HomeMy WebLinkAboutFile Documents.931 Gibson Ave.0037-2019-BRES (4) 06,5 .87ABIILIZA .Se
ROCK SOLID
SOLUTIONS
DESIGN•BUILO
October 31, 2019
To: City of Aspen
Project: 931 Gibson Temp Shoring Plans
RE: Response to October 22, 2019 Comments
ENGINEERING REVIEW COMMENTS AND CORRECTIONS
Excavation Stabilization Requirement
1. Plans must be stamped and signed by a Colorado Profession Engineer.
Plans have been stamped.
2. Provide substantiation for all soil parameters. Also note, the coefficient of friction does
not appear to reflect the recommended value in the soil report, which states, "Resistance
to sliding at the bottoms of the footings can be calculated based on a coefficient of
friction of 0.45."
An estimate of the on-site soil properties was made by two Rock Solid Professional
Engineers with specialties in Geotechnical Engineering and extensive experience in the
area. The most critical soil property in the design of a temporary soil nail wall is the
allowable bond stress, Qa. The 15 psi value used in the analysis for this project is a
conservative value for the sands, gravels, and cobbles that exist at the site.
The friction angle of the soil, ck, is a different parameter than a coefficient of friction, µ,
between soil and concrete.
3. How will excavation occur for the 20' deep drywell in this corner of the property? Please
clarify.
Drywell location (per sheet C301) and shoring has been added to plan set dated
10/23/19.
195 Lodgepole Circle,Parachute, CO 81635 RECEIVED
Office: (970) 903-3028 Fax: (970) 712-5715
01/22/2020
ASPEN
BUILDING DEPARTMENT
4. Please depict location and depth of utilities located within vicinity proposed system.
Utility locations have been added to plan set dated 10/23/19. The water line will be
below the soil nail wall or sleeved through the shotcrete facing.
5. Please verify with geotechnical engineer that 1:1 slope is achievable.
An estimate of the on-site soils was made by two Rock Solid Professional Engineers with
specialties in Geotechnical Engineering. A sloped configuration in accordance with
OSHA Regulations 29CFR 1926 Subpart P Appendix B was selected for stability of the
soil on site. The on-site soil is estimated to be classified as Type B soil as defined in 1926
Subpart P Appendix A. A 1:1 slope is allowed for Type B soils. If the soils on site are
not cohesive enough to allow this configuration, the Rock Solid Professional Engineer on
site will direct the excavation and stabilization team to modify the slope stabilization
area. The Rock Solid engineers are comfortable with this situation and will be on site to
monitor slope stability.
6. Wall location appears to be within drip-lines of existing trees. Please obtain approval
from Parks Department to locate wall here or adjust design.
Trees to be removed,per plan sheet L2.00, are shown in red on the plan set dated
10/23/19. Shoring walls are outside the drip lines of all trees that will remain.
If you have any questions or concerns regarding this letter please contact us.
Respectfully,
71/4/614--
Stephanie M. Nocks, P.E. Donald J. Berger, P.E.
stephanienocks@rocksolidblasting.com dberger@rocksolidblasting.com
RECEIVED
ROCK SOLID /22/2020
SOLUTIONS
0F,IO,..O ASPEN
BUILDING DEPARTMENT