As the topic says, Limit state. Let first know the meaning of the topic. It’s the acceptable limit for safety and serviceability of structure or member just before failure. For more simply, the structure is unfit to use when it reaches limit state. Limit state can be achieved due to collapse or serviceability. afore described about two different things that are collapse and serviceability. These two thing have different aspect.
Limit state of collapse
Generally collapse due to flexure, compression, shear, torsion. In this creep and shrinkage is not included.
Limit state of serviceability
It is due to deflection, cracking, vibration, corrosion. Here creep is included.
Assumption in LSM
- Plain section before bending remains plane after bending (i.e. strain variation is linear). incase of deep beam, it is not plane.
- Maximum compressive strain in concrete is limited to 0.0035.
- Tensile strength of concrete is ignored.
5. Stress and Strain diagram of steel under compression & tension is taken as follows :
Mild Steel
HYSD
