Finite Element Analysis Of Composite Piers With Concrete Filled Steel Tube

Continuous rigid-framed bridges are one of the main bridge types of prestress concrete beam bridges with long spans. Because of their high adaptability to landform, mature technology of design and construction, high spanning ability and reasonable cost, they are universally used and have become the main bridge type of pre-stress concrete bridges.With the development of continuous rigid-frame bridges with high piers and long spans, the concrete-filled steel tube structure is an excellent choice for high piers and widely used abroad due to its good mechanical properties and comprehensive economical benefits. For certain reasons, concrete-filled steel tube piers have not drawn attention of bridge designers in China. Steel tubes are more and more used in the construction of high-rise buildings, arch bridges, underground structures, and port engineering while less used as high piers, and great achievements have been made. With the development of expressways and urban rail transportation and the construction of numerous flyovers and overpasses, concrete-filled steel tube with its advantages in structure and construction can accelerate the construction speed and reduce cost. In addition, concrete-filled steel tube also can bring satisfied solutions to problems caused by reduction of the section size of pier columns and brittleness of high strength concrete. With the deepening of the study of concrete-filled steel tube piers, their structural forms will be continuously developed. The thesis, based on the third pier of the Heishigou Super Major Bridge, is to carry out numerical analysis as follows:The purpose of the computational analysis is to instruct the carrying out of model tests, which is to analyze bearing capacity of model based on prototype. In order to obtain computational models, prototypes are designed in accordance with similarity theory. Based on the third pier of the Heishigou Super Major Bridge, in the beginning of the thesis is to introduce the theoretical basis of model tests, three theorems of similarity phenomena and criteria which model tests must obey. Similar constants of model tests are established. The model size and bearing capacity are designed. Then the rest is to set up computer models with finite-element software called ANSYS and to theoretically analyze the model piers, according to two load combinations including service load and action of earthquake. Some conclusions of structural behaviors for composite piers with concrete filled steel tube have been gotten and ready for comparing with the test results afterwards. In the end of the thesis is to theoretically study and computationally analyze the load bearing capacity for composite piers with concrete filled steel tube and set up calculation formulas with eccentricity of reduction factor and slenderness for composite piers with concrete filled steel tube. The load bearing capacity for composite piers with concrete filled steel tube has been analyzed by the software ANSYS. By comparing the results with the theoretical calculation, the thesis analyzes differences between them and points out the deficiency of theoretical calculation.