Pilot Application of Intelligent Drone Inspection for the Hangzhou Bay Cross-Sea Bridge

Project Overview:

The Hangzhou Bay Bridge is the most convenient passage across the Hangzhou Bay, connecting the Tongjiang–Sanya coastal corridor—the main trunk of China’s “Five Vertical and Seven Horizontal” national highway network—and the Shenyang–Haikou Expressway. It also forms an important part of Zhejiang Province’s planned highway network for 2010, which consists of “Two Verticals, Two Horizontals, Eighteen Connectors, Three Bypasses, and Three Corridors.” The bridge’s construction provides a convenient and efficient link between southeastern Zhejiang regions such as Ningbo and Zhoushan and Shanghai, and together with the Shanghai-Hangzhou and Hangzhou-Ningbo expressways, it helps create a two-hour transportation circle among Shanghai, Hangzhou, and Ningbo. With a total length of 36 kilometers, the bridge broke ground on November 14, 2003, and opened to traffic on May 1, 2008. The completion of this bridge is of great significance for promoting the development of the Yangtze River Delta economic zone, realizing Zhejiang Province’s overall economic development strategy, and perfecting China’s national highway trunk road system.

With the rapid development of the transportation industry and growing societal concern over bridge safety, traditional manual inspection methods can no longer meet the demands for efficient, low-risk, and intelligent inspections. Drone technology—especially the application of low-altitude drones—provides an effective solution to address the shortcomings of conventional inspection approaches. Low-altitude drones not only significantly enhance inspection efficiency, replacing traditional bridge inspection vehicles and rope-access robots and thereby reducing labor costs, but also enable automatic identification of bridge defects through the integration of high-definition cameras and intelligent algorithms. This advancement is driving bridge inspection operations toward greater automation, precision, real-time monitoring, and digitalization, providing strong assurance for the long-term safe operation of the Hangzhou Bay Cross-Sea Bridge.

This project, titled “Pilot Application of Intelligent Drone Inspection for the Hangzhou Bay Cross-Sea Bridge,” aims to leverage drone technology for intelligent inspection of highway bridges, thereby enhancing the efficiency, safety, and digitalization level of bridge maintenance and management. The pilot project is being conducted on the Hangzhou Bay Cross-Sea Bridge, covering approximately 20 km of concrete box girders and the inspection of three cable-stayed bridge towers. It employs advanced drone platforms, data processing techniques, and AI algorithms to collect and analyze large-scale data, thus driving the digital transformation of highway bridge management.

Project Highlights:

Achieve autonomous cruising flight under the bottom of box girders in signal-free areas. By employing a fusion algorithm that integrates images captured by binocular vision sensors with pose parameters output by inertial measurement units, the drone can autonomously fly beneath bridges.
Maintenance inspection and monitoring operations are fully automated. The entire process—from inspection flights and data collection to defect identification—is now fully automated, enabling bridge visual inspections to be completed without any manual intervention, thereby significantly reducing the intensity of manual labor and minimizing human error.
Establish a visualized system for presenting inspection results. By leveraging automated drone inspections and high-definition image stitching, we have developed a fully digital, visual, high-precision, and traceable bridge inspection results presentation system.
A complete equipment system has been developed, based on the DJI Matrice M350 platform, with cloud-based processing at its core and a mobile vehicle-mounted platform as its supporting infrastructure. This system boasts replicable and scalable application potential.

Honored Achievements:

Second Prize in the Final of the Drone Application Competition for Highway and Bridge Inspection;
Ministry of Transport’s Pilot Project for Low-Altitude Drone Application in Highway Inspection and Patrol;

Project Showcase: