CYCLIC LOAD-DRIFT BEHAVIOR OF EXTERIOR BEAM-COLUMN JOINTS RETROFITTED WITH ULTRA-HIGH-PERFORMANCE CONCRETE

Abstract

Exterior beam-column joints play a crucial role in the seismic performance of reinforced concrete (RC) frame structures, yet the application of Ultra High Performance Concrete (UHPC) for strengthening them remains limited despite its potential. This study evaluates UHPC’s effectiveness in enhancing the load capacity and seismic behavior of these joints. Three full-scale specimens—one conventional RC joint designed for high ductility (DCH) per Eurocode 8, and two UHPC-retrofitted joints without stirrups—were tested under cyclic loading. The UHPC-retrofitted joints exhibited load capacities 18.9% and 24.5% greater than the control, along with improved drift and energy dissipation. These findings demonstrate UHPC’s potential to enhance seismic resilience and offer a viable retrofitting solution for RC structures in earthquake-prone regions. However, the limited use of UHPC highlights the need for further research to promote its broader adoption in structural design.