HomeMy WebLinkAbout03808~'-· 1 o0
. t @·~ -{'~
I~~~
.I'
• (O<J. vo {p( 11(03 i . i" "'r •
-·~ • ' 1~p,..~
,v ../
i
GARFIELD COUNTY BUILDING AND SANITATION DEPARTMilfiT
109 81h Street Suite 303
Permit N: 3808
Assessor's Parcel No.
:;·.
~>\; ;
l
Glenwood Springs, Colorado 111601
Phona (303) 945-8212
$ lNDIVIDUAL SEWAGE DISPOSAL PERMIT
This does not constitute
a building or use permit. I'
' PROPERTY
Lega~ Description of Assessor's Parcel No.
h SYSTEM DESIGN
r ..
~
I
I
f
I
' .\
'
I
,.
(
_,_t~D~f9.~0~~-Septic Tank Capacity (gallon) ______ Q.ther
If Percolation Rate (minutes/inch) (a Ubeltlf B~s (i~ --P.-1 .
Required Absorption Area -See Attached '3 I :!i J/l ~ ~ -= ( '{. ~
Special Setback Requirements: 31 b i{:!. (,,,\ p_.,J ..:: ..;ilS) IM0j;, 0/lo) in..
"\>ate~W~-/~[-~D_'? __ lnspector /JwY/ J1u~L
•
FINAL SYSTEM INSPECTION AND APPROVAL (as installed)
Call for Inspection (24 hours notice) Before Covering Installation
_,.
System Installer'
/tJOO~ Septic Tank Capacity ~
~' °';4-<.; Septic Tank Manufacturer or Trade Name
• •• 1 '
Septic Tank Access within 8" of surface
-~;
Absorption Area / i;l /'!?A
Ii Absorption Area Type and/or Manufacturer or Trade Name t.um6u
Adequate compliance with County and State regulations/requirements-<.,,;c="-'.:J"-------------------
Other----------------------/-'--_,,o...,..<;:<'--,...p.------------~
Date "/-/ Q -0 -::;.
RETAIN WITH RECEIPT RECORDS AT CONSTR CTION SITE
•CONDITIONS: I
1. All installation must comply with all requirements of the Colorado State Board of Health Individual Sewage Disposal Systems Chapter .'
25, Article 10 C.R.S. 1973, Revised 1984.
· 2. This permit is valid only for connection to structures which have fully complied with County zoning and building requirements. Con-
nection to or use with any dwelling or structures not approved by the Building and Zoning office shall automatically be a violation or a
requirement of the permit and cause for both legal action and revocation of the permit.
3. Any person who constructs, alters, or installs an individual sewage disposal system in a manner which involves a knowing and material
variation from the terms or specifications contained in the application of permit commits a Class I, Petty Offense ($500.00 fine-6 f
months in jail or both).
;
While -APPLICANT Yellow -DEPARTMENT
t
INDIVIDUAL SEWAGE DISPOSAL SY~TEM APPLICATION
CONTRACTOR W\\.t-E..~ ~ '(':{ E.'f.c."111>;"fio1:,\
ADDRESS /2.qJ C=rj e.I') 'Lt.ID ~E;.l\.IAllO~ !? ~ tbbf PHONE cr8t./ -3,oe
DOVE> Of>\\JI~ Co~C..\.E.11:.
O'l 5 0 Covo\ '1"l ~Q 2 Lt~ -I'\ <1:-w C-1\ ••,;n .. i=. a I Ip 47
PERMITREQUESTFOR ~ NEWINSTALLATION ( )ALTERATION ( )REPAIR
Attach separate sheets or report showing entire area with respect to surrounding areas, topography of area, habitable
building, location of potable water wells, soil percolation test holes, soil profiles in test holes (See page 4).
LOCATION OF PROPOSED FACILITY:
Near what City of Town <bi..M \.WOP .C.,~ ~ Size of Lot 'Z.,.i<,. A::.
