HomeMy WebLinkAboutObservation of ExcavationEngineeringo Inc.
CryIL/OEOTECHNICAL
December II,2020
Evan Schreiber
Lightbox Development
Mobile: (917) 960-5666
evan@lishtboxdevelop ment.com
RE: Open Hole Observation
Schreiber Residence
Lot 10, The Ranch at Coulter Creek PUD,
Meadow Circle atCattle Creek Ridge Road
Carbondale, Garfield County, Colorado
Project No. 20-3447
Dear Evan:
At the request of Ryan Ivy, on November 6 and L6, and on December 3 and 10, 2020,we
visited the construction site for your residence, on Lot 10, The Ranch at Coulter Creek PUD, Cattle
Creek Ridge Road, at the southwest corner of Meadow Circle and Cattle Creek Ridge Road (address
not available yet), Carbondale, Garfield County, Colorado. The purpose of our site visits was to
observe the soils exposed in the foundation excavations for the proposed residence and compare
them with the findings and recommendations of the Soil's and Foundation Investigation, under the
same project number, dated July 24,2019.
The excavation consisted of four benches. The lowest and middle bench, was for the
basement of the main residence, and it was about 8 to 14 feet below the existing grade and about 8
feet below the other three benches. The bench for the garage was on the east side of the excavation
and east from the middle bench, and it was in unsuitable soil, as observed during the first site visit.
The garage area was also below the proposed garage level and it required structural fill. The
excavation foe the garuge area was widened by five feet on the outside perimeter for the placement of
the structural fill. The bench to the north of the basement area was stepped into two benches above
the basement area and it was into undisturbed, light brown, calcareous, sandy clay with some gravel.
The bench on the west side of the excavation and west from the middle bench as well as the bottom
of the middle bench were into large, basalt cobbles and boulders. These areas were overexcavated by
the removal of the large basalt boulders that also required structural fiIl in order to bring the elevation
to the proposed foundation elevation.
The basement area, the garage area, and the west bench were constructed with structural fill
in order to achieve the required foundation elevation. The first layer of the structural fill for the
garage and the basement areas consisted of a 6-inch thick base layer of minus 3-inch road base
covered with a layer of Tensar triaxial geogrid with additional l2-rnch thick layers of minus 3-inch
road base also covered with Tensar, triaxial geogrid. The total depth of the structural fill in the garage
area varied, as did the grade from the east edge of the existing ground to the proposed garuge
P.O. Box 7 24, Eagle CO 8 I 63 1 T eI: 97 0 -390-03 07 www.LKPEngineering. com
psf.
Evan Schreiber Residence
December 11,2020
Page2 of 2
Project 19-3347
elevation. The structural fill was placed in stepped benches with the final two lifts covering the entire
garuge area. The total depth of structural fill in the basement area was about two feet.
The structural fill on the west bench consisted of minus 3-inch road base and varied in
thickness from few inches to less than a foot, just enough to level the subgrade.
The soil exposed in the excavation is suitable for the recommended bearing capacity of 3000
We recommend compliance with the recommendations of the above-named soil report during
the remainder of the construction, specifically with the sections on drainage, grading and irrigation.
The discharge from the perimeter drain in the basement area will have to be either daylighted or
directed to an interior sump pump.
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 in the completed
foundation excavation only. We are not responsible for technical interpretation by others of the
data presented in this report.
There is no other warranty either expressed or implied.
Ifyou have any questions, please do not hesitate to call.
Sincerely,
LKP Engineeringo Inc.
\2
/"-;@rrh4
Luiza Petrovska, PE
J:\ WP X4-LKP\ 201 9\1 9-3347OPEN-STRUC-FILL.DOCX
P.O. Box 724,EagIe CO 81631 Tel: 970-390-0307 www.LKPEngineering.com