-inches of structural fill. Drain age Recommendations Gradins antl dyainase are crítical foy the lons-tenn nerformance 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 first ten feet away from the structure. It is also recotnmended that landscaping within five feet of the structure include primarily desert plants with low water requirements. In addition, it is recommended that automatic irrigation (including drip lines) within ten feet of foundations be minimized. HBET recommends that downspout extensions be used which discharge a minimum of ten feet fi'orn the structure or beyonil the backf,rll 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 flrfteen feet from the struchlre. In adclition, an imperrneable mernbrane is recommended below subsurface downspout drain lines. Dry wells should not be used. In order to limit the potential for surface moisture to impact the structure, a perimeter foundation drain is recommended. In general, the perirneter founclation drain should consist of prefabricated drain materials or a perforatecl pipe and gravel system with the flowline of the drain at the bottom of the foundation (at the highest point). The perirneter drain should slope at a rninimum of l.0o/o to daylight or to a sump with pump. An impermeable membrane is also recommended at the base of the clrain to limit the potential for moisture to infiltrate into the subsurface below the founclations. General Notes The recommendations included above are based upon the results of the subsurface investigation and on our local experience. These conclusions and recomrnendations are valid only for the proposed construction. @*,*,'**'nr* JX:U008 ALL PROJECTS\01842 - Shanc Wule\o1842-0001 46 High loilt D[\200 - Gco\01842-0001 LR09:6l8.doc 46 High Point Drive #0 r 842-000 l 09126/L8 As discussed previor"rsly, the subsurface conditions encountered in the test pits were fairly consistent. HrJwever, the precise nature and extent of subsurface variability may not become evident until constluctìon. The recommendations contained lrerein are designecl to reduce the risk and magnitude of movements and it is extlemely critical that ALL of the recornmendations herein be applied to the design and construction. However, HBET cannot predict long-tenn changes in sul¡surface moisture conditions andlor the precise magnitude or extent of any volume change in the native soils. Where sìsnilicønt íncreases ìn suhsurfuce moisture occur due to poor gruding, imnroper stormvtater mønagement, utilítv line føilure, excess irrigation. or otlter cøuse, duríng or øfter construction. sìgnifr,cont movements øre nossible. In adclition. the success of the structure foundations, slabs, etc. is critically dependent upon proper construction. Therefore, HBET should be retained to provide materials testing, special inspections, and engineering oversight during ALL phases of the construction to ensure conformalrce with the recommendations herein. 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 repolt, Respectfully Submitted: Huddleston-Berry Engineering and Testing, LLC Michael A. Berry, P.E. Vice President of Engineering Huddlcston-Bcrn' I rrirì.(,,r'¡i. kdilr, l.l I 4 3 010 s/26/A X:U008 ALL PROJECTS\01 842 - Shane Wale\O1842-0001 46 High loht Dù100 - Gco\O1 842-0001 LR092ô 18.doc FIGURES G Garfield Gounty Land Explorer Gurfr,eld County Garfield County, Colorado t' Site Locat¡on 6't ütlðn {t FIGURE 1 Site Location Map \ Garfield County Land Explorer Printed by Web User 1 inch = 1.,505 feet 1 inch = 0.28 m iles 0 0.2 "zþ' 0.4 0.8 Miles Garf¡eld County carfield County Coloredo ww.gârlield.county,aoñ colo.àdo D5claimer THs¡9ô eomÞilatbn ol r&rd5 âs they âppear in the6€ñ€ld coúty ffices åfieÉi&the âre shtrn. nisdraw¡tgìs þ be usd odyfor reteßftè purp6es ånd tk øunryb nd rsPonsldê for any hâalrades hèÉ¡n @nblÈd O Copyright Garfield County, ColoÞdo I All Rights Reserved Printedr 9/2012018 d 12¿9:06 Plvl C Garfield Gounty Land Explorer Gurfield County Garfield Gounty, Colorado .:i ir lrA TP-I A TP-2 FIGURE 2 Site Plan Garfield County Land Explorer Printed by Web User 1 inch = 94 feet l. ¡nch = 0.02 m ¡les 0 0.0r2s -S^.ol.'o.02s 0.05 Iúì es Garfield county Gãrfield county colorado www.gãrf íeld-countþ(om colo.