Legal Description or Address LOT I L ( J So 6 D i '\J I'S I O "1
WASTES TYPE: M_ DWELLING ( ) TRANSIENT USE
( ) COMMERCIAL OR INDUSTRIAL ( ) NON-DOMESTIC WASTES
( ) OTHER-DESCRIBE ______________ _
BUILDING OR SERVICE TYPE: {Z.t..-;;, U7 f ~ -r~ f\L.. -~~~~~-~~-------.,.-------~
Number of Bedrooms Number of Persons t/ -~---
( ) Garbage Grinder f)i{J Automatic Washer (>()"Dishwasher
SOURCE AND TYPE OF WATER SUPPLY: ~WELL ( ) SPRING ( ) STREAM OR CREEK
If supplied by Community Water, give name of supplier:
,PISTANCE TO NEAREST COMMUNITY SEWER SYSTEM: __ l~""-n_.e... _______ _
Was an effort made to connect to the Community System? ~ -5ew1c..t. Ct.os~t? lo Sl"'-'W1"
VtE-iil sd•
A site plan is required to be submitted that indicates the following MINIMUM distances:
Leach Field to Well: 100 feet
Septic Tank to Well: 50 feet
Leach Field to Irrigation Ditches, Stream or Water Course: 50 feet
Septic System (septic tank & disposal field) to Property Lines: 10 feet
YOUR INDIVIDUAL SEWAGE DISPOSAL SYSTEM PERMIT WILL NOT BE ISSUED WITHOUT
A SITE PLAN. (J ( flt Eieo-1".U.lo\ • \'Jot.>tler.. wec.E... ,~·-I'\'. rto fiu
GROUND CONDITIONS: se.c:. i.v.,e L\ ............. '" ...,.....,. &o~s P..T ~ \T""e OF """~WM 15.t'Co\M ,...,.-., '"~
Depth to first Ground Water Table_Q""-"'C-\,_<.L.-'t=l'C=-· ------,---..------------
Percent Ground Slope E'...1\-n r..£ ~ E. o l..oT ulfo 4 :SC..OPE:.. OF-
(-'SU ~Pl.U-e "Z.. OE" ~ <$1£.0"'(l!c.~ ~£.'1or-T-51"lE. CO~~filOMS
2
r
TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED:
t;4 SEPTIC TANK
( ) VAULTPRIVY
( ) PITPRIVY
( ) AERATIONPLANT ( ) VAULT
( ) COMPOSTING TOILET ( ) RECYCLING, POT ABLE USE
( ) INCINERATION TOILET ( ) RECYCLING, OTHER USE
( ) CHEMICAL TOILET( ) OTHER-DESCRIBE ______________ _
FINAL DISPOSAL BY:
(A ABSORPTION TRENCH, BED OR PIT
( ) UNDERGROUND DISPERSAL
( ) ABOVE GROUND DISPERSAL
( ) EV APOTRANSPIRATION
( ) SAND FILTER
( ) WASTEWATERPOND
( ) OTHER-DESCRIBE _______________________ _
WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE? No
PERCOLATION TEST RESULTS: (To be completed by Registered Professional Engineer, if the Engineer does the
Percolation Test)
Minutes_~'3o~ _ _,per inch in hole No. 1 Minutes --~b~o~ _ _,per inch in hole No. 3
Minutes <oo per inch in hole No. 2 Minutes per inch in hole No._
f\uwo\!.'{"I\ -~""" ""''<---
Applicant acknowledges that the completeness of the application is conditional upon such further mandatory and
additional tests and reports as may be required by the local health department to be made and furnished by the applicant
or by the local health department for purposed of the evaluation of the application; and the issuance of the permit is
subject to such terms and conditions as deemed necessary to insure compliance with rules and regulations made,
information and reports submitted herewith and required to be submitted by the applicant are or will be represented to
be true and correct to the best of my knowledge and belief and are designed to be relied on by the local department of
health in evaluating the same for purposes of issuing the permit applied for herein. I further understand that any
falsification or misrepresentation may result in the denial of the application or revocation of any permit granted based
upon said application and in legal action for perjury as provided by law.
Signed ~ Uue Date 'l/'Z¢/v:s
' ----'--------PL EASE DRAW AN ACCURATE MAP TO YOUR PROPERTY!!
3
@)
• i.f-~11-"'f"o \7lA..,-M1''(> Ft)
~c." "Tio~"\ Of' \:\o u"> If. ;----s
""'"' J.jl A. ' :Z,
\.'.) ::,,.
'-'-
2185-331-00-95 7
8.L M
\wvEo: -
,,..,,, J
UH ~~-' 1oi oos IWll'\
~s koa-"151
"4CT,, ci "'. <>:
@"! \\ (§) 'f.
\.
t. @ • ·n """' . < UllA
:i )
®
,. ...
z
0 @)
i) ::s
Cl $
"' t.
~ ~
re p.. @) ~
~
0
"'4CT .. """' . Q
~·
~.
J
'"'"" ,.,,, A.
@
Co. Rd. WOOD
@ CD
·:§) @) <§)
.14 A. .70 " .71 A.
This Parcel Is Splic By Two Sections
The Upper Portion Of This Map Is From County Plat Map #2185-34
The Lower Portion Of This Map Is From County Plat Map #2395-03
I •
' • Hepworth-Pawlak Geotechnical, lnc.
