Study On Seismic Behavior Of Y-Shaped Hybrid Column With Cast-Steel Joint

With the development of economy and technology, from the end of last century, high -rise building, super high-rise building and mega-structure are built on a large scale. To adapt the new type of building and meet architecture requirement, steel-concrete hybrid structure system has been used in many buildings. Vertical hybrid structure system has been widely used in and abroad, especially in Japan, according to its economy superiority and seismic performance. However, compared with its application on practical project, the research on seismic design method of vertical hybrid structure is slowly developed. There are no uniform methods in transfer story design, and the rules in the regulation are conservative, within some limitations.In this dissertation, the Y-shaped hybrid colunn in the long span vertical hybrid structure of Pudong airport secondary terminal is choosen to be investigated. According to the results of full-scale analysis, the dual Y-shaped column with cast steel joint and the single Y-shaped column are simplified, with the precondition of guaranteeing the critical part. Three kinds of specimens are designed. Through nine times pseudo-static tests of the six specimens, their capacity, deformation ablity are abtained. The characteristic of the specimens under load, mechanism of transfering force, and the failure patterns are understood. Based on the data of these tests, the hysteretic loops, skeleton curves are drawned. The seismic performance of the specimens are evaluated from the aspects of strength, stiffness, ductility and energy dissipation. After comparing the results of the tests to the load effects in the practical project, the coefficient of strength margin of the prototype members are calculated.Numerical analysis of the Y-shaped columns are done with the help of the finite element software ANSYS. The monotonic load curve, hysteretic loops, and the distribution of the stress-strain are abtained, with and without condisering the bond-slip between the structural steel and concrete. After comparing the numerical results to the tests, the monotonic load curve of the model with the string element in it is relatively reasonable. However, all the hysteretic loops are not very exact.In the end, the study on the hybrid column is summarized, and some suggestions are proposed, to the design and further study.