1) Comparison of working stress method and limit state method

1)     Comparison of working stress method and limit state method.

Working Stress 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.

Limit State Method 

This method is based on the actual stress strain curves of steel and concrete. For concrete the stress strain curve is nonlinear.

Working Stress method

In this method the factor of safety are applied to the yield stresses to get permissible stresses.

Limit State Method

In this method partial safety factors are applied to get design values.

Working stress Method

No factor of safety used for loads.

Limit state method

Design loads are obtained by multiplying partial safety factors of loads to the working loads.

Working Stress method

Exact margin of safety is not known.

limit state method

Exact margin of safety is known.

Working stress method

This method gives thicker so less economical.

Limit state method

This method is more economical it gives thinner section.

working stress method

This method assumes that the actual loads , permissible stresses and factor of safety are known. So it is called the deterministic method.

Limit state method

This method is bases upon the probalistic approach which depends upon the actual data or experience, hence it is calles non deterministic method.