1' i 5020 County Road 154
I
Glenwood Springs, Colorado 81601 •• Phone: 970-945-7988
Fax: 970-945-8454
hpgeo@hpgeotech.com
I
I
I
I
I
I SUBSOIL STUDY
FOR FOUNDATION DESIGN AND PERCOLATION TEST
I
PROPOSED RESIDENCE,
TRACT UB, L/J SUBDIVISION, CHEL YN ACRES
GARFIELD COUNTY, COLORADO
I JOB NO. 101 400
I JUNE 29, 2001
I
I
I
I PREPARED FOR:
I KEN CALL
P.O. BOX 1011
I GLENWOOD SPRINGS, COLORADO 81602
I •
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
• •
. .
•
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
June 29, 2001
Ken Call
P.O. Box 1011
Glenwood Springs, Colorado 81601 Job No. IOI 400
Subject: Report Transmittal, Subsoil Study for Foundation Design and Percolation
Test, Proposed Residence, Tract llB, L/J Subdivision, Chelyn Acres,
Garfield County, Colorado
Dear Mr. Call:
As requested, we have conducted a subsoil study for design of foundations and
percolation testing at the subject site.
Subsurface conditions encountered in the exploratory borings drilled at the proposed
building area, below about 'h foot of topsoil, consist of 17 to 18 feet of stiff to hard,
slightly sandy clay, overlying weathered claystone/siltstone bedrock. Groundwater was
not encountered in the borings at the time of drilling.
The proposed residence can be founded on spread footings placed on the natural clay
subsoils and designed for an allowable bearing pressure of 3 ,000 psf. The footings
should also be designed for a minimum dead load pressure of 1,000 psf.
The report which follows describes our investigation, summarizes our findings, and
presents our recommendations. It is important that we provide consultation during
design, and field services during construction to review and monitor the implementation
of the geotechnical recommendations.
If you have any questions regarding this report, please contact us.
Sincerely,
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
~~Pff'cze
Trevor L. Knell
Rev. By: DEH
TLK/ksw
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
.
'
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PROPOSED CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SITE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GEOLOGIC ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
FIELD EXPWRA TION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SUBSURFACE CONDITIONS ................................... 3
FOUNDATION BEARING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
DESIGN RECOMMENDATIONS ................................. 4
FOUNDATIONS ........................................ 4
FOUNDATION AND RETAINING WALLS ..................... 5
FLOOR SLABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
UNDERDRAIN SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SITE GRADING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SURFACE DRAINAGE ................................... 9
PERCOLATION TESTING ................................ 10
LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
FIGURE 1 -LOCATION OF EXPLORATORY BORINGS AND PERCOLATION
TEST HOLES
FIGURE 2 -LOGS OF EXPLORATORY BORINGS
FIGURE 3 -LEGEND AND NOTES
FIGURES 4 & 5 -SWELL-CONSOLIDATION TEST RESULTS
TABLE I -SUMMARY OF LABORATORY TEST RESULTS
TABLE U -PERCOLATION TEST RESULTS
H-PGEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study and percolation testing for a
proposed residence to be located on Tract 118, L/J Subdivision, Chelyn Acres, Garfield
County, Colorado. The project site is shown on Fig. l. The purpose of the study was
to develop recommendations for foundation design and infiltration septic disposal
system design. The study was conducted in accordance with our agreement for
geotechnical engineering services to Ken Call, dated May 23, 2001.
A field exploration program consisting of exploratory borings was conducted to
obtain information on subsurface conditions. Samples of the subsoils and bedrock
obtained during the field exploration were tested in the laboratory to determine their
classification, compressibility or swell and other engineering characteristics. The
results of the field exploration, laboratory and percolation testing were analyzed to
develop recommendations for foundation types, depths and allowable pressures for the
proposed building foundation and average percolation rates of the subsoils. This report
summarizes the data obtained during this study and presents our conclusions,
recommendations and other geotechnical engineering considerations based on the
assumed construction and the subsoil conditions encountered.
PROPOSED CONSTRUCTION
At the time of our study, design plans for the residence had not been developed.
The building is proposed in the area roughly between exploratory Borings 1 and 2 as
shown on Fig. 1. We assume the proposed residence will be typical of the area and
consist of one to two stories of wood frame construction over a walkout basement.
Lower floor level may be structural over crawlspace or slab-on-grade. We expect
excavation for the building will have a maximum cut depth of one level, about 10 feet
below the existing ground surface. For the purpose of our analysis, foundation loadings
for the structure are assumed to be relatively light and typical of the assumed type of
construction. We expect the septic system will be located to the east and downhill of
the proposed residence.
H-P GEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
-2-
If building loadings, location or grading plans are significantly different from
those described above, we should be notified to re-evaluate the recommendations
contained in this report.
