Seismic Behaviour Of Steel Plate Shear Walls And Composite Shear Walls With Two-Side Connections

The steel plate shear walls with two-side connections and the steel- concrete composite shear walls with two-side connections that are connected only with frame beams by high-strength bolts or welding seams, possess the following advantages over the shear walls with four-side connections: They can reduce the reliability on frame columns and thus prevent the premature failure of columns. They can also be placed along the spans with small span-depth ratio specimens to accommodate the arrangement of doors, windows and corridors. They can modify the stiffness and strength of steel shear walls by changing the dimensions and number of the wall plates. In this dissertation, the steel plate shear wall with two-side connections, the slited steel plate shear walls with two-side connections, and the steel-concrete composite shear walls with two-side connections, by the way of combined experimental and theoretical research, were analyzed systematically from the aspects of elastic buckling analysis, experimental research and finite element analysis. Seismic behaviors and load-bearing mechanism were investigated and simplified computational methods and design suggestions were proposed for applications in engineering practice. The main works are listed as follows:(1)The elastic buckling analysis was carried out on the steel plate shear walls with two-side connections and with other two sides free, the steel plate shear walls with two-side connections and with other two sides constrained, and the steel plate shear walls with two-side connections and with other two sides stiffened. The calculation formula of elastic buckling strength was established and the critical rib stiffness ratio was proposed as main parameter measuring the constraining effect of ribs. A quasi-static test of one steel plate shear wall with two-side connections and with other two sides free and two steel plate shear walls with two-side connections and with other two sides stiffened were carried out under cycle horizontal loads to obtain the energy dissipation capacity and deformation characteristics. Experimental results showed that, steel plate shear walls with two-side connections performed high initial stiffness and bearing capacity. Tension field formed along diagonal line in elastic-plastic stage, developed the post-buckling strength to bear loads and dissipate energy, so that good energy dissipation and ductility can be reached. Finite element method was employed to study the shear-resistant static behavior, and further more, the load-bearing mechanism and the influence of main parameters were investigated, and finally design method of ribs was proposed.(2)The elastic buckling analysis was carried out on slited steel plate shear wall with two-side connections and other two sides constrained. The steel plates had a span-width ratio of 1.0 and 1~3 rows of vertical slits. Comprehensively considering the overall buckling of steel plate with slits and the local buckling of steel strips between slits, the slitting law, width-thickness ratio being less than 15 and depth-width ratio being more than 3, which makes the slited steel plate in-plane work and makes steel strips between slits form plastic hinges to bear loads and dissipate energy was proposed. Quasi-static tests on five steel plate shear walls with two-side connections and with other two sides stiffened was carried out under horizontal cyclic loads. The energy dissipation capacity and deformation characteristics were analyzed in detail and the mechanism of the walls under external loads was investigated. Finite element method was employed to study the shear-resistant static behavior, and further more, the load-bearing mechanism and the influence of main parameters were investigated, in which the parameters of steel strips between slits were the major factors to shear-resistant property. From the experimental research and finite element analysis, appropriate slitting law was put forward and verified. The steel plate shear walls satisfying the above law basically were kept in-plane working and performed relatively full hysteretic loops, which meant good ductility and energy dissipation capacity, although the initial stiffness and strength were significantly reduced compared with that of steel plate shear walls with two-side connections.(3)The computational method of composite shear walls'composite section stiffness and superposed section stiffness were proposed based on small deflection plate theory and computational formula of elastic buckling strength. Therefore critical concrete plate thickness completely restraining the out-plane deflection was obtained from the perspective of elastic buckling analysis. Quasi-static tests on six steel-concrete composite shear walls with two-side connections, and one steel plate-concrete composite shear wall with one row of slits and two-side connections were carried out under horizontal cyclic loads. Results demonstrated that the specimens with corners stiffened behaved high initial stiffness and strength, and the steel plates basically worked in-plane. The seismic behavior was substantially improved than that of steel plate shear wall with two-side connections, because the composite shear walls had full hysteretic loop, the good energy dissipation and ductility, higher stiffness and strength, more energy-dissipation area and larger energy-dissipation factor. Concrete slabs with proper design can make them to participate in bearing horizontal load in later period so as to increase the stiffness and strength of composite shear walls. Finite element method was employed to study the shear-resistant static behavior, and further more, the load-bearing mechanism was investigated, and consequently, the critical concrete plate thickness was proposed from the perspective of elastic-plastic analysis.(4)The simplified skeleton curve models of the above three types of shear walls with two-side connections were established, based on the property of steel plate in-plain working. An eccentric cross-bracing model, which facilitates the structural system analysis, was also proposed. The model, involving the differences of stress between the tensile field and compressive field, can simulate accurately the skeleton curves and more reasonably the interaction between beam and plate. In additions, based on the experimental research and theoretical analysis, design method and suggestions of the three kinds of shear walls with two-side connections were proposed.