Nonlinear Finite Element Analysis of Inclined Beam–Column Connections With Reduced Beam Section Under Cyclic Loading

Abstract

Steel moment-resisting frames experienced significant connection failures during the 1994 Northridge and 1995 Kobe earthquakes, prompting extensive research into improved connection details. This study investigates the nonlinear seismic behavior of inclined beam–column connections incorporating Reduced Beam Section (RBS) configurations subjected to cyclic loading through advanced finite element analysis. The primary objective is to evaluate structural performance parameters including moment capacity, plastic rotation, ductility ratio, energy dissipation, and failure mechanisms of RBS connections at various inclination angles. A comprehensive three-dimensional nonlinear finite element model was developed using ABAQUS software, validated against experimental data, and subjected to parametric analysis involving different RBS geometries and beam inclinations. The hypothesis posits that inclined RBS connections demonstrate superior ductility and controlled plastic hinge formation compared to conventional vertical configurations. Results indicate that RBS connections at 15° inclination achieved optimal performance with plastic rotations exceeding 0.04 radians, demonstrating 32% higher energy dissipation capacity and improved ductility ratio of 3.45 compared to conventional connections. The study confirms that strategically designed RBS configurations in inclined beam–column assemblies effectively shift plastic hinge formation away from critical weld zones, enhancing overall seismic resilience of steel moment frames.