×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

ASCE 7-16 Seismic Earth Pressure on Basement Walls

ASCE 7-16 Seismic Earth Pressure on Basement Walls

ASCE 7-16 Seismic Earth Pressure on Basement Walls

(OP)
How is everybody handling questions on Seismic pressures against basement walls? Typically, soil pressure against a basement wall is considered "at rest" loading. The only reference I've heard of on this topic is from 2010 Seismic Earth Pressures on Deep Building Basements by Lew, M., Sitar, N., Al-Atik, L., Pourzanjani, M. and Hudson, M.B.

Time has passed, and codes are updated. Now we are getting requests from structural engineers to quantify the lateral pressure on basement walls during a seismic event. From Lew, et al. 2010, we have the notion that basement walls are to be designed for the at rest conditions, with no increase for seismic loading, due to the lack of documented earthquake damage to basement walls.

Given the circular path ASCE 7-16 and IBC 2018 take us on, I would like some guidance on how to better understand this topic and be able to respond to client requests.

Thanks in advance

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

I will suggest you to look CH .19 SOIL–STRUCTURE INTERACTION FOR SEISMIC DESIGN.

and the document at https://www.nehrp.gov/pdf/nistgcr12-917-21.pdf

The Geotech people shall furnish the dynamic horizontal passive springs and vertical springs..

The dynamic soil loading, the passive resistance of the soil may cause additional loads on basement sidewalls.

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

(OP)
HTURKAK,

Thanks for the info. That document was published in September 2012. Is this the basis for the updates in IBC and ASCE 7? Or, are they going down a different path completely with their updates?

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

Good question. Yes, in the last decade there has been a lot of published papers on seismic loading on walls of all types. And yet there is no broad industry-accepted code guidance.

"... due to the lack of documented earthquake damage to basement walls."
I know all these PhDs are real smart, but that was not a smart statement. Absence of evidence is not evidence of absence.
A 10ft tall basement wall in Southern California and a 10 tall basement wall in Texas should not both be designed ignoring seismic loads.

As a minimum, as a baseline I suggest seismic loads per AASHTO LRFD Bridge Design Spec (2017) suggests for walls and abutments greater than 8 ft tall.
I am not suggesting that AASHTO is the answer; some of that code language gives me heartburn. But it is a national committee-governed document that has relatively broad acceptance. And has incorporated some of the UCB / UCLA / Caltrans sponsored research.

Also note that Caltrans puts an upper limit cap on seismic lateral earth forces (amends AASHTO so it doesn't become ridiculous).

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

If you perform a google search for 'Nathaniel Wagner lateral earth pressure' you will get some more recent research data.
Nathanial Wagner of Slate Geotechnical Engineers, is a recent post-grad & recently licensed Geotech; who has been working on the Millennium Tower Perimeter Pile Upgrade.
What I don't understand (complete ignorance) is why the lateral earth pressure is applied to the basement/foundation wall area and not the shoring wall immediately abutting the basement/foundation wall.

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

(OP)
ATSE and epoxybot, great comments! I'll be studying Dr. Wagner's research in the coming weeks.

I guess I've not seen many basement walls with an additional shoring wall adjacent to them. I would think the lateral earth pressure should be applied to whatever structure in contact with the backfill, no matter what the arrangement.

RE: ASCE 7-16 Seismic Earth Pressure on Basement Walls

In the past I've used Wood's elastic method for seismic earth pressures on non-yielding walls, such as concrete tanks or shafts. My reference for that method is ASCE 4-98. Might be outdated now...

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close