Weld access hole

The weld access hole or rat hole is a structural engineering technique that allows welding flanges of I-beams and T-beams across their full width and also minimize the induction of thermal stresses with a combination of partially releasing the welded section, avoiding welding the T section where the flange joins the web and improving cooling conditions.

The configuration adopted for web access holes also affects the performance of moment connections due to factors such as stress concentrations.