Question

Assertion (A): In a parabolic symmetrical three-hinged arch the bending moment at any section due to dead load is zero.

Reason(R): In influence line diagram for moment at a section of an arch, the simply supported moment diagram and ${}^{\prime }{H}_{x{y}^{\prime }}$ diagram have equal areas.

• A. A is false but R is true
• B. A is true but R is false
• C. Both A and R are true but R is not a correct explanation of A
• D. Both A and R are true and R is the correct explanation of A

Answer 1

The correct option is D Both A and R are true and R is the correct explanation of A

A three hinged parabolic arch subjected to uniformly distributed load throughout the span, has zero bending moment everywhere because the beam bending moment and bending moment due to horizontal thrust are equal.