HomeMy WebLinkAboutCorrespondencegLrnF-ol-z/- þ84/CorresTon/uØ
6eoþ¿4 thv¿s*Colleen W¡Éh
From:
Sent:
To:
Cc:
Subject:
Attachments:
bruceh@sopris.net
Tuesday, June 1,2021 8:15 AM
Colleen Wifth
'Megan Cerise'
[External] RE: BLMF-OS-21-6841 - Cerise Minor, Lot 2 - permit under review
21-7-138.2 (02-16-21) Lot 2 Subsoil STudy.pdf; 21'7-138.3 (02-15-21) Lot 3 Subsoil
Study si g ne d.pdf; 21 -7 -1 38J (02-17 -21) Septi c Su bsoi I STu dy si g ned.pdf
*ba refarÊ
rece/',re/
Colleen-
Here is the geotechnical investigation report I got from them. Let me know if you need anything else.
Bruce
From : Col I een Wi rth <cwi rth @ ga rf iel d-cou nty. com >
Sent: Friday, May 28,20213:30 PM
To: megancerise@gmail.com; bruceh@sopris.net; mneídlinger@skylinehomes.com
Subject: BLMF-05-21-684L - Cerise Minor, Lot 2 - permit under review
This afternoon, I finished the building structure and zoning compliance review for the manufactured dwellíng, garcge
and foundation at Cerise Minor Subdivision, Lot 2, and have two remaining comments:
L. As the building application form check box for DRIVEWAY PERMIT is blank, I ask the owner or owner's
representative to contact Garfield County Road & Bridge Dept at phone (970) 625-8601- to obtain a driveway
permit (other otherwise have them confirm your dríveway is exempted from a permit).
2. Under the zoning compliance review for this lot location, there is a subdivision recorded plat note #10: stating:
"A site specific geotechnical investigation shall be complete d prior to the issuonce of a building permit. Etc" .
Do you have a copy of a geotechnical investigation report for the site? lf so, can you or the geotechnical
engineer email an electron¡c copy to me at cwirth@garfield-countv.com ?
This completes my questíons, I look forward to hearing back from you. Garfield County Community Development office
is closed on Monday, May 3L. We reopen to general public at 8:00 am Tuesday, June 1.
Have a lovely holiday weekend!
Colleen Wirth
Plans Examiner
Garfield County Building Division
L08 8th Street, Suite 401
Glenwood Springs, CO 8L601
cwirth@earfi d-countv.com
1
office (970) 945-L377 ext. L610
rcrt Kumar & Assoclates, lnc.^
Geotechnical and Materials Engineers
and Environmental Scientists
An Employcc Owncd Compony
5020 CounÇ Road 154
Glenwood Springs, CO 81601
phone: (970) 945-"7988
fax: (970) 945-8454
email: kaglanwood@<umarusa,com
www.kurnarusa.com
Offrce Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Sunlnit Coun!, Colorado
February T6,2021
Trish Cerise
16724 Highway 82
Carbondale, Colorado 81623
trishcerise@ gmail. com
Project No. 21-7-138.2
Subject:
Dear Trish:
As requested, Kumar & Associates, Inc. performed a subsoil study for foundation design at the
subject site. The study was conducted in accordance with our agreement for geotechnical
engineering services to you dated January 18,202I. The data obtained and our
recommendations based on the proposed construction and subsurface conditions encountered are
presented in this report. Evaluation of potential geologic hazard impacts on the site is beyond
the scope of this study.
Proposed Construction: The proposed residence will be located in the area of Pit 2 on the site
as shown on Figure 1. Ground floors are proposed to be structural over a crawlspace or slab-on-
grade. Cut depths are expected to range between about 2 to 4 feet. Foundation loadings for this
type of construction are assumed to be relatively light and typical of the proposed type of
construction.
If building conditions or foundation loadings are significantly different from those described
above, we should be notified to re-evaluate the recommendations presented in this report.