SITE CONDITIONS
The area of the proposed residence was vacant at the time of our field work and
is located on an inside comer of Van Dom Road. An existing residence and well is
located to the south of the proposed building area. A culvert runs beneath Van Dom
Road onto the site. The ground surface in the building area is relatively flat and sloping
down to the east at about 20% grade. There is about 5 feet of elevation difference
across the assumed building footprint. Vegetation consists of grass and weeds with
sagebrush and scrub oak in the northwest portion of the building area.
GEOLOGIC ASSESSMENT
The lot is located on colluvial deposits overlying the Maroon Formation on the
east side of the Grand Hogback. The near surface deposits in this area consist mostly of
fine-grained soils transported downslope by gravity. These deposits are derived from
clay rich formations such as the Mancos or Morrison formations and can be expansive if
wetted. Methods for mitigating the expansive clays are described below.
A mapped landslide feature (Kirkham, 1995) exists to the west of the property.
The lot appears to be located below the toe of the landslide. We know of no
documented movement of this landslide.
Bedrock outcrops of Dakota Sandstone exist to the west high on the ridge, but
there are no indications of rockfall impact to the property.
There is no indication of recent debris flows on the site. The potential for future
debris flows is low and can be mitigated by methods outlined in the "Surface Drainage"
section of the report.
The project area could experience moderately strong earthquake related ground
shaking. Modified Mercalli Intensity VI ground shaking should be expected during a
H-PGEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
- 3 -
reasonable service life for the development, but the probability for stronger ground
shaking is low. Intensity VI ground shaking is felt by most people and causes general
alarm, but results in negligible damage to structures of good design and construction.
The facilities should be designed to withstand moderately strong ground shaking with
little or no damage and to remain serviceable with some damage under stronger ground
shaking. The region is in the Uniform Building Code, Seismic Risk Zone 1. Based on
our current understanding of the earthquake hazard in this part of Colorado, we see no
reason to increase the commonly accepted seismic risk zone for the area.
FIELD EXPLORATION
The field exploration for the project was conducted on June 4, 2001. Two
exploratory borings were drilled at the locations shown on Fig. 1 to evaluate the
subsurface conditions. The borings were advanced with 4 inch diameter continuous
flight auger powered by a truck-mounted Longyear BK-51HD drill rig. The borings
were logged by a representative of Hepworth-Pawlak Geotecbnical, Inc.
Samples of the subsoils were taken with a 2 inch l.D. spoon sampler. The
sampler was driven into the subsoils and bedrock at various depth with blows from a
140 pound hammer falling 30 inches. This test is similar to the standard penetration test
described by ASTM Method D-1586. The penetration resistance values are an
indication of the relative density or consistency of the subsoils and hardness of the
bedrock. Depths at which the samples were taken and the penetration resistance values
are shown on the Logs of Exploratory Borings, Fig. 2. The samples were returned to
our laboratory for review by the project engineer and testing.
SUBSURFACE CONDITIONS
Graphic Jogs of the subsurface profiles encountered at the site are shown on
Fig. 2. Below about 1h foot of topsoil, the subsoils consist of stiff to bard, slightly
H-P GEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
-4-
sandy clay. At depths of about 18 and 19 feet in Borings 1and2, respectively,
weathered claystone/siltstone bedrock was encountered.
Laboratory testing performed on samples obtained during the field exploration
included natural moisture content and density, percent fmer than sand size gradation
analyses and liquid and plastic limits. Swell-consolidation testing was performed on
relatively undisturbed drive samples of the clay subsoils. The swell-consolidation test
results, presented on Figs. 4 and 5, indicate low compressibility under relatively light
surcharge loading and a low to moderate expansion potential when wetted under a
constant light surcharge. Liquid and plastic limits testing indicates the clay soils are
medium plastic. The laboratory testing is summarized in Table I.
No free water was encountered in the borings at the time of drilling. The
subsoils were slightly moist to moist.
FOUNDATION BEARING CONDITIONS
The clay soils encountered at the site possess low to moderate expansion
potential when wetted. The expansion potential can probably be mitigated by load
concentration to reduce or prevent swelling in the event of wetting below the foundation
bearing level. Surface runoff, landscape irrigation, and utility leakage are possible
sources of water which could cause wetting.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory borings
and the nature of the proposed construction, we recommend the residence be founded
with spread footings placed on undisturbed natural clay soils.
The design and construction criteria presented below should be observed for a
spread footing foundation system.
1) Footings placed on the undisturbed natural clay soils can be designed for
an allowable bearing pressure of 3 ,000 psf. The footings should also be
H-PGEOTECH
I
I ,---
I
I
I
I
I
I
1--9
I
I
I
I
I
I
I
19
I
-5 -
designed for a minimum dead load pressure of 1,000 psf. In order to
satisfy the minimum dead load pressure under lightly loaded areas, it
may be necessary to concentrate loads by using a grade beam and pad
system. Wall-on-grade construction is not recommended at this site to
achieve the minimum dead load.
