Monitoring system for Tsing Ma Bridge

In Hong Kong, a 1377 metres main span suspension bridge, namely the Tsing Ma bridge is now under construction and will be completed by mid 1997. The bridge will carry a dual three-lane expressway at the top deck and two rail tracks for the airport railway plus two emergency carriageways at the lower deck. It forms the key element in the transportation facilities necessary to link the urban areas of Hong Kong and the hinterland to the new airport at Chek Lap Kok. In order to secure the comfort and safe traffic operation, protect the vast investments made in this bridge, facilitate future bridge maintenance works and to verify the validity of the design assumptions and parameters used in the design and construction stages, the Highways Department of the Hong Kong Government decided to install a Wind And Structural Health Monitoring System (WASHMS) for this bridge. This paper outlines the background and objectives for the development of the WASHMS and introduces the system layout and its operation. The approaches used in setting the WASHMS for Tsing Ma bridge will be modified slightly and then applied to form the WASHMS of the other two cable-stayed bridges with central spans of about 430m - the Kap Shui Mun Bridge and the Ting Kau bridge which are now under construction. Both bridges are also scheduled for completion in mid 1997.