Question

Which of the following is the most economical type of arch dam?

(a) Constant radius type

(b) Variable radius type

(c) Constant angle type

(d) Variable angle type

This question was addressed to me during a job interview.

My question is based upon Arch Dams topic in section Arch and Buttress Dams of Irrigation Engineering

Answer 1

The correct option is (c) Constant angle type

Easiest explanation: A special type of variable radius arch dam in which the central angles of the horizontal arch rings are of the same magnitude at all elevations is called a constant angle arch dam. Such a dam proves to be economical as the design can be made by adopting the best central angle of 133°-34′.