Seismic Performance of Lightly Reinforced Concrete Exterior Beam-Column Joints

This paper presents the experimental results of four lightly Reinforced Concrete (RC) exterior beam-column joints with and without beam stubs under cyclic loading with constant column axial force applied at the top of the column. The parameter investigated was the type of reinforcement used in the beam, i.e. plain and deformed bars. Test results showed that when the hooks anchored down in the column increased the tensile stress in the diagonal concrete strut in the joint core, this led to diagonal crack of the concrete and a decrease in the joint shear strength. The seismic performance of the exterior RC joints without beam stub was also observed to be much improved when the hook tail of beam reinforcements was bent inside the joint core. The strut-and-tie model based on the recorded strain in the joint transverse reinforcement could be used to determine the force flow in the joint core.