Seismic design of steel bridges

In the aftermath of the 1995 Hyogo-ken Nanbu earthquake and the extensive damage it imparted to steel bridges in the Kobe area, it is now generally recognized that steel bridges can be seismically vulnerable, particularly when they are supported on nonductile substructures of reinforced concrete, masonry, or even steel. In the last case, unfortunately, code requirements and guidelines on seismic design of ductile bridge steel substructures are few [12,21], and none have yet been implemented in the United States. This chapter focuses on a presentation of concepts and detailing requirements that can help ensure a desirable ductile behavior for steel substructures. Other bridge vulnerabilities common to all types of bridges, such as bearing failure, span collapses due to insufficient seat width or absence of seismic restrainers, soil liquefactions, etc., are not addressed in this chapter.