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. The natural period of the 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 – inducted ground motions. Active control and passive control are used for the control of bridges responses under earthquake excitation, in addition to methods such as increasing of structural strength and capacity. Seismic isolation is one of the passive control methods that increases the natural period of structures and damping in a specified level and reduces applied force to structures effectively In this paper, it was studied Rio-Torto a 13-Span viaduct in Italy, and the responses were controlled and compared for isolated and Non-Isolated cases under the uniform and Non-Uniform ground motions for Irpinia, Imperial Valley and Northridge earthquake records. Non-Linear time history analysis was selected for this purpose. Studying results indicate that using seismic isolation systems sensibly reduce the structural responses and the possibility of the creation of plastic hinges in structural elements. In addition considering the multi-support excitation causes increasing the responses in Non-Isolated cases than isolated ones