Research on seismic resilience of prestressed precast segmental bridge piers reinforced with high-strength bars through experimental testing and numerical modelling

摘要

Precast segmental bridge piers are vigorously pursued, especially in low- and medium- seismicity regions, for their merits in accelerating construction, reducing environmental/traffic disturbances, enhancing quality control, etc. Recently, unbonded tendons are utilized to reduce the residual displacement and to facilitate fast rehabilitation of key bridges in the urban traffic system. To further enhance the resilience, prestressed precast segmentally-erected (PPC) piers were fabricated and tested, reinforced with a hybrid of unbonded tendons and high-strength (H) energy dissipation (ED) bars. In this study: (1) cyclic loading tests for the PPC piers with "H" ED bars were reported, and the seismic resilience was quantitatively evaluated and compared with the PPC piers with normal-strength (L) ED bars; (2) the computationally efficient fiber-based finite element (FE) model is developed for the tested PPC piers. Experimental results demonstrated that the "H" ED bars brought out apparent amelioration, in terms of load-carrying, ductility and self-centering capacities. In consideration of rising seismic resilience, "H" ED bars are recommended to replace currently large-scale adopted "L" ED bars in the PPC pier of vital bridges. Through validation with experimental results, the proposed fiber-based FE model is able to provide satisfactory predictions for seismic responses of the tested PPC piers.