Analyses On Dynamic Characteristics And Seismic Behavior Of Steel Box Tied Arch Bridge

Arch bridge is characterized by its beautiful appearance, easily constructed and relative lower cost, and its span can be increased when the rib of arch is made of the steel box or truss of steel box, so it can be considered as a most competitive style among the long-span bridges. With the increasing construction of long span arch bridge in our country, investigators and devisers should increasingly attach more importance to their dynamic behavior, and some typical dynamic matter of bridges, such as seismic response, wind induced vibration, coupled dynamic vibration between bridge and vehicle should not be ignored.Thereby, this paper takes the railroad through tied-arch bridge with steel box rids as engineering background. Author analyzes its dynamic characteristics and seismic behaviors using the finite element program, and abstract it as follows:1. Establish 3-D finite element model of this whole bridge, calculate its dynamic characteristics. Then, on the basis of this result, comparing the theoretical and practical results of other bridges of such type, summarize dynamic characteristic of these bridges.2. Modify above model along with altering structural form or the constitution of the bridge, calculate the variety of dynamic character, analyze this factors which will affect, discuss appropriate ways to optimize the dynamic character.3. Applying the anti-seismic theory, the anti-seismic capability of steel box tied arch bridge is analyzed by time-history analysis. Basing on the results of time-history analysis, the structure form of this bridge has been changed mainly centering on the style and number of the cross supports collocation, using parallel rib or X rib and the style of hanger. And the results can be reference for other bridges of the same type on seismic resistance. The good and sound collocation style of the cross supports can be confirmed and used to serve for the practical engineering only after considering their effect on the dynamical characteristic and anti-seismic characteristic of the bridge.