The effective length of a battened column is

Explanation:

• In battened columns, due to the tendency of the members to shear and bend between battens, additional flexibility is introduced.

• As per IS 800:2007, for battened built-up columns, the effective length is taken as 1.05 times the actual effective length of the equivalent single section.

So, the effective length is increased by 5% to account for the additional slenderness due to battens.

Additional Information

• A battened column is a built-up compression member composed of two or more individual sections (typically channels or angles) connected together with batten plates to act as a single unit.
• The battens restrain the members from buckling independently and ensure load-sharing. 

• The battens provide lateral support, but the column is still more flexible than a solid single section because of:

1. Shear deformation between the individual components.

2. Lateral deflections of the components between battens.