HomeMy WebLinkAboutObservation of Excavation 10.12.2022lGrtiffi'ff'å'*"5020 County lLoad 1.54 Clenwood Springs, CO 816ûl phone: {970) 945-7988 fäx: {97û) 945-8454 enraii : kaglenwcod(øjkunarusa.com lv¡ryg.ku!:r!u!la-sa!lAn Emdoycc ormrcd compony Officc l¡carions: Denver (HQ). Parker. Colorado Springs, Irort CoÌlíns, Clenwood Springs, and Summit Cìounly, Colorado October 12,2022 Boulder Construction Services Attn: Matt Jurmu 901 County Road 231 Silt, Colorado 81652 matt. i urnr u(l¿ibqrul dercs.qo m Project Ns.22-7-146 Subject: Observation of Excavation, Proposed Residence,L-et 3, Spring Ridge Reserve, Dry Park Road, Garfield County, Colorad<¡ Dear Matt: As requested, a representative of Kumar & Associates, [nc. observed the excavation at the subject site on October 12,2022 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for tkre found¿tion design are presented in this report. We previously conducted a subsoil study for design of found¿tions at the site and presented our findings in a report dated March25,2022, Froject No.22-7-146. We understand the proposed residence has been designod to be foundsd on spread footings bearing on the natural sandstone bedrock and sized for an allowable bearing pressure of 5,000 psf. At the time of our visit to the site, the foundation excavation had been cut in multiple levels frorn I to 8 feet below the adjacent ground surface. The grade level steps w€re generally between I and 3 feet down to the north and east. The materials exposed in the bottom of fhe excavation consisted of moderately weathered to hard siltstone/sandstone bedrock. No f?ee water w¿s encountered in the excavation and the rock was slightly rnoist. The bedrock 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 5,000 psf. [,mse disturbd soil and rock should be removed in the footing areas to expose the undisturbod r¡¿tural bedrock. Other recorrunendations presented in our previous report which are applicable should also be observd. The recommendations submitted in this letter are basd on our observation of the soils exposod within the foundation excavation and the previous subswface exploration at ttre 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 excavafion conditions for possible changes to recommendations contained in this letter. Our seffic,€s do not include determining the presence, prevention or possibility of rnold or other biological contaminants (MOBC) developing in the future. If the client is conceneed about MOEC, then a prcfessional in this special field of practice should be consulted. Boulder Oonshrretion Serviaes October 12"2022 Page2 If you have arny qurotionr or nccd û¡rúø asoistanoe, pløse call c¡ur offioe. Sincerely, Kumar & Associates, Robert L. Rev. by: SLP RLD/kac $w wllt Kumar & Associates, ln6. @ Project No.22.7-146