SEISMIC FORCE DUE TO STEM SELF-WEIGHT??? CANTILEVERED RETAINING WALL

[keenkeem]

I'm doing a retaining wall and am using a software for such project. I came across with an option that tells me whether to neglect seismic force due to stem self weight or not. Checking this options amplifies the resulting force and is indeed helpful for someone that desires a more conservative design. I just would like to ask as to how it is calculated? I think its a function of mass of the stem and acceleration due to gravity. If perhaps you knew how, kindly leave your comments below thanks.

 

[AndreBC]

keenkeem :

For a simple static load method, usually the seismic force will be calculated as lateral load working at the center of mass gravity, let just call it H(eq).
H(eq) = W x a/g ;
with W = mass or self weight of the structure
a = maximum earthquake acceleration at ground surface (in g (gravity) unit such as 0.3 g, 0.4 g, etc)
g = gravity
But to use it you have to input the max earthquake acceleration first, which may vary depend on your site location area and
soil condition at the site (soft soil, medium soil, hard soil?). I don't know if your software has already include these factors ?
FYI, this method is really conservative, because it assume the seismic as a permanent load, not a temporary cyclic load.

 

[keenkeem]

very well said thx