Steel Buildings in Europe

Title APPENDIX D Worked Example: Design of portal frame using elastic analysis 14 of 44 4 - 95 buckling about z-z axis:  Curve b for hot rolled I sections   z  0,34 EN 1993-1-1 Table 6.2 Table 6.1  1 = y f E  = 355 210000  = 76,4 EN 1993-1-1 §6.3.1.3 z  = z 1 cr 1  i L = 76, 4 1 43,1 5275  = 1,60  z =     2 z z z 0,2 0,51       =     2 0,51 0,34 1,60 0,2 1,60    = 2,02 EN 1993-1-1 §6.3.1.2  z = 2 2 1      = 2 2 2, 02 2, 02 1, 60 1   = 0,307 N b,z,Rd = M1 z y   Af = 3 10 1, 0 355 11600 0,307     = 1264 kN N Ed = 168 kN < 1264 kN OK Lateral-torsional buckling resistance, M b,Rd The lateral-torsional buckling resistance of a member is calculated as a reduction factor,  LT , multiplied by the section modulus and the yield strength of the section. The reduction factor is calculated as a function of the slenderness, LT  , which depends on the critical moment of the member. The expression for the critical moment, M cr , is given below. The factor C 1 accounts for the shape of bending moment diagram of the member. Appendix C of this document provides values of C 1 for different shapes of bending moment diagrams. For the case of a linear bending moment diagram, C 1 depends on the ratio of the bending moments at the ends of the member, given as  . For the total length of the column (without the haunch): 0 616 0     1, 77 1  C Appendix C of this document M cr = z 2 t 2 z w 2 z 2 1 EI L GI I I L EI C    = 2 4 2 5275 10 2142 210000 1, 77      4 2 4 2 4 9 10 2142 210000 89,3 10 81000 5275 10 2142 10 1249            M cr = 909  10 6 Nmm Appendix C of this document