Comparative Research On Analytical Methods For Seismic Response Of Continuous Rigid Frame Bridges With High Piers

In recent years,with the deepening of the western development strategy will be significant,the state invested heavily in roads and railways and other infrastructure construction in the western region.Because of China's western region,mostly mountainous terrain,topography and complex geological conditions,the bridge structure in the line often account for a large proportion of which high bridge pier is one of the typical.High Pier Bridge is a typical irregular bridge,beyond the scope of the existing domestic and international norms,no ready-made norms to follow.Therefore,the high bridge pier seismic is one of the hot researches.Of the three seismic analysis methods: the response spectrum method,while statistically significant,is the linear elastic method;nonlinear behavior of the time history analysis(NL-THA method)can accurately simulate the structure,but the computational efficiency is too low,and depending on the results the selection of seismic waves,are very one-sided;traditional down assay(SPA method)has been widely used to analyze the structure of nonlinear dynamic state after entering the response,but it does not reflect the contribution of higher modes.Based on this,the existing theories on the basis of the analysis down to study for high pier continuous rigid frame bridge seismic response analysis Modal down analysis(MPA method),and with the traditional method and the NL-THA and SPA systematic and comprehensive method Comparative study on the applicability of each method of analysis,accuracy,practicality and representation of the results and other aspects of the merits of the main research work and conclusions include:(1)MPA in response to a high prediction accuracy for high pier continuous rigid frame bridge longitudinal bridge to earthquakes,especially in key cross-section of the internal forces and deformation,and does not change with PGA varies;transverse prediction accuracy of the seismic response of the slightly there are not as good;both the longitudinal and transverse direction is concerned,CPA and SPA method for its seismic response prediction accuracy is poor,MPA applicability significantly better than the SPA and CPA l method;(2)The ability to curve the different methods SPA equivalent method to calculate the CPA method,MPA method results greater impact,especially for the MPA law;bridge with respect to the longitudinal direction,the transverse direction of the newmethods used herein may be more substantial improve MPA method along the pier within the range of high prediction accuracy,including along the pier and the distribution of high value,but PGA is large,it should be improved.Overall,MPA method accuracy was significantly higher than SPA and CPA method;(3)To select a different reference point for the SPA displacement method to calculate the CPA method,MPA method results greater impact,especially on MPA law;Reference Point-Comprehensive method can greatly improve the MPA along the pier with high-precision calculations,including along Piers high value and distribution,and the PGA larger computing MPA error method tends to decrease.3 With the size of ground motion(PGA),bridge site site category as the object of MPA Law on high pier continuous rigid frame bridge in calculation errors were further studied.The results showed that:(1)In the longitudinal bridge,in addition to the outer pier top moment response,with the PGA of increasing,MPA method compared SPA method,moment CPA method,shear deformation response calculation error is minimized;in terms of displacement of pier top,SPA precision method and MPA calculated fairly;(2)In the transverse direction,with the PGA of increasing seismic forces and deformation along the pier height error MPA method calculated first and then decreases and then increases,but the calculation method was always higher than the accuracy of MPA and SPA method;(3)The type of venue the SPA method to calculate the CPA method,MPA method precision has a certain impact,and the impact related to the size and PGA,but the impact did not show obvious rule,in any venue,MPA method calculated high pier moment,shear,deformation,displacement response demand calculation errors were significantly lower than the overall CPA and SPA method.