ABSTRACT
Ambient vibration test is one of the SHM technologies widely used for monitoring civil infrastructures. It uses natural excitations such as traffic and winds thus it has the merit of easy performing especially for large-scale structures which are difficult to be excited by artificial forces. Even though ambient vibration and modal identification technologies have been widely applied, it has been recognized that the identified modal parameters such as frequencies, damping ratios, and mode shapes couldn’t effectively support decision making of structural management (Ko et al. 2002; Brownjohn et al. 2003b; Yang et al. 2004; Conte et al.2008). The importance of directly utilizing on-line monitoring data such as strain and displacement for performance evaluation and warning is being increasingly realized. Zhang et al. (2015) studied the vertical deflection of the Sutong Yangtze River Bridge, and it is pointed out that the deflection is a good indicator for structural long-term performance evaluation.
