Reference channel selection strategy in system identification of bridge structure

Based on basic idea of natural excitation technique (NExT) and eigen value realization algorithm (ERA), a solvtion process was formulated adopting NExT/ERA and multiple reference channel. The strategies for determining reference channels were suggested and investigated in the mean time. First, two evaluation criteria concerning modal frequencies and modal shapes were proposed to evaluate the identification results; then, according to the criteria, the strategies for multiple references selection were proposed and discussed herein. The strategy could be used to exclude bad references. In complex structures too many sensors might be on nodes of natural modes, using the proposed strategy many sensors were excluded and only a few necessary sensors were retained. By applying the proposed method to Bill Emerson Bridge well known worldwide as a ASCE benchmark model for structural control problems of cable-stayed bridges, the study nere was proved to be meaningful. The results provided a helpful reference for system identification of general cable-stayed bridges.