Site Conditions: The lot is relatively flat with a slight slope dovvn to the south. Vegetation
consists of grass and weeds. There was about 2 to 3 inches of snow on the site at the time of our
site visit on January 20,2021.
Subsur{ace Conditions: The subsurface conditions at the site were evaluated by excavating an
exploratory pit in the building area atthe approximate location shown on Figure 1. The log of
the pit is presented on Figure 2. The subsoils encountered, below about 1 foot of topsoil, consist
of I foot of medium stiff, sandy silty clay overlying relatively dense, slightly silty sandy gravel
with cobbles and small boulders dor¡¿n to the excavated depth of 7Vz feet. No free water was
observed in the pit at the time of excavation and the soils were moist.
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f,'oundation Recommendatlons: Considering the subsoil conditions encountered in the
exploratorypitarrdthenatureoftheproposedconstruction,*e'@
placed on the undisturbed nafnr^l ooil desisned for an allowable soil bearing pressure of 2,000
psf for support of the proposed residence. The clay soils tend to compress under loading and
there could be some post-construction foundation settlement. Footings bearing on the gravel
soils should have a low settlement potential. Footings should be a minimum width of 18 inches
for continuous walls and 2 feet for columns. Loose and disturbed soils encountered at the
foundation bearing level within the excavation should be removed and the footing bearing level
extended down to the undisturbed natural soils. We should observe the completed foundation
excav4tio¡_.1þ confirm suitable bearing conditions. Exterior footings should be provided wittr-
adequate cover above their bearing elevations for frost protection. Placement of footings at least
36 inches below the exterior grade is typically used in this a¡ea. Continuous foundation walls
should be reinforced top and bottom to span local anomalies such as by assurrúng an ursupported
length of at least 12 feet. Foundation walls acting as retaining structures should be designed to
resist a lateral earth pressure based on an equivalent fluid unit weight of at least 50 pcf for the
on-site soil as backfill, excluding organics and rock larger than
6 inches.
Floor Slabs: The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded
slab-on-grade construction. To reduce the effects of some differential movement, floor slabs
should be separated from all bearing walls and columns with expansion joints which allow
unrestrained vertical movement. Floor slab control joints should be used to reduce damage due
to shrinkage cracking. The requirements for joint spacing and slab reinforcement 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 beneath basement level slabs to facilitate drainage.
This material should consist of minus 2-inch aggregate with less than 50%o passing the No. 4
sieve and less than 2Yopassingthe No. 200 sieve.
All fill materials for support of floor slabs should be compacted to at least95Yo of maximum
standard Proctor density at a moisture content near optimum. Required fill can consist of the on-
site soils devoid of vegetation, topsoil and oversized rock.
Underdrain System: Although free water was not encountered during our exploration, it has
heen or¡r experience in the area that local perched grounclwater can develop cluring times of
heavy precipitation or seasonal runoff. Frozen ground during spring runoffcan create aperched
condition. We recommend below-grade construction, such as retaining walls, deep crawlspace
and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain
Kumar & Associates, lnc. o Project No. 21-7-138.2
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system. Shallow crawlspaces (less than 4 feet) and slab-on-grade floors near exterior grade
should not need an underdrain.
If installed, the drains should consist of drainpipe placed in the bottom of the wall backfill
surrounded above the invert level with free-draining granular material. The drain should be
placed at each level of excavation and at least I foot below lowest adjacent finish grade and
sloped at a minimumlYoto a suitable gravity outlet or sump and pump. Free-draining granular
material used in the underdrain system should contain less than 2%opassingthe No. 200 sieve,
less than 50% passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel
backfill should be at least l%feet deep.
Surface Drainage: The following drainage precautions should be observed during construction
and maintained at all times after the residence has been completed:
l) Inundation ofthe foundation excavations and underslab areas shouldbe avoided
during construction.
2) Exterior backfill should be adjusted to near optimum moisture and compacted to
at least 95% of the maximum standard Proctor density in pavement and slab areas
and to at least 90Yo of the maximum standard Proctor density in landscape areas.
