Steel Buildings in Europe

Part 11: Moment Connections 11 - 4 Mode 1 Mode 2 Mode 3 Figure 1.2 Behaviour modes of an equivalent T-stub The expressions to calculate the resistance in the different modes are given in Table 6.2 of EN 1993-1-8. 1.2.2 Column web in transverse tension The design resistance of an unstiffened column web in transverse tension is given by expression 6.15 in EN 1993-1-8, and is simply the resistance of a length of web, with a reduction factor  for the interaction with shear in the column web panel. For bolted connections, § 6.2.6.3(3) states that the length of web to be assumed at each row, or for each group of rows, is equal to the length of the equivalent T-stub determined for that row (or group of rows). 1.2.3 Beam web in tension The design resistance for a beam web in tension is given by § 6.2.6.8 and is the same as that for the column web in transverse tension, (see Section 1.2.2), but without an allowance for shear. The length of the beam web in tension is taken to be equal to the length of the equivalent T-stub determined for that pair (or group) of bolts. 1.3 Plastic distribution A plastic distribution of forces in bolt rows is permitted, but this is only possible if the deformation of the column flange or end plate can take place. This is ensured by placing a limit on the distribution of bolt row forces if the critical mode is mode 3, because this failure mode is not ductile. According to § 6.2.7.2(9) of EN 1993-1-8, this limit is applied if the resistance of one of the previous bolt rows is greater than 1,9 F t,Rd , where: F t,Rd is the tensile resistance of a single bolt The limit is applied by reducing the resistance of the row under consideration, to a value F t r ,Rd , such that: x tx,Rd t ,Rd / F F h h r r  , where: F tx,Rd is the design tension of the furthest row from the centre of compression that has a design tension resistance greater than 1,9 F t,Rd h x is the lever arm from the centre of compression to the row with resistance F tx,Rd h r is the lever arm from the centre of compression to the row under consideration.