LIMIT STATE METHOD OF DESIGN OF RCC STRUCTURES

Limit state method for the design of RCC structure can be defined as......

"The acceptable limit for the safety and serviceability of the structure before failure courses"

Therefore the concept of design with limit state method is to achieve acceptable probabilities or we can say that acceptable values, for a particular structure, so that the structure will not become unfit for use and will not reach a limit state.

Limit state method refers to the method which considers the ultimate strength of the material at failure (which is ignored in working stress method) and also assures that the structure is serviceable for its intended period of design.

There are two types of limit state methods 

1. Limit state of collapse 

2. Limit state of serviceability

1. Limit state of collapse

We can say that the structure is in a limit state of collapse when that structure is partially or completely collapsed the reason for the collapse of a structure may be due to the rupture of one or more members or elastic/inelastic stability or from loss of equilibrium etc....

To take care of this situation the limit state of collapse can be saved by providing resistance greater than the forces to which the structure is subjected to keeping a margin of safety through partial safety factor.

This limit states corresponds to: (a) flexure (b) shear (c) torsion

2. Limit state of serviceability 

This limit state is related to the satisfactory performance of the structure at working loads. This limit state is categorized into two categories:

 (i) Limit state of deflection

 (ii) Limit state of cracking 

(i) Limit state of deflection:  according to this limit state to safeguard the structure fr