Effect of combined vertical and horizontal shear links on nonlinear behavior of eccentrically braced frames

Abstract

In this paper, the nonlinear behavior of a proposed eccentrically braced frame (EBF) system with combined vertical and horizontal shear links (CVH-EBF) is investigated. Pushover analysis is first performed on the two types of the shear links, using 3D nonlinear shell elements model, to derive their shear-deformation behavior laws. Then, 2D spring-link elements are defined, by multilinear idealization of the behavior laws, and inserted in 2D frame model representing the CVH-EBF. Finally, a parametric study is conducted to examine the effect of the vertical link (inverted Y-scheme) stiffness on the whole frame system nonlinear behavior, on the out-link elements internal forces, and on the appearance of plastic hinges and their locations. All the results are compared to those of the conventional EBF system. It is shown that the vertical shear link significantly improves the seismic capacity of the system and induces reduction in other frame elements internal forces, particularly in shear horizontal link. Adding a vertical link to an EBF system may be an efficient solution to improve its global capacity. This link is especially interesting since it can be easily replaced after damage.