Steel Buildings in Europe

Part 11: Moment Connections 11 - 6 M c,Rd is the design moment resistance of the beam cross-section, reduced if necessary to allow for shear, see EN 1993-1-1 § 6.2.5. For a haunched beam, such as a rafter, M c,Rd may be calculated neglecting the intermediate flange t fb is the flange thickness of the connected beam. For haunched beams, such as those commonly used for rafters in portal frames, the depth h , should be taken as the depth of the fabricated section, and the thickness t fb should be that of the haunch flange. If the height of the beam (rafter + haunch) exceeds 600 mm the contribution of the rafter web to the design compression resistance should be limited to 20%. This means that if the resistance of the flange is y,fb fb fb t b f then: 0,8 fb fb y,fb c,fb,Rd t b f F  1.5 Resistance of the column web panel The resistance of the column web panel is given by § 6.2.6.1 of EN 1993-1-8, which is valid for  69  w d t . The resistance of an unstiffened column web panel in shear, V wp,Rd is given by: M0 y,wc vc wp,Rd 3 0,9  f A V  where: A vc is the shear area of the column, see EN 1993-1-1 § 6.2.6(3). 1.6 Calculation of moment resistance Having calculated potential resistances in the tension zone (Section 1.2), the design resistance in the compression zone (Section 1.4) and the resistance of the column web panel in shear (Section 1.5), the effective design resistances in the tension zone may be determined. According to EN 1993-1-8 § 6.2.7.2(7), the total design resistance in the tension zone must not exceed the design resistance in the compression zone. Similarly, the total design resistance in the tension zone must not exceed the design resistance of the column web panel, modified by a transformation parameter,  . This is expressed as:  wp,Rd t,Rd F V   The transformation parameter,  is taken from § 5.3(7), and may be taken from Table 5.4 as 1.0 for one-sided connections. If either the resistance in the column web panel or in the compression zone is less than the total design resistance in the tension zone, the resistances in the tension zone must be reduced.