Connections shall be chosen and installed to achieve the required structural performance.

Steelwork connections should:

  • be in accordance with the guidance in this chapter, or
  • where other forms of connection (e.g. high strength friction grip bolts) are required, be designed by an engineer in accordance with Technical Requirement R5.

Only weld, cut or drill steelwork where it is required by the design.

Bolts for connections should comply with the design information and relevant British Standards, including:

BS 4190‘Specification for ISO metric black hexagon bolts, screws and nuts.’
BS 4395‘Specification for high strength friction grip bolts and associated nuts and washers for structural engineering.’
BS 4604‘Specification for use of high strength friction grip bolts in structural steelwork.’
BS 5135‘Specification for arc welding of carbon and carbon-manganese steels.’

The connection methods detailed in this chapter are suitable for connecting steel beams used to support floor loads only, using black bolts or welding.

Conditions for the use of this method are:

  • beams should only support timber floors in accordance with this chapter
  • both beams have been chosen from Table 3
  • beams do not differ in depth by more than 40mm.

Connections between steel sections should be designed by an engineer in accordance with Technical Requirement R5,
where the above conditions are not met.