Question

Slenderness ratio when ends are assumed to be fixed for a plate girder is

(a) 2.45 d

(b) 8.5 d/t

(c) 2.45 d/t

(d) 8.5 t

The question was asked in final exam.

My question comes from Web Buckling & Crippling topic in portion Design of Beams of Design of Steel Structures

Answer 1

Correct choice is (c) 2.45 d/t

The explanation: When ends are assumed to be fixed, effective length = d√2/2 = d/√2, minimum radius of gyration = t/√12. Therefore slenderness ratio = (d/√2)/( t/√12) = 2.45d/t, where d = depth of web, t = thickness of web.