LIMIT STATE METHOD
The limit state method, also known as load and resistance factor design (LRFD), is a technique that considers the ultimate strength of the material which is ignored in the working stress method and also assures that the structure is serviceable for its intended period of design.
Within the limit state method of design, the construction shall be designed to withstand all load libel to behave on it throughout its life with the suitable factor of safety.
It will also satisfy the limits of all serviceability requirements such as deflection and cracking etc. The stresses are derived from the design load and are compared with the design strength. This method can also be referred to as non-deterministic because the method is based on a probabilistic approach that relies on real data or experience.
Advantages of limit state method:
- It uses a modern way of designing a structure that encompasses a wide range of logical and technical considerations.
- It includes separate considerations of different kinds of failure, type of material, and type of load.
- This provides an economical design of the structure.
Disadvantages of limit state method:
- It uses a possible approach for design so it cannot provide sufficient power and serviceability during the worst combination of loads and peak conditions.