Steel Buildings in Europe

Part 4: Detailed Design of Portal Frames 4 - 63 12 SECONDARY STRUCTURAL COMPONENTS 12.1 Eaves beam The cold-formed member that connects the individual frames at eaves level (indicated as (2) in Figure 12.1) is generally known as an eaves beam. The primary function of the eaves beam is to support the roof cladding, side walls, and guttering along the eaves, but it may also be used to provide lateral restraint at the top of the outer flange of the column. 1 2 3 5 6 1 Built-up or composite cladding 2 Cold rolled eaves beam 3 Rafter stay 4 Column stiffener 5 Circular hollow section acting as eaves strut Figure 12.1 Haunch detail with eaves beam 12.2 Eaves strut If vertical side wall bracing capable of resisting tension and compression is provided at both ends of the structure (see Section 9.2), an eaves strut is not required other than in the end bays. However, it is good practice to provide a member between the columns to act as a tie during erection and provide additional robustness to the structure. If a circular hollow section is used to restrain the plastic hinge at the bottom of the eaves as illustrated in Figure 12.1, this can fulfil the role of a longitudinal strut as well as restraining the plastic hinge. If a member is provided as an eaves strut above this level, it is ineffective in restraining the plastic hinge at the bottom of the haunch.