The maximum slenderness ratio λ for a member normally acting as a tie in a roof truss or a bracing system, but subject to possible reversal of stresses resulting from the action of wind or earthquake forces is
- A430
- B350Correct
- C250
- D180
Solution
Concept
Slenderness limits of members
Step-by-step solution
1. Always in tension: 400. 2. Normally a tie but liable to stress reversal by wind/earthquake: 350. 3. Compression member due to dead and live load: 180; due to wind/seismic: 250.
Explanation
Ties that may be subjected to reversal of stress behave partly as compression members, so a lower limit (350) is used than for members always in tension.
Why the other options are wrong
430 is not a code limit. 250 and 180 are limits for compression members.
Shortcut
180 / 250 / 350 / 400.
Common mistake
Choosing 400.
Correct answer: B) 350