Correct Answer - Option 2 : Muler-Breslau Principle
Concept:
According to Muller Breslau Principle:
- “If an internal stress component (shear force, bending moment etc) or reaction component is allowed to act through a small distance thereby causing deformation of the structure, the curve of the deformed shape represents to some scale, the influence lines for that stress or the reaction component.”
Application: Muller-Breslau's Principle is applicable to all structures, determinate or indeterminate.
Note:
- The Influence Line Diagram (ILD) for statically determinate structures is a straight line but for statically indeterminate structures, it is curved.
- The given beam is symmetrical beam having symmetry about B, so ILD for span AB is the same as that of span BC.
- To determine the shape of ILD for the given two-span continuous beams, Force method of analysis is used by considering reaction at support B as redundant.
- In the case of determinate systems, the ILD can be obtained directly by allowing unit deformation corresponding to the constraint.
- For indeterminate structure, it is applicable only when the material is within the elastic limit and obeys Hook's law so that the law of superposition holds good.
