Steel Buildings in Europe

Part 11: Moment Connections 11 - 18 Sign convention: The bending moment is positive when it generates compression stresses in the lower flange and tension stresses in the upper flanges (Figure 4.1). IPE 300 M > 0 IPE 300 IPE 300 M > 0 Figure 4.1: Sign convention for bending moment 4.3 Notes to the tables 4.3.1 Apex connections Tables 4.4 to 4.6 summarize the design moment resistances for the apex connections subject to positive moments. They can be compared with the plastic moment resistance of the cross-section (Table 4.3). Table 4.3 Plastic moment resistance of the cross section (kNm) Profile S235 S275 S355 IPE 300 148 173 223 IPE 400 307 359 464 IPE 500 516 603 779 Bolts outside the profile have a major influence on the moment resistance when they are in tension. The stiffener welded to the tension flange always increases the moment resistance, but not to the same degree. The moment resistance is lower than the plastic moment of the cross-section. However this is not a problem since the member resistance is usually reduced by the buckling effects, including lateral-torsional buckling. The minimum span length to consider the apex connection as fully rigid is relatively low. In practice, these connections will always be used for portal frames with a span length greater than this minimum value, and so can be considered rigid. At the apex, the shear force is small and this verification will never be critical in common practice.