Flexural behavior of reinforced concrete one-way slabs strengthened via external post-tensioned FRP tendons

摘要

External prestressing is an efficient technology to strengthen existing structures, and using fiber-reinforced polymers instead of steel in external tendons is advantageous to avoid corrosion-related problems, though anchoring external fiber-reinforced polymer tendons is still a major issue. An innovative anchoring technology is proposed in this paper for the external fiber-reinforced polymer tendons aimed to strengthen one-way reinforced concrete slabs. Six slab specimens were designed and manufactured to check the feasibility and reliability of the proposed technology. In one slab no external prestressing was applied (reference slab), while the remaining five slabs were strengthened by means of external post-tensioned glass fiber-reinforced polymer tendons, using the proposed anchoring system. The strengthened slabs differ for the prestressing level and external-tendon ratio. All slabs were tested up to failure and their flexural behaviors and failure modes were thoroughly investigated. The tests show that the proposed anchoring technology is reliable and efficient. A method for the calculation of the stress in the tendons at ultimate is also proposed. Finally, the numerical results are shown to agree fairly well with the test results.