Probabilistic Seismic drift-based capacity model of unbonded prestressed reinforced concrete columns: Prediction model and dispersion

Abstract

Structures designed with high ductility often have significant residual displacement. As a self-centered structure, unbonded prestressed reinforced concrete (UBPRC) columns can effectively reduce residual displacement. However, the quantitative analysis of their structural capacity is still insufficient, and further research is needed to quantitatively analyze the effects of various design parameters. In this study, predictive expressions for the drift limit states of UBPRC columns were derived based on a well-calibrated nonlinear finite element model. The effects of the design parameters, including the aspect, reinforcement, axial load, and prestressing force ratios, and the strengths of the reinforcement and concrete, on the drift limit state of UBPRC columns were studied. The results indicate that the aspect ratio, axial load ratio, yield strength of the longitudinal reinforcement, and transverse reinforcement ratio are the primary parameters affecting the drift capacity of UBPRC columns. In addition, these parameters have a logarithmically linear relationship with the drift ratios under different limit states. Accordingly, 58 (390,625) models were established in OpenSees, and simple and reliable predictive expressions for estimating the drift capacity were obtained through multivariate regression analysis. Moreover, after considering the uncertainties in the materials, it was observed that the capacity of the UBPRC columns exhibited a lognormal distribution. Based on the proposed predictive expression and uncertainty of the materials, the dispersion of the capacity of each limit state was obtained, which can be used in practical applications.