Full-scale testing of naturally buckling steel braces and evaluation of partially rib-strengthened sections to cumulative damage

Naturally buckling steel braces (NBBs) have been recently developed by the authors and co-workers to improve performance energy dissipation capacity of braced framed structures. In NBBs, a low-yield-point (LYS) channel high-strength (HSS) are connected using battens build up dual-material section. An intentional eccentricity is introduced along brace length subject bending loads in addition axial loads. Previous experiments demonstrated that this combined axial-flexural response stabilizes compression behaviour enhances its tensile post-yielding stiffness through novel deformation mechanism. paper, cyclic two full-scale NBB specimens with different section sizes eccentricities investigated experimentally. Gusset plate pin-connections accommodate in-plane used release ends from high ductility demands. Two low-cycle fatigue protocols increasing amplitudes repeated inelastic loading cycles at event local adopted. Test results show both exhibited stable hysteresis delaying onset 1.5 % story drift ratio (SDR). Notably, specimen larger provided strength under five 2.0 SDR. equivalent damping 0.4 was measured. experimental research, computational study performed aid finite element software ABAQUS evaluate partially strengthening method sections against buckling. It found NBBs can be enhanced 40% rib stiffeners critical locations, while use thicker provide further restrain growth 3.0% The paper develops physical equations support an analytical hysteretic model for predicting force-displacement relationship chevron NBBs. accuracy targeted conservatism proposed confirmed comparisons test results.