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HomeMy WebLinkAboutObservation of Excavation 03.23.2017H-PVKUMAR Gsotschnlcal Englneerlng I Englneedng Geology Malerials Testing | Ënvlronmantal 5020 County Road 154 Glenwood Spdngs, CCI 81601 Phone: {970} 945-7988 Fax {970} 945-8454 Email hpkglenwood@kumarusa.com Ofüce Locations: Parker, Glenwood Springs, and Summit Gounly, Colorado March 23,2An Chuck Sakys 3450 Enduro Drive Lake Havasu City, Arizona 86404 çhucksakvs Ç gLr-ai l.qom Project No. 16-?-137-l Subject Observation of Excavation, Proposed Residence, Lot 23, Sun Meadow Estates, South Meadow Drive, Garfield County, Colorado DearChuck As reguested, a representative of H-P/Kumar observed the excavation at the subject site on March 16,2fr17 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for the foundation design are presented in this report. The services are supplemental to our agreement for professional services to you dated June 2?,2016. We previously conducted a subsoil .study for design of foundations at the site and presented our findings in a report dated July 5,20¡6, Project No. l6-7-137. The proposed construction is similar to that discussed in our previous report, Spread footings designed for an allowable soil bearing pressure of 1,500 psf were recommended for foundatian support with a risk of settlement. At the time of our site visit, the foundation excavation which was essentially complete had been cut in three levels from about 21o 3Vz feet below the adjacent ground surface. Steps.in grade between the levels were about I foot. The soils exposed in the bottom of the excavation consisted of stifl sandy clayey silt. The excûvation subgrade had been compacted. Results of swell-consolidation testing performed on samples taken from the site, shown on Figure l, indicate the soils are moderately compressible under condition.s of light loading and wetting with a moderate hydro-compression potential. The sample showed high compressibility when loaded after wetting. The sample may have been partly disturbed due to lhe sampling process. The Iaboratory testing is summarized in Table l. No free water lryas €ncounlered in the excavation and the soils were slightly moist. Chuck Sakys Marclr 23,2017 Page 2 The soit conditions exposed in the excavation are generally consistent with those previously encountered on the site and suitable for support ofspread footings designed for the recommended allowable bearing pressure of 1,500 psf. The risk of settlement is primarily if the bearing soils were to become wetted. Precautions such as adequate compaction of foundation backfill, positive surface drainage away from foundation walls, and limiting irrigation near foundation walls should be taken to prevent wetting. Prior to the footing construction, all loose and disturbed soils should be removed and the subgrade re-compacted as needed. The bearing soils should be protected from frost and concrete should not be placed on frozen soils. Other recommendations presented in our previous report which are applicable should also be observed. The recommendations submitted in this letter are b¡sed on our observation of the soils exposed within the foundation excavation and the previous subsurface exploration at the sile. Variations in the subsurface conditions below the excavation could increase the risk of foundation movement, V/e should be advised of any variations encountered in the excavation conditions for possible changes to recommendations contained in thi.s letter. lf you have any questions or need further assistance, please call our office. Sincerely, H-Ps David A. Young, P DAY/ltac Attachments Figure l, SwellConsolidation Test Results Table l, Summary of Laboratory Test Results Garfield County Building Dept. - Jim Wil.son ii$¡ilsonGlearfield-cpgnty.cont)cc: ll-P+KufvtAR Project No 16-7-137.01