Steel Buildings in Europe

Part 11: Moment Connections 11 - 8  a full penetration butt weld. For most small and medium sized beams, the tension flange welds will be symmetrical, full strength fillet welds. Once the leg length of the required fillet weld exceeds 12 mm, a full strength detail with partial penetration butt welds and superimposed fillets may be a more economical solution. 1.7.2 Compression flange welds Where the compression flange has a sawn end, a bearing fit can be assumed between the flange and end plate and nominal fillet welds will suffice. If a bearing fit cannot be assumed, then the weld must be designed to carry the full compression force. 1.7.3 Web welds It is recommended that web welds in the tension zone should be full strength. For beam webs up to 11,3 mm thick, a full strength weld can be achieved with 8 mm leg length (5.6 mm throat) fillet welds. It is therefore sensible to consider using full strength welds for the full web depth, in which case no calculations are needed for tension or shear. For thicker webs, the welds to the web may be treated in two distinct parts, with a tension zone around the bolts that have been dedicated to take tension, and with the rest of the web acting as a shear zone. Tension zone Full strength welds are recommended. The full strength welds to the web tension zone should extend below the bottom bolt row resisting tension by a distance of 1,73 g /2, where g is the gauge (cross-centres) of the bolts. This allows an effective distribution at 60° from the bolt row to the end plate. Shear zone The resistance of the beam web welds for vertical shear forces should be taken as: P sw = 2  a  f vw,d  L ws where: a is the fillet weld throat thickness f vw,d is the design strength of fillet welds (from EN 1993-1-8, § 4.5.3.3(2)) L ws is the vertical length of the shear zone welds (the remainder of the web not identified as the tension zone). 1.8 Vertical shear Design for vertical shear is straightforward. Generally, the bolts at the bottom of the connection are not assumed to be carrying any significant tension, and are allocated to carry the vertical shear. The bolts must be verified in shear and bearing in accordance with EN 1993-1-8 Table 3.4.