Steel Buildings in Europe

Part 2: Concept Design 2 - 42 Figure 5.2 Edge beam in composite construction 5.2.2 Typical beam spans and design criteria Secondary beams are typically 6 m to 15 m span at 3 m to 4 m spacing (3,75 m is generally the p referred m aximum span of the s lab). Prim ary beam s are designed with spans of 6 m to 12 m, when using IPE sections. A rectangular floor grid is often used, in which the secondary beams span the longer distance, in order that the secondary and prim ary beams are of sim ilar size. A typical structural arrangement is illustrated in Figure 5.3. Edge beams m ay be deeper than inte rnal beam s because of serv iceability requirements of the cladding. Also, the use of composite edge beam s requires placing of U-bars around the shear connectors. Limitations on tota l def lection will us ually govern for secondary beam s using S355 steel. Bending res istance will usually govern for most primary beams in S235 or S275.