Performance of connection joints of beam-column structure using Ultra-high-performance concrete under full-scale tests

This study examines the application of Ultra-High Performance Concrete (UHPC) in precast beam-column joints to improve structural performance. The studied joints included both adequately and inadequately reinforced conditions (strong and weak joints), constructed using UHPC and deformed rebars. The strong joints allowed the rebars to reach their yield strength under the design bending moment, effectively transferring loads and maintaining structural integrity during service conditions. These well-detailed joints exhibited ductile failure behavior, which is a desired characteristic in reinforced concrete design. In contrast, the weak joints experienced premature and brittle failures, underscoring the importance of proper detailing and reinforcement length. Finally, a practical design scheme was developed to determine the appropriate rebar lengths in UHPC connections to ensure structural integrity and safety. Overall, the integration of UHPC into precast concrete joints significantly enhanced bond performance, improved load transfer mechanisms, and contributed to more resilient and reliable construction practices.