Self-Centering Precast Concrete Dual-Shell Steel Columns

The testing, modeling, and design of an innovative bridge column technology for application in seismic regions is presented in this paper. This structural solution combines a precast concrete hollow-core column with selfcentering behavior and energy dissipation. The column consists of two steel shells running for its full-height, with concrete sandwiched in between. The shells act as permanent formwork, the outer one substituting longitudinal and transverse reinforcement, the inner one preventing concrete implosion. Large inelastic rotations can be attained at the end joints with minimal structural damage, since gaps are allowed to open in tension at these interfaces and to close upon load reversal. Self-centering behavior is ensured by post-tensioned longitudinal bars, which are designed to respond elastically. Energy dissipation is provided by internal or external steel devices which are allowed to yield axially. Experimental findings from quasi-static tests are shown, and numerical simulations of the tests as well as design considerations are discussed.