Analysis on Performance of the Existing Bridges Superstructure Based on Grillage Analytical Method

Theoretical basis of beam grid analytical method is introduced briefly in this paper and the parameters that must be pay attention to when we put the superstructure of bridge into the beam grid system also is referred to. At the same time calculation method of bending stiffness, shear resistant stiffness and tensional stiffness is discussed. Selection of the parameters of beam grid analytical method and converting of the structure system must be taken into consideration, when we analysis the existing bridges. In this paper the new Chengpeng flyover is taken for engineering background and according to the loading test results, the value of structure parameters and the structure connection form is modified and then the reasonable structure discrete model is put forward. On the basis of the model, structural mechanical properties in ultimate limit state and serviceability limit state can be evaluated accurately.