Structural Damage Assessment of FRP Strengthened Reinforced Concrete Beams under Cyclic Loads

Abstract

Worldwide, the need for structural retrofit is on the rise and the use of Fibre Reinforced Polymer (FRP) composite material systems is becoming an accepted method for repairs, rehabilitations, and strengthening of deficient structures. The great qualities of the FRP materials, certified in the laboratories and confirmed in the fields have all contributed to propel the material as a very promising one, though more works need to be done to certify the fatigue resistance and durability criteria. This research looked at the experimental investigations of Reinforced Concrete (RC) beams strengthened flexurally with externally-epoxy bonded FRP laminates under four point cyclic loads. Dynamic tests are used to assess damages in the FRP-strengthened RC beams under cyclic loads. 6 RC beams of 150 x 200 mm cross-section and length of 2.20m and were reinforced with four 12mm ribbed longitudinal steel bars. Three types of FRP laminates made of high modulus carbon fibre, high strength carbon fibre and glass fibre were adopted. The results confirm that dynamic-based method is an efficient way of assessing damage evolution in RC beams strengthened with FRP laminates under cyclic loads. The results offered a criterion that can be adopted for quick assessment of the efficiency of FRP composite systems before applying them to civil applications.