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HomeMy WebLinkAboutObservation of Excavation 08.22.2022''L � Kumar ni Associates, MInc.® Geotechnicaland Materials Engineers 5020 County Road 154 and Environmental Scientists Glenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 Z' 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 August 22, 2022 Uriel Mellin 144 Cliffrose Way Glenwood Springs, Colorado 81601 un el.mellin(d4iotmail. colas Project No. 22-7-526 Subject: Observation of Excavation, Proposed Residence, Lot 2, Block 2, Willow Creek Village, 88 Green Mesa Place, Garfield County, Colorado Uriel: As requested, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on August 2, 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. Hepworth-Pawlak Geotechnical (now Kumar & Associates) previously conducted a subsoil study for design of foundations at the site and presented the findings in a report dated June 27, 2000, Job No. 100 465. The current observation was performed in accordance with our agreement for professional services with you dated July 26, 2022. At the time of our visit to the site, the building excavation had been cut in 3 levels from 1 to 3 feet below the adjacent ground surface. The steps in grade were about one foot between levels. The soils exposed in the bottom of the excavation consisted of sandy silt. Results of laboratory testing performed on a relatively undisturbed sample of the silt showed a moisture content of 4.6%, a dry density of 82 pcf and a fines (silt) content of 81 %. No free water was encountered in the excavation and the soils were slightly moist. The footings for the building foundation had been constructed and foundation walls were formed. The silt soils exposed in the excavation are consistent with those previously encountered on the site and can be used for support of spread footings designed for the recommended allowable bearing pressure of 1,200 psf with the risk of settlement mainly if the bearing soils are wetted. Loose disturbed soils in remaining open footing areas (if any) should be moistened and compacted before placing concrete. Other recommendations presented in the previous report which are applicable, especially those to keep the bearing soils dry, 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 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. Uriel Mellin August 22, 2022 Page 2 If you have any questions or need further assistance, please call our office. Sincerely, Kumar & Associates, Inc. Steven L. Pa Rev. by: RLI SLP/kac Kumar & Associates, Inc. ' Project No. 22-7-526