Experimental Study on the Strengthening Effect of CFRP Sheets on Corrosion-Damaged, Eccentrically Loaded Reinforced Concrete Columns

• Published in: International journal of civil engineering (Tehran. Online) Vol. 22; no. 4; pp. 535 - 547
• Main Authors: Nguyen, Trung Hieu, Nguyen, Van Tuan, Pham, Xuan Dat, Nguyen, Manh Hung, Le, Phuoc Lanh
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2024
• Subjects: Civil Engineering; Engineering; Research Paper; Analytical model; Strengthening; CFRP sheet; Corrosion; Repair; RC column
• ISSN: 1735-0522; 2383-3874
• DOI: 10.1007/s40999-023-00911-8

This experimental study investigates the effects of carbon fiber reinforced polymer (CFRP) strengthening on eccentrically loaded and corrosion-damaged reinforced concrete (RC) columns. The experimental program comprises two main phases: (1) inducing accelerated electrochemical corrosion in steel-bar RC column specimens and (2) subjecting both undamaged and corroded specimens to eccentric compression until failure. Five RC column specimens, sharing identical geometry, reinforcement detailing, and concrete mix, were fabricated. One served as an undamaged control, while the remaining four underwent corrosion induced by electrochemical means. Two of the corroded specimens were strengthened with CFRP sheets after repairing their concrete covers with non-shrink grout, while the other two received neither repair nor strengthening. The study examines the structural behavior of the corrosion-damaged RC columns and evaluates the effects of repair and strengthening solutions, including non-shrink grout and CFRP sheets, under eccentric loading conditions. The experimental results reveal a significant enhancement in the performance of the corrosion-damaged RC columns after applying non-shrink grout and CFRP sheet wrapping. In comparison to the undamaged control RC column, the ultimate bending moment decreases by 16.8% for corrosion-damaged RC columns, while it increases by 15.2% for strengthened RC columns. Furthermore, in accordance with the guidelines outlined in ACI 440.2R-17, a calculation is presented to establish the axial load-bending moment interaction diagram for the strengthened RC columns. This calculation provided a deeper understanding of how CFRP sheet strengthening improves the strength of corroded RC columns subjected to eccentric loading.