The 120 billion-yuan (17.2 billion USD) Hong Kong – Zhuhai – Macao Bridge (HZMB) is a 55-kilometer-long bridge-island-tunnel complex across the Pearl River Estuary. It is the world's longest sea crossing. The bridge consists of a 6.7-km undersea tunnel, which is the country's first offshore immersed tunnel and the world's longest immersed tunnel for road traffic.
It combines a lot of titles in China’s road building history: the most sophisticated in terms of technologies, the most difficult in terms of construction and the largest in terms of the project scale for a bridge.
The HZMB project completion provided a ground for the use of the most advanced civil engineering technologies in recent years. CHC Navigation Construction and Marine Survey equipment were used during the project from the earlier survey to the bridge deck construction and to the safety monitoring afterwards, providing advanced solutions to contribute to the bridge’s on-time completion and safety acceptance.
Initial survey: bathymetric survey project on the inner side of HZMB
The area of the bridge’s inner region between the shores is 7.2 km2 with an average water depth of 2-3 meters with very shallow water of 0.5 meters. The use of usual survey boats would have led to inefficient and complex process due to the risk of stranding on shallow water.
To achieve the bathymetric survey, the contractor project team decided to use CHCNAV APACHE 5 Unmanned Surface Vehicle (USV). The survey lines were set at a distance of 20 meters, and the space inline as 5 meters. The bathymetric survey with the CHCNAV Apache 5 took only 5 days to provide accurate underwater topographic map.
Bridge deck construction: HZMB deck pavement works
The bridge deck pavement for Hong Kong-Zhuhai-Macao Bridge has been conducted using two methods: GMA (Guss Mastic Asphalt) and GA (Guss Asphalt). For the steel bridge deck pavement, the CHC advanced digital compaction construction system combined with Sinoroad bridge deck compaction QC monitoring system, achieved precise control on compaction times, speed and segregation temperature. The compaction uniformity of CB07 contract segment of HZMB reached above 95% from beginning to end -a value exceeding the 80% generally achieved in construction projects.
Safety monitoring: GNSS automatic deformation monitoring system
The HZMB construction company has also selected CHC’s GNSS real-time deformation monitoring system for the bridge’s automatic safety monitoring. 15 GNSS monitoring stations in the Zhuhai section and 66 GNSS monitoring stations in the Hong Kong section have been set up. The CHCNAV GNSS automatic monitoring system can display the structure deformation data in real time.