Successful Application of SST400 Inclinometer on Nansha Bridge for Structural Health Monitoring in China

On April 2nd, 2019, the Nansha Bridge (Humen Second Bridge Project) was officially opened after a series of strict tests. It’s a good news that Vigor Technology SST400 Inclinometers have been successfully applied in the engineering structure health monitoring system of Nansha Bridge.

Overview About Nansha Bridge

Nansha Bridge, formerly known as Humen Second Bridge, is located in Guangdong Province, China, above the main stream of the Pearl River.

It is another world-class super project following the Hong Kong-Zhuhai-Macao Bridge. This bridge was started on December 28th, 2013 and opened to traffic on April 2nd, 2019. The Nansha Bridge is a twin-tower double-span suspension bridge with a main span of 1,688 meters and a side span steel box girder with a length of 548 meters which is the largest steel box girder suspension bridge in the world.

The monitoring system of Nansha Bridge has hundreds of monitoring points for various monitoring items, such as ambient wind load, traffic load, bridge space displacement and structural dynamic characteristics monitoring.

In the Nansha Bridge project, the Vigor Technology SST460 static tilt sensors which are of dual axis, 10” precision and RS485 HEX communication protocol were successfully applied. Monitoring points were set on the bridge deck and the pier based on the SST400 inclination sensor to measure the structural deformation of the bridge deck under no-load or loaded conditions, and to evaluate the integrity and stability of the bridge structure.

The SST400 inclination sensor has built-in software and hardware filters, which can effectively eliminate the high-frequency attitude harmonics of the bridge structure under the action of the vehicle or the wind, and output the low frequency slowly-changing attitude of the bridge body and the pier, and intuitively reflect the true state of the bridge structure. In special applications, each axial raw acceleration data can be provided for further calculation of the index parameters.

The values outputted by the SST400 incline sensor provide data support for the safety assessment of the bridge and provide early warning of abnormal conditions.

Therefore, the bridge maintenance engineer can make decisions based on the monitoring results to ensure the safety of the long-span bridge during construction and use.