The Hong Kong-Zhuhai-Macau Bridge spans the Pearl River estuary between Macau and Zhuhai on one side and Hong Kong on the other. It is a busy shipping route, in particular for tankers. Therefore, when designing the piers that support the 22.9 km-long main bridge, the bridge builders factored in for ship collisions, equipping them with sensors to rapidly assess the potential effects of any impacts.

The sensors chosen for the job were the CS-1611LN tri-axial capacitive acceleration sensors from manufacturer ASC , based in Pfaffenhofen, to the north of Munich. The sensors were fitted laterally on the pierheads. They feature a measuring range of +/- 5 g, a sensitivity of 4 to 0.16 mV/g, and a current signal output of 4 to 20 mA; the latter facilitates loss-free signal transmission, even for cable lengths of over 100 m, as used for this and other bridges. The Krypton system from Slovenian company Dewesoft is used to evaluate the data provided by the sensors. Together, the sensors and software form the heart of the road link’s structural health monitoring.