Bridge Design for High Seismicity

[strucsteel]

How are bridges in high seismic zones of the US (west coast) different from those found anywhere else in the lower 48?

Do they use different technologies (high damping elastomeric bearings, lead-rubber bearings, supplemental dampers, etc.), or are the differences really just in

[1] design methodologies (displacement-based nonlinear static or dynamic vs. force-based linear elastic) and

[2] detailing (being careful to terminate rebar with appropriate lengths, and outside plastic hinge zones, etc.)?

If other technologies are used, I'm especially curious about what exactly is used.

Sorry about the run-on length, and thanks in advance to respondents.

 

[bridgebuster]

You should look at AASHTO, Division 1A of the Standard Specifications - Section 4 or LRFD Section 4. Both define the analysis requirements based on the Seismic Performance Category.

The west coast is generally SPC C & D which means Single Mode Spectral or Multi-Mode Spectral Analysis.

A bridge in SPC A has minimal analysis requirements.

The current philosophy is a displacement based design. The structure should yield but not collapse.

As far as bearings and detailing AASHTO provides guidance but the agency having jurisdiction over the bridge will have certain standards and policies.