Studies On Coupling Vibration Of Highway Vehicle-bridge System Under The Influence Of Creep

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. Shrinkage and creep are the inherent time-dependent characters of concrete which belongs to viscoelastic material. The creep is the main reasons why the deflection of the girder is larger than that of code. With the fast development of new technology and new material, bridge structures have inclined to be more light and gentle, so its dynamic problem should not be ignored when subjected to vehicle moving loads.By regarding the bridge and vehicles as a whole dynamic system, the paper adopts an effective method to analyze a real bridge dynamic interaction under moving vehicle loads. This method derives the governing equations of bridge-vehicle system with three-dimensional automobile model and spatial freedoms of bridge, solving the governing equations by Newmark-βmethod after reducing the bridge's freedoms with its mode-shapes which are obtained by FEM. After proving the designed computer program, the method is adopted to study the dynamic response of the bridges under moving automobile loads, comparing the calculation results and the real results. According to the paper, the impact coefficient approach to 1. Weight and speed are important to deflection in mid-span.Deflection changes great when considering creep, and then makes the dynamic response of bridge changes. The paper analysis the creep mechanism, the influencing factors, the theory and the calculation, and then creates a real bridge model through bridge structure analysis software, compares the creep's calculation results and real results. Through the model, dynamic response of bridge structures and coupling vibration of vehicle-bridge under the influence of shrinkage and creep are analyzed. Analysis results show that impact coefficient changes great when considering creep.