Development of a corrugated web shear link for steel moment-resisting frames

Abstract

Seismic codes set a minimum beam span-to-depth ratio for steel moment-resisting frames (MRFs) to ensure the formation of sufficiently long flexural plastic hinges at the beam ends. This requirement restricts the application of deep beams in framed-tube structures. To resolve this problem, this paper proposes using a replaceable corrugated web shear link at the beam mid-span. The proposed link is designed to ensure shear yielding in the link and prevent the formation of flexural plastic hinges at the beam ends. Given the use of a corrugated web in the proposed link, it eliminates the need for intermediate web stiffeners, which not only makes the link less expensive to build but also reduces the possibility of web fracture due to low-cycle fatigue by reducing the amount of welding involved in the construction process. The proposed design also makes it possible to replace the links damaged by strong ground motions, which improves the resiliency of the structure. The seismic performance of the proposed link was studied by experimentally-validated finite element modeling and analysis. For this purpose, single story-single bay MRFs with different span-to-depth ratios with and without the proposed system were modeled and analyzed under cyclic loading. In the numerical models, the corrugated webs of shear links were constructed with trapezoidal, zigzag, and curved geometries with different numbers of half-waves and corrugation angles. The results showed that the proposed system has lower strength degradation, more ductile behavior, and higher deformation and energy dissipation capacities than conventional MRFs.