Research On The Calculation Method Of Bridge Seismic Isolation Design

Nonlinear Time History Method is considered as a more accurate calculation method of Bridge Seismic Isolation Design Analysis.However, this method is very complex and cumbersome,and requires the design engineer to have some theoretical knowledge and experience of structural dynamic analysis.Thus the practical application of the Nonlinear Time History Method is limited.In recent years,extensive research on simplified analysis methed has been done home and abroad.In this paper, based on existing research, a comparing study on the Simplified Method,Multimode Spectral Analysis Method and Nonlinear Time History Method has been done.Nonlinear Time History Method is considered as a more accurate method for Bridge Seismic Isolation Design and Analysis. However, this method is very complex and cumbersome and requires design engineers to have some theoretical knowledge and experience of structural dynamics. Thus the practical application of the Nonlinear Time History Method is limited. In recent years, extensive research on simplified methed has been done both domestically and abroad.In this paper, based on existing research, a comparative study between the Simplified Method and more accurate methods using finite element analysis has been conducted.①Based on the literature, the applicable conditions of isolated bridges, the commonly used isolation devices and seismic analysis method of isolated bridges are summarized and demonstrated. The procedure for the simplified method and different ways for treating the cap beam and column masses are discussed.②Two Bridges including one with equal height columns and one with non-equal height columns are considered.Extensive comparative studies are performed regarding different analysis methods. The accuracy and applicability of the simplified method is discussed.③Three simplified methods are of different extent of complexity. A relatively complex adjustment factor needs to be calculated in the method taking into account the adjustment coefficient. While the method not taking into account the adjustment coefficient is simple and easily implemented. The initial values and the number of iterations with different methods may be different but the final results are the same.④ An example bridge with non-equal height columns is analyzed and the inadaptabilityof simplified methods is explored.⑤Some suggestions are made on the isolation design of the highway bridges...