Natural Frequencies of Corroded Reinforced Concrete Beams Strengthened with Carbon Fiber Composite Sheets under Fatigue Load

This paper presents the results of an experimental study on the natural frequencies of corroded reinforced concrete beams strengthened with carbon fiber composite sheets. The reinforced concrete beams were first subjected to reinforcement corrosion and then strengthened with carbon fiber composite sheets for fatigue tests. Modal tests were performed during fatigue loading. The natural frequencies were extracted and compared with each other. The obtained results showed little changes in the initial natural frequencies of the strengthened beams. The trend in the measured natural frequencies is sensitive to the deterioration of the beams due to fatigue loading. The test results indicated that the stress level in the reinforcing steel bars and the strengthening ratio of the composite sheets are the dominant factors to the natural frequencies of corroded beams strengthened with carbon fiber composite sheets. This study provides insight into the use of modal parameters to detect damage in reinforced concrete members and is useful for structural appraisal and assessment.