Cyclic performance of precast coupling beams with bundled diagonal reinforcement

• This study investigates the use of bundled diagonal reinforcement in coupling beams.
• The feasibility of precast construction of coupling beams is also explored.
• The effectiveness of diagonal reinforcing layout in slender coupling beams is examined.
• The precast coupling beams with bundled diagonal bars showed excellent performance.

Diagonally reinforced coupling beams designed according to current codes are expected to endure significant inelastic deformations during earthquakes. However, it is very difficult to fabricate the coupling beams in a construction site due to the congestion of reinforcement and the complex arrangement of diagonal reinforcement. For resolving the problems, this study developed precast coupling beams with bundled diagonal reinforcement. To verify the effectiveness of the proposed design method, experimental tests were conducted on four 1/2-scale coupling beam specimens subjected to cyclic loading. The test results suggest that the precast coupling beams with bundled diagonal reinforcement exhibited good ductility and energy dissipation capacities similar to those having code-specified diagonal reinforcement.