In high seismic regions, numerous older reinforced concrete (RC) buildings, constructed before modern seismic codes require strengthen to withstand major earthquakes. This research presents an experimental and numerical investigation of strengthen technique for shear walls that are susceptible to brittle failure modes due to deficient detailing or a lack of properly confined boundary elements. The strengthen process involves the addition of steel members. This study primarily focuses on comprehending the flexural characteristics and lateral resilience of a scaled specimen: post-tensioned (PT) walls. Following testing until failure, a strengthening strategy was implemented by attaching steel components to the lower section in the PT wall. These modified configurations are now recognized as the other specimen. Importantly, the ABAQUS model effectively simulates the lateral response of the tested specimens, with minor variations compared to the experimental results falling within an acceptable range. The strengthened walls exhibited ductile failure, as opposed to the original walls that experienced brittle failure. Furthermore, the incorporation of steel components had minimized cracking, increased load-bearing capacity, and improved stiffness and ductility. This enhancement is anticipated to minimize earthquake-induced damage, leading to shorter repair times.