Apex Joints between Rectangular Hollow Sections with Self‐Drilling Screws

Abstract In many light portal frames the section requirements for the rafter and the column are similar, so the use of similar rectangular hollow sections partially inserted one into another can be a good option for both eave and apex joints. The easiest way to connect members in these joints if the sections are thinner than 6mm is with self‐drilling screws. This work characterizes apex joints between partially sleeved rectangular hollow sections connected with self‐drilling screws. These easy‐to‐execute connections can be suitable for light portal frames, but it is necessary to classify them and establish some design rules and calculation methods before their use is extended. To this end, this paper presents an experimental work in which the moment‐rotation curves of the joints are obtained. The rotational stiffness and moment resistance are obtained from them, classifying the joints as semi‐rigid according to the Eurocode 3 1‐8 proposal. Finally, and considering the results of a previous characterization of the self‐drilling screws, a simplified component‐based analytical proposal is tested to obtain an adequate design equation for the rotational stiffness. The result is a first step to reasonably predict the structural behavior of this innovative joint in light portal frames.