HomeMy WebLinkAboutObservation of Excavation 11.30.2021rcrfffi,'*"
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An Emdoyac Owtcd Conrpony
5020 Counry Road 154
Glenwood Springs, CO 81ó01
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglenwood@kumarusa.com
www.kumarusa,com
Office l-ocations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit Counry, Colorado
Nove,rnber 30,2020
JDB Constn¡ction
Attn: Jay Billington
179 River Vista Drive
Gle,lrwood Springs, Colorado I 1601
jdbcon@yahoo.com
Project No. 19-7-653.4
Subject: Observation of Excavation, Proposed Residence, Lot96,Ironbridge,284 River
Bend Wuy, Garfield County, Colorado
Gentlernen:
As requested, a representative of Kumar & Associates, lnc. observed the excavation at the
subject site on November 30,2020 to evaluate the soils exposed for foundation support. The
findings of our observations and recommendations for the foundation design are presented in this
rryort. We previously conducted a subsoil study for design of foundations at the site and
presented our findings in a report dated Novernber 11,2019, Project No. 19-7-653.
The proposed residence is essentially the same as described in our previous report. Spread
footings placed on the natural gravel and sized for an allowable bearing pressure of 3,000 psf
were reoommended for the foundation support.
At the time of our visit to the site, the foundation excavation had bee,n cut in 3 levels from 3 to
6Yzfætbelow the adjacent ground surface. The excavation was ste,pped down to the east with
drop in the ground surface grade and where a crawlspace is proposed below the main building
floor level. The soils exposed in the bottom of the excavation consisted of silty sandy gravel and
cobbles with scattered boulders. The northwest (garage) and northeast (crawlspace) areas were
dug to just below the upper silt soils and onto the natural gravel soils. No free water was
encountered in the excavation and the soils were slightly moist.
The gravel soil conditions exposed in the excavation are consistent with those previously
encountered on the site and suitable for support of spread footings designed for the
recoûrmended allowable bearing pressure of 3,000 psf. Loose disturbed soils in the footing areas
should be removed to expose the undisturbed natural soils. The bearing soils should be protected
from frost and concrete should not be placed on frozen soils. Other recommendations presented
in our previous report which are applicable should also be observed.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous subsurface exploration at the site. Variations
JDB Construction
November 30,2020
Page2
in the subsurface conditions below the excavation could increase the risk of foundation
movement. We should be advised of any variations encountered in the excavation conditions for
possible changes to recommendations contained in this letter. 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 concerned about MOBC, then a professional in
this special field of practice should be consulted.
Ifyou have any questions or need fr¡rther assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
Steven L. Pawlak, P.
SLP/kac
Kumar & Associates, lnc. ft Project No. l9-7.653.4