Theoretical Procedure and Empirical Models to Fast Estimate Seismic Ductility of HSC-HSSB Column Considering Buckling

Abstract

The collapse resistance of reinforced concrete (RC) columns with high-strength concrete and high strength steel bar (HSC-HSSB) considering the buckling effect of longitudinal bars is investigated. A theoretical procedure is proposed in this paper, which can convert the discrete longitudinal reinforcement and the two-dimensional fiber section into a uniform ‘steel ring’ and a one-dimensional model with the thickness information of each material. The variable interval integration approach is used to significantly improve the procedure efficiency, and accuracy of procedure is verified by the existed experimental data. On this basis, the massive data sample of collapse capacity considering buckling is efficiently obtained to propose an empirical mathematical model. Through this model, the influence of the crucial factors on collapse performance are further quantitatively analyzed, which would significantly facilitate the development of appropriate preliminary designs. The analysis results reflect that ultimate limit curvature and curvature ductility decrease when considering bar buckling (ϕuB), and the model quantitatively reflects this phenomenon is derived. The limit curvature without considering buckling (ϕu) is about twice as large as ϕuB, and with the increase of fco and fy, effect of buckling is becoming increasingly apparent.