Steel Buildings in Europe

Part 4: Detailed Design 4 – 3 (a) fin plate (b) flexible end plate (c) web cleats Figure 2.1 Typical ‘simple’ beam to column connections For such simple frames, it is almost always economic to use:  HE sections for columns  IPE sections for beams  Flats, angles or hollow sections for diagonal bracing members. Figure 2.1 shows typical beam to column connections. 2.3 Sway and non-sway frames 2.3.1 Definitions A braced frame has sufficient structural components to transmit horizontal forces directly to the foundations. These components provide stability to the frame. They may be one or more concrete cores, which will usually contain the vertical services, lifts and stairs. Alternatively, they may be complete systems of triangulated steel members in vertical planes (acting in conjunction with floor diaphragms or horizontal bracing). In a braced frame, the beams are designed as simply supported. The columns carry axial loads and (generally) minimal moments. The beam to column connections are designed as nominally pinned, and hence not attracting any moment; sufficient rotation capacity must be provided. An unbraced frame is any frame which does not have either a concrete core or a complete system of vertical triangulation. At least some beam to column connections must be moment resisting in order to transmit horizontal forces to the foundations and to provide frame stability. It should be noted that horizontal structure and associated behaviour needs to be considered separately in two, usually orthogonal, directions. Thus a frame may be:  Braced in both directions  Braced in one direction and unbraced in the other  Unbraced in both directions