7 - Operational modal analysis for vibration-based structural health monitoring of civil structures

Abstract

Work to date on structural health monitoring systems for civil structures has been useful, but resembles existing bridge management systems. These management systems focus on processing collected data, but are unable to measure or evaluate the rate of structural deterioration for a specific bridge. In the last decade and a half or so, starting from the early 1990s, Operational modal analysis (OMA) has drawn significant attention in the civil engineering field as an attractive way to tackle this problem. OMA utilizes only response measurements of the structure under operational or ambient conditions to identify modal parameters. Compared with traditional experimental modal analysis (EMA), OMA does not require expensive excitation sources and can be applied to structures while they are in operation. The latter attribute is particularly attractive for vibration-based bridge health monitoring applications because the target bridge does not need to be closed to traffic to perform the modal parameter identification. This chapter discusses the use of OMA in long-term vibration-based structural health monitoring applications.