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Home My WebLink AboutSubsoil Study for Foundation Design 05.21.18H.PryKUMAR 5020 County Road 154 Glenwood Springs, C0 81601 Phone: (970) 945-7988 Fax: (970) 945-8454 Email: hpkglenwood@kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado SUBSOIL STUDY FOR F'OUNDATION ÐESIGN PROPOSED RESIDENCE LOT 44, FIRST EAGLES POINT 98 TALON TRACE BATTLIìMENT MESA GARFIELD COUNTY, COLORADO PROJECT NO.18-7-244 MAY 21,2018 PREPARED FOR: ESAU AND SAM RUIZ 924 RANDOLPH AVENUE RIFLE, COLORADO 81650 (gpconstructioninc @ live.com) Geotechnical Engineering I Engineering Geology Materials Testing I Environmental TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY PROPOSED CONSTRUCTION SITE CONDITIONS .. FIELD EXPLORATION.. SUBSURFACE CONDITIONS DESIGN RECOMMENDATIONS FOUNDATIONS IILOOR SLABS UNDERDRAIN SYSTEM. SURFACE DRAINAGE .... LIMITATIONS... FIGURE 1 - LOCATION OF EXPLORATORY BORINGS FIGURE 2 - LOG OF EXPLORATORY BORINGS FIGURE 3 - SWELL-CONSOLIDATION TEST RESULTS FIGURE 4 - GRADATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS I I 1 -2- a '.'...'.....,.'..- 3 ......,..........- 3 ,.',,,.',.''.,',._ 4 ,..',',.,,''',,,,- 4 ,,''''.'.'.'...'._ 5 -5- H-PÈKUIVIAR Project No._ FURPOSE A.NÐ SCOPE OF STUDY This report preseuts the results of a subsoil sLudy fur a proposecl residence to be located at Lot 44, First Eagles Point, 9B Talon Trace, Battlement Mesa, Garfield County, Colo¡aclo. 'fhe project site is shown on Figure 1. The plrrpose of the study was to clevelop recommendations for the foundation clesign. The stucly was conclucted in accordance with our agreement for geotechnical engineering services to Esau and Sam Ruiz dated April 3, 2018, An exploratoly boring'uvas clrilled to obtain information on the snbsurface conditions. Sarnples of the subsoils obtained during the field explolation were tested in the laboratory to detennine their classification, compressibility or swell ancl other engineering characteristics. The resnlts of the field exploration ancl labolatoly testing were analyzeclto clevelop recommendations for foundation types, clepths ancl allowable pressures for the proposed builcling foundation. This repot't summarizes the clata obtainecl during this study and presents our conclusions, design recomnìenclations aud othet'geotechnical engineering consiclerations basecl on the proposecl constrnction and the subsurface conclitions encountered. PROPOSED CONSTRUCTION The proposed resiclence will be a one story woocl frame strllcture above a crawlspace witl-l an attached gal'age. Garage floor will be slab-on-grade. Grading for the structnre is assumecl to be lelatively minor with cut depths between about 3 to 4 feet. We asslrlne relatively light foundation loadings, typical of the proposecl type of construction, If building loadings, location or gr'acling plans change significantly fi'om those clescribed above, we shoulcl be notified to re-evaluate the recommendations containecl in this report. SITE CONDITIONS The lot is vacant and vegetatecl with grass and weeds. The ground surface is relatively flat with a slight slope down to the north. H-PèKUMAR Project No.18-7-244 a'L- }-IET,D EXPLORATION The fielcl exploration for the project w¿ts conducted on April 13, 2018, One exploratoly boring was clrillecl at the location shuwn ort Figirrc 1 to evaluate the subsurface conditions. The boring was advancecl with 4 inch diameter continuous flight allgers powerecl by a trr-rck-monnted CME- 458 drill rig. The boring was logged by a representative of H-P/Kum¿ir. Sarnples of the sr"rbsoils r,vere taken with l% irich and 2ittchl.D. spoon sarnplers. The samplers were.driven into the subsoils at various depths with blows from a 140 pouncl harnrner falling 30 inches. This test is sirnilar to the standard penetration test described by ASTM Method D-1586. The penetration resistance values are an indication of the relative clensity or consistency of the subsoils ancl harclness of the beclrock. Depths at which the samples wel'e taken ancl the petretration resistance values are shown on the Log of Exploratoly Boring, Figure 2. 