PEER has just published Report No. 2015/13 titled “Self-Centering Precast Concrete Dual-Steel-Shell Columns for Accelerated Bridge Construction: Seismic Performance, Analysis, and Design”. It was authored by Gabriele Guerrini, Jose I. Restrepo, Athanassios Vervelidis and Milena Massari
This study presents an innovative bridge column technology for application in seismic regions. The proposed technology combines a precast, post-tensioned, composite steel–concrete, hollow-core column with supplemental energy dissipation, in such way to reduce on-site construction burdens and minimize earthquake-induced residual deformations, damage, and associated repair costs. The column consists of two steel cylindrical shells, with high-performance concrete cast in between. Both shells act as permanent formwork. The outer shell substitutes the longitudinal and transverse reinforcement, as it works in composite action with the concrete, whereas the inner shell removes unnecessary concrete volume from the column, prevents concrete implosion, and prevents buckling of energy dissipating dowels when embedded in the concrete. Large inelastic rotations can be accommodated at the end joints with minimal structural damage, since gaps are allowed to open at these locations and to close upon load reversal. Longitudinal post-tensioned high-strength steel threaded bars, designed to respond elastically, in combination with gravity forces ensure self-centering behavior. Internal or external steel devices provide energy dissipation by axial yielding. This report reviews the main principles and requirements for the design of such columns, presents experimental findings from two quasi-static reversed cyclic tests, and proposes numerical simulations of the observed behavior.