Research On Dynamic Performance For Widening And Reconstruction Concrete Beam Bridges Due To Moving Vehicles

The rapid economic growth has led to a sharp increase in the highway traffic volume in our country, and then more and more bridge widening projects is carried out by the local traffic department. In bridge widening projects, the possible damaging effects of traffic vibration on curing concrete stitch have been causing concern, and design engineers have to consider what traffic restrictions or mitigation measures are necessary。A large number of experimental data show that vehicle impact effect accelerates the destruction of the concrete stitch during actual operation. Therefore, it is very meaningful for the highway bridge widening projects to detailedly carry out the research on vehicle dynamic performance for the concrete beam bridge in bridge widening projects.Based on a typical engineering example and the theoretical and practical research results of the transverse structure for the concrete beam bridge in bridge widening projects, and combined the analysis program of vehicle-bridge coupling vibration, then the research on vehicle dynamic impact effect is conducted for the concrete beam bridge before and after widening. Besides, based on the research of the vehicle dynamic performance, the optimization scheme and suggestion for the bridge widening projects are presented, which provides a reference for the related engineering practice.Combined with existing research literature, the study analyses the failure mechanism of the concrete stitch for prestressed concrete simply supported T beam widening bridges, which determines the threshold vibration causing crack damage. Based on the research results of the measured data of the road vehicle load and the parameters of the typical vehicle model in China, the research on vehicle dynamic performance for the concrete beam bridge in bridge widening projects under the action of one vehicle and multi-vehicle is carried out, which proposes the related traffic control measures of limiting load, speed limit and lane limit etc. Combined with the existing research results, the new anti-traffic disturbance self-compacting concrete and reasonable construction technology is put forward, which provides a reference for the traffic control and reduction measures in bridge widening projects.The research shows that existing specifications is not give detailed rules and special instructions for the dynamic load impact effect of the key parts of the concrete stitch. Therefore, this paper analyses the failure mechanism and stress characteristics of the concrete stitch for prestressed concrete simply supported T beam widening bridges. The fine finite element model of the bridge was established by using ANSYS, based on the static and dynamic aspects, the vehicle dynamic response analysis on the key parts of widening bridge with different transverse connection structure is analyzed, which used the dynamic magnification factor of transverse bending normal stress evaluate the vehicle impact effect, and compared with the standard calculation value, then the research results provides a reference for joint design in bridge widening projects.