Correct Answer - Option 2 : 0.67 L
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%.