Plastic Analysis MCQ with answer and solution

Concept

Behaviour at a plastic hinge

Step-by-step solution

1. At a plastic hinge the moment equals the plastic moment Mp and stays constant. 2. The section rotates with no increase in moment, so the curvature there is idealised as infinite.

Explanation

In plastic analysis, deformation is assumed to be concentrated at the hinge. The rotation takes place at a point at a constant moment Mp, so the curvature is taken as infinite and the radius of curvature as zero.

Shortcut

Plastic hinge: moment = Mp, curvature = ∞, radius = 0.

Common mistake

Choosing "radius is infinite" (that is true for a straight beam).