ČSN EN 14399-7

This European Standard specifies, together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural countersunk bolts and nuts of system HR suitable for preloaded joints with thread sizes M12 to M36 and property classes 8.8/8 or 8.8/10 and 10.9/10. Bolting assemblies in accordance with this document have been designed to allow preloading of at least 0,7 fub × As1) according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt. For this purpose the components have the following characteristics: - regular nut height according to style 1, see EN ISO 4032; - thread length of the bolt according to ISO 888. Bolting assemblies in accordance with this document include washers according to EN 14399-6 or to EN 14399-5. NOTE: Attention is drawn to the importance of ensuring that bolting assemblies are correctly used if satisfactory results are to be obtained. For recommendations concerning proper application, reference to EN 1090-2 is made. General requirements and requirements for suitability for preloading are specified in EN 14399-2. Clamp lengths and grip lengths for the bolting assemblies are specified in the normative Annex A.