Design of a structural health monitoring system for long-span bridges

Structural health monitoring systems (SHMSs) have been adopted over the past decade to monitor and evaluate the structural health condition of long-span bridges. A SHMS is currently included as a standard mechatronic system in the design and construction of most large-scale and multi-disciplinary bridge projects, such as Stonecutters Bridge and SuTong Bridge in Hong Kong and China. The modular concept used in the design of the SHMSs for Tsing Ma Bridge, Kap Shui Mun Bridge and Ting Kau Bridge has a significant influence on the design of new SHMSs in Hong Kong and China. This modular concept has, however, been enhanced in the detailed design of the SHMS for Stonecutters Bridge by the Highways Department of Hong Kong. This paper introduces the enhanced modular concept of six integrated modules in terms of their respective functional performance requirements. The six integrated modules are the sensory system, the data acquisition and transmission system, the data processing and control system, the structural health evaluation system, the structural health data management system, and the inspection and maintenance system. Finally, it is concluded that a SHMS for long-span bridges should at least be able to monitor the loading and structural parameters set by the bridge designer so that the bridge performance under current and future loadings conditions can be evaluated. Such evaluated results should be able to facilitate the planning of bridge inspection activities, and be able to determine not only the cause of damage, but also the extent of remedial works, once the damage is identified.