Long-period Seismic Response And Antiseismic Performance Of Continuous Rigid Frame Bridge With High Piers

With the high rise building structures arised in city,the long-span structures were constructed in the western region,and the seismic damage characteristic of long-period structures,long-period ground motion and long-period structures become research hotspot in recent years.The seismic response characteristic was distinct different between general structures and the long-period structures like sky-high buildings,longspan bridges,storage tanks,et al,the long-period ground motion and common seismic was also quiet different in damage characteristic and intensity when structures subject to seismic.To investigate the dynamic response characteristics and seismic performance of long-period structures under strong ground motion,it was necessary to proposed the details of modals and researched the seismic response characteristic of the long-period structure,which is continuous rigid frame bridges with high piers,then from an engineering and seismological point of view,the parameter of A_p/V_p(the ratio of ground motion peak acceleration and peak velocity)was revealed ground motion frequency contents be proposed,which was to investigated the effect of long-period structures.The research of this paper can provided such reference for seismic fortification of flexible bridges.Based on the aim of this paper,the main research work include:(1)Based on the OpenSEES,a comprehensive study of the reinforced concrete nonlinear constitutive model,elastoplastic simulation method of element type,mesh density and boundary nonlinearity(focusing on back abutment-soil interaction)response effect on high pier continuous rigid frame bridge dynamic characteristics and earthquake,discusses the different details and different parameters effect of law,on this basis,puts forward the fine modeling principles and methods for seismic analysis of high pier continuous rigid frame bridge.(2)According to the characteristics of the response of high pier continuous rigid frame bridge of long-period earthquake,according to national standard design response spectrum to generate artificial earthquake wave,and selects three typical actual longperiod seismic records,long period seismic response of the nonlinear time history analysis method to contrast the cases of bridge design and actual wave spectrum;response spectrum and seismic response of vertical scale ratio the ratio based on the changes of the dynamic response of the bridge were revealed,the long period ground motion on the seismic response of the continuous rigid frame bridge amplification and its causes,and points out the deficiencies of present standard design response spectrum in long-period.(3)The value of A_p/V_p to form the spectrum characteristics of land vibration,is proposed based on bridge capability demand ratio(C/D)of the seismic performance evaluation method and calculation formula,the ground motion parameters are Ap 0.4g sine wave and real seismic records,analysis and comparison of the variation of the ground motion response demand A_p/V_p value to each of the key sections of the earthquake in the longitudinal and transverse bridge with high pier continuous rigid frame bridge,the bridge longitudinal and transverse direction of the bridge seismic performance index(C/D)changes with the A_p/V_p value,it is pointed out that the traditional seismic analysis,seismic design ground motion parameters of Ap as a single indicator will lead to the seismic performance of bridges have great dispersion,are not sufficient to ensure the seismic safety of the bridge the value of A_p/V_p,can be used as a supplementary index of bridge seismic design.