HomeMy WebLinkAboutObservation of Garage Excavation 6.29.12.pdfec:h HEPWOR1 H -PAWLAI( GEOIECHNICAL June 29,2012 Ken and Debbie Roberts P.O. Box 2466 Glenwood Springs, Colorado 81612 f;,-;-;" 'Iii ;',\,,1, ,,' ,'. Iv. :.,' _' \ '\~ it \ r', ,,;
:,,1 '.-', i-:' Job No. 111 054A Subject: Observation of Garage Excavation and Basement Subdrain, Proposed Residence, Lot GV-7, Filing 2, Aspen Glen, Bald Eagle Way, Garfield County,
Colorado Dear Mr. and Mrs. Roberts: As requested by Ken Melby, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the garage excavation at the subject site on June 29,2012
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 April 12, 2011, Job No. III 054A. We observed the house portion of the excavation as
repOlied in a letter dated May 8,2012. The garage foundation is designed for spread footings placed on the natural, dense granular soils and sized for an allowable bearing pressure of
3,000 pst: At the time of our visit to the site, the garage foundation excavation for the residence had been cut in one level fi·ol11 about 7 to 9Y, feet below the adjacent ground surface.
The soils exposed in the bottom of the excavation consisted of relatively dense, sandy gravel and cobbles. There was a thin layer of sandy clay mixed with gravel overlying the sandy
gravel in the northern half ofthe excavation. This is the transition layer fi·ol11 the overlying clay to the gravel and can be left in place but should be compacted prior to forming
footings. No free water was encountered in the excavation and the soils were moist from overnight rain. The house foundation was complete and the perimeter drain consisting of screened
rock up to about 6 inches above top offooting wrapped with filter fabric had been installed. A perimeter drain is not required for the garage foundation. The granular soils 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 3,000
psi Loose disturbed soils should be removed in the footing areas to expose the undisturbed natural soils. Other recommendations presented in our previous report which are applicable
should also be observed.
Ken and Debbie Robelis June 29, 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 offoundation 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 detelmining 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 ill this special field of practice should be consulted.
[fyou have any questions or need further assistance, please call our office. Sincerely, DEH/ljg cc: KLM Construction -Attn: Ken Melby (!<In]Qc,,-\:'k1ll111ent(mmtntck.colll) Kurtz and
Associates -Attn: Brian KUliz, PE Job No. I II 054A ~tech