Built-up Columns MCQ with answer and solution

Concept

In battened columns, shear deformation reduces strength, so IS 800:2007 increases the slenderness ratio by 10%.

Formula

λ_e = 1.1 × λ_max

Step-by-step solution

1. A battened column has main members joined by battens, not by a full web. 2. The battens and the joints bend under shear, so the column is more flexible. 3. IS 800:2007 accounts for this by increasing the slenderness ratio. 4. Effective slenderness ratio = 1.1 × maximum actual slenderness ratio. 5. Answer is (A).

Explanation

Battened columns deform more in shear than solid columns. To allow for this, IS 800:2007 takes the effective slenderness ratio as 1.1 times the maximum actual slenderness ratio. This gives a lower, safer design compressive strength.

Why the other options are wrong

B: 2.5 is far too large and is not a code value. C: 1.25 is not the code factor for battened columns. D: 0.9 would reduce slenderness, which is unsafe and wrong.

Shortcut

Battened column means 1.1 × λ (10% increase).

Common mistake

Confusing it with the 1.05 factor sometimes used for laced columns.