Question
What is key disparity between working stress approach and limit state approach?
Answer
Working stress approach, service loads are used in whole plan and strength of material is not utilized in full extent. In this means of plan, stresses acting on structural members are intended based on flexible way and they are designed not to beat certain acceptable values. In fact, whole structure during lifespan may only knowledge loading stresses far below ultimate state and that is reason why this means is known as working stress approach. In such scenario, most economical plan can hardly be obtained by using working stress advance that is now commonly used in design of temporary works.
For maximum state approach, for each material and load, a biased safety factor is assigned independently depending on material properties and load lands. So, each element of load and material properties is exactly assessed resulting in an extra refined and accurate analysis of structure. In this relation, material strength be capable of be utilized to its greatest value during its lifespan and loads be capable of be assessed with practical probability of occurrence. Boundary state approach is frequently used for majority of reinforced concrete design as it ensures utilization of material strength with least construction price input.