Steel Buildings in Europe

Part 5: Detailed Design of Trusses 5 - 47 35,6 mm 8,6 mm 44,2 mm (44,2 – 8,6 = 35,6 mm) Gravity loading 12,2 mm 3,1 mm 15,2 mm (15,3 – 3,1 = 12,2 mm) Uplift loading Figure 5.3 Rotations at truss supports In order for the global rotations at the supports to be free (assumption for truss with pinned connections to the column), the elongated holes introduced into the column on lower chord connection must allow a 35,6 mm movement towards the outside and 12,2 mm towards the inside. It is of course prudent to allow for a certain safety margin on the sizing of the elongated holes (say 50 mm), and to check after erection that, under self weight, the freedom of movement remains adequate in both directions. 5.2 Chord continuity It is often necessary to deliver large span truss beams to site in several sections; it is therefore necessary to provide continuous chord joints between these sections. Generally, the preferred method is to make such connections on site by bolting rather than by welding. The design of these bolted connections depends on the type of chord section to be connected. However, we can distinguish between two types of such connections:  Those in which the bolts are mainly loaded in tension : these use end plates  Those in which bolts are loaded perpendicular to their shank: these use splice plates. When the chords are made of a single profile/section in I or H, either of the connections can be used. When the chords are made of two double angle or channel sections, splice connections are generally used.