Study On The Structural Behaviors And Experiments Of Anchorage Zone Of Cable-Stayed Bridge

At present, large span cable-stayed bridges have sprang up over the country. The anchorage zone on pylon is the key parts for cable-stayed bridge and the forces acting on the zone are complicated. With the increase of span, the anchorage zone on pylon bear more heavy load because of the increase cable force. Study on the structural behavior of anchorage zone of cable-stayed bridge has attracted much attention in bridge circles. Based on the domestic and international research results, the Jintang bridge as a case, it has made the study on experimental research of different shear connectors for steel-concrete joint section of bridge pylon, transfer mechanism and utility computed methods of the anchorage structure. The main research work covers the following aspects:1,It is suggested that the Perfobond Leiste(PBL) shear connector could be applied for steel-concrete joint section of bridge pylon for the first time. In order to improve the reality of the experimental data, the loading device is fixed in the middle of the specimen instead of the push-out test. A new type of connector and traditional stud connector models for the joint section with different structural forms are put forward, and 3D FEM analysis and contrastable model experiments are carried out for models. The principal results of the simulation calculation, comparison of the results to the measurement values in the tests are provided, and some important conclusions in relation to the calculation and tests are generalized. Base on tests of these specimens, relation between load and slip, shear rigidity, ultimate bearing capacity, failure pattern etc. of shear connectors are discussed. The analysis results show that the calculating results coincide with the experimental results, and the PBL shear connector has much higher bearing capacity than stud connector for steel-concrete joint section of bridge pylon.2,The distribution function of bond stress on joint surface of the composite structures is derived based on elasticity and deformation plasticity theories.According to constitutive model of shear connectors, a constitutive equation of load-slip is established from statistical analysis of test data at different loads. The nonlinear shear rigidity is developed based on MATLAB program language and a calculation equation is provided. The methods to simulate the slip of connectors is suggested. Then a configuration algorithm based on the model is presented. A series of extending parametric analysis are carried out on models with different concrete strengthes, spacing interval of stud connector, size of the holes, diameter of the perforated rebar for PBL shear connector and thickness of the steel ribs by means of numerical simulation combining with full-scale experimental verification. Some useful conclusions are obtained by the parametric study.3,Taking the composite structure of steel anchor beam and steel corbel as project background,which is firstly used in the anchorage zone of Jintang bridge, a full scale segmental model test is performed. The pedestal loading system is designed to overcome the disadvantage of the reaction frame for loading in this paper. The stress redistribution of concrete and the anchor structure is obtained under many different situations. The structural performance satisfies the design requirement. The results show that the composite structure of steel anchor beam and steel corbel has enough safety tolerance and the PBL shear connector is feasible for steel-concrete joint section of bridge pylon.4,Based on the load-slip constitutive equation of the steel-concrete composite structure, stress analysis of the pylon cable anchor zone is simulated numerically. Through a series of analysis including stress distribution of tower wall concrete, steel anchor beam, steel anchor box and steel corbel, the numerical result shows good agreement with the experimental result, and the theoretical calculation model can reflect the real stress states. The composite structure transfer mechanism about steel anchor beam and steel corbel is analyzed according to these results.5,For the engineering convenience and convenient design, a new simplified analytical method of the anchor-hold structure is put forward. By means of that, the structural concept can be adjusted timely. Compared to the measured stress of the tower wall concrete, steel anchor beam and steel corbel, the conclusion is that the simplification of the physical model is visible. In combination with the model test and installation technological process of the steel anchor beam, the construction methods in detail are established. This article can provide information about the popularization and application of the steel anchor beam structure, construction scheme selection and construction process control.