Seismic Performance of Exterior Beam-Column Joints with Varying Diagonal Bars Diameters

Beam-column joints (BCJs) are structural components that are prone to failure. BCJ failures, triggered by earthquakes, can result in severe structural collapse. Joint damage can be reduced by adding diagonal bars. This study investigates the effectiveness and effect of changing the diagonal bar diameter as joint shear reinforcement in exterior reinforced concrete beam-column joints under cyclic loading. The joint geometry, material properties, and baseline details were adopted from Chalioris' research data. The Finite Element Method (FEM) with ATENA software was used to analyze joint performance with variation of diagonal bar diameters 8 mm, 10 mm, 12 mm, and 14 mm. Increasing the diameter of the diagonal bars increases the load capacity but does not always result in increased energy dissipation. Diagonal bars with a 14 mm diameter provide higher stiffness but decrease ductility. The findings show that well-designed joint reinforcement improves seismic performance, increases structural durability, and reduces the likelihood of major post-earthquake repairs.