The URL can be used to link to this page

Home My WebLink AboutSoils Report for Foundation DesginI(tA*ffifimfm*lffi-- An Employcc Oryncd Compony 5020 County Road 154 Glenwood Springs, CO 81601 phone: Q7q945-7988 fax: (970) 945-8454 email : kaglenwood@,kumarusa.com www.kumarusa.com Office l.ocations: Denver (HQ), Parker, Colorado Springs, Fort Co[ins, Glenumod Springs' and Sunmit Cormty, Colorado Soi ls eo, 5tr"^olPrql ErtG-' STTBSOIL STUDY FOR FOUNDATION DESIGN PROPOSED BARNDOMINIUM CONVERSION 751 MILLER LANE GARFIELD COUNTY, COLORADO PROJECT NO.24-7-112 FEBRUARY 21,2024 PREPARED FOR; HIGH COUNTRY BUILDERS ATTN: MARI( STEIBER P.O. BOX r.107 EAGLE, COLORADO 81631 mark@hi ghcountrybuildersofco. com TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY PROPOSED CONSTRUCTION SITE CONDITIONS. FIELD EXPLORATION SUBSURFACE CONDITIONS -2- FO UNDATION BEARING CONDITIONS DESIGN RECOMMENDATIONS .... -) - FOUNDATIONS J- SURFACE DRAINAGE.-4- LIMITATIONS............-4- FIGURE I - LOCATION OF EXPLORATORY BORINGS FIGURE ? - LOGS OF EXPLORATORY BORINGS FIGI]RE 3 - LEGEND AND NOTES FIGURE 4 and 5- SWELL-CONSOLIDATION TEST RESULTS FIGURE 6 - GRADATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS ..-l- 1 1 I Kumer &Asocirtca, lnc. o Project No.2&7-ll2 PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for a proposed barndominium conversion of the existing pole bam building located at75l Miller Lane, Garfield County, Colorado project site is shown on Figure l. The pulpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our agreement for geotechnical engineering services to High Country Builders dated January 17,2024 A field exploration progftIm consisting of exploratory borings was conducted to obtain information on the subsurface conditions, Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification, compressibility or swell and other engineering characteristics. The results of the field exploration and laboratory testing were analyzedto develop recoflrmendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION The proposed barndominium conversion will consist of adding a concrete slab to the east half of an existing pole barn and converting to a two story building for residential apartments. Ground floor will be slab-on-grade. Grading for the new construction is expected to be minimal with cut depths up to about 3 feet. We assume relatively light foundation loadings, typical of the proposed type of construction. If building loadings, location or grading plans change significantly from those described above, we should be notified to re-evaluate the recommendations contained in this report. SITE CONDITIONS The majority of the site is pasture as shown on Figure 1. There is an existing 100' by 60' pole bam on the west side of the site which is planned to be remodeled. The building has a gravel surfaced floor. Topography is nearly level with gentle slopes down to the south. There is about 2 to 3 feet of existing fill on the south side of the barn. FIELD EXPLORATION The field exploration for the project was conducted on January 18,2024. Two exploratory borings were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. The borings were drilled inside the existing pole barn. The borings were advanced with 4 inch Kumar & Assoclates, lnc. o Project No.24-7-112 a diameter continuous flight augers powered by a truck-mounted CME-45B drill rig. The borings were logged by a representative of Kumar & Associates, Inc. Samples of the subsoils were taken with a 2inchl.D. spoon sampler. The sampler was driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-l586. The penetration resistance values are an indication of the relative density or consistency of the subsoils. Depths at which the samples were taken and the penetration resistance values are shown on the Logs of -bxploratory Borings, Figure 2. The samples were relunrctl to our laboratory for review by the project engineer and testing. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The subsoils, below about 3 inches of gravel for the floor, consisted of about 1 to 2 feet of previously placed filIoverlying stiff to very stiff, sandy silty clay, underlain at a depth of 13 feet by intermixed silty sand and clay with scattered gravel down to the boring depths of 20 and 30 feet. Laboratory testing performed on samples obtained from the borings included natural moisture content and density, and gradation analyses. Results of swell-consolidation testing performed on relatively undisturbed drive samples of the silty clay soils, presented on Figures 4 and 5 indicate low to moderate compressibility under conditions of loading and wetting and a low hydrocompression potential when wetted under a constant 1,000 psf surcharge. Results of a gradation analyses performed on a small diameter drive sarnples (minus 1%-inch fraction) of the sancl and clay with scattered gravel are shown on Figure 6. The laboratory testing is summarized in Table 1. No free water was encountered in the borings at the time of drilling and