2) Based on experience, we expect settlement or heave of footings designed
and constructed as discussed in this section will be about 1 inch. There
could be some additional movement if the bearing soils were to become
wetted.
3) The footings should have a minimum width of 16 inches for continuous
footings and 24 inches for isolated pads.
4) Continuous foundation walls should be reinforced top and bottom to span
local anomalies and limit the risk of differential movement. One method
of analysis is to design the foundation wall to span an unsupported length
of at least 12 feet. Foundation walls acting as retaining structures should
also be designed to resist a lateral earth pressure as discussed in the
"Foundation and Retaining Walls" section of this report.
5) Exterior footings and footings beneath unheated areas should be provided
with adequate soil cover above their bearing elevation for frost
protection. Placement of foundations at least 36 inches below the
exterior grade is typically used in this area.
6) Prior to the footing construction topsoil and loose or disturbed soils
should be removed and the footing bearing level extended down to firm
natural soils.
7) A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
FOUNDATION AND RETAINING WALLS
Foundation walls and retaining structures which are laterally supported and can
be expected to undergo only a slight amount of deflection should be designed for a
lateral earth pressure computed on the basis of an equivalent fluid unit weight of 60 pcf
H-PGEOTECH
I
I .
1•
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
- 6 -
for backfill consisting of the on-site soils. Cantilevered retaining structures which are
separate from the residence and can be expected to deflect sufficiently to mobilize the
full active earth pressure condition should be designed for a lateral earth pressure
computed on the basis of an equivalent fluid unit weight of 50 pcf for backfill consisting
of the on-site soils.
All foundation and retaining structures should be designed for appropriate
hydrostatic and surcharge pressures such as adjacent footings, traffic, construction
materials and equipment. The pressures recommended above assume drained conditions
behind the walls and a horizontal backfill surface. The buildup of water behind a wall
or an upward sloping backfill surface will increase the lateral pressure imposed on a
foundation wall or retaining structure. An underdrain should be provided to prevent
hydrostatic pressure buildup behind walls.
Backfill should be placed in uniform lifts and compacted to at least 90 % of the
maximum standard Proctor density at a moisture content slightly above optimum.
Backfill in pavement areas should be compacted to at least 95 % of the maximum
standard Proctor density. Care should be taken not to overcompact the backfill or use
large equipment near the wall since this could cause excessive lateral pressure on the
wall. Some settlement of deep foundation wall backfill should be expected even if the
material is placed correctly and could result in distress to facilities constructed on the
backfill.
The lateral resistance of foundation or retaining wall footings will be a
combination of the sliding resistance of the footing on the foundation materials and
passive earth pressure against the side of the footing. Resistance to sliding at the
bottoms of the footings can be calculated based on a coefficient of friction of 0.35.
Passive pressure of compacted backfill against the sides of the footings can be calculated
using an equivalent fluid unit weight of 350 pcf . The coefficient of friction and passive
pressure values recommended above assume ultimate soil strength. Suitable factors of
safety should be included in the design to limit the strain which will occur at the
ultimate strength, particularly in the case of passive resistance. Fill placed against the
sides of the footings to resist lateral loads should be a nonexpansive, granular material
H-PGEOTECH
I
I .
1•
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
, ..
- 7 -
compacted to at least 95 % of the maximum standard Proctor density at a moisture
content near optimum.
FLOOR SLABS
The on-site soils possess an expansion potential and slab heave could occur if the
subgrade soils were to become wet. Slab-on-grade construction may be used provided
precautions are taken to limit potential movement and the risk of distress to the building
is accepted by the owner. A positive way to reduce the risk of slab movement, which is
commonly used in the area, is to construct structurally supported floors over a
crawlspace.
To reduce the effects of some differential movement, nonstructural floor slabs
should be separated from all bearing walls and columns with expansion joints which
allow unrestrained vertical movement. Interior non-bearing partitions resting on floor
slabs should be provided with a slip joint at the bottom of the wall so that, if the slab
moves, the movement cannot be transmitted to the upper structure. This detail is also
important for wallboards, stairways and door frames. Slip joints which will allow at
least 1 ~ inches of vertical movement are recommended. Floor slab control joints
should be used to reduce damage due to shrinkage cracking. Slab reinforcement and
control joints should be established by the designer based on experience and the
intended slab use.
A minimum 4 inch layer of free-draining gravel should be placed immediately
beneath basement level slabs-on-grade. This material should consist of minus 2 inch
aggregate with less than 50% passing the No. 4 sieve and less than 2% passing the
No. 200 sieve. The free-draining gravel will aid in drainage below the slabs and
should be connected to the perimeter underdrain system.
