Method for estimating fatigue damages of bracing members based on plastic strain energy

Bracing members in concentrically braced structures may be subjected to large cyclic deformations due to local buckling during a severe earthquake causing possible early fractures. This paper presents an empirical criterion with its algorithm patterns, which may be included in the dynamic analysis of concentrically braced structures, to predict the fracture of welded I-Section bracing members on the basis of experimental data. Comparing experimental results with the numerical analytic results using the criterion, it is found that the criterion employs the cyclic plastic strain energy of bracing members as fatigue damage parameters and can be applied to real-time estimation of low-cycle fatigue damage of bracing members under a loading history-dependent random state.