Experimental and Numerical Studies on Load‐Bearing Behaviour of Small‐Diameter Bolted Connections

Abstract

In steel structures, bolted connections are commonly used as non‐preloaded shear and tension connections. Current design and execution rules mainly cover bolt diameters from M12 to M36, although smaller M6 to M10 bolts are widely used in practice for structures such as greenhouses, façades and roofs. However, existing standards such as EN 1090‐2 only extend the provisions for hole clearance and tolerance of M12 bolts to these smaller sizes. These values can be disproportionately large for M6–M10 bolts, which can significantly influence the load‐bearing behaviour and assembly. Consequently, regulatory gaps remain, often necessitating costly project‐specific approvals. To address this issue, in the frame of a German IGF‐FOSTA research project, comprehensive experimental and numerical investigations have started to study the load‐bearing behaviour of small‐diameter bolted connections under tension, shear and combined loading. Particular emphasis is placed on the influence of hole geometry, clearance and tolerance. The study covers carbon and stainless steel bolts of different property classes. This paper presents first results for M8 and M10 bolted connections, providing initial insight into their tensile, shear, and interaction behaviour.