Retaing wall under seismic load

[struengineer]

I need to design a concrete retaining wall. In the design, the seismic load has to be considered. I did design a dam which considered seismic load from water behind but I have never designed such a retaining wall which seismic load from earth behind need to be considered. I use similar idea to try. It seems that I need a huge section of retaining wall because of the seismic load. I wonder if any one here who has similar experience can give me some idea as to how to design this retaining wall or tell me any book or example which I can read. Thanks!

 

[Qshake]

The best examples for including seismic induced forces in retaining wall design are found in

Principles of Foudation Engineering by Das and
Soil Dynamics by Prakash

All you really need to do is to determine the active earthquake pressure using the Monoabe-Okabe method or similar and also include the mass of the wall in your lateral forces. The mass of the wall is multiplied by the necessary accerlation coefficient. The final difference is the active earthquake force acts at 1/2H and not 1/3 as with traditional soil loads.

The above is for overturning and sliding analysis. It does not consider that there is a ground failure due to liquefaction.

I hope this helps.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[struengineer]

Thanks for help.

The safty factor should remain the same as 1.5 for sliding and 2 for overturning?

 

[sdz]

As I understand it safety factor is used for working strength design and the return period of the earthquake would be ~50 years. Earthquake loads in codes are commonly given for return periods of ~500 years which is for ultimate limit state design. Make sure you don't get them mixed up.