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HomeMy WebLinkAboutObservation of Excavation 04.19.2022 5020 County Road 154 Glenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 email: kaglenwood@kumarusa.com www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado April 19, 2022 Russell Cartwright 35 Willowview Way Parachute, Colorado 81635 russecart@gmail.com Project No. 21-7-440.01 Subject: Observation of Excavation, Proposed Residence, Lot 9, First Eagles Point, Battlement Mesa, 142 Eagle Ridge Drive, Garfield County, Colorado Dear Russell: As requested, a representative of Kumar & Associates observed the excavation at the subject site on April 6, 2022 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations are presented in this report. The services are supplemental to our agreement for professional services to you dated May 5, 2021. We previously prepared a subsoil study for design of foundations at the site and presented our findings in a report dated July 12, 2021, Project No. 21-7-440. The proposed construction is similar to that assumed for our subsoil study report and will consist of a 1 to 1½ story wood frame structure over crawlspace with an attached slab-on-grade garage. Spread footings bearing on the natural granular soils sized for an allowable soil bearing pressure of 2,000 psf were recommended for foundation support. At the time of our site visit, the foundation excavation which was essentially complete had been cut in one level up to about 4½ feet below the adjacent ground surface daylighting to the southeast. There was minor cut in the garage floor slab area. The soils exposed in the bottom of the excavation consisted of medium dense, clayey silty sandy gravel and cobbles. Results of swell-consolidation testing performed on samples taken from the site, shown on Figure 1, indicate the silty clay matrix soils are moderately compressible under conditions of loading and wetting with a low hydro-compression potential. No free water was encountered in the excavation and the soils were generally 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 2,000 psf. Loose and disturbed soils should be removed in the footing areas to expose the undisturbed natural granular soils and the subgrade compacted. 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 limited subsurface exploration at the site. Variations in the subsurface conditions below the excavation could increase the risk of Kumar & Associates