QUESTION
Does anybody have references on how to determine the amount of displacement of a retaining wall due to seismic forces? I understand there are FEM techniques but this is for a preliminary study so I am just looking for something that can be done manually.
REPLIES
ATSE
Not well defined.
See NCHRP Report 611 for a semi-readable explanation. See Prof Bray (UCB) and Kramer (UW) for a slightly more high-powered approach.
For simplified analysis (done by almost everyone except PhDs), there is a tradeoff between the pseudo-acceleration used in the design lateral forces and the resulting permanent wall displacement (via Newmark charts / equations).
For design acceleration = 0.5A, where A is the peak ground acceleration (g), horiz wall displ = 10*A (inches). So for A = 0.5g, displ = 5". Seems a bit high to me, but that’s what the smart guys say.
I think AASHTO commentary says expect 2" to 4" displ if using reduced (0.5A) accelerations. Seems like a good rule of thumb in the absence of other recommendations.
Even less well defined and understood is the permanent wall tilt.
SOURCE
https://www.eng-tips.com/viewthread.cfm?qid=426705
Above is a snippet.