The Research On Transverse Distribution Of Dynamic Response For Simply Supported Girder Bridge Under Moving Loads

The active duty small bridges in our country, the proportion of assembly simply supported beam bridge is quite large,and most of them have varying degrees of disease,but because of the simply supported beam bridges, advantages such as the simple construction procedures, high speed of construction etc, which makes it to be one of the most commonly used type of simply-supported beam bridge with small span.Through reading large numbers of literature at home and abroad, we have mastered the theoretical knowledge of the transverse distribution of load and as well as the basic analytical theory and numerical theory of the dynamics of the bridge. On the basis of the theory, studying the applied analysis of the grillage method in simply-supported hinge joint hollow slab bridge, and finding the most appropriate virtual sectional beam to ensure the accuracy of the result when modeling calculation With the grillage method. Based on the theory of computation of the static load transverse distribution coefficient, in this paper we analyzed the single beam and the whole bridge dynamic response under the moving loads respectively, accordingly,studying the transverse distribution of the hinged slab bridge under the moving load,and trying to analyzing the hinge joints under the most unfavorable shear. The main research work is as follows:(1)For an example of a simply-supported hinged hollow plank girder bridges,with the theory of hinged plate method and grillage method for finite element modeling respectively to calculate the load transverse distribution coefficient of the bridge.Midas software is used to modeling by grillage method,because there is no clear specification to stipulate the transverse cross section characteristic of the virtual beams,this paper will take representative three cross section to calculate which based on the precious research. Compared the calculation results to the results of the hinged panel method, select the most reasonable cross section as the virtual beam cross section in grillage method. At the same time also verify the accuracy of modeling and ensure the rationality of the subsequent dynamic analysis model.(2)Studying the dynamic response of a single beam under moving load, using Midas to establish the finite element model of a single beam and applying moving concentrated load so that obtained the numerical solution of a single beam underdifferent speed dynamic response, and then compared to the analytical solution which based on the theory calculation. Then analyzes the dynamic response of different span beams under moving load, contrast and analyze the law of doing the same, do the same contrast and analyze the regular pattern. On the basis of the previous analysis, study the impact coefficient under the moving load, according to the single girder equation and obtained the analytic expression of impact coefficient, and then compared it to the numerical solution. In order to verify the validity of the loading and modeling, and can be the basis of the analysis of whole bridge later.(3)We consult the static transverse distribution coefficient method,analysis the dynamic response of the whole bridge under moving load,by processing the dynamic deflection curve and analytical data so we can summarize the transverse distribution of loads.In the mean time extracting the hinge joint shear time history data under different working conditions and finding the most unfavorable shear hinge joints,so that we can provide research basis for damage mechanism analysis of hinge joints.In this paper, the research content and results,put forward some opinions and suggestions to how to select the reasonable virtual property values when modeling with grillage method, provides a certain reference for further study the dynamic characteristics and hinge joints in hinged plate girder bridge under moving load failure mechanism study.