The Effects Of Uniform And Non-Uniform Support Excitations On The Performance Of A Long-Span Viaduct Under The Non-Isolated And Isolated Conditions

Bridges are classified as important structures. Thenatural period of the majority of bridges is in the range of 0.2 to1.2 second. In this range the structural response is high becauseit is close to the predominant periods of earthquake – inductedground motions. Active control and passive control are used forthe control of bridges responses under earthquake excitation, inaddition to methods such as increasing of structural strengthand capacity. Seismic isolation is one of the passive controlmethods that increases the natural period of structures anddamping in a specified level and reduces applied force tostructures effectively.In this paper, it was studied Rio-Torto a 13-Span viaduct inItaly, and the responses were controlled and compared forisolated and Non-Isolated cases under the uniform and Non-Uniform ground motions for Irpinia, Imperial Valley andNorthridge earthquake records. Non-Linear time historyanalysis was selected for this purpose.Studying results indicate that using seismic isolation systemssensibly reduce the structural responses and the possibility ofthe creation of plastic hinges in structural elements. In additionconsidering the multi-support excitation causes increasing theresponses in Non-Isolated cases than isolated ones.

Keywords:

Seismic isolation , natural period , Non-Uniform Ground motion , Passive control , Time history Analysis