Research On Static Behavior Of Large-Span Truss Steel Bridge Joint With Rigid Cable

The Zengjiayan Bridge in Chongqing is a large-span suspension stiffened steel truss girder bridge.The main bridge span is arranged as(135m + 270 m + 135m).The special node is located at the connection between the stiffened suspension cable and the upper chord.Its construction is extremely complex and it is the key part of the full bridge.In this paper,the finite element analysis method is used to study the special node static performance.At the same time,based on the theoretical analysis results of special nodes,a special node scale test model is designed,and the model test parameter measurement and test loading scheme are designed to provide for the development of the test.Technical Support.The main work accomplished in this paper and the results achieved are as follows:(1)Using the spatial beam-plate element method to establish the full-bridge finite element model of the Zengjiayan Bridge,based on the overall analysis of the full-bridge,the most unfavorable special nodes of the full-bridge are judged and determined to be composed of A38A39 nodes on the side of the Suizhong District.Special nodes are the most unfavorable.For the mechanical characteristics of the plate-truss composite structure bridge,by establishing a multi-scale finite element model,the load and boundary problems of the special node finite element analysis are dealt with reasonably,and the stress characteristics of special nodes are analyzed.(2)According to the results of the multi-scale finite element model,loads and boundary conditions loaded in the main face are determined.The finite element model of the special node segment established was subjected to force analysis to obtain the stress level and distribution rule of the special node during in-plane loading.At the same time,overload analysis was performed to examine the special node safety reserve.(3)According to the similarity theory,according to the finite element analysis results of the special node,the scale of the experimental model is determined to be 1:2.5.The test model was designed according to the scale ratio,the load and boundary conditions of the test model were determined,and the loading method of the test was designed.At the same time,the rationality of the scale test model design of the special node was verified through the comparison of the finite element analysis results.(4)The test reaction force device was designed according to the requirements of loading and boundary treatment,and the local reinforcement design analysis was performed on the rod end of the test model with tensile and compressive loads.Taking into account the processing of the boundary in the model test,the design and verification of the fixed and articulated boundary conditions are performed.(5)Based on the finite element analysis results of the special node test model and the main contents of the test test,a test load test scheme for the scale model was designed to discuss the arrangement of the measurement points,the implementation of multi-point multi-stage loading,and the precautions for loading.