Experimental study on flexural performance of reinforced concrete beams subjected to different plate strengthening

Plate bonding technology is one of the most commonly used methods for strengthening existing structural beams. In this study, the strengthening effect caused by different plate materials, preloading conditions, end anchorage conditions was investigated at the same specimen scale. A total of nineteen reinforced concrete (RC) beams including two unplated (control) beams, five carbon fiber-reinforced polymer (CFRP) plated (CP-) beams, six carbon fiber plated (CC-) beams and six steel plated (SP-) beams were tested under four point bending. Tested parameters also include preloading condition, U-hoop end anchorage on carbon fiber plated specimen, and bolt anchorage on steel plated specimens. Finite element analysis was conducted to simulate the flexural properties of reinforced concrete beams strengthened by abovementioned strengthening methods. Results indicate that, compared with unplated specimens, all strengthened specimens showed improved structural behavior with steel plated specimens performed the best among all. In the same time, it shows that the pre-unloaded specimen is superior to load sustained specimen in cracking resistance, strengthening material utilization and strain lag between reinforcing steel rebar and strengthening materials. U-hoop end anchorage does not show significant influence on structural performance of CC- specimens. On the other hand, bolt anchorage improves ultimate capacity of SP- specimens significantly.