Required fill beneath slabs can consist of a suitable imported granular material,
excluding topsoil and oversized rocks. The fill should be spread in thin horizontal lifts,
adjusted to at or above optimum moisture content, and compacted to at least 95 % of the
maximum standard Proctor density. All vegetation, topsoil and loose or disturbed soil
should be removed prior to fill placement.
H-PGEOTECH
I
I . .
1•
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
' ''
- 8 -
The above recommendations will not prevent slab heave if the expansive soils
underlying slabs-on-grade become wet. However, the recommendations will reduce the
effects if slab heave occurs. All plumbing lines should be pressure tested before
backfilling to help reduce the potential for wetting.
UNDERDRAINSYSTEM
Although groundwater was not encountered during our exploration, it has been
our experience in mountainous areas and where clay soils are present that local perched
groundwater may develop during times of heavy precipitation or seasonal runoff.
Frozen ground during spring runoff can create a perched condition. Therefore, we
recommend below-grade construction, such as crawlspace and basement areas, be
protected from wetting by an underdrain system. The drain should also act to prevent
buildup of hydrostatic pressures behind foundation walls.
The underdrain system should consist of a drainpipe surrounded by free-draining
granular material placed at the bottom of the wall backfill. The drain lines should be
placed at each level of excavation and at least 1 foot below lowest adjacent finish grade,
and sloped at a minimum 1 % grade to a suitable gravity outlet. Free-draining granular
material used in the drain system should consist of minus 2 inch aggregate with less
than 50% passing the No. 4 sieve and less than 2 % passing the No. 200 sieve. The
drain gravel should be at least 11h feet deep. Void form below the foundation can act
as a conduit for water flow. An impervious liner such as 20 mil PVC may be placed
below the drain gravel in a trough shape and attached to the foundation wall with mastic
to keep drain water from flowing beneath the wall and to other areas of the building.
SITE GRADING
The risk of construction-induced slope instability at the site appears low
provided cut and fill depths are limited. We assume the cut depth for the basement
level will not exceed one level, up to about 10 feet. Fills should be limited to about 8 to
10 feet deep. Embankment fills should be compacted to at least 95% of the maximum
standard Proctor density near optimum moisture content. Prior to fill placement, the
subgrade should be carefully prepared by removing all vegetation and topsoil and
H-PGEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
' ''
- 9 -
compacting to 95 % standard Proctor density. The fill should be benched into the
portions of the hillside exceeding 20% grade.
Permanent umetained cut and fill slopes should be graded at 2 horizontal to
1 vertical or flatter and protected against erosion by revegetation or other means. The
risk of slope instability will be increased if seepage is encountered in cuts and flatter
slopes may be necessary. If seepage is encountered in permanent cuts, an investigation
should be conducted to determine if the seepage will adversely affect the cut stability.
This office should review site grading plans for the project prior to construction.
SURFACE DRAINAGE
The following drainage precautions should be observed during construction and
maintained at all times after the residence has been completed:
1) Excessive wetting or drying of the foundation excavations and underslab
areas should be avoided during construction. Drying could increase the
expansion potential of the soils.
2) Exterior backfill should be adjusted to near optimum moisture and
compacted to at least 95% of the maximum standard Proctor density in
pavement areas and to at least 90% of the maximum standard Proctor
density in landscape areas. Free-draining wall backfill should be capped
with about 2 to 3 feet of the on-site fine-grained soils to reduce surface
water infiltration.
3) The ground surface surrounding the exterior of the building should be
sloped to drain away from the foundation in all directions. We
recommend a minimum slope of 12 inches in the first 10 feet in unpaved
areas and a minimum slope of 3 inches in the first 10 feet in paved areas.
A swale or berm may need to be constructed uphill of the residence to re-
direct any flows produced by the existing culvert around the proposed
structure.
4) Roof downspouts and drains should discharge well beyond the limits of
all backfill.
H-PGEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
\~
' ' '
-10-
5) Landscaping which requires regular heavy irrigation should be located at
least 10 feet from foundation walls. Consideration should be given to
use of xeriscape to reduce the potential for wetting of soils below the
foundation caused by irrigation.
PERCOLATION TESTING
Percolation tests were conducted on June 5, 2001 to evaluate the feasibility of an
infiltration septic disposal system at the site. One profile boring and three percolation
holes were drilled at locations as shown on Fig. I. The test holes were drilled with 6
inch diameter auger and were soaked with water one day prior to testing. The soils
encountered in the percolation holes are similar to those encountered in the Profile
Boring shown on Fig. 2 and consist of very stiff to hard, slightly sandy clay.
Percolation test results indicate an infiltration rate between 30 and 60 minutes per inch
with an average rate of 50 minutes per inch. The percolation test results are presented in
Table II. Based on the subsurface conditions encountered and the percolation test
results, the tested area should be suitable for a conventional infiltration septic disposal
system.
