Static Test Study On Cable-Girder Anchorage Zone Of Lingang Railway-Highway Cable-Stayed Bridge

Thanks to technological progress and more reasonable utilization of resources,long-span rail-road cable-stayed bridges have developed rapidly in recent years.With the double live loads of moving vehicles and trains,the forces acting on the bridges are more complex than those on single-purpose bridges.The cable-girder anchorage,therefore,as the key structure to transfer forces between the cables and the girder,is especially critical.The subject of this thesis is the rail-road Yibin Lingang Yangtze River Bridge in Sichuan province,a single-deck multitrack bridge with a super-wide steel box girder.The author conducted tests and a FEA(Finite Element Analysis)study on the dual-cable steel anchor box structure—a new type of cablegirder anchorage—of the bridge to analyze the mechanical safety of its anchorage.The thesis is composed of the following parts:(1)A summary of the current status of development,structures,and mechanical features of domestic and foreign rail-road cable-stayed bridges,categories of the cable-girder anchorage structure,its application and research review.(2)Calculations of the overall forces acting on the rail-road Yibin Lingang Yangtze River Bridge,including the cable force and forces on the girder and the towers,and calculations of dynamic characteristics,to get the maximum cable load and identify the least favourable positions for cable-girder anchorage.(3)The design of a scale-model experiment on dual-cable steel anchor box structure of the Yibin Lingang Yangtze River Bridge based on similar theories,and the performing of the experiment to test the forces acting on the dual-cable steel anchor box in 2 situations—when bear same level of load and when one of the cable breaks,in order to conclude the mechanical features of the anchor structure.(4)The creation of a full-scale model,a scale model and a test model of the steel anchor box structure based on Nonlinear Theory,the verification of the effectiveness of the scale model and of the feasibility of the test model in which a stand is added;the verification of the effectiveness of the test results through the comparison analysis between the test model data and the FEA results;and calculations of the 3 models through FEA to get the stress distribution features and the mechanical ratios of different forces of each plate of the anchor box.(5)Analysis and calculations of a simplified model of steel anchor box structures with different number of cables,analysis of the mechanical sensitivity of the steel anchor box plates of different thickness,design optimization of steel anchor box structures.The conclusion is:when the cable force is big,the dual-cable steel anchor box has good mechanical performance and economics and a high level of mechanical sensitivity to the thickness of the anchor plate;plates added to the stress concentration areas of the anchor plates can effectively lower the concentration level of stress.