A novel efficient plastic hinge approach for direct analysis of steel structures

A robust and efficient plastic analysis method incorporated into beam-column elements is highly demanded for economic design and safety evaluation of structures under earthquakes and extreme events. This paper presents a novel approach for the direct analysis of steel structures allowing for material yielding by introducing an enhanced plastic hinge method to an advanced second-order beam-column element, which is derived based on a rigorous incremental-iterative force recovery procedure. The new element considers various critical factors at the element level, including transverse shear deformation, initial geometrical imperfections, and residual stresses. Thus, the approach enables the analysis and design of a wide range of steel structures using a single element per member, which contrasts with commercial software that requires many elements per member. Several benchmark problems are investigated and the results are in good agreement with those in literature and commercial software. The paper offers a reliable, efficient, and practical solution for direct analysis of steel structures in various engineering applications without the use of the conventional effective length method. • A 3D second-order beam-column element for direct analysis is derived based on a rigorous force recovery procedure. • An end-spring type refined plastic hinge approach is integrated into the proposed second-order beam-column element. • Accurate section stiffness models are introduced for both major and minor principal axes of wide-flange sections. • The consideration of transverse shear deformation, geometric imperfections, and residual stresses in members is included.