HomeMy WebLinkAbout3981 0
Ch en Northern, Inc Consulting Engineers and 5cienl sI5
5080 Road 154
Glenwood Springs. Colorado 81601
303 945 -7458
303 945 -2363 FaCSIm le
SUBSOIL STUDY
FOR F OUNDATION DESIGN
PROPOSED RESIDENCE
LOT 19, PINYON PEAKS SUBDIVISION
SAGE SWALE ROAD
MISSOURI HEIGHT'S .
GAD COUNTY, COLORADO
Prepared For:
James L. Pavers
303 East 17th Avenue, Suite 700
Denver CO 80203 -1274
Job No. 4 337 90 May 15, 1990
A member W the Fthl group of companies
TABLE OF CONTENTS
1
CON CLIISTON
PURL�SE AND SCOPE OF STUDY 1
PROPDSED QONS'TFdJCTION 2
STTE ODNDTTION 2
FIELD EXPLORATION 2
SUBSOIL CONDITIONS 3
FOUNUkTION RECOMMEJDATTONS 3
FLOOR SLABS 4
UNDERDRAIN SYSTEM 5
PERCOLATION TESTING 6
SURFACE DRAINAGE 6
LIMITATIONS 7
FIGURES 1 AND 2 — LAG OF EXPIARAIORY PITS
FIGURE 3 — swEarcoNsOLIDATION 2Fu2 RESULTS
FIGURE 4 — GRADATION TEST RESULTS
TABLE I — SUMMARY OF LABORATORY TEST RESULTS
TABLE II -- PERCOLATION TEST RESULTS
Chen @ Northern.Inc.
-3-
Samples of the subsoils were returned to our laboratory for review by the
project engineer and testing. Depths at which the samples were taken are shown
( on the Logs of Fycploratory Pits, Fig. 1.
SUBSOIL CONDITIONS
The subsoil conditions encountered at the site are shown on Fig. 1. The
1 subsoils consist of about 1 1/2 feet of topsoil overlying relatively stiff,
calcareous clayey sand and silt containing cobbles and boulders. The cobbles
and boulders consisted of pieces of gray vesicular bagalt.
Laboratory testing performed on samples obtained from the pits included
natural moisture content, gradation analysis, and Atte ter limits testing.
Results of a swell - consolidation test, shown on Fig. 3, indicate that the
subsoils have low compressibility under light loading. A small collapse
potential (settlement under constant load) was observed when the sample was
wetted. The sample was moderately compressive under increased loading after
wetting. Results of a gradation analysis performed on a large bulk sample taken
from Pit 1 (minus 3/4 -inch fraction) are shown on Fig. 4. The laboratory
testing is summarized in Table I.
No free water was encountered in the pits at the time of excavation and
the subsoils were slightly moist to moist.
FOUNDATION RECOMMENDATIONS
Considering the subsoil conditions encountered in the exploratory pits and
the nature of the proposed construction, we reccnrend the building be founded
with spread footings bearing on the natural subsoils below all topsoil.
The design and construction criteria presented below should be observed
for a spread footing foundation system. The construction criteria should be
considered when preparing project documents.
1
1 Chen Northern. Inc.
Moisture Content = 14 percent
- Dry Unit Weight = 83 pcf
Sample of: clayey si sand
•
From: Pit 2 at 3 feet
11111 11� �1111111
ulbilIl ��
ar 2 ■ ■ 111111i ►� Ir1111111■ ■1111111
■ 1111111 ��1�����I
hall Addit ona
3 1111111 ■ 1111111 wetti 9 111111
press re sue 4
1 1 --
u 1
5
I II
j .
I,
1 .
[!
p
r
111 1
0.1 1.0 10 100
I APPLIED PRESSURE — ksf
4 337 90 Chen - Northern, Inc. SWELL- CONSOLIDATION TEST RESULTS I Fig. 3
I I CA -1A -79