| The dynamic responses of highway horizontally curved beam bridges are studied through numerical simulation method. The vehicle–bridge system consists in two subsystems at the interface of the bridge and vehicle. Establishing the equations of motion for the bridge and the vehicles respectively, an iteration solution method is presented to analyze the coupling vibration response of vehicle-bridge system based on the same displacement and coupling force at the interface.Based on the assumption of rigid-body dynamics and dynamics of vehicle, the motion equation of vehicle model with nine degrees of freedom is derived. Road roughness, as a main motivation to vehicle, is an important content of the research of coupling vibration of vehicle-bridge. The road surface roughness of the bridge is considered as a stationary random process characterized by a power spectral density function of the surface irregularity .The road surface roughness is generated form the PSD function using trigonometric series superposition technique for grade A, B, C roads according to GB/T7031-86 criterion.A new numerical method for solving the coupled vibration of vehicle-bridge system is brought forward using finite element and mode superposition. The coupled equation system is performed with a step-by-step solution technique using the Newmark-βmethod. Because of the response of bridge resting with some low mode, the dimensions of matrix are reduced obviously.On the project background of A ramp of Chang Qing Nan Lu Bridge, analysis and calculation are done using program made by myself, which is proved to be reliable after comparing the results with experimental data. The influence of different factors to the dynamic response of bridges is analyzed, such as vehicle speed, loading lateral position, road surface roughness, radius of curvature, super elevation degree and damping of bridge. In the end, some conclusions are obtained which can provide data and theoretical references for the farther research in coupling vibration of vehicle-bridge on highway horizontally curved beam bridges.Through comparison of several national standards on Dynamic Amplificatory Factor, the leading factors which affect the DAF of highway horizontally curved beam bridges are concluded. The influence of different factors to the DAF of highway horizontally curved beam bridges is analyzed. |
