Study On Optimization Design Method Of Seismic Isolation Of Regular Girder Bridge

In this paper,the single-span span is less than 90 m,the substructure is single column pier or double column pier,and the pier height is less than or equal to 30 m,which is in the high intensity area,and has the need of relatively regular continuous girder bridge for shock reduction and isolation.Revised by comparing the calculation method of equivalent linearization,multi modal response spectrum in different high pier model and nonlinear time history method,structural internal force and displacement of the structure in the basic cycle three aspects,such as calculation,discuss the correction results and error distribution,and in part to fit its error structure internal force,so the corresponding empirical correction coefficient calculation equation,to further improve the calculation accuracy.At the preliminary stage of the design of relatively regular damping and isolation bridge,the isolation period is designed first and the design parameters of the damping and isolation support are deduced by using the modified equivalent linearization calculation method equation.Then the effect of the isolation bearing is checked by the equivalent linearization method.The main research work is as follows:1.After the correction,the accuracy of the calculation results of the two-mode response spectrum method has been greatly improved,and the overall calculation results are between the multi-mode response spectrum method and the nonlinear time history method.Therefore,the preliminary design results of the damping and isolation bridge will be inclined to be conservative and safe.2.When the error of internal force calculation of the two-mode response spectrum method is corrected by experience,it is more convenient to carry out the overall fitting calculation of the calculation results.For the engineering example in this paper,the error is controlled within 5%.3.In the preliminary design of the damping and isolation bridge,it is feasible to design the damping and isolation period of the damping and isolation bridge in advance according to the basic period of the ordinary bridge,so as to use the equivalent linearization calculation method to push back the parameters of the damping and isolation support and carry out the preliminary selection of the parameters of the damping and isolation support.4.In the preliminary design stage of the damping and isolation bridge,the modified dual mode response spectrum method can be used to design the bearing parameters of the damping and isolation bridge,and the effect of the damping and isolation support can be verified by the modified dual mode response spectrum method.The preliminary seismic isolation effect of the two-mode response spectrum method is between the nonlinear timehistory method and the multi-mode response spectrum method,and the calculated results are more accurate.Compared with the nonlinear time-history method,the design results are more safe and conservative.