|Working Stress Method
|Limit State Method
|This method is based on the elastic theory which assumes that concrete and steel are elastic and the stress strain curve is linear for both.
|This method is based on the actual stress-strain curves of steel and concrete. For concrete, the stress strain curve is nonlinear.
|In this method the factor of safety are applied to the yield stresses to get permissible stresses.
|In this method, Partial safety factors are applied to get design values of stresses.
|No factor of safety is used for loads.
|Design loads are obtained by multiplying partial safety factors of load to the working loads.
|Exact margin of safety is not known.
|Exact margin of safety is known.
|This method gives thicker, sections, so less economical.
|This method is more economical as it gives thinner sections.
|This method assumes that the actual loads, permissible stresses and factors of safety are known. So it is called as deterministic method.
|This method is based upon the probabilistic approach which depends upon the actual data or experience, hence it is called as non-deterministic method.