Steel Structures - Beams

1. A beams takes
(a) tension
(b) compression
(c) transverse load
(d) axial load

2. Pick the wrong statement
(a) a beam section is usually chosen which can resist maximum bending moment occurring over its span
(b) Shear stress and deflection for chosen beam section are then checked for permissible limits
(c) check for web crippling and web buckling are secondary design requirement
(d) none of the above

3. In the design of a beam
(a) Z \ge \frac{V}{{{\sigma _{bc\,or\,bt}}}}
(b) Z \ge \frac{W}{{{\sigma _{bc\,or\,bt}}}}  
(c) Z \ge \frac{M}{{{\sigma _{bc\,or\,bt}}}} 
(d) none of the above
where V is shear force, W is load, and M is bending moment. Z is section modulus. {\sigma _{bc\,or\,bt}} is bending stress (compressive or tensile) calculated at a point at a distance y from neutral axis.

4. Moment of resistance of a beam is
(a) Z/{\sigma _{bc\,or\,bt}}
(b) Z{\sigma _{bc\,or\,bt}}
(c) M/{\sigma _{bc\,or\,bt}}
(d) V/{\sigma _{bc\,or\,bt}}

5. In a beam, compression flange is restrained against buckling then permissible compressive or tensile stress {\sigma _{bc\,or\,bt}} is given by
(a) 0.33{f_y}
(b) 0.50{f_y}
(c) 0.66{f_y}
(d) none of these
where {f_y} is yield stress in steel.

6. In above question if the beam is to bend about axis of minimum strength (y-y axis) then {\sigma _{bc\,or\,bt}} is given by
(a) 0.33{f_y}
(b) 0.50{f_y}
(c) 0.66{f_y}
(d) 0.87{f_y}

7. Permissible compressive or tensile stress for steel angle/tee/I/channel/flat section for nominal plate thickness less than or equal to 20 mm will be
(a) 150 MPa
(b) 165 MPa
(c) 180 MPa
(d) 151.8 MPa

8. The shear stress  at any point on the cross section of a beam is given by
(a) \frac{V}{{I\,x\,b}}\,x\,A\,x\,\bar y
(b) \frac{V}{{I\,/b}}\,x\,A\,x\,\bar y
(c) \frac{V}{b}\,x\,A\,x\,\bar y
(d) none of these
where V is shear force, I is moment of inertia of the section, b is width of section at the point where shear stress is calculated and A x   is moment of the area above the level where shear stress is calculated about neutral axis of the section.

9. For a rectangular beam section, shear stress 𝜏 is maximum at
(a) top
(b) middle
(c) bottom
(d) one third of depth from top

10. Maximum shear stress is
(a) 1.5 times average shear stress
(b) 2.0 times average shear stress
(c) 2.5 times average shear stress
(d) none of these

Answers

    1. (c)    2. (d)    3. (c)    4. (b)    5. (c)
    6. (c)    7. (b)    8. (a)    9. (b)    10. (a)

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