Question

What is very critical about gravity dams?

(a) Strength of the concrete used

(b) Strength of the masonry used

(c) Strength of the rock foundation

(d) The type of water stored in the reservoir

The question was posed to me in examination.

This intriguing question comes from Types of Dams topic in portion Dams and Reservoirs of Engineering Geology

Answer 1

Correct option is (c) Strength of the rock foundation

For explanation I would say: All the forces arising in a gravity dam as due to the thrust of the impounded water and the massive weight of the dam material- are assumed to be directly transmitted to the foundation rocks. Hence the strength of the foundation rocks is the most critical factor.