Analytical study on seismic behavior of proposed hybrid tension-only braced frames

The first intention of this study is to enable tension-only bracing (TOB) as the main lateral load resisting system. In order to attenuate deteriorating of the TOB hysteretic behavior, a simple mechanical device, called slack-free connection (SFC), is proposed by which buckling/slacking would not occur in the TOB. Using the TOB-SFC system in parallel with a wire rope brace, an innovative bracing system, called hybrid tension only brace (HTOB), is proposed, which has a non-deteriorating hysteretic behavior with tunable post-yield stiffness. Adopting the so called Incremental Dynamic Analyses, sensitivity of the HTOB on its post-yield stiffness is explored and also seismic behavior of the proposed HTOB is compared to other representative lateral load resisting systems. Obtained results indicate that a minor increase in post-yield stiffness can substantially reduce maximum and residual deformations of the HTOB. However, compared to other representative systems, HTOB still tends to experience higher residual deformations. This is due to the fact that the elastic-to-inelastic transition in hysteretic behavior of the HTOB is very sharp. Meanwhile HTOB would generally result in less maximum deformations compared to other representative systems because of its large energy dissipation capability.