Experimental parametric study of perforated steel plate fuses for mass timber seismic force resisting systems

Abstract

The lack of practical connections with reliable desired energy dissipation capacity as the main components of a seismic force resisting system (SFRS) is a major obstacle in using mass timber in tall buildings located in seismically active regions. A common method to dissipate seismic energy in timber structures is through the yielding of steel material found in the mechanical connections. Under the induced seismic motions, these dissipative connections are intended to yield while the rest of the structure remains intact with minimum damage. In this research, the focus is on the use of perforated steel plate as a dissipating energy device and a seismic fuse. Previous tests have demonstrated the potential use of perforated steel plates as seismic fuses in mass timber SFRS and confirmed their scalability and predictability. Despite promising results under monotonic loading, their behavior under cyclic loading can be improved. This paper presents an experimental parametric study investigating the effects of the number of rows, shape, and size of perforations, the steel plate thickness, and the steel link size on the mechanical performance of the perforated plates. The obtained hysteresis responses and envelope curves are compared. It is found that the ellipse and stagger patterns possess the largest ultimate displacement and stiffness, respectively. In addition, no significant enhancement in the ultimate deformation was observed in the cyclic response of the fuse, beyond three rows of perforations. Within the range of the configurations considered, the reduced ultimate deformation under cyclic loading remains a technical challenge that needs to be addressed if this type of seismic fuse is to be installed in SFRS. The results will assist with the design of future test programs on full-size mass timber connections consisting of such fuses.