In the working stress design method for Reinforced Concrete Structures design, concrete is assumed as elastic also concrete and steel act together as a single unit elastically i.e relationship between stress and strain is linear.
In the Limit state design method for Reinforced Concrete Structures design, concrete is assumed as elastic also concrete and steel act together as a single unit elastically i.e relationship between stress and strain is linear.
|Stress-Strain behavior is linear.||Stress-Strain behavior is nonlinear.|
|The Working Stress method is also called as modular ratio method or Elastic method||The Limit State method is also called as Plastic Method.|
|Working Stress Method is Uneconomical.||Limit State Method is Economical.|
|Working Stress Method is Stress based method.||Limit State Method is Strain based method.|
|In Working Stress Method Material is not allowed to cross the yield limit.||In Limit State Method Material is allowed to cross the yield limit.|
|In the Working Stress Method Factors of Safety are considered.||In the Limit State Method, Partial Safety factors are considered.|
|In the Working Stress Method, Tensile Stresses are considered in the design.||In the Limit State Method, Tensile Stresses are not considered in the design.|
|Creep and Shrinkage are not partially considered.||Creep and Shrinkage are fully considered.|
|The section plane before bending remains plane after bending.||A section that is plane normal to the axis of the structural component remains plane after bending.|
|To calculate the permissible stress Modular Ratio used.||To calculate the permissible stress – Ultimate stresses are considered as Permissible stresses.|
The working stress design usually results in relatively large sections of structural members, compared to ultimate load. Because of this, structures designed by working stress method gives better serviceability performance under working loads.
In the working stress method as the overall capacity of steel up-to, the yield stress is not used that is why we require more steel than the limit state method eventually resulting in uneconomical section.