Seismic Behavior Study On Multi-lateral Resistant Mixed Structure System

The steel-concrete mixed structure has been extensively applied in high-storeyed buildings and over high-storeyed buildings recently. The advantages of steel structure and concrete structure, such as high stiffness, superior fireproofing performance and low project cost, are displayed sufficiently in the mixed structure which is taken as a new type of structure and widely used in high buildings. Multi-lateral resistant mixed structure system was studied in this paper, which was composed of semi-rigid connection steel frame equipped with the buckling restrained brace and concrete core-tube.In allusion to the several problems about the multi-lateral resistant mixed structure during application, the following studies focused on the seismic behaviors have been conducted in this paper:1、The simplified model of the multi-lateral resistant mixed structure system was established in this paper. According to simplified formula of lateral displacement under the action of inverted triangle horizontal lateral loads, three groups of 18 simplified model of the same elastic lateral stiffness were designed. Through the dynamic elastic-plastic time history analysis under the action of the three different intensity earthquake, the relationships between the maximum layer lateral displacement and the stiffness ratios of the frame, brace and core tube are studied; Shear wall at the bottom(core) was evaluated based on the new modified Park-Ang damage model. The relationships between the damage degree and the stiffness ratios are studied. The design factors of best stiffness ratios were suggested according to the study of the maximum layer lateral displacement and the damage degree of the shear wall core.2、A 12 layer three-dimensional multi-lateral resistant mixed structure was designed based on the best stiffness ratios which was put forward in this paper. The dynamic elasticplastic response of this model was analysised under the action of the the rare earthquake, from multi-dimension like the structure deformation, stress, damage and energy response to compare the seismic performance of this structures system.3 、 Keeping the basic design model parameters unchanged, five models were designed by changing the layout forms of braces. Through the elastic-plastic time history analysis under the action of the rare earthquake, the layout of braces for the structural deformation were studied. Based on the seismic behavior of the energy response analysis, from the views of the hysteretic energy dissipation accounted for of the whole structure and the relationship of hysteretic energy dissipation distribution, the layout forms of braces for the hysteretic energy were studied. The advantages and disadvantages of the layout forms of braces were discussed, which are the reference for the design of multilateral resistant mixed structural system.