This thesis presents a study on the seismic performance of a retrofitted concrete building in Mexico City. The original lateral force resisting system consisted of reinforced concrete (RC) columns supporting waffle slabs along with RC walls located in the elevator core. After having suffered damages during an earthquake in 2017, the building was retrofitted by adding new RC shear walls. The structural response of the retrofitted building was evaluated using nonlinear analytical models. The response and performance of the newly-added RC wall components were studied employing nonlinear truss models and strain-based acceptance criteria. The results of the wall evaluations were compared with those obtained using the ASCE/SEI 41-17 methodology, which involves backbone moment-rotation relations and rotation limits for the plastic hinges of flexure-dominated walls. The results of the truss models were used to adjust the calibration of hinge models for each of the wall components. A three-dimensional nonlinear model of the entire building was developed employing nonlinear frame elements with plastic hinges for the walls. Two different calibrations of the hinge models were considered: the ASCE/SEI 41-17 moment-rotation curves and the adjusted curves derived from nonlinear truss models. The performance of the retrofitted building was, thereafter, evaluated using nonlinear static analysis, and the results obtained with the two hinge calibrations were compared.