Failure Initiation of Reinforced-Concrete Beam-Column Connections — Binomial Logistic Regression Based Probabilistic Model

The inelastic mechanisms leading to failure (characterized by strength degradation) initiation in a weak-beam-strong-column reinforced concrete beam-column (RCBC) frame connection subjected to seismic loading are either non-ductile joint failure prior to beam yielding or a ductile mechanism of beam yielding followed by joint failure. Using an extensive assembled database of interior and exterior beam-column joints, binomial logistic regression models are developed to provide a probabilistic estimate of qualitative inelastic mechanisms based on quantitative design parameters obtained from specimen material and geometry. The relative importance of these quantitative parameters is also quantified in this research. The models provide opportunity to an engineer designing new connection to modify geometrical and/or material parameters to obtain ductile mode of response; an engineer retrofitting damaged connection to obtain an understanding of factors influencing initiation of strength degradation and thereby develop suitable retrofit measures for similar connections at eminent risk of failure.