| The effects that steel corroded had on reinforced concrete beam modal parameters are studied in this paper. Three beams have been designed in this reinforced concrete beam modal analysis experiment. Modal parameters consider the impact of different corrosion damage location and damage degree. The dedicated modal analysis sofeware and hardware has been used to gather the structural dynamic signal in different corroded damage condition,and the modal Parameters sush as modal frequency, modal damping ratio, modal shape were obtained,the independence of the vibration mode which has been verified through modal correlation matrix shows that the placement of sensor is reasonable.Research shows that steel corroded damage position and corroded damage degree have an effect on the parameters such as modal frequency, modal damping ratio, modal shape. With the increase of the steel corrosion levels, the structural damage degree aggravated, and the natural frequency of test beam decreases while the damping ratio increased significantly. The empirical formulas of modal frequency, modal damping ratio and steel corrosion rate of reinforced concrete test beams are established respectively to determine whether a structure damage happened and determine the degree of structural damage.Modal vibration mode can be used for the location of steel corrosion damage, but its sensitivity and accuracy is not high for the corroded damage degree. In the event of a single and several area of damage of simply supported beam and continuous beam,the first order vibration mode ratio and the first order modal shape change ratio appear mutations in damage position, which can be use to accurately recognize damage position and qualitative discriminate damage degree.The research results in this paper show that corroded damage recognization based on modal parameters is a kind of convenient and efficient method, and it can be used as a new way to study the corroded damage and detection method of reinforced concrete structure. |
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