Steel Structures - Compression Members

Q.1. Which of the following take(s) compression forces
(a) strut
(b) rafter
(c) column
(d) all the above

Q.2. Select wrong statement?
(a) Stanchion is compression member
(b) boom in crane is a compression member
(c) compression member seldom fails by crushing
(d) tie is a compression member

Q.3. A compression member can withstand a maximum axial compressive load P witch is given by
(a) {\sigma _{ac}}\,x\,{A_{eff}}
(b) {\sigma _{ac}}\,x\,{A_{gross}}
(c) Any of the above
(d) none of these

Q.4. According to IS: 800-1984, Merchant Rankine formula for {\sigma _{ac}} is
(a) {\sigma _{ac}} = 0.5x\frac{{{f_{cc}}\,x\,{f_y}}}{{{{\left( {{f_{cc}}^{1.4} + {f_y}^{1.4}} \right)}^{1/1.4}}}}
(b) {\sigma _{ac}} = 0.5x\frac{{{f_{cc}}\,x\,{f_y}}}{{{{\left( {{f_{cc}}^{1.5} + {f_y}^{1.5}} \right)}^{1/1.5}}}}
(c) {\sigma _{ac}} = 0.5x\frac{{{f_{cc}}\,x\,{f_y}}}{{{{\left( {{f_{cc}}^2 + {f_y}^2} \right)}^{1/2}}}}
(d) none of these
where {\sigma _{ac}} is permissible stress in axial compression in MPa, {f_y}  is yield stress of steel in MPa, {f_{cc}}  is elastic critical stress in compression = {\pi ^2}E/{\lambda ^2}. 𝝀 is slenderness ratio l/r.

Q.5. If a compression member is held in position and restrained against rotation at both ends then its effective length will be
(a) 1.20L
(b) 1.00L
(c) 0.80L
(d) 0.65L
where L is unsupported length of compression member.

Q.6. In above question if the member is restrained against rotation at one end only then effective length is
(a) 1.20L
(b) 1.00L
(c) 0.80L
(d) 0.65L

Q.7. Maximum slenderness ratio for a member carrying compressive loads resulting from dead load and superimposed loads, will be
(a) 350
(b) 250
(c) 180
(d) 150

Q.8. In above question, maximum slenderness ratio for a member carrying wind/earthquake loads will be
(a) 350
(b) 250
(c) 180
(d) 150

Q.9. A member is carrying tension but subjected to reversal of stress due to wind or earthquake forces. What would be maximum slenderness ratio for this member?
(a) 500
(b) 350
(c) 250
(d) 200

Q.10. Permissible compressive stress for a compression member ___ with decrease in l/r ratio.
(a) decrease
(b) increase
(c) remains unchanged
(d) can not say

Answers

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

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