Numerical predictions of observed failure modes on non-ductile reinforced concrete frames

Abstract

This manuscript reports on numerical predictions of documented failure modes on two dynamic experimental datasets involving nonductile reinforced concrete (RC) frames. The numerical models are created using available methodologies in the Open System for Earthquake Engineering Simulation (OpenSEES). Failure mode limits are applied to the components' responses to identify flexural, shear on beam-column joints, pullout, and bond-slip failure modes observed in the experimental studies. The experimental datasets available are used in the assessment of the numerical predictions. The assessment of predictions indicated that the numerical models reproduce well the failure modes, global and local responses of the RC frames on the experimental datasets. The results demonstrate that (i) failure mechanisms involving pullout and bond-slip could dominate the collapse mechanisms on nonductile frames, and (ii) the underestimation of bond deformations on numerical analysis could overestimate section stiffness. The validated modeling methods are used to study the effects of the ground motion characteristics on the predicted failure modes. The results of numerical analysis of a 3-story frame under two sets of near-field and far-field ground motions highlighted the need to include modeling tools that capture bond-slip, pullout, and shear on joints. The formation of bond-slip under near-field motions is highly correlated to the motion's peak ground velocity levels, this correlation is less evident for far-field motions. Peak drift trends resemble the peak ground velocity trends for the near-field and far-field sets.