HomeMy WebLinkAboutB14-0363_B14-0363 HP Geotech letter_1419897480.pdfOctober 31, 2014
Scott S. Turnipseed, AIA
Attn: Scott Turnipseed
P. 0. Box 3388
Eagle, Colorado 81631
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Job No. 114 190A
Subject: Observation of Excavation, Southern Portion of Proposed Residence,
Lot 12, Block 2, Vail Village 61h Filing, 756 Forest Road, Vail, Colorado
Dear Scott:
As requested, a repre:sentative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on October 21, 22, 23 and 28, 2014 to evaluate the materials
exposed for foundation support. The findings of our observations and recommendations
for the foundation design are presented in this report. The services were supplemental to
our agreement for professional services to Scott S. Turnipseed, AIA dated May 21, 2014.
We previously conducted a subsurface study for design of foundations at the site and
presented our findings in a report dated July 29, 2014, Job No. 114 190A. The proposed
construction is generally similar to that discussed in our previous report. Ground floors
will be a combination of slab-on-grade and structurally supported over crawlspace. The
foundation design consists of spread footings bearing on the natural granular soils and/or
bedrock sized for an allowable bearing pressure of 3,000 psf as recommended in our
previous report. Only the foundation for the southern portion of the building will be
constructed at this time.
Du1ing our October 21, 22 and 23 site visits, the excavation was underway in the southern
(upper) levels with typically hard bedrock and difficult excavation being encountered.
On October 28, the foundation excavation for the upper (southern) three levels was
essentially complete. The foundation excavation in the southern portion had been cut in
about 4 levels from about 5 to 20 feet below the adjacent ground surface. The materials
exposed in the bottom of the excavation consisted of medium hard and weathered
limestone bedrock in the shallow cut areas and less weathered and hard to very hard
limestone bedrock in the deeper cut areas. There was about 1 foot of screened rock on the
excavation sub grade. No free water was encountered in the excavation. There was some
groundwater above and to the south of the excavation that was being adequately
controlled with a trench intercept drain and essentially no water was entering the
excavation. The exposed soils and bedrock were generally moist.
Scott S. Turnipseed, AIA
October 31, 2014
Page 2
The 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 3,000 psf. Loose and disturbed materials
should be removed in the footing areas to expose the undisturbed bedrock. Placement of
the one foot depth of free draining gravel on the base course surface is acceptable as
drainage and to act as a leveling course. The water seepage above the excavation should
continue to be collected and diverted away from the excavation. Other recommendations
presented in our previous report which are applicable should also be observed. We
should observe the northern portion of the excavation when completed.
The recommendations submitted in this letter are based on our observation of the
materials 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,
Job No. 114 190A
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