Life-cycle design of bridges in seismic regions based on lessons from the 2011 great east Japan earthquake

Many bridges in Tohoku region of Japan were damaged and collapsed due to strong ground motions and/or liquefaction during the 2011 Great East Japan earthquake. Bridge superstructures were washed away due to the subsequent tsunami. In addition, bridges in the coastal area deteriorated further due to chloride induced corrosion. It is important to note that the seismic events can cause multiple disasters. The bridges located near the coastline in Japan need to be designed taking into consideration the risk associated with seismic and tsunami hazards, and continuous deterioration. This paper provides a key aspect of lifecycle design of bridges under multiple hazards, with an emphasis on earthquake, tsunami and continuous deterioration based on lessons learned from the 2011 Great Japan earthquake. A simple durability design criterion of reinforced concrete (RC) bridge in a marine environment is proposed to determine the concrete quality and concrete cover to prevent the chlorideinduced reinforcement corrosion causing the deterioration of structural performance during the whole lifetime. In addition, reliability-based capacity design of bridges with a hierarchy of resistance of the various structural components necessary to avoid catastrophic damage and to ensure prompt restoration after an extreme event is discussed.