Modal Parameter Identification of Hydraulic Structures Based on ERA Method

Modal parameter has been considered as one of the indices in assessing the working state of hydraulic structures. The method for obtaining the modal parameter indices is crucial for health monitoring of hydraulic structures. Traditionally, model parameters are measured from prototype dynamic test (PDT) under the excitation of special equipments. The preparation is time consuming and the method is difficult to carry out. Aimed at these problems,the natural excitation technique (NExT) and the eigensystem realization algorithm (ERA) are combined to identify the modal parameters of ambient-excited hydraulic structure, and the false modal is eliminated by modal confidence factors. Finally, this method is applied to identifying the operational modal parameters of Ertan arch dam under different flood discharging states. This method provides a simple way to identify the modal parameters of large-scale hydraulic structure under ambient excitation.