The Influence of Steel Variability on the Reliability of Welded Beam‐to‐Column Joints

Abstract

Beam‐to‐column joints have a significant impact on the reliability of load‐bearing steel frame structures. Proper characterisation of the joint behaviour affects the distribution of internal forces and bending moments in frame structural members and affects their reliability level. This article addresses the effect of the variability of steel mechanical properties on the overall behaviour and reliability of welded beam‐to‐column joints. Monte Carlo simulations and parametric numerical analyses were performed to investigate the influence of the variability of mechanical properties on the behaviour (failure modes and resistances) of the joint and to generate data for the reliability analysis. Reliability analyses were performed to calculate partial resistance factors (γM1) for welded steel joints using the procedure given in Annex D of EN 1990. The analyses included the FprEN 1993‐1‐1:2022 and JCSS probabilistic models for mechanical properties of steel and two approaches for determining joint plastic bending resistance. It was concluded that FprEN model gives more favourable values of γM1. It was also found that the approach for determining joint plastic bending resistance can have a large effect on the partial resistance factor γM1 and ultimately on the reliability of the joint.