3. Specify the diameter of a round column 1.5 m long that is to carry a maximum load estimated to be 22 kN. Use a design factor na 4 and consider the ends as pinned (rounded). The column material selected has a minimum yield strength of 500 MPa and a modulus of elasticity of 207 GPa. 180 1200- 1100 160 1000 140) 900 800- 700- 600- 500 400 Critical unit load S sil 120 100 689 MPa 80 5-496 M Johnson, E 203 GPs. 5, 689 MP 60- Ortical unit oad MP Johnson, 300- 40 E-71 GPA. 200- 20- 100 5,496 MPs 0 20 40 Tangent points Euler, E 203 GP Euler, E-71 GPa 60 BO 100 Slenderness ratio Le Figure 3 120 140 160