I know this answer is late, but I now have a similar design situation and I
am pondering against my past experience, whether I should combine earth
pressure with seismic. UBC 97 Code sections 1612.2.2 & 1612.3.3 don't say
that H "should be" combined with seismic, what it says is, "where H is to be
considered" it should be added to the basic load combination. Now the
question is "where" do we consider H. I have always been taught to ignore
seismic forces acting on the portion of the building which lies underground
such as a basement. The reasoning is that the inertia forces of the
earthquake and the ground movement are in opposite direction. Therefore the
retaining wall either moves away from the retained earth or pushes against
it. At either case the load acting behind the wall becomes less severe than
the original earth pressure.
I would be interested to know if there are any hard rules about this
J. Karim Hosseinzadeh
JAMKAR ENGINEERING, INC. Tel. 949 250 0522
Newport Beach, California Fax 949 250 1527
----- Original Message -----
Sent: Wednesday, April 19, 2000 5:03 PM
Subject: Retaining Wall Loading
> Are seismic loads applied to a retaining wall in combination with the H
> UBC97 section 1612.2.2 & 1612.3.3 indicate that the H load should be
> with seismic. ASCE 7-95 does not give load combination that include E & H.
> Could anybody shed light on this? Thanks a lot!
> Rainier C. Catubig, S.E.
> San Diego, California