Abstract:Taking a 30-m equal-span simple-supported small box beam bridge in a high-intensity seismic region as the research object, a nonlinear dynamic analysis model is established by using the finite element software to mainly study the influence of the nonlinear model of reinforced concrete blocks and the ideal elastic-plastic block model on the seismic performance of bridges under the different design parameters. By comparing and analyzing the action mechanisms of the block strength and the initial clearance on the structural response, it is found that the nonlinear model of reinforced concrete blocks significantly reduces the displacement of the girder at twice the reference strength, and its hysteresis characteristics are close to the ideal elastoplastic block model and superior to the rigid assumption model. The girder displacement tends to stabilize when the initial clearance exceeds 0.09 m, and the adverse effect on the piers can be reduced. The research result shows that the nonlinear model of reinforced concrete blocks is relatively favorable for both beam body limiting and structural energy dissipation under reasonable parameter settings. Its performance lies between that of the elastic block model and the ideal elastoplastic block model, which provides a reference basis for the lateral seismic design of simple-supported beam bridges.