the subsoils were slightly moist to moist. FOT]NDATION BEARING CONDITIONS The subsoils at the site possess low bearing capacity and, in general, moderate settlement potential, especially when wetted. Lightly loaded spread footings or a thickened slab section koo.i-^ na rha nqrr*ql cnilc ahrurlrl hc fenqihle for forrndation sttnnort of the ngw constructionww6rlr6 vlr urv rrslusr - -_F F - with some risk of settlement. The risk of settlement is primarily if the bearing soils were to become wetted and precautions should be taken to prevent wetting. A lower risk of foundation settlement would be to remove a depth of the on-site soils (typically 3 feet) and replace in a moisture controlled and compacted condition. Provided below are recofirmendations for spread footings and thickened slab foundation bearing on the natural soils. If recommendations for structural fill below the foundation are desired, we should be contacted. Kumar & Associatcs, lnc. o Project No.2&7-112 --'t- DESIGN RECOMMENDATIONS FOTINDATIONS Considering the subsurface conditions encountered in the exploratory borings and the nature of the proposed construction, we believe the new building construction can be founded with spread footings or a thickened slab foundation bearing on the natural soils with some risk of settlement. The design and construction criteria presented below should be observed for a spread footing or thickened slab foundation system. 1) Footings or thickened slab foundations 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 designed and constructed as discussed in this section will be up to about I inch. There could be some additional settlement if the bearing soils were to become wetted on the order of lzto I inch. 2) The footings or thickened slab sections should have a minimum width of 18 inches for continuous walls ar;d2 feet for isolated pads. 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 grade is typically used in this area. A reduced frost cover may be feasible for thickened slab edges with the use of ground insulation board with some increased risk of post-construction movement. 4) Continuous foundation walls and slab sections should be heavily reinforced both transverse and longitudinally top and bottom to span local anomalies such as by assuming an unsupported leng& of at least 10 feet. Foundation walls acting as retaining structures, if any, should also be designed to resist a lateral earth pressure corresponding to an equivalent fluid unit weight of at least 55 pcf. 5) All existing fill, topsoil and any loose or disfurbed soils should be removed and the footing bearing level extended down to the firm 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. FLOOR SLABS The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab-on-grade construction. To reduce the effects of some differential movement, non-strucfural floor slabs should be separated from all bearing walls and columns with expansionjoints which allow Kumar & Assoclates, lnc. o Proiect No.21-l-112 -4- 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 ofsand and gravel base course should be placed beneath floor slabs for support and to facilitate drainage. This material should consist of minus 2-inchaggregate with at least 50olo retained on the No. 4 sieve and less than l2o/o passing the No. 200 sieve, preferably CDOT Class 6 material. All fill materials fbr support of tloor slabs should be compacted to at least 95% of maximum standard Proctor density at a moisture content near optimum. Required fiIl can consist of the on-site soils devoid of vegetation, topsoil and oversized rock. UNDERDRAIN SYSTEM The proposed shallow foundations should not need a perimeter foundation drain, provided that the exterior foundation wall backfill is well-compacted and good surface drainage, as described below, is maintained around the building. SURFACE DRAINAGE Positive surface drainage is an important aspect of the project to prevent wetting of the bearing soils. The following drainage precautions should be observed during construction and maintained at all times after the building has been completed: l) Inundation ofthe foundation excavations and underslab areas should be avoided during construction. Z) Exterior backfill should be adjusted to near optimum moisture and conpacted to at least 95Yo of themaximum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctor density in landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recorlmend 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 paved areas. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. 5) Landscaping which requires regular heavy irrigation, such as sod, and sprinkler heads should be located at least 10 feet from the building foundation. 