Finite Element Analysis of the Damage and Failure of RC Structural Components

Reinforced concrete (RC) structures constitute a significant portion of the building inventory. The quantitative performance assessment for such structures under extreme loading events is necessary to characterize the vulnerability of built communities to natural hazards. Three-dimensional finite element analysis of RC structures has been gaining popularity, due to its capability to capture the damage accumulation and the interaction of various mechanisms ultimately leading to structural collapse. This presentation is aimed to provide an insight on the use of three-dimensional, continuum-based models for the analysis of structural components under cyclic lateral loads, such as those experienced during an earthquake. A recently developed triaxial constitutive model for concrete is combined with a material model for reinforcing steel which can account for rupture due to low-cycle fatigue. The strain penetration effect is also explicitly accounted for in the models. The reinforcing steel bars are represented with nonlinear beam elements to explicitly account for buckling of the reinforcement. The modeling scheme is implemented in an explicit finite element program, which includes large-deformation formulations and element removal techniques to capture loss of concrete cover and rebar rupture. The analytical tools are validated with the results of experimental static and dynamic tests on RC columns and walls. The validation analyses are supplemented with a discussion elucidating modeling aspects, such as the well-established spurious mesh size effect for softening material response with the corresponding regularization procedures, and the significance of accurately modeling the bond-slip of the steel reinforcement.