Making good use of structural health monitoring systems of long-span cable-supported bridges

Many long-span cable-supported bridges have emerged in recent years, but are exposed to harsh environment conditions. The installation of long-term structural health monitoring (SHM) systems to the bridges has become a trend to monitor their loading conditions, assess their performance, detect their damage, and guide their maintenance with the utmost goals of ensuring their functionality, safety and sustainability. Nevertheless, it is not very clear how to make good use of SHM systems toward these goals. This paper takes the Tsing Ma suspension bridge in Hong Kong as an example and recapitulates the relevant works done by the author and his colleagues and students in the past 20 years to manifest how the SHM system installed in the bridge has been utilized since 1997. The SHM system installed in the bridge is briefly introduced first. How to use the SHM system for investigating highway loading, railway loading, wind characteristics, and temperature effects is then presented. Identification of time-varying natural frequencies and modal damping ratio of the bridge under strong winds using the data recorded by the SHM system is also demonstrated. Toward the performance assessment and damage detection of the bridge, SHM system-based computer simulation and damage assessment are targeted and some typical examples are given. The establishment of SHM system-based bridge rating system for bridge maintenance is also briefly introduced.