Seismic performance of repaired severely damaged precast columns with high-fiber reinforced cementitious composites

Post-tensioned precast concrete columns have advantage of re-centering capability for lateral movement by earthquakes. In this paper, cyclic tests were conducted for repaired and strengthened precast columns with severe damage by large lateral movement. Removing the damaged cover concrete and thickening by high performance fiber reinforced cementitious composite (HFRCC) was adopted. The jacket section had additional details of chemical anchors into the foundation and additional transverse reinforcing bars in the thickened concrete. The repair and strengthening increased the flexural strength and stiffness of prestressed precast concrete columns. The flexural strength of the repaired columns with additional chemical anchors was improved by more than 30%. When the shear failure of the jackets was prevented by adding transverse reinforcement, the repaired column showed stable flexural behavior at maximum load and thus enhances displacement ductility. Thickened jacket sections remarkably increased energy dissipation capacity through cracking and interface failure.