250+ TOP MCQs on Design Strength of Laterally Supported Beams -I and Answers

Design of Steel Structures Multiple Choice Questions on “Design Strength of Laterally Supported Beams – I”.

1. Which of the following aspects need not be considered for beam design?
a) deflection
b) material of beam
c) buckling
d) lateral supports
Answer: b
Clarification: The important aspects which need to be considered for beam design are moments, shears, deflection, crippling, buckling, and lateral support.

2. The design bending strength of laterally supported beams is governed by
a) torsion
b) bending
c) lateral torsional buckling
d) yield stress
Answer: d
Clarification: The design bending strength of laterally supported beams is governed by yield stress and that of laterally unsupported beams is governed by lateral torsional buckling.

3. The web is susceptible to shear buckling when d/t_w
a) <67ε
b) < 2×67ε
c) >67ε
d) < 70ε
Answer: c
Clarification: For beams with plastic, compact, semi-compact flanges and slender web (d/t_w > 67ε), the web is susceptible to shear buckling before yielding.

4. When there is no shear buckling,
a) V_p = V_n
b) V_p > V_n
c) V_p < V_n
d) V_p = 2V_n
Answer: a
Clarification: When there is no shear buckling (d/t_w ≤ 67ε), the nominal shear resistance V_n equals plastic shear strength V_p.

5. Plastic shear resistance is given by
a) f_y/√3
b) shear area x f_y x √3
c) shear area x f_y/√3
d) shear area / (f_y/√3)
Answer: c
Clarification: Plastic shear resistance is given by V_p = shear area x f_y/√3.

6. The design shear strength is given by
a) V_n
b) V_n/γ_m0
c) V_n x γ_m0
d) γ_m0
Answer: b
Clarification: The design shear strength is given by V_d = V_n/γ_m0 , where V_n= plastic shear resistance, γ_m0 = partial factor of safety.

7. The web area will be fully effective when shear force V
a) ≥ 0.6V_d
b) < 0.6V_d
c) ≤ 0.6V_d
d) >2×0.6V_d
Answer: c
Clarification: When shear force V ≤ 0.6V_d, the web area will be fully effective and entire cross section of beam will be effective in resisting the moment.

8. Which of the following is true about sections with high shear case V>0.6V_d ?
a) web area is ineffective
b) web area is fully effective
c) flanges will not resist moment
d) moment is not reduced
Answer: a
Clarification: When shear exceed the limit V&gt0.6V_d, web area will be ineffective and only flanges will resist the moment. Because of this for high shear case, moment capacity of beam is reduced.