Consider the following statements : The design strength of a tension member is the lowest of : 1. design strength due to yielding of gross-section. 2. rupture strength of critical section. 3. the block shear strength. Which of the above statements are correct ?
- A1 and 2 only
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3Correct
Solution
Concept
Modes of failure of tension members
Formula
Td = min (Tdg, Tdn, Tdb)
Step-by-step solution
1. Yielding of the gross section (Tdg). 2. Rupture of the net section at the bolt holes (Tdn). 3. Block shear (Tdb). 4. The design strength is the lowest of the three, so all three statements are correct.
Explanation
IS 800:2007 Section 6 requires checks for gross-section yielding, net-section rupture and block shear. The design strength is the minimum of them.
Why the other options are wrong
Each of the options with fewer statements omits one of the three failure modes.
Shortcut
Tension members: yield, rupture, block shear.
Common mistake
Forgetting block shear.
Correct answer: D) 1, 2 and 3