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HomeMy WebLinkAboutObservation of Excavation 01.20.2022Associates, Inc.0 1(+AKWW & Geotechnigl 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.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado January 20, 2022 Peak 3 Construction + Development Attn: Bryant Ragan 601 East Hopkins Avenue, Suite 202 Aspen, Colorado 81611 bryant(&-peak3 aspen. com Project No. 19-7-285.A Subject: Observation of Excavation, Proposed Residence, Lot SD-7, Aspen Glen, 1070 Bald Eagle Way, Garfield County, Colorado Gentlemen: As requested by Matt Korus of Peak 3 Construction + Development, a representative of Kumar & Associates observed the excavation at the subject site on January 17 and 20, 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 June 14, 2019, Project No. 19-7-285. The residence design is generally similar to that described in our previous report and will be supported on spread footings placed on the natural gravel soils or compacted structural fill and sized for an allowable bearing pressure of 2,500 psf. At the time of our initial visit to the site, the foundation excavation had been cut from about 2%2 to 5'/2 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation mainly consisted of silty sandy gravel with cobbles but the south end about 3 to 5 feet deep was still based in sandy silt and clay soils which were recommended to be removed. When observed on January 20, the south end had been lowered around 1 to 1 %2 feet and based in the dense, silty sandy gravel with cobbles. No free water was encountered in the excavation and the soils were slightly moist to moist. The natural gravel soils 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 disturbed soils in the footing areas should be removed prior to forming footings or placing structural fill. We should observe placement and compaction of structural fill below footing areas which we understand will be CDOT Class 2 (3/-inch) base course. 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 Peak 3 Construction + Development January 20, 2022 Page 2 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. If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associates, Inc. �0 fr • �; Steven L. Pawlak, Ai SLP/kac • S, cc: Peak 3 Constructi _ 3aspen.com) Kumar & Associates, Inc. 11 Project No.19-7-285.A