Damage localization in reinforced concrete beams strengthened with FRP sheets using modal strain energy method
Authors:   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam, Trần Mạnh Hùng ,   Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam, Phạm Minh Nhân ,   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam; Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam, Nguyễn Hữu Phương ,   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam; Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam, Trần Đệ Nhất Trương ,   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam; Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam, Nguyễn Chí Thiện ,   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam; Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam, Hà Minh Tuấn ,   Faculty of Civil Engineering, HUTECH University, 475A Dien Bien Phu Street, Binh Thanh District, Ho Chi Minh City, Vietnam, Ho Duc-Duy ,   Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam; Vietnam National University Ho Chi Minh City, Thu Duc District, Ho Chi Minh City, Vietnam
Published: March 2023

Civil structures are affected by many different factors from the environment, loads, aging of materials, … These factors are uncertain variables and affect the health of the structures. Therefore, structural health monitoring (SHM) is very essential to detect damages early for necessary maintenance. In this paper, damaged locations in reinforced concrete beams strengthened with FRP (Fiber Reinforced Polymer) sheets are identified by using the modal strain energy method. First, a reinforced concrete beam strengthened with FRP sheets is simulated by ANSYS APDL software in order to analyze the beam’s behavior and get vibration responses. The reliability of the simulation is verified by comparing the load - displacement relationship between numerical and experimental results. Next, the modal strain energy method is employed to determine the damaged locations (crack and debonding) in the beam. In which, a set of indicators to evaluate the accuracy of damage localization results is proposed. The feasibility of the method is demonstrated through two problems. For problem 1, five different damage scenarios including concrete damage and FRP debonding are examined to evaluate the modal strain energy method’s feasibility for damage detection in the target beam. For problem 2, damages occurring in the beams are analyzed and determined according to each load level corresponding to the real working of the target beam. The results show that the modal strain energy method has high accuracy in detecting and locating damages in reinforced concrete beams strengthened with FRP sheets.