Model Test And Theoretical Study Of Stress Distribution Of Cable Saddle Zone Of Extra-dosed Cable-stayed Bridge In Railway

Extra-dosed cable-stayed bridge is a new bridge structure in railway, the anchorage zone of which is a key power part of transmission. Most of anchoring manners are layered saddle, according to their structure is mainly divided into sub-steel-pipe and double casing saddle structure. Sub-steel-pipe saddle structure is a good solution to the problems of double casing saddle structure that the stress of the part of contact the lower of the saddle with the concrete is too large, difficult to install cable, steel cable extruded each other, preservative effects can not be checked and so on.In this paper, as the research object to a full-scale segmental model and the main tower of real bridge of an extra-dosed cable-stayed bridge in the new Beijing-Shanghai high speed railway, mainly covers the following aspects:1. An overview of domestic and foreign extra-dosed cable-stayed bridge development situation, characteristics and experimental research on anchorage zone of saddle, and summed up the conclusions and problems of the research in the field presently.2. Compared to the respective advantages and disadvantages of sub-steel-pipe and double casing saddle structure in detail and summary, and compared their application as well.3. A brief overview of the practical engineering background, the purpose of the model test and necessary material and loading device in the test were known. Developed a specific study protocol of the test, and designed the model of the test carefully. Arranged corresponding to the measuring point according to test purposes, completed the production of full scale segmental model of the main tower and the test platform.4. Described the loading system of the model test and the process of data acquisition, during the test, observed the phenomenon of test carefully, at the end of the test, collated the data which was collected on each stage in detail, and draw out the corresponding stress curves. Obtained the size and distribution law of stress around the lower part of sub-steel-pipe saddle structure concrete under the design load and under the load within safety factor respectively, and verified the reliability of the slippage resistance of the anchoring device.5. Finite element linear analysis of the segment of experimental model as well as main tower of real bridge by large software ANSYS. Completed geometric model accurately, mapped division of the grid, applied boundary conditions and the equivalent load, solving calculations and results output and so on, and then compared calculation results of the main tower of the real bridge and segmental model with test results.6. Finite element nonlinear analysis of the segment of experimental model by large software ANSYS. the force of the actual mechanism and destruction process of the reinforced concrete structure was studied. Obtained the ultimate load of test model can bear as well as steel and concrete stress-strain relationship, and draw a diagram of concrete crack distribution.