Free-draining wall backfïll should be capped with about 2 feet of the on-site, finer
graded 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 6 inches in the first 10 feet in unpaved areas and a minimum slope of 3
inches in the first l0 feet in pavement and walkway areas.
4\ Roof dor¡¡nspouts and drains should discharge well beyond the limits of all
backfill.
Limitations: This study has been conducted in accordance with generally accepted geotechnical
engineering principles and practices in this area at this time. rile make no warranty either
express or implied. The conclusions and recommendations submitted in this report are based
upon the data obtained from the exploratory pit excavated at the location indicated on Figure l,
the proposed type of construction and our experience in the area. Our services do not include
determining the presence, prevention or possibility of mold or other biological contaminants
(MOBC) developing in the future. If the client is concemed about MOBC, then a professional in
this special field of practice should be consulted. Our findings include interpolation and
extrapolation of the subsurface conditions identified at the exploratory pit and variations in the
subsurface conditions may not become evident until excavation is performed. If conditions
Kumar & Associates, lnc. o Project No. 2'l -7 -138.2
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this special field of practioe should be consultcd. Our findings include interpolation and
extrapolation of the subsurface conclitions identified at the exploratorypit and variations in the
subsurface conditions may not become evident until excavation is performed. If conditions
encountered during construction appear diffrrent from those described in this report, we should
be notified at once so re-evaluation of the recommendations may be made.
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 implementatjon of our recommendations, and to verify that the recommendations
have been appropriately interpreted. Signifìcant design changes may require additional analysis
or modifications to the recommendations presented herein, 'We rccommend on-site observation
of excavations and foundation bearing strata and testing of structural filI by a representative of
the geotechnical engineer.
If you have any questions or if we may be of further assistance, please let us know.
Respectfu lly Submitted,
Kumar & Ässociates,
Daniel E. Hardin,
Rev. by: SLP
DEH/kac
attachments Figure I - Loc.ation of Exploratory Pit
Figure 2 -I"ogof Exploratory Pit
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Kumar & Associates, lnc, {i Project No. 21-7.138.2
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APPROXIMATE SCALE-FEET
LOT 3
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LAT 2 O
PIT
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LOT 1
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21-7-138,2 Kumar & Associates LOCATION OF EXPLORATORY PIT Fig. 1
I
PIT 2
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t0 10
LEGEND
TOPS0IL; SLIGHTLY SANDY CLAY, R00TS AND ORGANICS, MEDIUM STtFF, MO|ST, DARK
BROWN.
CLAY (CL); SANDY, WITH SCATTERED ROUNDED COBBLES, MEDIUM STIFF TO STIFF, MOIST,
BROWN AND DARK BROWN.
GRAVEL (OV); SAUOY, SILTY, WITH COBBLES AND SMALL BOULDERS, DENSE, MOIST, GRAY
AND BROWN. ROCKS ROUNDED IN SHAPE.
NOTES
1. THE EXPLORATORY PIT WAS EXCAVATED WITH A BACKHOE ON JANUARY 20, 2021.
2, THE LOCATION OF THE EXPLORATORY PIT WAS MEASURED APPROXIMATELY BY PACING FROM
FEATURES SHOWN ON THE SITE PLAN PROVIDED.
3. THE ELEVATION OF THE EXPLORATORY PIT WAS NOT MEASURED AND THE LOG OF THE
EXPLORATORY PIT IS PLOTTED TO DEPTH.
4, THE EXPLORATORY PIT LOCATION SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE
IMPLIED BY THE METHOD USED.
5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY PIT LOG REPRESENT THE
APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.
6. GROUNDWATER WAS NOT ENCOUNTERED IN THE PIT AT THE TIME OF EXCAVATION. PIT WAS
BACKFILLED SUBSEQUENT TO SAMPLING.
21-7-138.2 Kumar & Associates LOG OF EXPLORATORY PIT Fig. 2