Optimal sensor placement in health monitoring of suspension bridge

Structural health monitoring (SHM) provides an effective approach to ensure the safety of structures. However, with the restriction of the cost of sensor system and data processing, only a small number of sensors could be available in the health monitoring system (HMS). In order to obtain the best identification of structural characteristics, optimal sensor placement (OSP) becomes an inevitable task in the design of HMS. This paper introduces the process for determining the OSP in HMS of a suspension bridge, in which four different OSP methods have been investigated, including the effective independence (EI) method, the effective independence driving-point residue (EFI-DPR) method, the minimized modal assurance criterion (minMAC) method and the principal subset selection-based extended EI (PSS-EI) method. Then, three criteria, which are modal assurance matrix (MAC), condition number (CN) of mode shape matrix and determinant of Fisher information matrix (FIM), were employed to evaluate the effect of the OSP methods respectively. The result showed that the PSS-EI method developed has the ability to guarantee the highest determinant of FIM, a relatively small off-diagonal term of MAC and agreeable CN, as well as the deployment of sensors in a uniform and symmetric fashion for the studied bridge. Finally, the scheme obtained by PSS-EI was adopted in the HMS.