Behaviour of fibre-reinforced beams with diagonal reinforcement

Diagonal reinforced coupling (DRC) beams can provide excellent strength, stiffness and energy dissipation capacities. However, fabricating DRC beams at construction sites is difficult due to reinforcement congestion and interference among the reinforcements due to the complex arrangement required by current design provisions. The objective of this study is to simplify the reinforcement details of DRC beams by reducing the transverse reinforcement around the beam perimeter that is required for the confinement of DRC beams. This is achieved by using high-performance fiber-reinforced cement composites (HPFRCC) for DRC beams. Experiments are conducted using six specimens under reversed cyclic loads to evaluate the hysteretic behaviours of the HPFRCC DRC beams. The test results show that the use of HPFRCC in DRC beams is very effective, providing a confinement effect with transverse reinforcement. HPFRCC DRC beams with half the transverse reinforcement required by ACI 318-11 provide almost identical energy dissipation capacities as concrete DRC beams detailed according to ACI 318-11.The authors would like to acknowledge the financial support provided by the National Research Foundation of Korea (no. 2014R1A2A1A11049488)