Keywords

Abstract

Beam-column joints; 

Rectangular spiral reinforcement; 

Cyclic loading; 

Seismic performance; 

Crack control; 

Energy dissipation

Beam-column joints are recognized as critical weak points in reinforced concrete (RC) frames, particularly in seismic zones. This study evaluates the seismic performance of conventional stirrup reinforcement versus an innovative continuous rectangular spiral reinforcement under cyclic loading conditions. Four full-scale specimens were tested, including a control specimen with conventional stirrups designed per IS 456:2000 and three specimens with varying rectangular spiral reinforcement configurations. Fe-500 grade steel was employed for longitudinal reinforcement, and Fe-250 grade mild steel for transverse reinforcement. Key metrics, such as load-carrying capacity, energy dissipation, and ductility, were analyzed to assess performance. The results reveal a substantial improvement in the seismic behavior of specimens with rectangular spiral reinforcement. BCJ-3 demonstrated a peak load of 45 N, 50% higher than the control specimen (30kN), while BCJ-4 showed a 25% improvement. Energy dissipation per cycle for BCJ-3 reached 450kN-mm, 80% more than BCJ-1 (250kN-mm). Cumulative energy dissipation for BCJ-3 peaked at 2200kN-mm, surpassing BCJ-1 by 57% and BCJ-4 by 35%. Additionally, the rectangular spiral specimens exhibited enhanced crack control, distributing and managing cracks more effectively under cyclic loading, thereby improving structural durability and resilience. These findings underline the potential of rectangular spiral reinforcement to significantly enhance seismic safety and stability in RC structures. By offering superior energy dissipation, higher load-carrying capacity, and better crack management, this reinforcement approach provides a robust alternative to conventional stirrups. The study provides valuable insights for updating design codes and promoting advanced reinforcement strategies to improve the durability and seismic performance of RC structures in earthquake-prone regions.

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