Hello Civil Engineers, Thank you for visiting howtocivil.com. By this article, you are going to learn the basic differences between the WSD(Working Stress Design )  Method and the USD (Ultimate Stress Design)  Method of Reinforced Concrete Structure Design. This comparative article on USD and WSD methods of design concrete structures will describe a brief comparison of these two methods based on their design methods, Strength, Durability, etc. You will get the theoretical Definition of Working Stress Design and Ultimate Stress Design and their Assumptions from the linked article.

 difference between WSD and USD Method

Difference Between WSD and USD Method

The Difference between Working Stress Design and Ultimate Stress Design  Method of Reinforced Concrete structure Are following,

 

WSD VS USD Method

 

USD(Ultimate Stress Design)  MethodWSD(Working Stress Design) Method
1 Ultimate Stress Design(USD) Method is define as the method of design structural members by considering the ultimate Strength of steel and concrete is called USD Method. Working Stress Design method is define as the method of design structural members by considering the allowable Strength of steel and concrete is called WSD Method.
2It’s primarily based on the strength concept of Concrete.It’s based on the linear theory or elastic theory.
3Factor of Safety is considered in this design. Factor of Safety is not considered in this design.
4It’s Consider to Design  Critical Combination of loadIt’s Consider to Design  carrying load
5It’s designing for elastic behavior of materials.It’s designing to plastic behavior of materials
6Materials strength to be used for member designModular Ratio used for member design
7 Stability of Structure is more than WSDStability of Structure is less than USD
8It’s a modern design method.It’s a pretty old design method.
9This method is used for mostly the biggest structures and developed nations.This type of method is used for mostly small structures and undeveloped nations.
10Economical Design method.Less economical Design method.

 

References : 

Reinforced Concrete Design

Design Ultimate Strength

 

If you want to add some difference between WSD and USD method, then please comments below and I will add those points with references of you. The final word is if you like The  Comparison of Working Stress Design and Ultimate Stress Design method then please don’t forget to share it. Thanks

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Ripon Chandra Malo

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Hi there! My name is Ripon Chandra Malo. I am a Civil(Geotechnical) Engineer. I always love to learn new things and want to share what I learned. Also , I am a part-time blogger and freelancer. I will try to share my knowledge in the different fields of civil engineering. If you have any questions to ask then please contact with me.

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