Experimental Study and Direct Strength Method for Cold-Formed Steel Built-Up I-Sectional Columns under Axial Compression

Figure 9

Buckling modes of built-up columns with the nominal length of 500 mm. (a) Distortional buckling + local buckling in web. (b) Local buckling in web. (c) Local buckling in the flange. (d) Plastic crush.

(a)

(b)

(c)

(d)