ADAGIO: non-linear quasi-static structural response using the SIERRA framework. Adagio is a quasistatic nonlinear finite element program for use in analyzing the deformation of solids. It is massively parallel, built upon the SIERRA finite element framework [1], and employs the ACME library [2] for contact search algorithms.The mechanics and algorithms in Adagio closely follow those previously developed in JAC2D by Biffle and Blanford [3] as well as JAS3D by Blanford et al. [4]. Adagio assumes a quasistatic theory in which material point velocities are retained but time rates of velocities are neglected. Sources of nonlinearities include nonlinear stress–strain relations, large displacements, large rotations, large strains, and frictional / frictionless contact mechanics. Quasistatic equilibrium is found using a nonlinear solution strategy which includes nonlinear conjugate gradients. This paper briefly describes quasistatic equilibrium, kinematics of deformation, stress updates and the nonlinear solution strategy used in Adagio. In addition, we briefly describe how Adagio is implemented within the SIERRA architecture. Finally, we demonstrate Adagio’s massively parallel capabilities on an example problem