Research Purpose: The purpose of this research is to analyze a G+20 reinforced concrete building in Amman, specifically focusing on its behavior under gravitational loading and wind, Applied Research Method: The research employs four types of static analysis: linear elastic analysis, geometric nonlinear analysis, physical nonlinear analysis, and physical and geometric nonlinear analysis. The OpenSees opensource program, developed at the University of California, Berkeley using C++ language, is used as the platform for the study, Principal Results: The research reveals significant differences in the results obtained from the various types of analyses performed. The linear elastic analysis, geometric nonlinear analysis, physical nonlinear analysis, and physical and geometric nonlinear analysis produce varying results. The effort (forces and stresses) experienced by a specific beam on different floors also exhibits reasonable variation, Major Conclusions: Based on the analysis results, it can be concluded that considering geometric and physical nonlinearity is crucial in accurately modeling the behavior of the reinforced concrete building. The use of the OpenSees program, along with the corotational formulation to account for large rotations and the P-Delta method for result validation, proves effective in capturing the complex behavior of the structure. The study highlights the importance of considering concrete cracking and reinforcement plasticity with precision to better understand the structural response.