SEISMIC RETROFIT TECHNOLOGY. IN: BRIDGE ENGINEERING: SEISMIC DESIGN

The seismic resistant retrofit design of bridges has been evolving dramatically in the last decade. Many of the retrofit concepts and details discussed in this paper have emerged as a result of research efforts and evaluation of bridge behavior in past earthquakes. This practice has been successfully tested in relatively moderate earthquakes but has not yet seen the severe test of a large-magnitude earthquake. The basic philosophy of current seismic retrofit technology in the U.S. is to prevent collapse by providing sufficient seat for displacement to take place or by allowing ductility in the supporting members. This paper's aim is to identify potential vulnerabilities to bridge components and to suggest practical retrofit solutions.