HomeMy WebLinkAboutObservation of Excavationk �Pw
..�a hi P le 5020 County Road 154
Glenwood Springs. CO 81601
- - ---� -- --- �- phone. (070) 945-7988
fax: (970) 94"454
email: ka_aIenwood(Qkumarusa,.com
An &np1o�►1�0 Owned C0111pQf1y Mn6ku(narVsa-.coM
pia lam; Dwww (HQ�, Polux. CokmdD SON$, F01 CON", Glenwood Springs. and Summit County. Cobrado
JLl� 3., 2023
Chris Mow
4190 Count} Road 103
Carbondale, Colorado 816.1.3
.�rncrnnstruccioni21 3 cLi kmail.com
S ubj ec t: Observation of Excavation, P
Garfield County., Colorado
1hiA L
Project No. 234-158
roposed Shop/ADU, 4190 County Road 103,
Dear Chris:
As requested, a represent ve of Kumar & Associates observed the excavation at the subject site
on .Tune 21, 2023 to evaluate the soils exposed for foundation support. The findings of our
obsen°ations and recommendations for the foundation support are presented in this report. The
services were performe� as additional services to, and in accordance with, our agreement for
professional engineering services to you dated February 16, 2023. We previously provided a
subsoiI study for the shaplADU foundation design in a report dated April 18, 2023, Project No.
23a-7-1584.
The proposed shoplADU will he a fro -story woad frame structure with aslab-on-grade dower
Level. Foundations were desired for an allowable sail bearing pressure 1,500 psf
At the time of our visit to the site, the foundation excavation had been cut in two bevels from 2 to
3V,-o feet below the adjacent ground surface. The sails exposed in the bottom of the excavation
consisted of stiff, sandy clayey s'I#. No free water was encountered i�xa the excavation and the
soils were mist.
Considefing the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural soi J designed for an allowable
sail bearing pressure of 1,500 psf can be used for support of the proposed shoplADU. The
exposed soils tend to compress whin wetted and there could be some post -construction
settlement of the foundation if the bearing soils became wet. Footings should be a minimum
with of 18 inches for continuous walls and 2 feet for columns. Loose and disturbed soils in
footing areas should be removed and the bearing level extended down to the undisturbed natural
saiIs. Exterior footings should be provided with adequate soil rover above their bean"ng
elevations for frost protection. Continuous foundation walls should be reinforced tap and bottom
to span local anomalies such as by assuming an unsupported length of at least 12 feet. Structural
fill placid within floor slab areas can consist of the on -sits soils compacted to of least 95% of
standard Proctor density at a moisture content near optimum. Backfill. placed around the
structure should be compacted and the surface graded to prevent bonding within at least 14 feet
of the building.
Chris Morrow
July 3, ?023
Page 2
The recommendations submitted in this letter are bas e-d on our observation of the soils exposed
within the foundation excavation and the previous subsurface exploration. Our services do not
include dete ining the presence, prevention or passibility of mold or other biological
contaminants (MOBC) developing in the future. If the client is concerned about MOB(, then a
professional in this special field of iiractice should he consulted.
If you haNre any qu
Sincerely,
estions or- need further assistance, plea
Kumar & Associates, It 0_R�G��;�.
aniel E.
foe
s �
7
--i- "�
aZ7
ri P E. .4., ,
Rey01
. by. SLP
DEH/kac
Kumar& Assodates, Inc,'