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HomeMy WebLinkAboutAlternative Foundation Design Report 04.26.19RECEIVED rcn Èî Krm&Assdd¡s,lnc, ûeotæhnical and Mater¡ål$ Enginsers and Environmental $ciertists APR 2 I 2019 5o2o county Road 154 G ARF I EL D c o u ¡¡flFn-iiiiål'åti,ca?r:;33; COMMUNITY DEVELOPMENT tax: iSzO) g4s-A454 email: kaglenwood@kumarusa.com An Emdo'yêË Otünðd ComPonY com Subject Offìce Locations; Ðenver (HQ),.Parker, Colorado Springs, Fort Collins, Glenwood Spríngs, ånd Summit Çounty, Colorado April26,2019 Heyl Construction Attn: Dave Heyl 65ó0 County Road 335 New Castle, Colorado 81647 d.hevl@heylcivjl.com Project No. 19-7-117 Foundation Alternative, Proposed Residence, Lot 3, Block 1, Oak Meadows 3, TBD Oak Crest Drive, Garfield County, Colorado Dear Dave: Based on conversations with you and Tyler Maier with Tamarack Grove Engineering, we are providing recommendations for an alternative foundation désign for the subject property. lVe previously provided a subsoil study report for foundation design for the subject property dated February 5, 2079, Project No. 19-7-1 I 7. As an alternative to designing for a minimum dead load pressure which was previously recommended, we recommend sub-excavating 3 feet of the nah¡ral clay soils below design footing grade and replacing the clay with structural fill. The other recommendations contained in the previous report should be followed. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory boring and the nature of the proposed construction, we recommend the residence be founded with spread footings bearing on a minimum of 3 feet of compacted structuralfill below footings with a risk of movement, mainly if the bearing soils become wet. 1) Footings placed on the compacted structural fill should be designed for an allowable bearing pressure of 3,000 psf. Based on experience, we expect initial settlement of footings designed and constructed as discussed in this section will be about 1 inch or less. Additional differential movements of about Yz lo 1 inch could occur if the underlying clay soils are wetted' 2) The topsoil, sub-excavation depth and any loose or disturbed soils should be removed below the foundation area. The exposed soils in footing areas after sub-excavation should then be moistened and compacted. Structuralfill should consist of cDor class 6 3Á -inch road base compacted to at least 98o/o oî standard Proctor density within 2% of optimum moisture content. The structuralfill should extend laterally beyond the footing edges equalto at least %the fill depth below the footing.3) A representative of the geotechnical engineer should evaluate the fill placement for compaction and observe all footing excavations prior to concrete placement to evaluate bearing conditions. If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associates, Inc. Daniel E. Rev. by: SLP DEHlkac cc: Tamarack Grove Engineering - Tyler Maier tlvler.maier(@tamarackgrove.com 24443 z 0o 4 I7I 1I L Kumar &Associates, lnc.Project No. 19-7-117