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HomeMy WebLinkAboutExcavation ObservationHEPWORTH - PAWLAK GEOTECHNICAL December 6, 20I2 Gray Builders Attn: Dale Gray P. O. Box 362 New Castle, Colorado 81647 (coloaska a@gmail.com) Subject: Dear Dale: I Icpwoith-Fv1,ik CitorozIinic il, lfc. 5(120 C)uziry RnaJ 1 7-1 Glenwood Srrings, (. lonJo 1001 Plvmr: 970-9 }5-19SS 9945-454 coral I: IiFOenuh1,,!eotech,i En Job No. 112 354A Observation of Excavation, Proposed Residence, Lot 13, Sunlight View II, 233 Meadow Wood Road, Garfield County, Colorado As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the excavation at the subject site on December 4, 2012 to evaluate the soils exposed for foundation support. The fundings 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 October 22, 2012, Job No. 112 354A. The residence will be a single story wood frame structure over crawlspace with an attached slab -on -grade garage. The building has been designed to be supported on spread footings using an allowable soil bearing pressure of 1,500 psf, as recommended with some risk of settlement. At the time of our site visit, the foundation excavation which was essentially complete had been cut in two levels from about 3 to 41/2 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of medium stiff to stiff, sandy silty clay with scattered gravel, cobbles and occasional boulders. The excavation subgrade had been compacted. 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 to expose the undisturbed natural soils and the subgrade re -compacted as needed. The bearing soils should be protected from frost and concrete should not be placed on frozen soils. A perimeter foundation drain around the building is not needed due to the shallow crawlspace provided there is positive surface drainage away from the foundation walls and the foundation backfill is adequately compacted as previously recommended. Other recommendations presented in our previous report which are applicable should also be observed. Parker 303-841-7119 o Colorado Sprinhs 719-63 3-5562 0 Silverthorne 970-468-1989 Gray Builders December 6, 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 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. If you have any questions or need further assistance, please call our office. Sincerely, HEPWORTH -- P F ,r K qio1rtL f+ lijpAL, INC. .ti David A. Young, P.E. a ; t w . 32-216 r DAY/ljg vo:°b■yvs am 4 -12 •f I.,4/4/4 61111011101 cc: Kurtz and Associates — Brian Kurtz Job No. 112 354A GAZtecii