SEISMIC BEHAVIOR OF ISOLATED BRIDGES

Computer Engineering electronics Engineering Civil Engineering

Bridges are lifeline structures. They act, as an important link in surface transportation network and failure of bridges during a seismic event will seriously hamper the relief and rehabilitation work. There are many cases of damage of bridges in the past earthquakes all over the world. Due to their structural simplicity, bridges are particularly vulnerable to damage and even collapse when subjected to earthquakes. The fundamental period of vibration of a majority of bridges is in the range of 0.2 to 1.2 second. In this range, the structural response is high because it is close to the predominant periods of earthquake-induced ground motions. The seismic forces on the bridges can be reduced if the fundamental period of the bridge is lengthened or the energy dissipating capability is increased. Therefore, the seismic isolation is a promising alternative for earthquake-resistant design of bridges. Considerable efforts have been made in the past two decades to develop improved seismic isolation design procedure for new bridges and comprehensive retrofit guidelines for existing bridges loading..