Weathering Impacts on the Tightening Behaviour of HV/HR‐Bolting Assemblies for Preloading.

In order to secure a specified preload level, suitability tests for preloading of HV and HR high‐strength structural bolting assemblies according to EN 14399‐4 and EN 14399‐3 are mandatory according to the specifications given in EN 14399‐2. However, in EN 14399‐2 and EN ISO 16047 actual working conditions and processes on the construction site are disregarded: influences of high and low temperatures as well as storage conditions under changing wet/dry conditions, both summarized as weathering impacts, are not covered in the suitability test. Consequently, this leads to a lack of knowledge regarding the effect of weathering impacts on the basic preloading and tightening behaviour of HV and HR bolting assemblies. From practical experiences it is known that different extreme temperature conditions as well as moisture on the threads of the bolting components have an influence on the tightening behavior, which led to failures of the bolting assemblies during the assembly in the past. The presented contribution intends to provide a first insight into the influence of weathering impacts on the tightening behaviour of HV‐ and HR‐bolting assemblies for preloading on the basis of tightening tests of HV and HR bolting assemblies under various temperatures (‐20 °C, +23 °C, +50 °C) and moisture conditions (dry, hoarfrost, little direct/indirect rain impact, changing dry/wet condition etc.). [ABSTRACT FROM AUTHOR]