LIMITATIONS
This study has been conducted in accordance with generally accepted
geotechnical engineering principles and practices in this area at this time. We make no
warranty either expressed or implied. The conclusions and recommendations submitted
in this report are based upon the data obtained from the exploratory borings drilled at
the locations indicated on Fig. 1, the assumed type of construction and our experience
in the area. Our findings include interpolation and extrapolation of the subsurface
conditions identified at the exploratory borings and variations in the subsurface
conditions may not become evident until excavation is performed. If conditions
encountered during construction appear to be different from those described in this
report, we should be notified at once so re-evaluation of the recommendations may be
made.
H-PGEOTECH
I
I
19
I
I
I
I
I
I
t-e
I
I
I
I
I
I
I ... I
I
' ' '
-11 -
This report has been prepared for the exclusive use by our client for design
purposes. We are not responsible for technical interpretations by others of our
information. As the project evolves, we should provide continued consultation and field
services during construction to review and monitor the implementation of our
recommendations, and to verify that the recommendations have been appropriately
interpreted. Significant design changes may require additional analysis or modifications
of the recommendations presented herein. We recommend on-site observation of
excavations and foundation bearing strata and testing of structural fill by a
representative of the geotechnical engineer.
Sincerely,
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
Trevor L. Knell
Reviewed by:
REFERENCE
Kirkham, R.M. and Others, 1995. Geologic Map of the Cattle Creek Quadrangle,
Galfield County, Colorado. Colorado Geological Survey Open File Map 95-2.
Kirkham, R.M. and Rogers, W.P., 1981. Eanhquake Potential in Colorado -A
Preliminary Evaluation. Colorado Geological Survey Bulletin 43 .
H-PGEOTECH
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I 101 400
I
APPROXIMAlE SCALE ,. = 100'
, ' .
I
I I I
I -.t..__ I
I I I
I I I
I I I ---UTIU1Y
I I I ASEMENT
/
6300
1---4-I I I
t I I--t--_I
\ I
\ I
f
/
/
I I I l
I \ I \
I BORING 1 \ \
PROPokEO •tv ~2
\ \ RESIDE~fE ~ ~ P-3\\
BMING 2 P-1 \PROFlt.2
\ \ \BORING\
I
I
I
I
I I \ \
EXJSTING,l I I \
Yt£LL 'f' I TRACT I 11B \
J I I I
I I I I
I I I I
I I J I
I I I I
EXISTING / / I I
I RESIDENCE; I I I
I I I I I
I I I I I
I I I I
I I I I I
/ I I
\
\
I
\
/--I I 1--I
6290 ~ 62;0 62,0 6250
6280
\
\
I
I
\ \
I \
\
I
I
I
I
I
I
HEPWORTH-PAWLAK
GEOTECHNICAL, INC.
LOCATION OF EXPLORATORY BORINGS
AND PERCOLATION TEST HOLES Fig. 1
1--~~~~~~~--~--
' . '
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
6285
6280
6275
6270
6265
6260
101 400
BORING 1
ELEV.= 6284'
12/12
W0-11.0
i----<D0-105
-Z00-83 u.-38
Pl-11
18/12
-13.9
00-120
-200-91
23/12
50/J
BORING 2
ELEV.= 6280'
17/12
W0-15.0
00-115
43/12
9/12
50/8
PROFILE BORING
ELEV.-6274'
15/12
42/12
37/12
Note: Explanation of symbols Is shown on fig. 3.
HEPWORTH-PAWLAK
GEOTECHNICAL, INC. LOGS OF EXPLORATORY BORINGS
6286
6280
6275
6270
6265
6260
Fig. 2
1 ..--.-~~~~~~~~~~~~~~~---
L.EGEND:
I
I
I
I
I
• • •
TOPSOIL; slightly sandy clay, slightly organic, loose, sllghtly moist, brawn.
CLAY (CL); sllghtly sandy, stiff ta hard, slightly moist to moist, brown to red-brown, slightly
calcareous.
WEA 1HERED CLA YSTONE/SIL TSTONE; hard to wry hard, sllghtly moist, red-brown. Maroon F ormatlon.
Relatlwly undisturbed driw sample; 2-fnch 1.0. Callfornla llner sample.
I Drfw sample blow count; Indicates that 39 blows of a 140 pound hammer falling 30 Inches were
39/12 required ta drive the Callfarnla sampler 12 fnchss.
I
I
NOTES:
1. Exploratory borings were drUled on June 4, 2001 with a 4-fnch diameter continuous flight power auger.
2. Locations of exploratory borings were measured approximately by pacing from features shown on the site
plan provided.
