Steel Buildings in Europe

Part 11: Moment Connections 11 - 9 1.9 Stiffeners Components of the joint may be strengthened by providing additional material, although this means additional expense. Table 1.3 summarises the opportunities to strengthen moment resisting joints. Types of stiffeners are illustrated in Figure 1.3. Table 1.3 Stiffeners Stiffener type Effect Comments Compression stiffener Increases the resistance to compression Generally required in portal frame connections. Flange stiffener in the tension zone Increases the bending resistance of the column flange Diagonal shear stiffener Improves the column web panel resistance and also strengthens the tension flange A common solution – connections on the minor axis may be more complicated. Supplementary web plate Increases the column web resistance to shear and compression Minor axis connections are simplified. Detail involves much welding. See §6.2.6.1 of EN 1993-1-8. End plate stiffener Increases the bending resistance of the end plate Should not be used – a thicker end plate should be chosen. Cap plate Increases the bending resistance of the flange, and the compression resistance (in reversed moment situations) Usually provided in the column, aligned with the top flange of the rafter. Generally provided for the reversal load combination, but effective as a tension stiffener to the column flange. Flange backing plate Increases the bending resistance of the flange Only effective to increase mode 1 behaviour. See EN 1993-1-8, §6.2.4.3 1 1 2 3 4 5 6 1 Compression stiffener 2 Column flange stiffener 3 Cap plate 4 Shear stiffener 5 Supplementary web plate 6 End plate stiffener Figure 1.3 Types of stiffeners