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HomeMy WebLinkAboutObservation of Excavation 10.09.24Kumar & Associates, Inc.® If 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.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado October 9, 2024 Peak3 Sundance, LLC Attn: Sam Williams 310 Market Street Basalt, Colorado 81621 samba peak3aspen.com Project No. 24-7-208.06 Subject: Observation of Excavation, Proposed Residence, Lot SD-6, Aspen Glen, 1042 Bald Eagle Way, Garfield County, Colorado Gentlemen: As requested, a representative of Kumar & Associates, Inc. observed the completed excavation at the subject site on October 8, 2024 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 provided recommendations for design of foundations at the site in a report dated March 28, 2024, Project No. 24-7-208. We observed the completed excavation including the garage area. The residence has been designed to be supported by spread footings placed on the natural gravel soils and sized for an allowable bearing pressure of 3,000 psf. At the time of our initial visit to the site, the foundation excavation had been cut in one main level from about 2 to 4'h feet below the adjacent ground surface. Thirteen interior pads had been excavated in the building interior. The garage area excavation was nearing completion. The soils exposed in the bottom of the excavation consisted of dense gravel soils. No free water was encountered in the excavation and the soils were slightly moist. The soil conditions exposed in the excavation are generally consistent with those expected to be encountered on the site. It was recommended to deepen the footing bearing areas down to the dense gravel soils. We understand it is desired to replace the sub -excavated depth with compacted structural fill of CDOT Class 6 base course. The structural fill should extend laterally beyond the footing edges a distance equal to at least one-half the depth of fill below the footing but at least one foot. The structural fill should be compacted to at least 98% of standard Proctor density at near optimum moisture content. We should perform compaction testing of the fill on a regular basis. The native gravel soil or compacted structural fill are suitable for support of spread footings designed for the recommended allowable bearing pressure of 3,000 psf. 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 our previous experience in the area. Variations in the Peak3 Sundance, LLC October 9, 2024 Page 2 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. Daniel E. Hardin, P. DEH/kac cc: Peak 3 Construction inkles (nick gpeaUaspen.com) Kumar & Associates, Inc. 0 Project No. 24-7-208.06