Modeling of reinforcing bar buckling in structural walls

Abstract

Buckling of longitudinal reinforcement is a critical damage state that is frequently observed in reinforced concrete structures after major seismic events that warrants the replacement of the structural component or render the entire structure unfit for rehabilitation if it is wide spread throughout the structure. The reason for the emphasis placed on adequate design/detailing against buckling of longitudinal reinforcement is that it inhibits the energy dissipation capacity of the reinforcing steel in the plastic hinge regions and consequently limits the ductile deformation capacity of the structure as a whole, especially if it occurs in a critical component of the lateral load resisting system such as structural walls. Buckling may also cause sudden loss of axial load carrying capacity in vertical structural members, triggering possible collapse mechanisms. Therefore, it is of utmost importance to demystify the factors affecting this phenomenon and accurately model it in order to improve the abilities of existing nonlinear finite element modelling approaches, which are essential for performance-based design and assessment of structures, so that engineers can predict and avoid this failure mechanism and therefore provide safe designs that would guarantee that the structure maintains its intended performance level under different earthquake intensity scenarios. Motivated by the aforementioned incentives, three constitutive hysteretic steel models incorporating buckling effects were proposed and investigated in this study by implementing them into the FSAFE model—an FE modeling approach to simulate the hysteretic lateral load behavior of RC walls—to assess each model’s effectiveness in capturing the bucklinginduced degradation in the lateral load-displacement responses of four wall test specimens.