Derivation of working stress design method?

Derivation of Working Stress Design Method

The working stress design method is a method of engineering design that ensures that the stresses in a structure do not exceed a specified allowable stress. This method is based on the assumption that the actual stresses in a structure will be less than the allowable stresses, and that the structure will therefore be safe.

The working stress design method is derived from the following equation:

$$σ_{max} = σ_{allow} \cdot n$$

where:

* σmax is the maximum stress in the structure

* σallow is the allowable stress

* n is a safety factor

The safety factor is a number that is used to account for the uncertainties in the design process. These uncertainties include:

* The variability of the material properties

* The accuracy of the design calculations

* The possibility of unforeseen loads

The safety factor is typically chosen to be a value between 1.5 and 3.0.

The working stress design method can be used to design any type of structure. However, it is most commonly used for the design of concrete and steel structures.

Advantages of the Working Stress Design Method

The working stress design method has a number of advantages, including:

* It is a simple and straightforward method to use.

* It is based on well-established principles of engineering mechanics.

* It is relatively conservative, which means that it is less likely to lead to structural failure.

Disadvantages of the Working Stress Design Method

The working stress design method also has a number of disadvantages, including:

* It can be inefficient, as it requires the use of a safety factor that is greater than 1.0.

* It can be difficult to choose the appropriate safety factor.

* It does not account for the possibility of brittle failure.

Comparison of the Working Stress Design Method to Other Design Methods

The working stress design method is one of a number of different design methods that can be used to design structures. Other design methods include:

* The ultimate strength design method

* The load and resistance factor design method

* The plastic design method

Each of these design methods has its own advantages and disadvantages. The best design method for a particular project will depend on the specific requirements of that project.