This part of this European Standard specifies, together with prEN 14399-1, the requirements for assemblies of high-strength structural bolts and nuts of system HR suitable for preloaded joints with large widths across flats, thread sizes M12 to M36 and property classes 8.8/ 8 and 10.9/ 10.
Bolt and nut assemblies to this part of this European Standard have been designed to allow preloading of at least 0,7 fub´As according to ENV 1993-1-1 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt. For this purpose the components have the following characteristics:
¾ nut height according to style 1 (see ISO 4032)
¾ thread length of the bolt according to ISO 888
Bolt and nut assemblies to this part of this European Standard include washers according to prEN 14399-6 or to prEN 14399-5 (under the nut only).
NOTE Attention is drawn to the importance of ensuring that the bolts are correctly used if satisfactory result are to be ob-tained. For recommendations concerning proper application, reference to ENV 1090-1 is made.
The test method for suitability for preloading is specified in prEN 14399-2.