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 warranff either express or implied. Kumar & Associates, lnc. o Propcf No.24-7-ll2 5 The conclusions and recommendations submitted in this report are based upon the data obtaind from the exploratory borings drilled at the locations indicated on Figure 1, the proposed tlpe of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the futue. If the clie,lrt is concemed about MOBC, then a professional in this special field of praotice should be consulted. Our findings include interpolation and exhapolation of the subsurface conditions identified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is performed. If conditions encountered during constnrction appear different from those described in this report, we should be notified so that re-evaluation 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 infomration. As the project evolves, we should provide continued consultation and field services during consFuction to review and monitor the implementation of our recommendations, and to veriff that the recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation of excavations and foundation bearing strata and testing of structural fill by a rqlresentative of the geotechnical engineer. Respectfully Submittd, Kumar & Associates, lnc. Robert L. Duran, P.E. Reviewed by: David A. RLD/kac P 6nw ltI Kumar & Associatee, lnc.6 Project No.2b7-112 ANTONELLT LANE/CR216 .\ ,:i| : ,:n* { .i: 2 BORING ' EXISTING POLE BARN BUILDING r "qiBi;*; t,>"*"#th.'# .{ffi];;.** + (\l $t E() lr.lzJ ErdJJ =-. .,,.. : ;....,itrlt*,. f-.ffi $'ffit 751 MILLER LANE 100 0 APPROXIMATE SCALE-FEET 24-7-112 Kumar & Associates LOCATION OF EXPLORATORY BORINGS Fig. 1 I N b BORING 1 BORING 2 0 (5)(3)0 18/12 25/12 WC=8.4 DD=96 5 34/12 WC=7.4 DD=1 02 2e/12 WC=6.7 DD=1 O1 -2OO=82 5 14/12 WC=8.2 DD=96 -200=85 24/12 1010 FtlJtd LL I fFo-lrlo 15 37 /12 WC=6.3 DD=116 *4=0 -200=65 30/12 15 FIJ bJl! I IF(L lrJo 20 33/12 34/12 20 25 25 30 26/12 30 Fig. 2LOGS OF EXPLORATORY BORINGS24-7-1 12 Kumar & Associates I LEGEND (5)GRAVEh THICKNESS ]N INCHES SHOWN IN PARENTHESES TO LEFT OF THE LOG. n FILL; SILTY SANDY CI-AY, GENERALLY STIFF, SLIGHTLY MOIST, BROWN. CLAY (CL); SILTY, SLIGHTLY SANDY TO SANDY, STIFF TO VERY STIFF, SLIGHTLY MOIST, BROWN. CLAY AND SAND (CL-SC); INTERUTXED SILTY, SCATTERED GRAVEL, VERY STIFF/DENSE, MOIST, BROWN. DRIVE SAMPLE; 2-INCH l.D. CALIFORNIA LINER SAMPLE. ta/,rz DRIVE SAMPLE BLOW COUNT. INDICATES THAT 18 BLOWS OF A 140-POUND HAMMER'-,'- FALLING 50 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES. NOTES 1. THE EXPLORATORY BORINGS WERE DRILLED ON JANUARY 18,2021 WITH A 4-INCH-DIAMETER CONTINUOUS-FLIGHT POWER AUGER. 2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PI.AN PROVIDED. 5. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE NOT MEASURED AND THE LOGS OF THE EXPLORATORY BORINGS ARE PLOTTED TO DEPTH. 4. THE EXPLORATORY BORING LOCATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED. 5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOGS REPRESENT THE APPROX]MATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL. 6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AT THE TIME OF DRILLING. 7. I.ABORATORY TEST RESULTS: WC = WATER CONTENT (%) (ASTM D2216); DD = DRY DENSITY (pcf) (ASTM 02216);+4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ISTV OCSIS); -200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D1 140). 24-7-112 Kumar & Associates LEGEND AND NOTES Fig. 3 & + o ! N SAMPLE OF: Sondy Sllty Cloy FROM:BoringlO4' WC = 7.4 %, DD = 102 pcf 1 l h d h I i' NO MOVEMENT UPON WETTING .i = -- "' --t --=* -i" --i' I DE Ilrl.o I zo F o =ovlzo C) 0 -1 -2 -5 -1 t0 24-7 -1 12 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. 4 ? 1 0x J-1lrl =o t_2 zo F 6 oozoc)-4 -5 -6 -7 1.0 APPUED t00 SAMPLE OF: Sondy Sllty Cloy FROM:Borlng2O2' WC = E.4 %, DD = 95 pcf ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING I I ! I 24-7-112 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. s aa E H to 2tt lo 40 to to m to ao loo t T E DIAM CI.AY TO SILT COBBLES GRAVEL O T UQUID UTIIT SAND 37 X PIASTICITY INDEX SILT AND CIIY 6I X SAMPLE 0F: Vcry Sondy Sllly CloY FROII:BorlnglOt4' Ihn t d roulh spplt onlt to lh.rmplo rhloh r.n llt d. Th.trrllirt nport aholl not b. nprcduo.d, rr@pl ln full, wnhoul lhr ud{t nqppilol of Kunor & ArElols' lno.Slln qnqlyrb lafng b p.rfomtd ln omrdonci rlth ASlll D6Ol5, Asfll D7926. ASlll C.ISE ondlor ASTU Dll,l0. HYDROHEfER ANALYSIS slEvE ANALYSTS ntE tt Drroa r,r Hs 7 Hlsur! tdlu 4lr U.S. tfr NDARD SERIES a{i & cE n 3euARE Otfllllloa at^. ,l^. 1 ltt tI Lllirtr I .t - J I I i I t .i I I I i I I i i i. I -rt -t ;'I __', ' SAND GRAVEL FINE MEDIUM FINE COARSE 24-7-112 Kumar & Associates GRADATION TEST RESULTS Fig. 6 rcn l0m & lssocHcs, hG.6 Geotechnical and Materials Engineers and Environmental Scientists TABLE 1 SUMTilARY OF LABORATORY TEST RESULTS SATPL 2 1 BORING 4 2 I 4 9 4 ffit DEPTH iLOCAIION 6.7 8.4 6.3 8.2 7.4 (%l NATURAL ]IIOISTURE CONlENT r01 96 116 96 t02 NATURAL DRY DEI.ISITY foc{l 0 (%| GRAVEL 37 (%) SA.ID GMDATION 82 63 83 PCRCENT PASSING NO, 200 stEl/E LKIUID LIMIT tw lhl PLASTIC INDEI (psfl UNCONFINED COMPRESSIVE SIRE]GTH Sandy Silty Clay Sandy Silty Clay Very Sandy Silty Clay Sandy Silty Clay Sandy Silty Clay SOLTIPE No. 24.7-112