Limit State Method

Limit State Method

• Limit state is the state at which the structure becomes unfit for use.

Two types of Limit states :

1. Limit state of Collapse

• Also known as Ultimate Limit State

• Adequate margin of safety shall be available for normal overloading

• This includes limit state of strength like overturning, sliding, buckling, fatigue, flexure, compression, etc

2. Limit State of Serviceablity

• Satisfactory performance under service load (deflection, crack, vibration, leakage, loss of durability, etc)

• If a structure has reached just before the limit state of serviceability and loads are removed, the structure 

regains its original shape, however a structure achieving Collapse load can not recover its original shape and 

dimension