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HomeMy WebLinkAboutObservation of ExcavationKumar & Associates, Inc.® K 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 Employe' Owned Company www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado March 27, 2024 Revised April 2, 2024 Terry and Heidi Ruonavaara 1015 Hidden Valley Drive Glenwood Springs, Colorado 81601 thruonavaara(a)msn. com Project No. 21-7-795.A Subject: Observation of Excavation, Proposed Residence, Lot 44, Spring Ridge Reserve, 1284 Hidden Valley Drive, Garfield County, Colorado Terry and Heidi: As requested, a representative of Kumar & Associates, Inc. observed the excavation at the subject site on March 22 and 27, 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 conducted a subsoil study for design of foundations at the site and presented our findings in a report dated November 30, 2021, Project No. 21-7-795. At the time of our initial visit to the site, the foundation excavation had been cut to one level from about 11/2 to 5%2 feet below the adjacent ground surface with depth decreasing toward the north end. The shallower north and northwest part of the excavation exposed brown sandy clay topsoil, while the remainder of the excavation exposed brown to red sandy silt and clay soil, with some red sandstone exposed in the garage area. The excavator was advised that the northern part of the excavation needed to be deepened to penetrate the topsoil and expose the sandy silt and clay soil. At the time of our visit on March 27, the northern part of the excavation had been deepened about 12 to 20 inches, exposing the sandy silt and clay soil. 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 1,500 psf. Loose and disturbed soils should be removed in the footing areas and the expose soils should be moistened to near optimum and compacted prior to the placement of concrete. The bearing soils should be protected against 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 Terry and Heidi Ruonavaara March 27, 2024 Revised April 2, 2024 Page 2 for possible changes to the 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, IPp0.RE u, 15222 Steven L. Pawlak, P.E.��� SLP/kacSS%IONA�EN�� Kumar & Associates, Inc. 0 Project No. 21-7-795.A