Abstract
The present paper describes the damage state and redundancy of steel piers sustaining highway bridges under specified design or unexpected earthquake strength, in which the redundancy is the index measuring the safety level introduced to clear their seismic performance. This is given by the ratio of the standard lateral seismic coefficient corresponding to the earthquake load coinciding with the horizontal capacity to that coded by the Japanese Specifications for Highway Bridges. The damage state and redundancy of steel bridge piers are determined by using their characteristics obtained by the elastic-plastic finite displacement analysis. This analysis is carried out by the general purpose finite element program MARC2012.10. As a result, it is defined what damage state a bridge pier would fall if the unexpected earthquake hits, by the equal-energy approach. The evaluation index is used, given by a combination of the horizontal capacity and horizontal displacement.
