Load‐deformation behaviour of preloaded connections with friction shims under static and cyclic loads

Abstract

Low‐deformation and fatigue‐resistant structures, for example in bridge construction, require non‐slip connections, which can be realized with high strength friction grip (HSFG) bolts, fitted bolts and injection bolts. In the case of HSFG bolts, the use of friction shims – a connection element developed in mechanical engineering – can result in an increased slip resistance, especially for corrosion protected components with rather low slip factors. In order to guarantee a safe and reliable application of friction shims in preloaded connections for bridge construction, various shim configurations and surface treatments have been investigated. The friction shims vary in the size of the (diamond) particles and the base or carrier material. Blasted coated and hot dip galvanized test specimens were considered as surface treatments, including variations in blasting abrasive, steel grade and galvanizing process parameters. In addition to material characterizations (roughness, layer thickness, microsections etc.), these investigations include static test according to EN 1090‐2, Annex G, cyclic tests to determine the fatigue resistance as well as FE‐simulations to analyse essential influencing parameters.