Repair Strategies for Earthquake-Damaged CFST Bridge Columns: Fid-Bau Portal

Repair Strategies for Earthquake-Damaged CFST Bridge Columns

Bumstead, J. / Korat, J. / Stephens, M. T.

Concrete filled steel tubes (CFST) are composite structural elements which provide an economical alternative to traditional RC columns for their ease of construction and efficient structural properties. Recent research has resulted in practical and structurally robust CFST column connections for highway bridge construction in seismic regions. One such connection, referred to as the embedded ring (ER) connection, is a fully restrained, full-strength moment resisting connection which relies on an annular ring, welded to the end of the steel tube, and embedded in the cap beam or foundation. This paper is focused on the development of practical repair strategies for the ER CFST connection following seismic events. Several repair strategies which rely on plastic hinge relocation have been numerically investigated. In each strategy, the damaged region of the CFST is encased in a concrete pedestal, and different methods are used to transfer force from the CFST column into the pedestal. Namely, shear studs, steel rings, and simple weld beads have been investigated. Preliminary results indicate that all repair methodologies are effective shifting inelastic deformation away from the damaged region and restoring the stiffness and strength of the CFST column.