Seismic Performance Assessment of a TMT Rebar

In this study, the behavior of thermomechanically treated Fe 500S rebar under cyclic loading in a completely reversed triangular waveform at ambient room temperature and strain amplitudes ranging from 0.3 to 1.0% has been examined to understand its behavior under seismic conditions. Low cycle fatigue behavior has been studied following the plastic strain energy approach while focusing on the failure mechanisms through critical examinations of the fracture surfaces. These have been supplemented with measurement of tensile property and characterization of microstructure. It has been observed that selected rebar undergoes severe cyclic softening until fracture at all strain amplitudes suggesting reduction of its seismic resistance. The studied material follows a near Masing behavior. The energy life equation is formulated which can be used for structural design purposes. Fatigue cracks always initiate at the rib roots and propagate adjacent to the rim section weakening the core for fast fracture.