Preloaded bolted connections with duroplastic gap filling materials

In steel construction, bolted connections are preloaded either for load-bearing capacity reasons or for serviceability reasons. Single and multi-section connections of wind turbines, offshore plants, bridges etc. are typical application examples. Imperfections due to fabrication and assembly may lead to a gap formation and consequently pose a risk e.g. for the controlled application of the required preload level as well as for the prevention of cavity corrosion. Therefore, the formation of gaps must be kept to a minimum. In cases where packing plates cannot be used, gap filling materials might be an alternative for gap compensation. MM1018 of Diamant Polymer GmbH represents a two-component reaction resin system based on epoxy resins. Within the framework of the German (ZIM) cooperation project Bri-San-T - DuroFüllSta, systematic investigations into the use of MM1018 (liquid and pasty) in preloaded bolted connections were carried out. In addition to the determination of slip factors according to EN 1090 2, Annex G under consideration of various practical boundary conditions such as gap thickness, curing time, temperature and surface condition, also relaxation tests were carried out to determine possible preload losses over the service life of the structure. The presented contribution intends to provide an insight into the main experimental findings for the gap filling material MM1018. © 2023 The Authors. Published by Ernst & Sohn GmbH.