Vehicle-bridge Coupling Vibration Responses Of Bridge With Corrugated Steel Webs

Coupling vibration of vehicle-bridge is an important subject of the bridge research field. Predecessors have affirmed through both theoretic and practices that the vehicle moving loads would lead to more deformations and stresses for bridge structures than the equivalent static loads.Through finite element analysis and experimental study, this dissertation makes systematical research on vehicle-bridge coupling vibration of concrete box-girder with corrugated steel webs.In this paper, three-dimensional car model is used and based on the principle of modal synthesis method, the vehicles and the concrete box girder bridge with corrugated steel webs can be taken as an interaction system. The natural vibration characteristics of the bridge can be obtained by using finite element method. According to the vehicle-bridge coupling vibration theory, the control matrix of modal parameters of the concrete box girder bridge with corrugated steel webs can couple with the dynamic parameters matrix of the vehicles. By considering the effect of the variation of damping ratio on vehicle-bridge coupling vibration response and inputing the irregular pavement function which can be taken as a excitation to the bridge, the program which considers the effect of the irregular pavement on vehicle-bridge coupling vibration response is compiled. By analyzing the relationship between vehicle speed, irregular amplitude, irregular wavelength and dynamic load coefficient, it can be obtained that vehicle speed and surface roughness both are the most important factors. By analyzing the relationship between different forms of damping, variation of damping ratio and impact coefficient, and comparison of theoretical and experimental results, it can be obtained that damping is one of the most important factors. Meanwhile it also analysis the effect under complicated conditions, such as the different radial truck, the different axial pattern and the form of bridge passing. The result can provide beneficial reference to the dynamic design, the vibration control and dynamic performance evaluation of the concrete box girder bridge with corrugated steel webs. A formula for calculating the frequency of externally prestressed simply supported concrete beam, which is derived from classical frequency equation considering the influence of external tendons, is used to calculate the natural frequency of a test box girder with corrugated steel webs, with considering the characteristics of the section of box girder with corrugated steel webs. The results of the natural frequency before prestressed can be calculated. In aspect of the dynamic performance, it provide beneficial reference to the layout location of the prestressed reinforcement in order to avoid the resonance between the box girder with corrugated steel web and the prestressed tendon.