Concept: Factor of safety
=| Yield‌stress |
| Working‌stress |
Yield stress is defined as the stress at which first fibre failure occurs
.Working stress is defined as the stress which is safe to work on or it is the yield stress with factor of safety that the structure will not going to yield at this stress for a particular surrounding condition.
Values of factor of safety (partial) for load combination:
Where, DL = Dead load, LL = Live load WL = Wind load EQ = Earthquake load
Important Points: In WSM, the combined factor of safety is considered for incorporating effects of material quality and type of load.
In LSM, separate factors of safety called as partial safety factors are considered for material quality and type of load.