Steel Buildings in Europe

Part 11: Moment Connections 11 - 3 r =1 r =2 r =3 r =4 Figure 1.1 Extended end plate in a haunched eaves connection 1.2.1 End plate and column flange in bending When determining the potential tension resistance of the end plate in bending, F t,ep,Rd and the column flange in bending , F t,fc,Rd, EN 1993-1-8 converts the real yield line patterns into an equivalent T-stub. Generally, a number of yield line patterns are possible – each with a length of equivalent T-stub. The shortest equivalent T-stub is taken. When bolts are located adjacent to a stiffener, or adjacent to the rafter flange, the increased resistance of the flange or end plate is reflected in a longer length of equivalent T-stub. Bolts adjacent to an unstiffened free edge will result in a shorter length of equivalent T-stub. . Effective lengths of equivalent T-stubs  eff are given in Table 6.4 of EN 1993-1-8 for unstiffened flanges, in Table 6.6 for unstiffened end plates and in Table 6.5 for stiffened flanges (or end plates). . In all cases, effective lengths of equivalent T-stubs are given for individual bolt rows and for bolt rows as part of a group – the length of the equivalent T-stub for a group of bolts is assembled from the contributions of the rows within the group. The beneficial effect of stiffeners depends on the geometry of the stiffener, the location of the bolt and the proximity to the web. This is addressed in Figure 6.11 of EN 1993-1-8, which provides an  factor used in determining the effective length of equivalent T-stub. When the bolt is sufficiently far from both web and stiffener, the stiffener has no effect – the effective length is the same as that in an unstiffened zone. Once the effective length of T-stub has been determined, the resistance of the T-stub is calculated. Three modes, as illustrated in Figure 1.2, are examined:  Mode 1, in which the flange of the T-stub is the critical feature, and yields in double curvature bending  Mode 2, in which the flange and the bolts yield at the same load  Mode 3, in which the bolts are the critical component and the resistance is the tension resistance of the bolts.