Numerical Study on the Influence of Web Corrugation Geometry on Cyclic Performance of Link Beams in Eccentric Braced Frames

Abstract

This investigation delves into the essential role of link beams within eccentric braced frames, serving as the key structural element responsible for withstanding the lateral drifts induced by earthquakes, even when subjected to substantial deformation. Due to lack of a wide comparative assessment on the influential variables on the cyclic response parameters and equivalent damping of the link beams with corrugated webs, a comprehensive parametric study was conducted in this investigation. To do so, a selection of 18 distinct case studies has been meticulously curated to consider several influential variables. These include the shape of corrugations, which could be trapezoidal or have a curved web plate, the specific angles at which the corrugated web plate is configured, as well as the number of angles or curvatures present in the web plate. To facilitate a thorough analysis, finite element micro models have been developed and subjected to both monotonic and cyclic shear loading conditions. The outcomes of these analyses reveal a notable improvement in the capacity for rotation and the efficient dissipation of energy as the angles and the number of angles in the corrugated web plates increase. Furthermore, the models with 90-degree corrugation (T-90) demonstrate ductility levels that are either on par with or surpass the benchmark model, as evidenced by ductility factors ranging from 12.34 to 17.85, compared to the F model's factor of 12.62. In addition, the T-90 models exhibit an enhanced cyclic response, as indicated by their higher overstrength Factor (Ω₀) values, which range from 1.36 to 1.41. These findings affirm the superior performance of the T-90 models compared to the F model. Remarkably, one of the case studies featuring a 90-degree web corrugation displays a higher ultimate capacity and a greater capacity for energy dissipation, all while using 4.5% less steel. This highlights the cost-effectiveness of implementing optimized corrugated link beams in structural designs.

Keywords

backbone / corrugated web / cyclic loading / cyclic response parameters / eccentric braced frame (EBF) / equivalent damping / finite element method / link beam

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