What Are Limit States & Types In Civil Engineering?
Earlier, I discussed on the principles of design and methods in civil engineering. In that post, we saw various principles, methods, codes and the use of codes in civil engineering.
This post is an excerpt, which discusses the limit states employed in civil engineering.
Limit state design is just one of the methods employed for designs in civil engineering especially in concrete structures.
So, what is limit state design?
Limit State in civil engineering takes account of all conditions that will make a structure unfit for use. A structure may cease to be fit for use in a variety of ways. This may be due to collapse or rupture, excessive deformation, excessive cracking, etc. Each of these ways constitutes a limit state. The two principal limit states are:
- Ultimate Limit State
- Serviceability Limit State
Ultimate Limit State: This requires that the structure withstands with an adequate factor of safety against collapse, the loads for which it is designed.
Serviceability Limit State: This requires that under working loads, deflections, cracks are minimised so that appearance or efficiency of the structure is not impaired.
Other limit states in civil engineering include: durability, fire resistance, excessive vibration, fatigue, etc.