'lhe sample,s were t'etunted to our laboratory fol leview by the project engineer and testing. SUBSURFACB CONDITIONS Graphic logs of the subsr:rface conditions encoLultelecl at the site are shown on Figure 2. T'he subsoils consist of I I feet of stiff, sandy silt with scattered gravel overlying silty gravel ¿ind sand with cobbles to the depth explorecl of 2l feet. Laboratory testing performed ou samples obtained from the bolings includecl natural moisture content and gradation analyses. Results of swell-consolidation testing performed on a relatively undisturbed drive sample of the sancly silt soils, presented on Figure 3, inclicate low to moderate compressibility under conditions of loading trnd wetting. Results of gradation analyses performed on a small diarneter drive sample (minus l% inch fraction) of the co¿lrse granular subsoils are shown on Figule 4. The laboratory testing is summarized in Table L No fi'ee water was encoLlntered in the boring at the time of drilling and the subsoils were slightly moist. H.PIKUMAR Project No.18-7-244 -3- DESIGI{ RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratoly boring ancl the nature of the ploposed construction, we lecommend the builcling be founded with sprcacl footings bearing on the natulal soils. The design and construction crjteria presented below should be otrserved fol a spread footing foundation system. 1) Footings placed on the undisturbed natural soils should be designed for an allowable bearing pressure of 1,500 psf. Based on experience, we expect settlement of footings clesigned ancl constructed as cliscnssed in this section will be about I inch or less. 2) The footings shoulcl have a minimum wiclth of l8 inches for continuous walls and 2 feet for isolated pacls. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 36 inches below exterior gracle is typically used in this area. 4) Continuous founclâtion walls should be reinforced top and bottom to span local anomalies such as by assuming ar1 Llnsupported length of at least 12 feet. Foundation walls acting as retaining structures should also be designed to resist a lateral earth pressure corresponding to an equivalent fluid unit weight of at least 50 pcf. 5) All existing fill, topsoil and any loose or clisturbed soils should be removed and the footing bearing level extended down to the relatively stiff natural soils. The exposed soils in footing area should then be moistened and compacted. 6) A representative ofthe geotechnical engineer should observe all footing excavations'prior to concrete placement to evaluate bearing conditions. H-PVKUIVIAR Project No. 18-7-244 -4- FI-OOR SI,ABS The natnral on-site soils, exclusive of topsoil, are suitatrle to sr"rpport lightly loadecl slab-on-grade construction. To recluce the effects of some differential urovement, floor slabs shoulcl be separated from all bearing walls and columns with expansion joints which allow nnrestrainecl vertical movement. Floor slab control joints should be usecl to reduce damage due to shrinkage cracking. The recluirelnelìts for joinL spacing ancl slab reinforcement should be establishecl by the clesigner basecl on experience ancl the intendecl slab use. A minimum 4 inch layer of free- draining gravel should be placed beneath slabs to act as a leveling collrse. Tiris material sho¡ld consist of minus 2 inoh aggregate with at least 50olc retainecl on the No. 4 sieve ancl less than ZVo passing the No. 200 sieve, All fill materials for support of floor slabs should be compactecl