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HomeMy WebLinkAboutObservation of Excavation 08.18.2023I(+rtHffi,ffiffi*ifü*-" -, An Emdoyûa olrnçd ConPonY 5020 County Roail 154 Glenwood Springs, CO 81ó01 phone: (970) 945-7988 fax: (970) 945-8454 ernail : kaglenwood@kumarusa.com u¡ur¡¡.kuutausa.çg!CI Offrce Locations: Denver (HQ), Parlier, Colo¡aclo Springs, Foú Collins, Glenwood Springs, and Summit County, Colorado August 18,2023 Charlie Ellsworth P. O. Box 1167 Silt, Colorado 81652 charl e s f¿D fr onti erp avi n s. com Project No.23-7-226 Subject:Observation of Excavation, Proposed Steel Building,670 County Road 266, Garfield County, Colorado Dear Charlie, As requested, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on August 16,2023 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for the foundation design are presented in this report. We previously conducted a subsoil study for design of foundations at the site and presented our findings in a report dated May 8, 2023, Project No.23-7-266. The proposed construction is sirnilar to that discussed in our previous report. The building has been designed to be supported on spread footings bearing on the natural fine-grained soils sized using an allowable bearing pressure of 1,500 psf based on recommendation provided in our report, with some risk of settlement' At the time of our visit to the site, the foundation excavation had been cut in 2 levels from I to 5 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of stiff, silty sandy clay with scattered gravel and cobbles. Four to six inches of screened rock had been placed over the natural soils in the slab-on-grade areas. No free water was encountered in the excavation and the soils were slightly moist. The soil conditions exposed in the excavation are consistent with those previously encountered on the site and suitable for support of spread footings designed for the recommended allowable bearing pressure of 1,500 psf. Loose and disturbed soils should be removed in the footing areas to expose the undisturbed natural soils. Other recommendations presented in our previous report which are applicable should also be observed. The recommendations submitted in this letter are based on our observation of the soils exposed within the foundation excavation and the previous subsurface exploration at the site. Variations in the subsurface conditions below the excavation could increase the risk of foundation movement. We should be advised of any variations encountered in the excavation conditions for possible changes to recommendations contained in this letter. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants Charlie Ellsworth August 18,2023 Page 2 (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associ lnc. Mello, Staff Engineer Reviewed by: Robert L. Duran, P SMMlkac qlßH J Kumar & Associates, lnc. A Project No.23-7-226