Question

If F is a dimensionless factor, the defection in rigid plate of radius a is__________

(a) \(∆=\frac{pa}{E} 1.5F\)

(b) \(∆=\frac{pa}{E} 1.18F\)

(c) \(∆=\frac{a^2}{2E} 1.18F\)

(d) \(∆=\frac{pa}{E} 2F\)

I have been asked this question during an interview.

This is a very interesting question from Stresses in Flexible Pavements topic in division Design of Flexible & Rigid Pavement of Geotechnical Engineering II

Answer 1

The correct choice is (a) \(∆=\frac{pa}{E} 1.5F\)

Easiest explanation: The defections for a two layer system is obtained from,

\(∆=\frac{pa}{E} 1.5F,\) for flexible pavement

\(∆=\frac{pa}{E} 1.18F,\) for rigid pavement.