Abstract
A mathematical model describes properties of concrete under a two-dimensional state of stress. The effects of strain rate\#\= the time rate of change of strain\#\= on the mechanical properties are incorporated in the model. Appropriate assumptions are introduced in the model where experimental data were lacking; it was assumed, for example, that strain rate effects on mechanical properties of concrete under biaxial states of stress are identical to those revealed by uniaxial tests, because experimental data were available only for the latter case. Because no data were available for complete stress and strain reversals, the stress-strain curves in unloading and reloading where hypothesized in terms of the skeleton stress-strain curve. A method is developed for nonlinear analysis of response of concrete gravity dams to earthquake ground motion wherein mechanical properties of concrete are defined by the mathematical model mentioned. Each dam monolith is treated independently and idealized as an assemblage of two-dimensional finite elements.