| The cable-girder anchorage area of cable-stayed bridge bears huge static and dynamic loads.Its safety and durability are the key points in the control design of cable-stayed bridge,and it is often used as one of the controlling structures in the construction design.Lingang Yangtze River Bridge is a long-span cable-stayed bridge with rail and road in the same floor.The highway and railway are arranged on the same floor.The deadweight load is large and the force is complex.In order to ensure the safety of the bridge,this paper adopts model test and numerical simulation is the research method of combining the lingang bridge double cable beam anchorage structure to carry out the structure behavior and model test research,explore the suspension cable beam anchorage zone stress distribution and power transmission way,provide a reference for optimization design,rational construction,relevant research work and achievements are as follows:(1)Selection of yibin lingang combined bridge model experiment in the largest stress of anchorage structure considering factors such as the test conditions and test feasibility,A 1:3scale test model of cable-beam anchorage structure is designed on the basis of the original structure,and it is used to explore the stress distribution law of anchorage structure and force transmission way;A control test is designed on the basis of the original structure to compare and analyze the difference of the cable-beam anchoring structure caused by different bearing plate structures.A model loading method and force transmission truss system suitable for complex cable-beam anchorage zone are proposed.At the same time,the finite element verification analysis of the scale model and the full-scale model proves that the scale model is effective and can well represent the full-scale model for testing.(2)Static load experiments of steel anchor boxes were carried out to analyze the complex stress state of anchorage-related plates under cable force loads.The results showed that the steel anchor boxes had good mechanical properties.No matter in Experiment 1 or Experiment2,they were stable under the design load and 2.5 times the design load,and were always in the elastic stage.When the load reaches 5 times the design load,the steel anchor box structure shows an obvious yield point,which proves that the safety factor of the anchor box structure is high.The stress distribution on the side and side of the anchor web is opposite to that in the middle.In the position where the side and the beam web are connected,the near side of the bearing plate bears the tensile stress,while the far side of the bearing plate bears the compressive stress.In the middle side,the close side of the bearing plate bears the action of compressive stress,while the far side of the bearing plate bears the action of tensile stress.It is inferred that the cable force in the anchor web structure diffuses downwards from the bearing plate diagonally.(3)The finite element software ANSYS-WORKBENCH was used to build a threedimensional fine nonlinear finite element model for Model 1 and Model 2,It is used to simulate experimental constraints and cable force load,and verify the validity of the test.As a verification and supplement to the model test,the plate thickness optimization design was carried out on the basis of the full-scale model at the same time.The results show that the stress variation trend of the finite element is basically the same as the measured results,and the average error is about 10%,which verifies the accuracy of the experiment.Found in the finite element model,the transverse stress in the lower part of box girder web plate structure position is obvious,characterized by large tensile stress function,Comparing the results of the two model tests,it is found that the extended bearing plate of Model 2 can disperse the cable load better,the cable force from the bearing plate vertical downward transmission instead of on both sides of the oblique,to some extent,it improved the force of the stay. |
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