## ABSTRACT

The effect of local buckling on global behaviour at the ultimate limit state is such that the yield stress cannot develop in all of the fibres of the cross-section. A consequence of this is that the limiting elastic moment of resistance cannot develop. The reduction in strength is due to premature buckling of the slender elements of the cross-section which are in

(c) Flexural buckling

N

N

(g) Web buckling/bearing

(b) Distorsional buckling − translation and rotation

at the nodes

(e) Torsional buckling

N

N

(d) Lateral-torsional buckling

W

(a) Local buckling − rotation only at the nodes

Before After

(h) Shear buckling

(f) Torsional-flexural buckling

N

N

a redistribution of the stresses to the stiffer edges as shown in Figure 6.3.