Energy Dissipation And Self-Centering Capacities Of Posttensioning Precast Segmental Ultra-High Performance Concrete Bridge Columns

The research aims to better balance energy dissipation (ED) and self-centering capacities of posttensioning (PT) precast segmental ultra-high performance concrete bridge columns by adjusting common design parameters. A numerical model is established based on the equivalent plastic hinge model and validated by the cyclic loading test. The validated model is used to conduct a parametric study to investigate the effects of seven common design parameters on ED and self-centering capacities. The results show the proposed numerical model can accurately predict ED and self-centering capacities of the proposed bridge columns. The effect of the strength-yield ratio can be neglected when it is more than 1.2. The lower aspect ratio can first weaken and then improve the equivalent viscous damping ratio with drift ratio up, while the lower aspect ratio can reduce the residual drift ratio. With larger ED bar ratio, smaller unbonded length of ED bars and lower PT tendon ratio, the equivalent viscous damping ratio, and the residual drift ratio are significantly increased. It is not a perfect way to improve ED capacity by increasing the ED bar ratio, which can significantly magnify the residual drift ratio and limitedly enhance the equivalent viscous damping ratio, besides economical considering. Improving the gravity loading ratio and the initial PT stress are deemed to be effective ways to reduce the residual drift ratio because they not only have little influence on the equivalent viscous damping ratio but also result in no more costs.