Seismic Response Analysis Of Special-shaped Concrete-filled Steel Tube Arch Bridge

Widely recognized by the society,concrete-filled steel tube arch bridges have achieved rapid development due to their advantages of high rigidity,beautiful structure,strong spanning ability,excellent stress performance,and outstanding durability.At present,as a type of bridge,the concrete-filled steel tube arch bridge plays an important role in the transportation process.Its destruction during the earthquake not only caused traffic disruption,but also seriously affected the development of the national economy and the lives of people in disaster areas.Therefore,research on its seismic performance is particularly important.With the continuous development of arch bridge construction,the span of concrete-filled steel tube arch bridges becomes larger and larger,and the research and analysis of the seismic performance of long-span concrete-filled steel tube arch bridges are more rigorous and complicated.In order to ensure the safety of long-span concrete-filled steel tube arch bridges under earthquake action,analysis and research on the dynamic characteristics response and seismic performance of long-span bridge structures were carried out to accurately understand the seismic failure mechanism and dynamic response under earthquake excitation,but research in this field is still full of challenges.In order to study the seismic performance of the long-span concrete-filled steel tube arch bridge,this paper takes the example of the Yitong River Bridge main bridge—260-meter-span steel-tube concrete special-shaped arch bridge project as an analysis and research object.The internal force and displacement response of CFST arch bridge under excitation were studied.The main research contents are as follows:(1)Summarize the development situation of concrete-filled steel tube arch bridges,discuss the current development of bridge seismic analysis and research technology and the seismic response analysis methods applicable to long-span concrete-filled steel tube arch bridges,and clarify the content to be studied and analysis methods to be used in this paper.At the same time,various theories and calculation methods for seismic response analysis of bridges are described.(2)Based on an actual project,a full bridge finite element model is established to discuss the modeling methods of each component and structure of a concrete-filled steel tube arch bridge,calculate the natural vibration characteristics of the arch bridge,verify the mass system,damping system,stiffness system,and boundary condition system of the established bridge model through dynamic characteristics response analysis,and analyze the seismic response characteristics and rules of the structure to a certain extent to lay the foundation for bridge structure response by spectrum analysis and time history analysis.(3)Based on the analysis of dynamic characteristics,the acceleration response spectrum method is used to analyze the seismic response of the bridge at the two probability levels of E1 and E2,and the CQC response spectrum combination method is used to perform the single bridge: along the bridge and across the bridge,Vertical bridge direction and the combination of the two directions: analysis of seismic response of longitudinal bridge direction and vertical direction,transverse bridge direction and vertical direction;compare and analyze the influence of internal force and displacement of key parts of the arch bridge under the intense of unidirectional seismic waves and coupled seismic waves and draw the change law of the seismic effect of the structure.(4)Based on the acceleration response spectrum and artificially synthesized seismic waves,the time-history analysis method is used to calculate the response analysis of the concrete-filled steel tube arch bridge under the uniform excitation of artificially generated seismic waves.Summarize the response laws of such bridge structures under earthquakes,and study the weak links of bridge structures under earthquakes.In summary,through the modal analysis of long-span concrete-filled steel tube arch bridges and the study of seismic coupling effects in different directions and different spaces,we have a deeper understanding of the weak links of concrete-filled steel tube arch bridges in earthquake resistance.Provide some reference for the design and construction of a concrete-filled steel tube arch bridge.