Seismic Response Analysis Of Continuous Steel Truss Bridge With Rigid Cable

Double-layer continuous steel truss bridge with three main truss stiffened by rigid rib is a new kind of superstructure, which belongs to truss bridge but has some difference from traditional truss structure because of its parabolic rigid ribs in static and dynamic characteristics. There is so little reference material on research about such unique superstructure that it is very instructive significant to discuss its seismic response in order to analyze the dynamic response of the long-span steel truss bridge with rigid cable under earthquake effect. Based on the research of DONGJIANG bridge, the paper discussed the following aspects by analyzing the finite element model.1,Firstly, the paper discussed the importance and necessity of seismic resistance on bridge constructions, then described the process of the development of seismic resistance theory and current situation. Among of so many research methods on anti-seismic design, the dynamic time-history analysis method is the most universal one, which is considered as the main research approach on seismic response analysis because of its perfect theories.2,The corresponding dynamic differential equation should be selected to describe the dynamic characteristic of long-span continuous steel truss bridge stiffened by rigid rib based on the theory of structural dynamics. The multipoint excitation problem should not be ignored according to the variability of ground motion under seismic excitation. Considering the multipoint excitation, the paper pointed that the relative dynamic differential equation should be established and chose the most appropriate solution under the current research achievements.3,The ANSYS is able to simplify the actual structure into three-dimensional structure model, which is the research object of the dynamic analysis. The structural self-vibration characteristics, including natural frequency and modal shape, were being solved by modal analysis in the finite element software.4,The paper analyzed such superstructure seismic response under uniform excitation only considering the material elasticity and discussed the different structural response applied by earthquake load in different directions.5,Considering the spatial effect, such paper analyzed the structural seismic response under traveling wave excitation. And many useful conclusions, which were concluded by comparing the response data between uniform excitation and traveling-wave effect, proved the importance of the traveling-wave effect.6,The large mass method (LMM) was introduced to solve the problem of seismic loading, especially relating to the multipoint acceleration time-history excitation. In the end, it is feasible for the LMM to solve the multipoint excitation in seismic response analysis.