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HomeMy WebLinkAboutObservation of Excavation 09.27.2016HPEKUMAR Geo echnlcal Engineering I Eng neering Geology Materials Testing 1 Environmental 5020 County Road 154 Glenwood Springs, CO 81601 Phone: (970) 945-7988 Fax: (970) 945-8454 Email: hpkglenwood®kumarusa.com September 27, 2016 Joe Hultquist 402 Munroe Street Rifle, Colorado 81650 i oe @ you n g-sery ices.com Subject: Dear Joe: Office Locations: Parker, Glenwood Springs, and Silverthome, Colorado Project No. 16-7-393 Observation of Excavation, Proposed Shop Building, 540 Ridge Road, West of New Castle, Garfield County, Colorado As requested, a representative of H-P/Kumar observed the excavation at the subject site on September 2, 2016 to evaluate the materials exposed for foundation support. The findings of our observations and recommendations are presented in this report. The services are supplemental to Hepworth-Pawlak Geotechnical's (now H-P/Kumar) agreement for professional services to you dated July 17, 2014. We previously observed backhoe pits at the site for design of the building foundation and presented our findings in a report dated July 31, 2014, Job No. 114 282A. The proposed construction is similar to that discussed in the report. Spread footings bearing on the bedrock materials encountered at shallow depths designed for an allowable bearing pressure of 3,000 psf were recommended for foundation support. At the time of our site visit, the foundation excavation for six of the planned ten footing pads for the building foundation had each been cut in one level from about 3 to 31/4 feet below the adjacent ground surface. The materials exposed in the bottom of the excavations consisted of weathered and medium hard sandstone/claystone bedrock. We understand similar bedrock materials were exposed in the bottom of the other four footing pads when later dug. No free water was encountered in the pad excavations and the bedrock materials were generally moist. The conditions exposed in the excavations are consistent with those previously encountered on the site and suitable for support of spread footings designed for the recommended allowable bearing pressure of 3,000 psf. Loose and disturbed materials should be removed in the footing areas to expose the undisturbed claystone/sandstone bedrock 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 excavations, information provided to us regarding the footing pad excavations not observed by us, and the previous subsurface exploration at the site. Variations in Joe Hultquist September 27, 2016 Page 2 the subsurface conditions below the excavations 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. If you have any questions or need further assistance, please call our office. Sincerely, H -P KUMA ors: bcfeed, ♦!. 'a De F'1"e Y. ■ CA x Y w J r n W 6 David A. Young, P.E. ?MI. DAY/ksw tyT0;S� H -P .t KUMAR Project No. 16-7-393