A study on the seismic behavior of Reinforced Concrete (RC) wall piers strengthened with CFRP sheets: A pushover analysis approach

The use of reinforced concrete (RC) shear walls (SW) as an efficient lateral load -carrying system has gained recent attention. However, creating openings in RC shear walls is unavoidable due to architectural requirements. This reduces the walls' strength and stiffness, resulting in the development of wall piers. In this study, the cyclic behavior of RC shear walls with openings, reinforced with carbon fiber reinforced polymer (CFRP) sheets in various patterns, was numerically investigated. Finite element analysis (FEA) using ABAQUS software was employed. Additionally, the retrofitting of sub -standard buildings (5, 10, and 15 -story structures) designed based on the old and new versions of the Iranian Code of Practice for Seismic -Resistant Structures was evaluated. Nonlinear static analyses, specifically pushover analyses, were conducted on the structures. The best pattern of CFRP wrapping was determined and utilized for retrofitting the sub -standard structures. Various structural parameters, such as load -carrying capacity, ductility, stress contours, and tension damage contours, were compared to assess the efficiency of the retrofit solution. The results indicated that the load -carrying capacity of the sub -standard structures was lower than that of standard ones by 57%, 69%, and 67% for 5, 10, and 15 -story buildings, respectively. However, the retrofit solution utilizing CFRP showed promising results, enhancing the capacity by 10-25%. The retrofitted structures demonstrated increased yield strength, ultimate strength, and ductility through CFRP wrapping and effectively prevented wall slipping.