Reinforced concrete structural walls are frequently used as a lateral load resisting system in buildings. In some buildings affected by relatively recent seismic events, the response of the structural walls, traditionally labeled as excellent, has been somewhat unexpected and deserves attention.This dissertation focuses on enhanced numerical methodologies for the verification of the seismic response, including softening, of reinforced concrete structural wall systems. First, a Truss Model for reinforced concrete coupled structural walls is developed. Bar bond-slip, dowel action, and confining effect of the foundation are considered. Two cyclic tests, on scaled seven-story coupled walls (from literature), are used for validation. It is shown that the compressed wall piers resist most of the base shear force and that the coupling beams at lower levels develop the largest shear forces. Second, using the same benchmark test specimens, two models for the nonlinear cyclic analysis of reinforced concrete coupled walls are developed, i.e., Modified Beam-Truss Model and Enhanced Beam-Truss Model. The role of the strain penetration in diagonally reinforced coupling beams on the hysteretic energy dissipated is studied. It is verified that the computational-efficient proposed models predict well the overall response and the sliding shear failures of coupling beams. Third, the Beam-Truss Model developed in a previous study for the nonlinear cyclic analysis of reinforced concrete components is extended to compute out-of-plane buckling in structural walls. The novel Beam-Truss Model computes accurately the force  displacement responses and the buckling behavior of three test specimens reported in literature used for validation. Finally, the Beam-Truss Model is enhanced to compute the out-of-plane nonlinear shear response of wall piers in the analysis of Core-Wall-Building systems. Using the proposed model and pushover analyses, a comprehensive study on a 14-story archetype Core-Wall building is carried out. It is shown that the in-plane shear response has a large influence on the lateral strength and displacement capacity, whereas the out-of-plane shear response mainly influences the displacement capacity.