Dynamic Analysis Of The Large Displacement Bridge Expansion Joint

The large displacement bridge expansion joint is the important component of a large span bridge. The dynamic analysis of the large displacement bridge expansion joint is mainly through two methods in this paper. Firstly, dynamic analysis of the expansion joint structure is carried by the theory of dynamic analysis and numerical calculation. Sencondly, simulation analysis of the expansion joint structure is carried by the finite element analysis software ABAQUS.Firstly, this paper determines important structural parameters of the research object, such as:structure size, quantity and distribution location of center beams and cross beams; stiffness and damping of lower supports, upper supports and shear springs, etc. Secondly, the fuction form and position of the wheel pressure load are determined, function position. At the same time, the impact factor of wheel pressure load and the range of speed are selected according to the current codes. Then structure statics analysis of the expansion joint is beginning. There are mainly stiffness, strength and fatigue analysis for center beams and cross beams, accoding to different standards of domestic and overseas. Finally, it is the dynamic calculation. The influence from structure parameters of the expansion joint to the dynamic response is got by changing the structure parameters and the working stations. And two calculation methods (the theoretical calculation and the simulate of finite element software) are used for accuracy. The calculation results can be applied to determine the impact factor of the load and the structure parameters of key parts, so as to provide a theory basis for the rationalization design of expansion joints.Conclusions of the research include:firstly, through the stiffness, strength and fatigue analysis, it can be concluded that the expansion joint basicly meets the design requirements. And the domestic standard is more strict, but there are still structural failures. Secondly, the impact factor is the important design index of the expansion joint structure. In the vertical dynamics calculation, changes of the impact factor is studied under the conditon of different speeds and structural parameters. At the same time, the characteristics such as bending deformation of the structure, bounce and attenuation are also studied. Thirdly, in the horizontal dynamics analysis of the expansion joint, if considering braking fuction, horizontal displacement of the center beam will be very big. But the big damping characteristics of shear springs can make vibration weaking soon.Because the dynamic analysis and calculation are more resonable than the statics analysis, the results of calculation are more practically significative for design and production.