HR fasteners

Currently, HR refers to hexagon bolt and nut assemblies according to standard EN 14399-3. These bolt assemblies are used in bolt connections of preloaded, load-bearing steel constructions.

All system components (bolt, nut, washers) must be produced by the same manufacturer. Preloaded bolt connections are used for ensuring slip resistance, for structures located in seismic regions or structures that are otherwise subjective to dynamic loads. Preloading is also utilized for improving fatigue resistance and long-term durability.

The HR system is to use thick nuts and long thread lengths in the bolt assembly to obtain ductility by plastic elongation of the bolt. The longer thread length is necessary to ensure that the induced strain is not localized.

It is strongly prohibited to mix up the HR system bolt assembly components. Bolts and nuts for both systems are standardized in separate parts of the product standard EN 14399 and clearly marked as components for separate systems.

HR bolt, nut and washers assembly for high-strength bolting manufactured by BERVEL GmbH includes the following types of fasteners (parts):

 

  •         Hexagon bolt for high-strength structural bolting with large width across flats DIN EN 14399-3-2015 (DIN 6914), ISO 7411:1984.

  •         Hexagon nut for high-strength structural bolting with large width across flats DIN EN 14399-3-2015 (DIN 6915), ISO 4775:1984.

  •         Plain washer for high-strength structural bolting, hardened and tempered DIN EN 14399-6-2015 (DIN 6916); ISO 7415:1984.