HomeMy WebLinkAboutB14-0033 soils report . . � � `� ` a � ��
LKP Engineering, Inc. .
CNIL/GEOTECHNICAL
June 16, 2014
Mr.Bob Boymer RE: Open Hole Observation-Hot Tub-South Wall
P.O. Box 1001 Lot 30,Glen Lyon Subdivision
Vail,CO 81658 1250 Westhaven Circle, Town of Vail
Eagle County,Colorado
Project No. 14-2943
Dear Mr. Boymer:
At your request,on June 13,2014,we visited the construction site for the proposed addition at
1250 Westhaven Circle,Town of Vail,Eagle County,Colorado. The purpose of our site visit was to
observe the soils exposed in the foundation excavation for the proposed addition. We observed the
excavation addition for the south wall of the new hot tub location.An Assumed soil bearing pressure of
2000 psf was used on the structural drawings done by Mr. Tim Boyle,File No. Ferg-S4,dated March 14,
2014.
The excavation consisted of a rounded"L"shaped trench that was approximately 15 feet by 25
feet. The trench was approximately 15 feet south of the existing residence. The soil exposed in the
foundation excavation consisted of light brown, sandy, gravel with large sandstone boulders. The
excavation cuts ranged from about four to six feet below the existing grade.
The soil exposed in the foundation excavation for the proposed addition is suitable for the <.
designed maximum allowable soil bearing pressure of 2000 psf. The bottom of the excavation was
compacted. Soft spots were not reported.
We recommend a minimum of 48 inches of backfill cover for frost protection of the
footing subsoils. The bottom of the excavation was compacted. Soft spots were not reported.
Foundation walls retaining earth and reta.ining structures that are laterally supported
should be designed to resist an equivalent fluid density of 60 pcf for an"at-rest"condition.
Laterally unrestrained structures, retaining the on-site earth, should be designed to resist an
equivalent fluid density of 40 pcf for the"active" case.
The above design recommendations assume drained backfill conditions and a horizontal
backfill surface. Surcharge loading due to adjacent structures, weight of temporary stored
construction materials and equipment, inclined backfill and hydrostatic pressure due to
undrained backfill should be incorporated in the design. They should try to prevent the buildup
of hydrosta.tic pressure behind the retaining wall.
The site surrounding the building structure should slope away from the building in all
directions. A minimum of 12 inches in the first 10 feet is recommended in unpaved areas, and
three inches in the first 10 feet in paved areas. The top of the granular foundation backfill
should be covered with a minimum of 1 foot of relatively impervious fill to reduce the potential
of surface water infiltrating the foundation subsoils.
Surface water naturally draining toward the proposed building site should be diverted
around and away from it by means of drainage swales or other approved methods. The roof
P.O. Box 2837,Edwards,CO 81632 Tel(970)926-9088
Mr. Bob Boymer
Page 2-Project No. 14-2943
June 16, 2014
drains and downspouts should extend and discharge beyond the limits of the backfill.
It is not recommended to introduce excess water to the foundation soils by installing
sprinkler systems next to the building. The installation of the sprinkler heads should insure that
the spray from the heads will not fall within 10 feet of foundation walls,porches or patio slabs.
Lawn irrigation must be controlled.
To reduce the risk of surface water infiltrating the foundation subsoil, we recommend
installation of a foundation perimeter drain. The foundation perimeter drain should consist of a
4-inch diameter,perforated pipe, sloped to a suitable gravity outlet, at a 1/4 inch per foot for
flexible or at a 1/8 of an inch for rigid pipe. The bottom of the trench adjacent to the footing
should be lined with a polyethylene moisture barrier glued to the foundation wall. The drain pipe
should be covered with a minimum of 6 inches of-3/4-inch free-draining granular material.
Geotextile (Mir� 140N or equivalent) should be used to cover the free-draining gravel to
prevent siltation and clogging of the drain. The backfill above the drain should be granular
material to within 2 feet of the ground surface to prevent a buildup of hydrostatic pressure.
This report has been prepared according to locally accepted Professional Geotechnical
Engineering standards for similar methods of testing and soil conditions at this time. The
findings and recommendation stated above are based on the soil conditions observed and tested
in the foundation excavation only. There is no other warranty either expressed or implied.
Sincerely, ,
LKP ENGINEERING INC. ��'' RE ��"'�
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P.O. Box 2837,Edwards,CO 81632 Tel(970)926-9088