Nonlinear Earthquake Analysis of Concrete Arch Dams. ADAP-88 is a finite element analysis program for computing the earthquake response of arch dams including the nonlinear effect of contraction joint opening. The nonlinear joint elements are combined with shell, solid and fluid finite elements to model a complete arch dam system. Special consideration is given to resolving the stress distribution near the joints by using a refined mesh of solid elements. A numerical procedure for solving the equations of motion assumes that the nonlinearity in the model is restricted to the joints. The cantilever monoliths between contraction joints are modeled as linear substructures, resulting in a significant reduction of computation in the iterative solution of the nonlinear equations of motion. Includes a finite element mesh generator for typical arch dam geometries. The computer program RESVOR is used to compute the added mass for the water impounded in the reservoir, assuming the fluid is incompressible.