Experimental and analytical investigation on the behavior of metallic Box-Shaped Dampers (BSD)

A Metallic Box-Shaped Damper (BSD) which is introduced here, is an effective energy dissipator device which is very simple and low-cost. BSD is a box made of several steel plates which is mounted along diagonal members of a braced frame. The lateral movement of the structure leads to the formation of plastic hinge in the damper. The function of this damper is far from complex, and its governing relationships are derived from basic mechanical equations. The validity of these relationships has been verified by performing both experimental tests and numerical analyses. The wide hysteresis curve and the presence of two levels of plastic energy dissipation enable it to withstand moderate and severe earthquakes. Unlike many existing seismic dampers, the stiffness and strength of the BSD device, are not interdependent parameters and the designer can choose the required stiffness while keeping the strength constant. The existence of customizable parameters such as steel type, overall dimensions of the box and also thickness of steel plates provides excellent ability for designers to obtain desirable behavior in terms of ultimate capacity, stiffness and energy dissipation, hence, implementing an adjustable fuse in structures. Also, selecting the appropriate design parameters can minimize the maximum plastic strain, which further increases the displacement capacity of BSD. In this research, four specimens of BSD investigated experimentally in two types. The results of this research show that the hysteresis plot of the BSD is wide and ductility factor is 19.3 and 11.2 in tension and compression, respectively.