Ultimate Behaviors of Tie Plates Used as Bridge Restrainer

The prevention of the falling out of bridge girders during earthquakes has been recognized a critical factor in the seismic design of bridges. Among the various treatments and devices the bridge restrainer tie plate is an important structural element. It directly prevents the falling out by connecting a girder to another girder or a pier. In a normal service, the tie plate does not carry load; it works only when girders undergo extraordinary displacement. Despite its importance and functions, the current design method for tie plate restrainers does not seem to reflect the function very well. The objective of the present work is to investigate the mechanical properties of tie plates in a bridge restrainer and to determine their ultimate strength and deformation. We study their failure in detail both experimentally and analytically. Although the present study deals with static behaviors, the results give much essential information toward the design of tie plates based on their ultimate strength, energy absorption, and dynamic behaviors.