A Fully Precast Pier System for Accelerated Bridge Construction in Seismic Regions

Abstract

As the demands on the country’s aging infrastructure continue to grow, new methods of construction that prioritize speed of construction, reliability, and environmental impact will have an outsized impact on how the country rebuilds and rehabilitates its infrastructure. Accelerated bridge construction or ABC for short, is one such method that is already being implemented in many states in the United States, such as Idaho. Precast concrete offers many advantages for ABC. The use of precast concrete for bridge substructures in seismic regions is of great interest but the required detailing of connections needed to sustain the forces and displacements generated by earthquakes is a challenge. In addition, having adequate construction tolerance between precast elements is important. As such, this research proposes a new fully precast pier system that employs ABC methods for applications in seismic regions. The system offers many advantages, in addition to better construction tolerances compared with some previously investigated connections between precast elements. The seismic performance of the system is experimentally investigated using large-scale structural testing and subsequently compared to the benchmark cast-in-place (CIP) specimens. The proposed precast system uses structural steel tubes (pipes) filled with concrete in the plastic hinge zones that are meant to serve as seismic energy dissipaters enhancing the structural performance of the pier. In this type of connection, the concrete filled steel pipe provides shear/flexural resistance as well as confinement to the concrete at the plastic hinge. Results from the large-scale structural testing of the proposed ABC precast pier and benchmark CIP pier showed that the former outperformed the latter in various aspects. Given the superior performance of the precast system investigated in this research, it has been implemented in a bridge in Idaho located in an area of high seismicity.