Repair of Yielded and Buckled Reinforcement in Concrete
Excessive yielding and buckling of reinforcement occurs in severely damaged concrete structural members. The reinforcement may have buckled, elongated or excessively yielded in such members.
The causes for buckling and yielding of reinforcement in concrete structures occur due to unexpected application of loads for which the member was not designed or due to durability problems in concrete.
The unexpected load such as earthquake forces, increase in occupancy loads, heavy wind loads etc. Under such circumstances, the reinforcement in load bearing concrete members may buckle or yield.
Buckling and yielding of reinforcement may also occur in structures as it gets old and durability problems such as corrosion of steel reinforcement which may have reduced the strength of concrete.
Fig: Buckling of Reinforcement in RCC Column
The repair of fractured, excessively yielded and buckled reinforcement can be done by replacing the damaged portion of steel reinforcement with new steel using butt welding or lap welding.
Additional stirrup ties are added in the locations of damages and then jacket concreted to provide required confinement of concrete in the repaired zone and prevent future buckling of member.
Sometimes additional steel reinforcement will have to be anchored into existing masonry or concrete structural members. In such cases, a hole larger than the bar diameter is drilled. The hole is filled with grouting material such as epoxy, cement or other high strength grouting materials. The reinforcement bar is then pushed into place and held till the grout hardens.