Seismic testing of high-strength steel eccentrically braced frames with a vertical link

Abstract

The link beams of eccentrically braced steel frames are relied on for energy dissipation through inelastic deformation, but the frames and braces should be elastic enough to resist the strain hardening effect of the link. To reduce steel consumption, high-strength steel with 460 MPa nominal yield stress is used in frames and braces, while normal-strength steel with 345 MPa nominal yield stress is used in vertical links. The seismic behaviour of high-strength eccentrically braced steel frames was investigated in this study. Two half-scale specimens were tested under cyclic loading; the only difference between the two specimens was the link length. The failure modes of the structure, the ductility and energy dissipation capacity were analysed. The experiments indicated that the main failures were concentrated in the short vertical link, while the frames and braces kept their elastic status. The bearing capacity of the shear yielding specimen was higher than the flexural yielding specimen, the ductility of the former was better than the latter and more energy was absorbed in the former than in the latter at the same displacement. The results indicate that this new structural system provides good energy dissipation and ductility and is an excellent dual resistance system.