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HomeMy WebLinkAboutObservation of ExcavationGtech HEPWORTH - PAWLAK GEOTECHNICAL January 11, 2012 Peter Robson 73 Corral Drive Carbondale, Colorado 81623 rcdcon@yahoo.com Hepworth-Pawlak Geotechnical, Inc. 5020 County Road 154 Glenwood Springs, Colorado 81601 Phone: 970-945-7988 Fax: 970.945-8454 email: hpgeo@lipkeorech.com Job No. 1 1 1 348A Subject: Observation of Excavation, Proposed Residence, Lot E-8, Aspen Equestrian Estates, Equestrian Way, Garfield County, Colorado Dear Mr. Robson: As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the excavation at the subject site on January 11, 2012 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 9, 2011, Job No. 111 348A. At the time of our visit to the site, the foundation excavation had been cut in one level from 3 to 5 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of slightly silty sandy gravel with cobbles. No free water was encountered in the excavation and the soils were moist. Excavation of the main house area was complete and excavation of the garage area was almost complete at the time of our site visit. Other areas of the excavation subgrade were being protected from frost with insulating blankets. 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 2,000 psf. Loose and disturbed soils should be compacted or removed in the footing areas to expose the undisturbed natural soils. The bearing soils should be protected from frost and concrete should not be placed on frozen soils. Other recommendations presented in our previous report which are applicable should also be observed. Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silverthorne 970-468-1989 January 11, 2012 Page 2 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. If you have any questions or need further assistance, please call our office. Sincerely, HEPWORTH — PAWLAK GEOTCHNICAL, INC. t\111'rklisii9iilll 1, o CJ y% Daniel E. Hardin, P. Reviewed by: SLP DEH/ljg 4 2443 ,; ,/,(4ii'�SO NAL�I%G`�`��\` rl4t1Irn1riIjk "M' Job No. 111 348A Gtech