Abstract
The 2011 earthquake of the Pacific coast of Tohoku occurred on March 11th. Several natural rubber bear-ings of the viaduct in Tohoku district were fractured due to this earthquake. This type of damage was the first experienced in Japan. In this research, a three span continuous plate girder bridge with reinforced concrete piers was selected as a structure for examination. Natural rubber bearings were set up on the top of each pier. A fracture model of the natural rubber bearing was proposed in this research. Dynamic response analysis of the highway bridge considering the hardening and the fracture of the natural rubber bearing was conducted using T-DAP III. The observed record of the nearest point to the damaged highway bridge in Sendai was se-lected as seismic input motion. From the results of the dynamic analysis of the highway bridge, an increase of relative displacement in the natural rubber bearing, depending on the fractured bearing was confirmed in longitudinal direction. The possibility of a fracture progress of the natural rubber bearings was verified. And transversal direction, the rotational motion of the girder occurred after the fracture of natural rubber bear-ings. From these results, the response of the highway bridge considering hardening and fracture of natural rubber bearing was made clear.
