Performance of Railway Bridges during the 2011 Tohoku Earthquake

Damage and performance of railway bridge structures during the 2011 Thoku Earthquake are reported. Although the scale of the earthquake was historically the largest known, seismic damage to structures was smaller and less time was required for recovery of service compared with an earlier major earthquake. Upgrading of seismic code and planned seismic retrofits performed after the 1995 Kobe Earthquake were found effective for reducing seismic damage to bridges and civil structures; damage to bridge superstructure, with complex geometry and damage to secondary structural systems such as electric-power poles, now became the prominent type. Enormous structural damage observed for areas affected by severe tsunami forces (which had offered great challenge to structural engineering) is also reported. Following this, bridge performance (under the force of the 2011 Thoku earthquake and subsequent tsunami) is studied using data recorded by monitoring systems installed on bridges that were located in strong motion areas. Based on this experience, advantages of and challenges to the structural health monitoring system are also discussed.