Structural Identification of a Long-Span Truss Bridge

An ongoing research project involving structural identification of the Commodore Barry Bridge, a major long-span truss bridge over the Delaware River, is described. Structural identification is an approach in which a constructed facility and its loading environment are objectively characterized by field observations, measurements, and controlled experiments in conjunction with an analytical model. This process is a necessary precursor to performing health monitoring of the bridge. Long-span bridges have attributes that make utilization of experimental and analytical techniques on them quite different than for short-span bridges. The concept of structural identification and the methods used in applying it to a long-span bridge are presented and discussed. The structural characteristics of the bridge are described and conceptualized. Development of the three-dimensional analytical model and the model characteristics are summarized. Static and dynamic analyses are conducted to help locate anomalies and errors in the model. The experimental techniques necessary for structural identification of a long-span bridge are defined. A limited-scale health-monitoring system, which integrates operational data with structural performance and loading environment data, was designed and installed on the bridge. Mechanical and electrical characteristics of the monitor system and issues related to management of the data from this system are discussed. The monitoring system currently has over 80 channels of different sensor types collecting various data from the bridge. In addition, data from the system can be viewed from a remote location in real time.