Ultrahigh-Performance Concrete for Posttensioned Precast Bridge Piers for Seismic Resilience

Precast concrete bridge substructures accelerate construction. Precast concrete piers can also limit residual displacements after earthquakes when used with nonemulative connections. This paper investigates the use of ultrahigh-performance concrete (UHPC) to eliminate damage under moderate to high seismic activity for posttensioned self-centering precast piers. Large-scale laboratory testing was used to assess damage in pier specimens. Specimens were constructed in segments, where the column segment above the foundation had varying details: conventional concrete with mild steel reinforcing bars, UHPC with mild steel reinforcing bars, and UHPC without mild steel reinforcing bars. Specimens were subjected to quasi-static cyclic lateral loading, allowing and disallowing shear slip. The use of UHPC led to minimal damage at displacements much larger than the seismic demand. The difference in damage of UHPC segments with and without mild steel reinforcement was negligible. A comparison of hysteretic responses of different specimens revealed that strength, stiffness, and energy dissipation depended on shear slip more than the material type when shear slip was allowed. For tests without shear slip, specimens with UHPC had higher strength and stiffness.