HomeMy WebLinkAboutAdddendum to Subsoils Report 11.24.2023lGrtnffififfiffifr'#'i'*"5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (9?0) 945-8454
enrail : kaglenrvood(g!)kumarusa.com
wwrv.k umarusa.comAn Employcc Ourad Compony
Oflice l,ocations: Denver (HQ). Parker. Colorado Springs, Fort Collins, Clenwood Springs, and Surnmit County, Colorado
Novernber 24,2023
Colorado Rocky Mountain School
Attn: Joe White
1493 County Road 106
Carbondale, Colorado 81623
iwhite@cnns.ors
Project No. 23-7-227
Subject: Addendurn to Subsoil Study for Foundation Design, Proposed Second'Story
Addition, CRMS Dining Facility, 1493 County Road 106, Carbondale, Colorado
Dear Joe:
As requested, Kumar & Associates, Inc. has reviewed the structural plans for the existing
building and is providing recommendations for increased bearing capacity in the area of the
existing column footing pads on the north, east, and south sides of the building. The current
study was conducted in supplemental to our agreement for geotechnical engineering services to
Colorado Rocky Mountain School dated March 29,2023. We previously performed a subsoil
study for foundation design for the proposed second story addition and presented the findings in
a report dated May 19, 2023.
We have reviewed the structural plans for the original building dated June26,1964by Moore &
Bush Architects, Project No. 10 62 22. The existing column footings are shown to be 2'x 2' and
bearing on the relatively dense natural granular soils about 3 feet below the adjacent ground
surface. We understand that the additional loading from the proposed second story addition will
approximately double the existing loading on the column footing pads.
Based on the subsurface materials encountered in the exploratory pit for the previous subsoil
study for foundation design, our review of the structural plans for the existing building, the
nature of the proposed construction, and our experience in the area, spread footings placed on the
undisturbed natural granular soil designed for an allowable soil bearing pressure of 4,500 psf can
be used for support of the proposed second story addition. The matrix material of the bearing
soils tends to compress under load and there could be some post-construction settlement on the
order of up to about % to %-inch of the foundation which should occur as the load is added.
Other recommendations presented in our previous report which are applicable should also be
observed.
The recommendations submitted in this letter are based on the previous limited subsurface
exploration at the site. Variations in the subsurface conditions below the building 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.
Kumar & Associates,
-2-
oemery@g4alc.com
bmalone@klaa,com
llh.rltt
Kumar & Assoclateg, lnc. o ProJec't Na. 23-7-221