Seismic Responses Study Of Concrete Self-anchored Suspension Bridge

As a Particular kind of suspension bridge , and Preserving the exquisite configuration of conventional suspension bridge,self-anchored suspension bridge has made an appeal in field of engineering by its elegant and Picturesque disorder figure. It has become a competitive design scheme in middle-,and small-span bridges in cities. However,due to complexity of its structure,from the document that has existed,there is little research of dynamic behavior for self-anchored suspension bridge. So its very important to give a research on this aspect. On the base of summarizing documents at home and abroad, this paper investigates the dynamic behavior and seismic response of self-anchored suspension bridge. The main research work covers the following aspects:(1) Considering the effect of geometric nonlinearity and pretension of suspension rod, the internal force and deformation of self-anchored suspension are computed. By using 3D finite element model of Shaoxing Jiefang Road third Bridge, the numerical solution has been solved, and compared with the test result of scene. The disparity is small. This outcome proves the model is proper. This model can be used to analysis the dynamic response of this bridge.(2) Based on Large-displacement Non-linear Elastic Generalized Variation Principle, coupling effect of axial and flexural action, shearing strain energy, torsion strain energy of stiffening girder being considered,the large-displacement incomplete generalized potential energy functional of space coupling free vibration of a three-span concrete self-anchored suspension bridge is presented. By constraint variation, the linear free vibration differential equation is obtained when the nonlinear items are discarded. In this Paper, the example's analytic solution of frequency of free vibration has been solved. Compared with numerical solution, the results inosculate well. This approach provides theoretical basis for analysis of natural vibration character of concrete self-anchored suspension bridge.(3) Dynamic behaviors of concrete self-anchored suspension bridge mainly include natural vibration frequency and principal mode, which is the base and precondition of dynamic analysis for self-anchored suspension bridge. Shaoxing Jiefang Road third Bridge,a concrete self-anchored suspension bridge with the main span of 240m, is taken for example, and the first 30 frequencies and corresponding vibration modes are given by using 3D finite element model. At the same time, effects caused by varieties of rigidity of stiffing girder, stiffness of tower, section of main, section of suspension rod are computed. The results provide reference for optimizing earthquake-resistant of self-anchored suspension bridge.(4) The seismic response of Shaoxing Jiefang Road third Bridge is analyzed by the response spectrum Method and time-history method. The results give directions to the preliminary design of self-anchored suspension bridge.(5) Considering different wave speeds, The seismic response of Shaoxing Jiefang Road third Bridge is analyzed by the traveling wave effect. The results show the influence to the seismic response, and are useful to the design and construction of bridge.