Investigations Of The Hysteresis Performance Of The Steel Frames Infilled With Composite Panels

Generally, the infilled walls in frame structures are intended to serve as internal partitions or external claddings. Therefore, the structures are always designed without taking account of the infilled walls in the overall behavior of the buildings. Nevertheless, although infilled walls are considered as non-structural parts in a frame, it has been widely recognized that the existence of infills within the interior of the buildings considerably improve their lateral stiffness, ultimate strength and energy dissipation capacity against earthquakes. In the present paper, cyclic loading tests were carried out on the steel frames infilled with composite panels, and then ABAQUS was used to conduct the numerical simulation, and finally, a simplified calculation model was proposed. Major achievements of the dissertation are as follows:(1) Low cyclic loading tests on eight full scale one-bay, one storey test specimens were carried out. Six mainly influential parameters including panel thickness, panel type, panel position, column orientation, beam-to-column connection type and connecting method of panel to steel frame are considered. Seismic behaviors are evaluated according to the experimental phenomena, hysterics loops, skeleton curves, curves of strength degradation, and curves of stiffness degradation, ductility index and viscous damping coefficient. Test results show that the failures of panels mainly occurred around the embedded parts, but the integrity of the panels is better than the traditional walls. The success of connection between panel and steel frame is significant to the mutual work of the two parts. Both of increasing the panel thickness and strengthening the connection can improve the seismic behavior of structure. Finally, seismic design recommendations based on the analysis of ductility index and energy dissipation of the structures are presented.(2) ABAQUS/Standard was used to conduct non-linear analysis on the structures. In the numerical simulation, Beam elements and Shell elements were adopted to simulate the steel frames and composite panels respectively, and the reinforcements of panels were defined in the shell elements. The column bottom was treated as key parameter, so not only the slip of the column bottom was measured; bus also the rotational stiffness was computed. As a whole, a good agreement can be found in stiffness and strength, but the energy-saving capacity was overestimated. (3) A simplified calculation model was proposed based on the existing research results. The composite panel was replaced by an equivalent strut, of which the width can be obtained by assuming the lateral stiffness of the strut equals to that of the panels. Different reduction parameters of stiffness were given for each specimen, and a reasonable value was suggested.