to at least 95o/a oT maximum standarcl Proctor density at a moistltre 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 duling our exploration, it has been our experience in the area that local pelched grounclwater can develop during times of heavy plecipitation or seasonal runoff. Frozen ground during spring runoff can also create a perched condition. We recommend below-grade constructiolt, such as retaining walls, deep crawlspace ancl basement areas, be protectecl from wetting and hydrostatic pressure builclup by an underclrain system. The proposed garage and shallow crawlspace (less than 4leet below exterior grade) shoulcl not neecl an underdrain, provicled that good surface drainage is maintained arouncl the outside of the house. If installed, the drains should consist of drainpipe placed in the bottorn of the walt backfill surrounded above the invert level with free-draining granular material. The clrain should be placed at each level of excavation and at least 1 foot below lowest acljacent finish grade and sloped at a minimttm lVa to a suitable gravity ontlet or sump and pump. Free-draining granular H-PVKUMAR Project No. 18-7-244 -5- material used in the unclerdrain system shoulcl contain le.ss than 27o passing the No.'200 sieve, less thatt 507o passing thc No. 4 sieve and have a maximnnr size of 2 inches. The clrain gravel backfill should be at least lt/z fccL dccp. SURFACE DRAINAGE The following clrainage precautions should be observecl during construction and maintaincd at all timcs aftel the residence has been completed: 1) Inundation of the foundation excavations ancl nnderslab areas should be avoided during construction. 2) Exterior backfill should be adjLrsted to near optimum moisture and compacted to at least 95Vo of the maxitnum standard Proctor density in pavement and slab areas and to at least 9}o/o of the maximuur standard Proctor density in lanclscape ateas. 3) The ground sllrface surrouncling the exterior of the builcling should be slopecl to drain away from the fbundation in all directions. We recomrnencl a minimum slope of 6 inches in the first 10 feet in unpaved areas and a minimurn slope of 3 inches in the first 10 feet in paved areas. Free-draining wall backfill (if any) should be capped with about 2 feú of the on-site soils to reduce surface water infiltration. 4) Roof clownspottts and clrains should discharge well beyond the limits of all backfill. 5) Landscaping which requires regular heavy irrigation should be locatecl at least 5 feet from founclation walls. Consideration should be given to use of xeriscape tcr redttce the potential for wetting of soils below the building caused by irrigation. LIMITATIONS This study has been conductecl in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory boring drilled at the location indicated on Figure 1, the proposed type of H-PVKUIVIAR Project No. 18-7-244 6- construction and our experience in the area. Our services clo not include cletermining the presence, pt'evention or possibility o1'mold ol other biological contami¡ra.nts (N4OBC) cleveloping in the future. If the clienl ìs concernecl ahout MOBC, then a professional in this special fielcl of plactice should bc consultcd. Or,rl findings include intelpolation and extrapolaLion of the sttbsttt'face conditions identifiecl at the exploratory boring ancl variations in the subsurface conclitions may not become eviclent until excavation is performed. If conditions encounterecl cluriug cottstruction appear diffcrent from those describecl in this l'eport, we should be notified so that re-evaluation of the recomruellclations rnay be made. This report has beeu preparecl for the exclusive use by our client for clesign pllrposes. We are not responsible for technical intelpletations by othels of our infolmation. As the ploject evolves, we