Bemessung und Ausführung von Verbindungen mit Schließringbolzen im Stahlbau

Design and execution of joints with lock-bolts for steel structures.

A large number of mechanical joints for steel structures is generated with conventional bolts. Still, this proven joining technology has some significant disadvantages. These include the big scattering of inserting the preload using the torque-tightening method, the risk of self-loosening by cyclic loads causing a cross movement of the components as well as the low fatigue resistance for axial loads. The lock-bolt technology was already invented in the 1930s and mainly used for the aviation and space industry in support of its evident advantages. Due to demands from different industrial markets, like aviation, truck, trailer, rail, bus, agriculture, mining, military and steel construction industry, the lock-bolt technology was further developed and applied. Its application, particularly in the mechanical engineering sector, was mainly possible due to individual investigations performed by the users of the technology. These investigations were costly but necessary due to the lack of consistent design rules, which hindered a broader implementation and the calculation of lock-bolt connections in the construction and building industry. Within the scope of several research projects funded by the AiF (German Federation of Industrial Research Associations) the Fraunhofer-Application Center for Large Structures in Production Engineering successively developed calculation rules, which will be introduced to the reader within the scope of this paper with the aim to utilise the advantages of this joining technique. Furthermore, the applicability in the building industry with general technical approvals will be exemplified and current applications demonstrated.