Repair of Yielded and Buckled Reinforcement in Concrete
In cases where concrete structural members have been severely damaged, the reinforcement within them may exhibit excessive yielding or buckling. This can manifest as buckled, elongated, or overly yielded reinforcement within the member. The underlying causes for these issues can typically be traced back to either unexpected loads being applied to the member, for which it was not designed, or problems related to the durability of the concrete.
Unforeseen events such as earthquakes, higher occupancy loads, or heavy wind loads can place unexpected loads on load-bearing concrete members. In such situations, the reinforcement within these members may experience buckling or yielding. Additionally, as structures age, durability issues such as corrosion of steel reinforcement can occur, potentially reducing the strength of the concrete and leading to buckling or yielding of the reinforcement.
Fig: Buckling of Reinforcement in RCC Column
Repairing fractured, excessively yielded, and buckled reinforcement in structural members can be achieved through various methods. One common approach is to replace the damaged portion of steel reinforcement with new steel using either butt welding or lap welding techniques. Additionally, stirrup ties are added to the locations of the damages to provide additional support, and then a jacket of concrete is applied to the repaired zone to confine the concrete and prevent future buckling of the member.
In some cases, when additional steel reinforcement needs to be anchored into existing masonry or concrete structural members, a hole larger than the diameter of the reinforcement bar is drilled. The hole is then filled with grouting material such as epoxy, cement, or other high-strength grouting materials. The reinforcement bar is then inserted into the hole and held in place until the grout hardens, ensuring proper anchoring of the additional steel reinforcement into the existing structure.