Rapid repair and replacement of earthquake-damaged concrete columns using plastic hinge relocation

Abstract

A rapid repair and replacement method is developed for earthquake-damaged concrete columns. Headed steel bars enclosed in a carbon fiber-reinforced polymer (CFRP) shell filled with non-shrink concrete are used to relocate the column plastic hinge. The method employs a steel collar with steel studs to increase bond of the column to non-shrink concrete within the CFRP shell. Two columns were damaged under quasi-static cyclic loads and were repaired with this method. The first column required epoxy injection of the cracks to restore stiffness; the second column was completely severed from the cap beam before repair to simulate replacement of a column with unrepairable damage. The plastic hinge was successfully relocated, the lateral force and displacement capacity were restored, and failure of the repaired columns included concrete crushing and steel bar fracture. This is an accelerated bridge construction method that could be used to repair columns with repairable damage as an emergency repair, replace columns with unrepairable damage, or construct new bridges.