shoulcl provicle continuecl cousultation ancl fielcl services during constrnction to review ancl monitor the implernentation of our teconunendations, and to verify that the recontntendations have been appropriately interpretecl. Significant design changes rnay require aclditional analysis ol moclifications to the recommenclations presented hereirr. We recorumencl on-site observatio¡ of excavations and {'oundation bearing stl'at¿ì and testing of structural fill by a representative of' the geotechnical engineer'. Respectfully Subrnittecl, H-P+ KU Louis E. Eller Reviewed by Lte4- ,.4â,3 :': " i:j, II It"A ¡-! Daniel E. Hardin, P.E. LEE/kslv t( / H.PèKUMAR Project No.18-7-244 a.-"" ^-"Ñ 25 50 APPROXIMATE SCALE-FEET LOT 44 o BORING I 18-7-244 H-PryKUMAP LOCATION OF EXPLORATORY BORING Fig. 1 BORING 1 LEGEND 0 srLT (ML); SANDY, CLAyEy W|TH SCATTERED GRAVEL, STIFF, SL|GHTLY MOIST, LIGHT BROWN, CALCAREOUS. GRAVEL AND SAND (GM-SM); StLTy, MtDtUM DENSE, M0|ST, BROWN. 24/12 WC= 1 2.6 DD=81 28/12 WC= 10.6 DD=88 W 5 ! I DRIVE SAMPLE, 2-INCH I.D. CALIFORNIA LINER SAMPLE. t- L¡J t¡JtL IT È-fL t¡Jô DRTVE SAMPLE, 1 3/S-|NCH t.D. SpLtT Sp00N STANDARD PENETRAT|ON TTST. 10 so/12 ,1¿11,7 DRIYE SAMPLE BL0W C0UNT. INDICATES THAT 24 BLOWS 0F A-'l.- 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRTD TO DRIVE ÏHE SAMPLER 12 INCHES. 15 50/ 4 NOTES f. THE EXPLORATORY BORING WAS DRILLED ON APRIL 13, 2018 WITH A 4-INCH DIAMETER CONTINUOUS FLIGHT POWER AUGER. 2. THE LOCATION OF THE EXPLORATORY BORING WAS MEASURED APPROXIMATILY BY PACING FROM FEATURES SHOWN ON lHE SITE PLAN PROVIDED. 20 5ols.s 3. THE ELEVATION OF THE EXPLORATORY BORING WAS NOT MEASURED AND THE LOG OF THT TXPLORATORY BORING IS PLOTTED TO DEPTH. 4, THE EXPLORATORY BORING LOCATION SHOULD BE CONSIDERED ACCURATE ONLY TO THE DTGREE IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOG REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND ÏHE TRANSITIONS MAY BE GRADUAL. 6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORING AT THE TIME OF DRILLING. 7. LABORATORY TEST RESULTS: WC = WATER CONTENT (%) (ASTM D 2216); DD = DRY DENSITY (pct) (lSrv D 2216); +4 = PERCINTAGE RETAINED ON NO. 4 SIEVE (ASTM D A22); -200 = PERCENTAGE PASSING N0. 200 SIEVE (ASTM D 1140). WC= I .l.0 *4=18 -200=53 18-7 -244 H-PryKUMAR LOG OF EXPLORATORY BORING Tis. 2 .l SAMPLE OF: Sondy Silt FROM:Borlngt@5' WC = 10.3 %, DD = 88 pcf .l l ,l :it:ì I I I I I I.t'I -l I I I ,lr. 1;l Iririli I t-----'1 I i ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING : i I Ì '- - --'l---..-i irl i I I ¡ I i Iil i , I i : i i I I I I I i I I I I ln 1 N JJl¡l =an I zo t- o =otnz.oo 0 -1 -2 -3 -4 - KSF t0 100 18-7-244 H-PTKUIVIAR SWTLL-CONSOLIDATION TEST RESULTS Fig. 3 t00 90 ıo 70 ao 50 40 50 20 t0 o ¡rRsu{ HYDROMETER ANALYSIS SIEVE ANALYSIS CL€AR SQUAAE OPEXIXCS -t I I ,t I I I .__..L Iir,.I o to 20 t0 ß 50 60 70 ao 90 too TtuE RSÆti6 7 HRS t5 t¿tN 60 ¡rI ! åf, & E T E g a I II f tr ,oo2 .oo5 .a2a r52 CLAY TO SILT COBBLES GRAVEL 18 X SAND LIQUID LIMIT SAMPLE OF: Grovelly Sondy Slll Molrlx 29X PI-ASTICITY INDEX SILT AND CLAY 53 % FROM:BorlnglO15'&20' Ih.¡. h¡l r.¡ull¡ opply only lo lh. rompl$ vhlch mre l.lrd. Th.lr¡llng nperl rholl nol b. repreduç.d,cxc.pl ln full, vllàoul lhc vrltlrngpp@ol of Kumor & A¡toclqlar, lnc. Sl.vr cnollrl! lodlng b prrfomod ln occordonc. Tllh ASIM D,122, ASll, C156 ond/or ASTM Dll,l0. SAND GRAVEL FINE MEDIUM COARSE FINE COARSE 18-7 -244 H-PryKUMAR GRADATION TEST RESULTS Fig. 4 H.P*I(UMARTABLE 1SUMMARY OF LABORATORY TEST RESULTSProject No18-7-2MSOIL TYPESandy SiltSandy SiltGravelly Sandy Silt MatrixUNCONFINEDCOMPRESSIVESTRENGTHlosflATTERBERG LIMITSPLASTIC¡NDEX(%lLIQUIDLIM¡T(%\PERCENTPASSINGNO.200SIEVEs3GRADATIONSAND(%)29GRAVEL(%\18NATURALDRYDENSITYlocfì8188NATURALMOISTURECONTENT(%\t2.610.611.0SAMPLE LOCATIONDEPTHtfr)2W5t5 &.20BORING1