Earthquake Stresses in an Arch Dam

The forces of inertia manifested in a structure during an earthquake are ordinarily taken into account in the design. In this paper formulas are derived for determining the stresses due to the horizontal effect of an earthquake on an arch dam for two different conditions: First, the acceleration of the earthquake is assumed to occur along the canyon, that is, horizontally up stream; and, second, the acceleration is assumed to occur across the canyon, that is, horizontally at right angles to the first condition. The vertical effect of the earthquake is omitted from consideration because of its minor importance. Arches with hinged ends as well as with fixed ends are considered, and illustrative numerical examples are given (see T able 1). The derivation of the formulas is based on Castigliano's Theorem of Least Work.