Steel Buildings in Europe

Part 2: Concept Design 2 - 60 5.8.2 Beam spans and design criteria In this form of construction with d eep decking, the m aximum span of the decking is lim ited to approxim ately 6 m for a 300 mm dee p slab, in order to avoid tem porary propping. The maxim um spa n of the ASB beams is in the range of 6 m to 10 m, depending on their size and spacing. 5.8.3 Services integration Unrestricted distribution of services below the floor is provided. Small services and ducts (up to 160 mm diameter) can be passed through holes in the beam webs and between ribs in the decking, as shown in Figure 5.20. The following floor zones m ay be used in schem e design using asymm etric beams and deep decking. 600 – 800 mm with light services (and a raised floor) 800 – 1000 mm with air conditioning (and a raised floor) 150 300 50 800mm 200 50 50 1 2 3 4 1 Raised floor 2 Ducting through beam 3 Slimline fan coil unit 4 Lighting and Ceiling Figure 5.20 Typical floor construction using asymmetric beams and deep decking 5.8.4 Fire protection Fire engineered ASBs have relatively thick webs and with the web a nd top flange encased with concrete require no additional fire protection for up to 60 minutes. Other ASB sections require fire prot ection for greater than 30 minutes – normally by board to the bottom flange. 5.9 Beam connections All the f loor system s reviewed in this section utilise s imple connection s (nominal pins), which are not assum ed to develop significant m oments. To realise this assum ption in practice, the connection deta ils must be ductile, in order to accommodate the rotation that develops at the connection. Full depth connections, where the end plat e is welded to the web and flanges, are prov ided for floor m embers that are s ubject to tors ion, such as integrated beams or slim floor beam s. For any floor solution, the possib ility of torsional loading in the construction stage should be checked, as connections with torsional resistance, or temporary restraints may be required.