I AE1evatlon11 of exploratory borings were measured by Interpolation between contour lines on the site plan
'W'provlded and checked by level surwy.
I
I
I
I
I
I
I
I
I
4. The exploratory boring locations and elevations should be considered accurate only to the degree Implied
by the method used.
5. The llnes between materlals shown on the exploratory boring logs represent the approximate boundaries
between materlal t)'l>e& and transitions may be gradual.
6. No free water woe encountered In the borings at th• time of drRllng.
Fluctuatlon In water level may occur with time.
7. Laboratory Testing Results:
WC = Water Content ( ill: )
OD -Dry Density ( pcf )
-200 -Percent pa•lng Na. 200 alew.
LL = Liquid Limit ( X )
Pl -Plasticity Index ( ill: )
101 400 HEPWORTH-PAWLAK
GEOTECHNICAL, INC.
LEGEND AND NOTES Fig. 3
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
. .
•
M
c:
~ c: a ...
i:l
I
c ~ .. e ...
E
8
•
M
a
Ii c: a ... >< w
l
c
0
Ii .. e ...
E
0 u
..
101
.
3
2
1
0
1
2
3
0.1
0
1
2
3
4
0.1
400
' , .
I
Moisture Content = 13.9 percent
Dry Density = 120 pcf
Sample of: Sllghtly Sandy Clay
From: Boring 1 at 10 Feet
........,
"" ~
Expansion " ' upon
wetting '
~ "'~ '\
\
1.0 10 100
APPLIED PRESSURE -kaf
Moisture Content = 17.4 percent
Dry Density -115 pcf
Sample of: Slightly Sandy Cloy
From: Boring 1 at 15 Feet
~ -,--........ ....._
\ .........
I'-. )
Expansion
upon
wetting
1.0 10 100
APPLIED PRESSURE -ksf
HEPWORTH-PAWLAK SWELL CONSOLIDATION TEST RESULTS fig. 4
GEOTECHNICAL, INC.
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
l\
.
•
M
c
~ c a c.
i!I
I
c a .. : .. c.
~
0
• 101
.
1
0
1
2
3
4
5
0.1
400
. • •• '
Moisture Content -15.0 percent
Dry Density = 115 pcf
Sample of: Slightly Sandy Cloy
from: Boring 2 ot 5 feet
-
~ -......, ... ~-.........
' Expansion
upon
wetting
1.0 10 100
APPLIED PRESSURE -ksf
HEPWORTH-PAWLAK SWELL CONSOLIDATION TEST RESULTS Fig. 5
GEOTECHNICAL, INC.
-------------------• • HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE I JOB NO. 101 400
SUMMARY OF LABORATORY TEST RESULTS
SAMPLE LOCA110N NATURAL NATURAL GRADATION PERCENT ATTERBERG UMITS UNCONF1NED
BOlllNO DEPTH MOISTURE ORY GRAVEL SAND PASSING LIQUID PLASTIC COMPRESSIVE SOIL OR
lffftl CONTENT DENSITY , .. , , .. , NO. 200 LIMIT INDEX STRENGTH BEDROCK TYPE , .. , lootJ SIEVE , .. , , .. , IPSFI
1 5 11.0 105 g3 36 1g Slightly Sandy Clay
10 13,g 120 g1 Slightly Sandy Clay
15 17.4 115 Slightly Sandy Clay
2 5 15.0 115 Slightly Sandy Clay
..
~
~ .
I .
-
HEPWORTH-PAWLAK Gl!!CSliEt;HNICAL, INC.
1•
I
I
I
I
I
I
I
I
I
I
I -
I
I
I
I
~'
TABLE II
PERCOLATION TEST RESULTS JOB NO. 101 400
HOLE NO. HOLE DEPTH LENGTH OF WATER DEPTH WATER DEPTH DROP IN AVERAGE
(INCHES) INTERVAL AT START OF AT END OF WATER PERCOLATION
(MIN) INTERVAL INTERVAL LEVEL RATE
!INCHES) (INCHES) (INCHES) (MIN./INCH)
P-1 34 15 10 9 1
9 8 1
8 7 Y.. Y..
7 Y.. 7 Y..
7 6 Y.. Y..
6 Y.. 6 Y.. 30
P-2 39 15 12 11 % %
11 % 11 Y.. y.
11 Y.. 11 y. y.
11 % 11 %
11 10 % %
10% 10 Y.. % 60
p.3 39 15 10 9% %
9% 8% Y..
8% 8 %
8 7 v. %
7% 7% y.
7 Y.. 71' y. 60
Note: Percolation test holes were drilled with 6-inch diameter auger on June 4, 2001 ·
Percolation testing was conducted on June 5, 2001. The average percolation rates were
based on the last two readings of each test.