Lateral Behavior of Precast Segmental UHPC Bridge Columns Based on the Equivalent Plastic-Hinge Model

摘要

The concept of an equivalent plastic-hinge model was used to evaluate the lateral behavior of precast segmental ultra-high-performance concrete (UHPC) bridge columns. The columns consist of precast UHPC segments that were integrated by unbonded post-tensioning (PT) tendons and complemented with energy dissipation (ED) bars. The equivalent constitutive relationships of the PT tendons and the ED bars were analytically derived to meet the plane section assumption for the sectional analysis. Cyclic loading tests were conducted on three specimens to validate the proposed equivalent plastic-hinge model. The test results revealed that the proposed model showed good accuracy for predicting the lateral skeleton curve, stiffness, and opening at the base joint. Using the validated model, a parametric study was conducted to investigate the effects of nine main design parameters on the lateral behavior of the column. The parametric study showed that increasing the PT level is more economical to enhance the PT force than relying on the larger ratio of the PT tendons when the PT level is no more than 44% of the yield strength. Finally, a simplified formula for the effective stiffness was developed through regressive analysis. The effective stiffness depended on the aspect ratio, the number and unbonded length of ED bars, and axial loading ratio.