×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

At-Rest, At-Rest Sloping Backfill, and At-Rest Seismic

At-Rest, At-Rest Sloping Backfill, and At-Rest Seismic

At-Rest, At-Rest Sloping Backfill, and At-Rest Seismic

(OP)
For a recent design of a non-yielding (at-rest) wall.....

For At-Rest Earth Pressure (level).... Ko = 1 - sin(phi) ---- Jaky, 1944
For At-Rest Seismic Earth Pressure.... Koe = 2*kh (where kh = 1/2 PGA-M) ---- Wood (1973); Whitman (1991); Al Atik and Sitar (2010)
For At-Rest Earth Pressure (sloping).... Ko = (1 - sin(phi))/(1 + sin(beta)) ---- Kezdi 1972
For At-Rest Static and Seismic with sloping backfill... K and Koe = ~2*M-O (Mononobe-Okabe for active earth pressure) ---- Wood (1973); Whitman (1991); Al Atik and Sitar (2010)


This is my conclusion for at-rest pressures as the majority of studies is in regards to active pressures.


Also, Al Atik and Sitar have now re-inverted the triangle to 0.33+H above the base, back from the upside down triangle for seismic pressure resultant force.

And, they have concluded that if the static factor of safety is designed at 1.5 for active forces and the ground acceleration is < 0.4g, additional seismic design is not required.

RE: At-Rest, At-Rest Sloping Backfill, and At-Rest Seismic

Another more recent document that discusses at-rest pressures is EM 1110-2-2502.

RE: At-Rest, At-Rest Sloping Backfill, and At-Rest Seismic

(OP)
Thanks CWEngineer. As I found in my research it is difficult to find the At-Rest seismic portion (Koe not discussed in this paper). The Active is discussed in the paper and refers to the traditional Mononobe Okabe equation.

The static At-Rest earth pressure in this equation for total pressure does not seem correct as the equation is taking a linear distribution with depth (z) and not a triangular, trapezoidal, or rectangular (z^2). For instance, if you use the equation for similar cases and calculate Active pressure and At Rest pressure, with the equations presented, the At Rest result is much lower after inputting the equivalent fluid pressure (Section 3-10), and should be greater than Active.

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!


Resources