چكيده به لاتين
In the first section of the present study, using the finite element method, investigates the effectiveness of fiber-reinforced polymers (FRPs) in improvement of the behavior characteristics of single and multi-story SPSWs by comparing the respective behaviors of infill wall and moment frame in reinforced and corresponding unreinforced SPSWs considering the wall-frame interaction. The effects of the system aspect ratio/height as well as the fiber type/orientation/content (thickness or number of layers) are also considered in the study. The results show that in general, the use of FRPs improves the system strength/energy dissipation/secant stiffness, while it adversely affects the system ductility and it has no significant or clear effect on the system initial stiffness/damping ratio. The use of FRPs slightly increases the level of stresses in the frame, while it delays the growth of stresses in the infill wall and therefore, affects the infill wall shear contribution wall in the initial stages of loading. In single-story SPSWs, the use of FRPs affects only the infill wall behavior, while in multi-story ones, it affects both of the infill wall and frame behaviors, due to a greater degree of interaction between them. The system aspect ratio is not important factor in evaluating the behavior of FRP-reinforced SPSWs.
In the second section of this study, the nonlinear behavior of single- and multi-story steel plate shear walls (SPSWs) strengthened with three different patterns of fiber reinforced polymer (FRP) laminates (including single-strip, multi-strip and fully FRP-strengthened models) is studied using the finite element analysis. In the research, the effects of orientation, width, thickness and type (glass or carbon) of FRP sheets as well as the system aspect ratio and height are investigated. Results show that, despite an increase in the system strength using FRP sheets, ductility of reinforced SPSWs is decreased due to the delay in the initiation of yielding in the infill wall, while their initial stiffness does not change significantly. The content/type/reinforcement pattern of FRPs does affect the nonlinear behavior characteristics and also the mode and pattern of failure. In the case of multi-strip and fully FRP-strengthened models, the use of FPR sheets almost along the direction of the infill wall tension fields can maximize the effectiveness of reinforcement. In the case of single-strip pattern, the effectiveness of reinforcement is decreased for larger aspect ratios. Moreover, a relatively simplified and approximate theoretical procedure for estimating the strength of SPSWs reinforced with different patterns of FRP laminates is presented and compared with the analytical results.
