| Square concrete-filled steel tubular column-slab structure has become a new kind of structure system with the development of materials and facture technology. It has been more and more popular by structural engineers. This structure can not only play a functional flexibility in the using, but also take advantage of the excellent mechanical properties of the concrete-filled steel tubular column in load-bearing, so it has a wide range of adaptability. However, up to now, the working mechanism of square concrete-filled steel tubular column-slab structure under the horizontal load is still not clear, so that in the application, this structure is subject to more constraints on the design.In this paper, though the theoretical analysis and finite element analysis, the model of square concrete-filled steel tubular column-slab structures under the horizontal load, the equivalent space frame model and the dynamical characteristics of square concrete-filled steel tubular column-slab structure are systematically studied. The main contents covered are present as follows:1) With the aid of the finite element software ANSYS, the node models of square concrete-filled steel tubular column-slab structures with different dimensions are established. According to the principle that the top displacement of the square concrete-filled steel tubular column-slab connection equals to the one of the beam-column connection under the horizontal load, the calculating formulas of equivalent beam width coefficient are given by the elastic finite element analysis.2) The calculation models of equivalent space frame and equivalent plane frame for square concrete-filled steel tubular column-slab structures are established. In the thesis, the calculating results of equivalent plane frame model are considered to be " accurate " results. By comparing the board belt bending moment and maximum story drift under the horizontal load, several design suggestions about the division of intersecting-girdle in space frame are put forward.3) With the same column grid network, quantity of concrete and subjected the same loads, the models of full-scale structure,equivalent plane frame structure and equivalent space frame structure for square concrete-filled steel tubular column-slab structures are established using finite element analysis program. For each structure, the modal analysis and elastic dynamical time-history analysis after inputting seismic wave are calculated. The time-history displacement curve and the time-history story shear curve are compared among three kinds of structures., the comparison of the analytical results shows that the analytical model proposed in this thesis is feasible. |
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