Question

An arch is a pure compression form.

(a) True

(b) False

This question was addressed to me in exam.

I want to ask this question from Jack Arched and Flat Terraced Roof topic in division Different Type Roofs, R.C.C of Civil Engineering Drawing

Answer 1

Right answer is (a) True

Easiest explanation: It can span a large area by resolving forces into compressive stresses and, in turn eliminating tensile stresses. This is sometimes referred to as arch action. As the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust. As the rise, or height of the arch decreases, the outward thrust increases. In order to maintain arch action and prevent the arch from collapsing, the thrust needs to be restrained, either with internal ties or external bracing, such as abutments.