Precast concrete elements for accelerated bridge construction are under-utilized in seismic regions. Connections and systems developed specifically for seismic performance can help deploy accelerated construction in seismic regions. This research assessed the seismic performance of a novel hybrid post-tensioned precast segmental pier specimens with emulative and non-emulative joints through large-scale quasi-static cyclic testing.
The pier is composed of three precast concrete column segments, and can be constructed with precast foundation and precast pier caps for rapid construction. The bottom column segment is connected to the foundation by a socket type joint that emulates cast-in-place connections. The upper two column segments are connected to the adjacent precast elements with non-emulative rocking joints, enabling self-centering after the removal of lateral load.
A simplified analytical model is developed to capture bending and rocking displacements that occur at emulative and non-emulative joints, respectively. A design procedure based on the model was developed to select important design parameters that are coupled with each other.
Pier specimens were constructed, where the bottom segment had varying material and design details: conventional concrete with mild steel, Ultra-high performance concrete (UHPC) with mild steel, and UHPC with high-strength steel. Specimens were tested under quasi-static cyclic lateral loading. The properties of UHPC were selected to achieve damage control and balance between bending and rocking through material scale testing.
The test results show that this novel precast concrete bridge pier can strike a balance between self-centering and energy dissipation, and that analytical models can predict the behavior relatively well. Tension was observed near the interface of emulative and non-emulative pier segments. The damage near the emulative joint included concrete cracking and spalling, and can be reduced when replacing conventional concrete with UHPC.