Question

Which limit states deals with strength, overturning, sliding, buckling, fatigue fracture, etc.?
1. Ultimate limit states
2. Strain limit state
3. Stress state
4. Serviceability limit states

Answer 1

Correct Answer - Option 1 : Ultimate limit states

Concept:

Limit State Method:

Limit states are the acceptable limits for the safety and serviceability requirements of the structure before failure occurs. The design of structures by this method will thus ensure that they will not reach limit states and will not become unfit for the use for which they are intended. Limit State Design requires two principal criteria to be satisfied:

• The ultimate limit state (ULS) 
• The serviceability limit state (SLS)

Ultimate limit state(ULS): 

• It ensures that the structure you are going to build is stable and strong enough against any loads it is going to endure, such as dead loads, live loads, wind loads, earthquake loads, their combinations, and so on. 
• Ultimate limit states deal with strength, overturning, sliding, buckling, fatigue fracture, etc.
• The ULS is a purely elastic condition.

Serviceability limit state (SLS):

• It ensures that your designed structure is comfortable and useable enough for human use.
• The serviceability limit state deals with vibrations and deflections (movements), as well as cracking and durability. 
• It might also involve limits to non-structural issues such as acoustics and heat transmission.