Methodologies for Evaluating the Importance of Highway Bridges

Keywords: Highway bridges. Bridge prioritization. Importance ratings. Retrofitting.

Abstract: The location of a structure with respect to seismic hazards, its seismic vulnerability and its importance are factors which are used in determining what seismic design or seismic retrofit level a structure belongs in. This research evaluated methods for determining the importance of a structure and how to use this importance in seismic design retrofitting specifications. This report develops a method for determining the importance of a bridge. The importance ranking of a bridge is then used in proposed revisions to seismic bridge design and retrofitting specifications. Depending on the relative importance bridge ranking, design or retrofitting requirements will be increased or decreased (e.g. the higher the importance ranking, the greater the seismic design or retrofitting requirements). This report also provides for existing importance methods to be used with the seismic design and retrofitting specifications.