Test Of Storey Model And Analysis Method For Elasto-Plastic Seismic Response Of Tall Building Hybrid Structures

Tall building hybrid structures (TBHS), which are composed with steel frame and concrete core-tubes (shear-walls) or with composite steel frames and concrete core-tubes (shear-walls), become fast developing structure system of the tall buildings in China. They make full use of the respective advantage of the steel and concrete. The seismic response of the TBHS is an important criterion to decide whether such structure system should be widely popularized. To restrict the response of the structure in the elastic stage through structure design is not economic, so the seismic response of the TBHS is the hot spot for the scholars in recent years. The seismic performance of the storey model of the TBHS is researched through the low reversed cyclic loading test. Based on the existing research results, the study on the dynamic elasto-plastic analysis of the TBHS is improved and the nonlinear model of member, the algorithm of the member and structures and the simple analysis methods of some structures are discussed in this dissertation. The following aspects are mainly discussed:1. Six different types of the storey model of TBHS are researched through low reversed cyclic loading test and the hysteretic curves of each specimen are obtained. It can be concluded that the seismic performance of the steel frame-shear wall structure and steel composite frame-shear wall structure is better than that of the reinforcement concrete frame-shear wall structure from the curves. The influence of the axial compression ratio on the seismic performance of the structure systems is obtained by the value of ratio. The role of the outer frame in the TBHS to resis seismic action is showed throughout the test process.2. Numercical problems will appear when dealing with the declined segment of the force-deformation curve through the flexibility method, so the correct solution can not be obtained. The reason is analyzed and the solving method is put forward. Through the new method, the declined segment of the force-deformation curve is treated well comparing to the existing method and the defects of the existing methods are remedied.3. Through the mathematical and mechanical methods, it is proved that the multi-vertical-line-element model (MVLEM) is a nonlinear element model of the shear wall which is based on the Timoshenko beam theory. The mechanical properties of the MVLEM are analyzed systemically and the model is connected to the beam element of the continuum, so the fact that the properties of MVLEM can not be understood clearly from the model is put forward is changed. The meaning of C which is an important parameter of the MVLEM is analyzed. The effects of changing the value of C are pointed out. Then, based on the Euler-Bernoulli beam theory, an improved MVLEM is created. The solution is more accurate and the calculating speed is faster by adopting the new model. The differences between the two popular nonlinear models of the shear wall, MVLEM and multi-layer shell model are compared in theory and in practical applications through the examples.4. A simplified nonlinear element model of frame-tube structures is established. The model is based on the equivalent membranes analogy and the shear lag effect can be considered. Adopting the simplified model, the amount of calculation is greatly reduced and the model is suitable for quick evaluations of frame-tube structures in nonlinear analysis during the preliminary design stage. Then, the extension of such processing method to the tube structures is discussed.5. The dynamic elasto-plastic analysis are carried out on the low reversed cyclic loading test of the storey model of TBHS and a pseudo-dynamic experimental research of a 1/10 scale 15-storey steel-concrete hybrid structure. The results proved that the nonlinear element models of the TBHS adopted in this dissertation are validated and the demands of the structure design can be satisfied by using those models, but there are still some problems to be solved in the future.