The limit state are broadly grouped into two major categories

1. limit state of strength
2. limit state of service ability

limit state of strength using appropriate factor of safety, are those connected with failure under the probable and most unfavorable combination of load on the surface which may endanger the safety of life and property

It include

1. plastic collapse

2. stability against sway, overwriting & sliding.

   1. Limit state of serviceability

Limit state of serviceability is related to the satisfactory there are four major type of serviceability limit state applicable to steel structure

They are

1. deflection
2. durability
3. vibration
4. fire resistance