Flexural repair of hollow rectangular bridge columns failed due to earthquake-type loading

Abstract

The purpose of this research is to develop a repair technique for hollow-bridge columns that have failed, due to fracturing or buckling of longitudinal rebars, so that bridge function can be quickly restored after earthquakes. In order to validate the proposed technique, two full size and three scaled-down hollow bridge columns, which had previously failed under tests conducted in conjunction with other projects, were repaired using the proposed technique and subsequently retested. To restore the column's flexural strength, the fractured longitudinal bars were replaced with dog-bone shaped bars. In addition, a steel jacket was emplaced in the plastic hinge region in order to enhance the deformation capacity of the repaired columns. Test results showed that the damaged columns could be repaired within three days, effecting a 90% restoration of the original column's flexural strength and a comparable degree of restoration of ultimate displacement to the original columns. However, it was also found that there was only a 50% recovery of the column's original stiffness and ductility.