Low-cycle fatigue performance and damage sequence investigation of I-shaped steel braced systems and braced frames

Abstract

Simulations of 12 braced systems (I-shaped steel (Q355B) brace with the gusset plate connection) and 5 braced frames (single diagonal) are conducted. The results show that the low-cycle fatigue life of the braced system and the braced frame is determined by the minimum value of the fatigue life between the gusset plate connection and the brace. For the gusset plate connection, small value of clearance distance and large value of loading amplitude lead to small fatigue life. The ability for ductility property and energy dissipation of the braced system is optimal when the fatigue life of the gusset plate connection and brace is similar. The critical plane method (LZH model) and ductile damage method are applied to predict the fatigue life and investigate the fatigue damage of the specimens. These two methods have good applicability not only on fatigue life prediction but also the damage sequence of each component (including the gusset plate connection and the brace). Based on experimental data from related literature, fatigue parameters that are used in life prediction methods of steel Q355B (including the base metal and welding material) are calibrated.