Stability of energy-dissipating steel fuses in an innovative seismic system for cold-formed steel structures

摘要

This paper describes modeling directed toward the development of an innovative energy-dissipating seismic system for buildings framed from cold-formed steel members. The system consists of shear walls with integrated butterfly-shaped steel links designed to yield under seismic action, thus acting as replaceable energy-dissipating fuses. The shear deformation of the wall under lateral seismic action induces shear and bending in the fuse links. The links yield nearly uniformly along their length due to their butterfly shape. However, the significant slenderness of the fuses, when sized for cold-formed steel structural applications, can make them prone to buckling; and, instability of the fuses is detrimental as it decreases their energy-dissipation capacity. The effect of buckling on the hysteretic response of the fuses and a cold-formed steel framed wall with fuses is investigated, and numerical simulations using a commercial finite-element software are carried out for both single steel links and an entire shear wall system. Parametric studies on single fuse links are performed to investigate their behavior and to estimate the occurrence of buckling. Formulas are provided to allow for selecting the number and size of fuses necessary to achieve a targeted seismic performance in terms of capacity and critical drift. The numerical results obtained by modeling the shear wall system with fuses show that a significantly improved hysteretic behavior, compared to conventional cold-formed steel framing sheathed with wood structural panels, can be achieved if fuse buckling is prevented. This demonstrates the potential feasibility of the new system in the construction industry. The paper also lays the foundations for future work, including dynamic analysis of a full building model with the proposed seismic system, and laboratory testing of shear walls with fuses to further validate the exploratory findings presented here.