The main reason for using lacing in built-up steel columns is to
- AIncrease compressive strength
- BReduce slenderness ratioCorrect
- CImprove resistance to lateral-torsional buckling
- DProvide better load transfer
Solution
Concept
Purpose of lacing
Step-by-step solution
1. The question says "lacking", which is a typo for "lacing". 2. Lacing connects the two main components of a built-up column so that they act as one unit. 3. It reduces the unsupported length of each component, hence the slenderness ratio.
Explanation
Lacing ties the channels or angles of a built-up column and prevents the individual components from buckling between the connections, which reduces the slenderness ratio of the components. It also resists the transverse shear.
Shortcut
Lacing/battens = tie the components, reduce slenderness.
Common mistake
Choosing "increase compressive strength".
Correct answer: B) Reduce slenderness ratio