This numerical study presents a Finite Element Modeling (FEM) for Closed Curved Beams (CCBs). This study aimed to capture the effect of Stainless-Steel Layers (SSLs) and Engineered Cementitious Composite (ECC) as sustainable strengthening material on the structural performance of RC CCBs under pressure loads. The numerical analysis is implemented based on ABAQUS and validated well with the previous experimental results. A parametric study and a numerical validation for RC CCBs strengthened with SSLs and ECC were prepared and studied by 18 beams divided into 5 groups. The main studied parameters were: number/layout of SSLs with varied thicknesses and ECC layer with varied thicknesses and configuration. The structural behaviour was improved by the SSLs numbers and thicknesses were increased. The cracking load was improved by about 16-43% for studied SSLS groups and the ultimate capacity was significantly increased by about 29-66%. The elastic stiffness was enhanced by 1.2-4.1 times higher than the unstrengthen beam. The reflection of ECC layer was studied. The cracking was improved by the increase the thicknesses by about 18-25%. The ultimate capacity was significantly increased by about 56-76%. The elastic stiffness was enhanced by about 1.4-3.3 times higher than the master beam