Waves Engineering provides BS EN 14399-3 and BS 4395 Pre-loaded fasteners with thick nuts and long thread lengths in the bolt assembly to obtain ductility predominantly by plastic elongation of the bolt. The longer thread length is necessary to ensure that the induced strain is not localized. These bolts are relatively insensitive to over tightening during pre-loading although suite control is still important. Furthermore, if severely over-tightened during pre-loading the ductile failure mode of the bolt assembly is predominantly by bolt breakage, which is readily detectable.
High strength friction grip / structural bolting for pre-loading are supplied in two grades – Grade HR8.8 and HR10.9 – and in different coatings – such as Self-Colour, Galvanized, Zinc Plated and Hot Dip Galvanized.
Depending on the grade and selected tightening method, an additional component is required for installation (bolt face washer, nut face washer, direct tension indicators washer), which is not a standard part of the CE assembly.
Waves Engineering is one of only few companies available on the Qatar market, that is capable of supplying k-class K1 and K2 high strength structural pre-loaded bolt assemblies (System HR, EN 14399-1) for tightening with predefined torque values according to the k-factor.
Direct Tensions Indicator Washers (DTI Washers) are a specially designed component, allowing precise tension (preload) to assure correct force and reduce the risk of nut loosening or over tightening.