Abutment inertia seismic force

[TobyT]

Have a single span bridge with a cantilever type abutment about 30' height.

I used the Mononobe Okobe method to get the Seismic active earth pressure coefficient on the cantilever type abutment. How do I incorporate the inertial force of the abutment concrete as an overturning moment in a seismic event? Is this necessary? Thanks.

 

[Qshake]

First, check AASHTO I'm not sure that is necessary for single span bridge.

Beyond that you need to use F(lateral) = W(a) and so for every part of the abutment you need to calculate a lateral force and then determine the resultant of all parts along with the distance of the resultant force from the point of the stability check.

Regards,
Qshake

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[TobyT]

thanks for the info.

 

[yakpol]

WSDOT BDM recommends to use inertia force equal to horizontal acceleration coefficient times abutment weight (including footing). This force is used for stability and sliding analysis only, not for rebar design.

As good as anything...