Repair of Prestressed Concrete Beams with Damaged Steel Tendons Using Post-Tensioned Carbon Fiber- Reinforced Polymer Rods

Research implementing unibody clamp anchors and a simple mechanical stressing device to post-tension external, unbonded carbon fiber-reinforced polymer (CFRP) rods is presented. The experiments described in the paper concern three prestressed concrete beams: one was used as the control beam and the other two were damaged. Damage consisted of cracked concrete that was removed and internal steel tendons that were cut to simulate vehicle collision, corrosion, or both. The repair system was then applied to the two damaged concrete beams. The CFRP repair system performed well, increasing the ultimate strength and flexural capacity of the damaged beams to meet or exceed the strength capacity of the control. An analytical model considering the tendon stress at ultimate and the distribution of internal forces was developed to explore design recommendations for the use of the unibody clamp anchors and stressing device for post-tensioning CFRP rods.