Seismic Design of Bridges 1

[Jackcsh]

According to AASHTO 3.10.9.2 and 4.7.4.3 it seems that if a bridge is in seismic zone 1, no seismic analysis is required except for a connection load at the bearings and a minimum bearing length requirement. Does this mean that the piers and abutments do not have to be checked for any seismic loads? Some coworkers say you still have to check foundations for 0.25*permenent load.

 

[msquared48]

25% of the dead load seems high, even for a higher seismic region.

That being said, with the preponderence for change in the seismic codes of the IBC and AASHTO, It would not be a bad idea considering the life span of the bridge.

I would ask them for a specific code reference under AASHTO.

Mike McCann
MMC Engineering

 

[bridgebuster]

You only need to check the superstructure to substructure connection.