Seismic Effect Analysis And Seismic Measures Of Large Span Continuous Rigid Frame Bridge In High Intensity Area

The large span continuous rigid frame bridge is used more and more in the high intensity mountain area,and the span is becoming larger and larger,and the requirements for the earthquake resistance are becoming more and more strict.In order to analyze and study the action rule and influence factors of seismic action on the design of Long-span Continuous Rigid Frame Bridge in high intensity area,based on the actual project,the finite element analysis software MIDAS CIVIL 2015 and orthogonal test design are used to analyze the various models.The structure adopts the seismic response method of response spectrum and the time-history analysis method under frequent earthquakes action El and rare earthquake action E2,so as to study its seismic action rule and give aseismic measures.(1)According to the engineering background,the finite element modeling of the structure is carried out,and its dynamic characteristics are analyzed.It is concluded that the lateral and vertical stiffness of the structure is weaker,and the dynamic response is mainly contributed by the lower mode.The response spectrum method,dynamic time history method and static method are applied to study the seismic action rule.The results show that the earthquake action not only influences the substructure of the rigid frame bridge,but also plays an important role in the superstructure.(2)Through the comparative analysis of the effect of different peak sections on the seismic effect of each control section under different earthquake intensity,the design load types of control load of the main span middle-section,main span cantilever root section and the two section of the pier are obtained.(3)The aseismic analysis and static analysis of the 9 models are carried out by using the direct analysis method and the variance analysis of orthogonal test.The sensitivity and optimal combination of the side to middle span ratio,the bottom curve power and the pier height to the seismic load combination effect and the basic load combination effect of each control section are summarized.(4)The nonlinear time history analysis method is applied to seismic isolation and isolation analysis of all kinds of seismic isolation bearings.The friction isolation bearing has the best isolation effect,and its application in engineering is verified.