Studies On Vehicle-Bridge Interaction Of Long-Span Continuous Rigid Frame Bridge

With the increase of highway transportation and the development of bridge construction, bridges are tending towards longer, lighter and more flexible. The dynamic responses of long-span highway bridges under high-speed and heavy vehicles have deserved general concerns by bridge researchers. The long-span continuous rigid frame bridge, a representative highway bridge, is regarded as the research object in the thesis. The dynamic responses of vehicle-bridge vibration system under moving vehicles are investigated. The influence of different vehicles conditions is disscused.The primary achievements at present are concluded roundly according to vehicle analysis model, bridge analysis model, surface roughness of road and numerical method of the reseach on vehicle-bridge interaction of highway bridges. Dynamic analytical model of long-span continuous rigid frame bridge and motion equation of bridge are established with the finite element method. The vehicle model used in this thesis is a 7 degree-of-freedom curving two wheels model. The motion equations of vehicle are derived using the D'Alembert principle. Vehicle-bridge vibration system can be divided into two subsystems at the interface of wheel and bridge, one for the bridge and the other for the vehicle. The vehicle-bridge coupling relationship, including the geometrical compatibility condition and the static equilibrium condition between vehicle and bridge, is established. Then, the governing equations of vehicle-bridge system are setup. A separated iterative method is used to work out three-dimensional coupling vibration program (DAVBS: Dynamic Analysis of Vehiche-Bridge System)。The reliability of DAVBS is proved using bridge dynamic tests.The dynamic responses of the long-span continuous rigid frame bridge are studied with Boxi Jinshajiang river highway bridge by DAVBS program. In the vehicle-bridge analysis for response, the effects of vehicle type, two-way direction, vehicle speed and road surface roughness are discussed. The influences of road surface roughness and vehicle speed on the dynamic responses of vehicles running on the bridge are investigated. The studied results can provide a certain scientific basis for dynamic analysis of the long-span continuous rigid frame bridge.