èdo Oiscla¡mer This ir å compilatbn ol recorde as ü€y âpp€a. in the Gafiêld Courty Otrc€s ¿fred¡ng the area 5hMn. 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O Copyright Gârlêld counlt colo.ado I All Rights Rese.ve.i Prinred: 912012018 at 1:03:34 PlVl APPENDIX A Typed Test Pit Logs BHUS TAB.GDT 9/2Of 8!ÐoLmo{zc=@mvo@ÞN)!o<)otrmz-.1(,JÂ,foã0¡ooçç{{P l.J6ææcæuÕÕæôF¿dl-5àrıoÊ\¡ôìiæCEGocþtsJ(la|.rC)1'norflo-l5oÞ{ızoof€ooat=-lIc)o-ItÐomo-tz=mso,Ta'5llLaoo{mU,{!-{zc=@m7.{TIl,mo.Tlz;FMoxôoGr>g;Ei<2Ø=om¿oE,mxoIoz(}ozvc)ovoÞmU'-ln-{mI@Nl\)00-.{0)nFf@0)oxJooooJo-moxmo(E(!oo3!t-m-tmg@N)l\)0oÞ'n-{mnmxc,Þoz{mzIoì.1mxoP-.{ızeono>ErO#Eçs*E8FÈf4-tızo"?o7oczItfl|'m-tız{m(t-{!-.1LNmÞ3DEPTH(fÐGRAPHICLOG--{mÐr-UmU)on1'--lozSAMPLE ÏYPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN(tsf)DRY UNIT WT(pcOMOISTUREcoNrENT (%)--{-+ST-t [DørmÐoFINES CONTENT(%)LIQUIDLIMITPLASTICLIMITPLASTICIryINDEXs¡Or{..É. rs.. lr'Jf-. l: l/"j..rr:l\r. t/- J\-. -17_Øô)5ö.@t---{É='=oß)lo'ØIol,øIt--0rdc)øa3ooo@(t0¡5o.ct)t--tr-v(D_4"3e.a-3og3Ø=-Ø-â-6)ID(oNl'\)û\¡oì{IDo3ooØ=ß)æboo!+ BHDRIVË-GPJ GINT US LAB.GDT 9/20/18!nImf)zc3trm7otrmzU'Jô)lo=olo-(Dc@Þ\)ooçç^ôF{!i'J-ãüü?lr*uø=- øå;bã6æeo. F- o F. P,,l-æqo < 9J5 ô (UJ 5=^ei¿ı-t r¡æ=æu+xec0@oaR"'t@E.qat-'I(l;Ptnc){5c){ızlc>lolfilãllolldllølloIta!noLmç){z=m5o):Eı'=It-'oo{mU,-{!-{zc=@m7I!tñt1'omfIzo-.1u5G)6rnrct(Fu)omxoÞjoz=m¿otr,mxoIozôoz-{Ac,{ovtrIman{mtll-IN()o3!l-m{mI-{0)of@Clx=oooo'fo¿moxmtrt@@oN)NcoonoÞ>ÞçËËËñãgsH| 99onocImm-lız?o"¡{m.J'-{!=g,mDEPTH(ft)GRAPHICLOG-lmnf-UmU'oÐl,Io2SAMPLE TYPËNUMBERRECOVERY O/"(ROD)BLOWCOUNTS(N VALUE)POCKET PEN,(tsÐDRY UNIT WT(pcr)MOISTUREcoNTENT (%)-l- --{=ms;0lgt@m7oFINES CONTENT(%)LIQUIDLIMITPLASTICLIMITPLASTICIryINDEXfto¡r ); lf; ,i tí.v-.r\, , t2,, 1\ .t4U'Â)foCN.-JÉ.3o(o!)lØ-lo1'ØIr-ûch=0)4fo.Ir{=.=ooo(DØ!,oFoooa3:lı-o3Õ_Ø3ogc3@of3oØ!0)!oo APPENDIX B Laboratory Testing Results Huddleston-Bemy Engineering & Testing, LLC 640 White Avenue, Urút B Crand Junction, CO 81501 970-2ss-8005 970-255-68 I 8 GRAIN SIZE DISTR¡BUTION CLIENT Shane Wade PROJECT NAME 4ô Hiqh Point Drive PROJECT NUMBER 01842-OOO1 PROJECT LOCATION Glenwood Sprinos. CO U.S. SIEVE OPENING IN INCHES6 4 3 21.5 1314 U.S. SIËVE NUMBERS HYDROMETER 1 1416 2A 30 40 50 60 100140200 t-To ul =d) É.L!z LL Fz Lrl(J É. LllÀ 100 95 90 85 BO 75 70 65 OU 55 50 45 40 35 30 25 20 15 10 5 0 100 l0 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS I vl \q L I I \ COBBLES GRAVEL SAND SILT OR CLAY coârse fine coarse medium fine Specimen ldentifi cation Classification LL PL PI Cc Cu o TP-1, GBI slzolB SANDY S|LT(ML)32 25 7 Specimen ldentification D'l00 D60 D30 D10 %Gravel %Sand %silt o/oClay o TP-î, cB1 st2018 9.5 0.087 0.4 42.7 56.9 UN Øz t(, Huddleston-Berry Engineering & Testing, LLC 6.40 White Avenue, Unit B GrandJunctioq CO 81501 970-255-8005 970-255-68 r 8 ATTERBERG LIMITS' RESULTS CLIENT Shane Wade PROJECT NAME 46 l-.linh Point Drive PROJECT NUMBER 01842-0001 PROJECT LOCAT¡ON Glenwood Sorinos. CO P L A s T I c I T I N D E X 60 50 40 30 20 10 CL-ML @ 0 20 80 I LIQUID LIMIT Specimen ldentification LL PL PI #200 Classification o TP.I, GBl 812018 32 25 7 TT SANDY S!LT(ML) ô ı Fôq @f IAf Fz(, Àq U Éô Fzıù I(' I @ ooIN ØF =:- o É.U @tú F N Þô di Øl t---zo Èq U É.ô FzoÈ I T- N o zotr ù o(-) Huddleston-Befry Engineering & Testing, LLC 640 Wlite Avenue, Unit B Crand.Iunction, CO 81501 970-25s-800s 970-2ss-68 l I MOISTU RE.DENSITY RELATIONSHIP cLl ENT Shane Wade PROJECT NAME 46 Hioh Point Drive PROJECT NUMBER 01 842-0001 PROJECT LOCATION Glenwood Sprinqs, CO Sample Date: Sample No.: Source of Material: Description of Material 812212018 18-064r 145 TP.I SANDY SILTIMLI Test Method:ASTM D6984 140 135 TEST RESULTS Maximum Dry Density 104'0 PCF Optimum Water Content 23.5 % 130 125 GRADAT¡ON RESULTS (% PASSTNG) #200 #4 314', 57 100 100 ootF u)z uJo to ATTERBERG LIMITS 1 20 LL PL PI 32 25 7 115 Curves of 100% Saturation for Specific Gravity Equalto 110 2.80 2.70 2.64 105 100 95 5 15 WATER CONTENT, % 90 0 10 20 25 30