What is the theoretical value of effective length of a compression member when it is 'effectively held in position at both ends but not restrained against rotation'?

Question

Question

This question was previously asked in

UPSC ESE (Prelims) Civil Engineering 19 Feb 2023 Official Paper

Answer 1

Effective length for compression members under different end conditions is given as:

Degree of end restraint	Theoretical value	Recommended value
Effectively held in position and restrained against rotation at both ends.	0.50L	0.65L
Effectively held in position and restrained against rotation at one end	0.70L	0.80L
Effectively held in position at both ends, but not restrained against rotation.	1.00L	1.00L
Effectively held in position and restrained against rotation at one end and at other end restrained against rotation but not held in position	1.00L	1.20L
Effectively held in position and restrained against rotation at one end and at other end partially restrained against rotation but not held in position	-	1.50L
Effectively held in position at one end but not restrained against rotation and at other end restrained against rotation but not held in position.	2.00L	2.00L
Effectively held in position and restrained against rotation at one end and at other end not held in position and not restraint against rotation.	2.00 L	2.00L

Where L is the unsupported length of column.

For battened struts, the effective length should be increased by 10%.