Kamran Amini - Concrete Research Centre, Department of Civil Engineering, Islamic Azad University, Qazvin۱
Kianoush Taghikhani - Concrete Research Centre, Department of Civil Engineering, Imam Khomeini International university, Qazvin
Amir Yavari۱ - Concrete Research Centre, Department of Civil Engineering, Islamic Azad University, Qazvin۱

Lifeline systems consist of Bridges, Roads, Tunnels, Communication networks, Water and Gas Transmissions, Airports, etc, are known as a general parameter for all cities especially Megacities survival. Any trouble in their operation particularly in times of crisis (earthquake, flood, tempest, war, etc) will increase irreparable losses of life and property. Large lifeline systems such as bridges are susceptible to earthquake damages, and their performance, integrity and stability according to their special application in current-day transportation, during and after an earthquake have significant implications on public safety. Bridges are one of the most importance lines to control rescue operations during and after earthquake. So, there is an urgent need to recognition the effective factors on bridge damages in an unforeseen exigency. Hence, their vulnerability significantly should be under continual surveillance and bridges stability has to be controlled by retrofitting and rehabilitating. In this study the seismic performance of various types of bridges during the past earthquakes is presented. The objective of this study is to present typical failure modes of bridges and providing some clues in order to reduce the seismic vulnerability of such structures. Results of this study demonstrated that there are some typical failure modes in bridges. Hence, by considering some special practical consideration the seismic vulnerability of bridges may decrease.

vulnerability, earthquake, structural properties, retrofitting