Light FRP Strengthening of Poorly Detailed Reinforced Concrete Exterior Beam-Column Joints

Experiments have demonstrated the effectiveness of fiber-reinforced polymer (FRP) materials for the seismic strengthening of deficient reinforced concrete (RC) beam-column joints. However, only a few studies have focused on the seismic response of joint subassemblies that are designed to withstand moderate seismic actions where a strong column-weak beam mechanism is expected. In these circumstances, the high strain demand on the beam's plastic hinge may be critical for existing FRP-strengthening layouts. The present work analyzes the results of three experiments on full-scale, poorly detailed RC beam-column joints, with a strong column-weak beam hierarchy tested in the as-built and FRP-strengthened configurations. The proposed FRP-strengthening layouts are designed according to the recent trend of minimizing the level of disruption caused by their application. Accordingly, light FRP-strengthening solutions that are applied to the joint panel wholly from the exterior of a building or have a minimum impact on its downtime are tested and their performance is analyzed in terms of the global and local response.