Abstract
Dynamic nonlinear FEM analyses have been carried out on a concrete arch dam, in which the nonlinearity due to joint opening and the material nonlinearity of the dam have been taken into account to investigate the influence of both kinds of nonlinearity on the earthquake response of the dam. Taking the material nonlinearity into consideration in addition to joint opening, considerable permanent displacement and considerable amount of joint opening occur in the response of the dam. Perimetral joint opening at the contact area of the dam body and its foundation together with material nonlinearity releases the cantilever tensile stresses at the base of the upstream face and increases the arch compressive stresses at the mid-height of the crown cantilever. During vertical joint opening between the cantilevers of the dam accompanied with material nonlinearity, the tensile stresses can not develop across the joints, and so arch tensile stress release occurs in that area. The dam has more remarkable tendency to displace toward upstream and downward directions, which results in considerable increase of compressive stress in cantilever at the base of the downstream face. The release of the tensile stresses and the redistribution of the internal forces by converting the cantilever action to the arch action or vice versa due to the joint opening in concrete arch dams are accelerated by the material nonlinearity. It may be said that the above process results in the stable stress state in the actual dams.
