Finite element analysis and retrofit of the existing reinforced concrete columns in Iraqi schools by using CFRP as confining technique

Abstract

Abstract There are many studies about the use of carbon fiber-reinforced polymer (CFRP) to strengthen concrete members such as columns, beams, and slabs. The effectiveness of these strengthening techniques has been proved by enhancing the mechanical properties of concrete structures. So, CFRP has been used to strengthen and repair existing concrete structures in Iraq. For example, in Al-Mosul city, the strengthening and repairing system is done for concrete members such as beams, columns, and slabs using the Near Surface Mounted or confinement technique. Therefore, the research aim is to use CFRP for maintenance as an alternative material to strengthen and repair concrete members in Iraqi schools. This article employs methods to enhance and repairing of some of concrete columns at Al-Abeer school in Najaf city by using modern materials as an alternative method of maintenance. In addition, finite element analysis was carried out using Abaqus software to verify the effectiveness of strengthening. The reinforced concrete (RC) column strengthened by using fiber-reinforced polymer as a confining technique increased compressive strength by about 91% compared to the control column. In addition, the value of strains increased to nearly 100% in the longitudinal direction with the stability of the value of the lateral strains, despite the occurrence of a significant increase in the compressive strength capacity. So, the values of vertical displacement at stress 4 MPa were 22.3 mm for the strengthened RC column and 5 mm for the control RC column. Thus, the strengthened RC column increases the values of compressive strength with a decrease in displacement to approximately 22%. Four years ago, the strength of the school building was assessed, thus the success of the strengthening.