Working Stress Method
In Working Stress Method the design is based on elastic theory and hence the reinforced concrete is assumed ad an elastic material
In working stress method, the structural members are designed for working loads and design stressed or permissible stresses in the material are obtained by dividing the ultimate stress by a factor known as a factor of safety
Permissible stress=Ultimate stress/Factor of safety
The value of factor of safety ranges from
- For concrete factor of safety is 3
- For steel factor of safety is 1.28
WSM is simple and reasonable reliable
In wsm, the failure criterion is the stress
Drawbacks of working stress method
- This method gives uneconomical sections for the design purpose
- Stress-strain curve for concrete is assumed as linear, which is not true
- Factor of safety does not predict the true margin of safety in wsm.
- The failure criteria assumed is stress, but the strain criteria are reliable.