Stress concentrations due to misalignment at butt welds in plated structures and at girth welds in tubulars

Butt welds are important connections for the integrity of most types of welded structures. In this paper some of the work that provides a basis for stress concentration factors for butt welds in plated structures, tubular sections, foundation piles, pipelines and shell structures is assessed. Eccentricities at plate thickness transitions and with fabrication tolerances give increased hot spot stress due to local bending when the plates are subjected to in-plane loading. This paper includes improved equations for stress concentration factors for girth butt welds in tubulars based on calibration with numerical data obtained from axisymmetric finite element analyses. In addition it includes recommendations on stress concentration factors to be used in fatigue design rules and for fatigue assessment of plated structures, tubular sections of different diameter to thickness ratios, foundation piles and pipelines.