HomeMy WebLinkAboutObservation of Excavation 11.04.20221(+A its ni AssacfaieInc.® Geotechnical and Materials Engineers 5020 County Road 154 and Environmental Scientists Glenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 email: kaglenwood@kumarusa.com An Employee Owned Company www.k-umarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado November 4, 2022 Becky Ciani P.O. Box 2913 Glenwood Springs, Colorado 81602 beck y(Lt masomnorse.com Project No. 22-7-294 Subject: Observation of Excavation, Proposed Residence, Lot 80, Filing 9, Elk Springs, 0146 Kingbird Drive, Garfield County, Colorado Dear Becky: As requested by Cole Ule, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on November 4, 2022 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 17, 2022, Project No. 22-7-294. The proposed construction is similar to that discussed in our previous report. Spread footings bearing on the natural soils sized for an allowable bearing pressure of 2,500 psf were designed for foundation support based on the recommendations provided in our subsoil study report. At the time of our visit to the site, the foundation excavation had been cut in one level from 3% to 6 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of a leveling course of road base structural fill up to around %2 to 1 foot thick over dense, basalt gravel, cobble and boulders in a highly calcareous sandy silt matrix. 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 2,500 psf. Loose and disturbed soils should be removed in the footing areas to expose the undisturbed natural soils. 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 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 (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. Becky Ciani November 4, 2022 Page 2 If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associates, Inc. w� Shane M. Mello, Staff Engineer Reviewed u Steven L.P SMM/kac Cc: COIF Kumar & Associates, Inc. Project No. 22-7-294