For mid-rise and high rise buildings, slender reinforced concrete (RC) structural walls are commonly used as the main structural elements to resist lateral applied loads in high seismically areas around the globe. These RC structural walls can provide substantial deformation capacity, stiffness, and lateral strength through the contribution of their boundary elements by carrying the increasing compression and tension load cycles. The current seismic design practice is intended to maintain high compressive behavior with substantial yielding in tension at the wall-end regions to achieve a ductile response. In such way, there are three main modes of damage typically developed in the RC wall boundary elements include reinforcing steel bar buckling, bar rupture due to low-cycle fatigue, and concrete crushing. Therefore, accurate numerical tools such as the finite element (FE) analysis are needed to predict the nonlinear response of RC structural walls under seismic loads. The main goal of this study is to develop a robust and reliable numerical tool that can be used to predict the nonlinear seismic response of RC structural walls with different geometric shapes. To accomplish this goal, first, a uniaxial stress-strain relationship that accounts for buckling and low-cycle fatigue phenomena for reinforcing steel bars.is developed. Second, an analytical model to estimate the buckling length of reinforcing steel bar embedded in RC elements is developed. Third, a numerical FE strategy to model RC walls with different geometric shapes using regularized shell elements and beam-column displacement based elements is developed. Finally, the seismic performance and collapse of RC core wall building is investigated by using the developed modeling approach in this study.