This draft 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 × As ) 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.