System design and demonstration of performance monitoring of a butterfly-shaped arch footbridge

This paper presents an overview of the structural performance monitoring system for a butterfly-shaped arch footbridge located at The Hong Kong Polytechnic University. The system is the product of a multidisciplinary academic collaboration of the pooling expertise of four academic departments, namely, structural engineering, traffic engineering, surveying, and optical communication engineering. This system consists of 88 sensors of 13 types, including an advanced Brillouin optical time-domain analysis technology, an optical fiber Bragg grating technology, a global navigation satellite system (GNSS), and high-performance video cameras. The paper summarizes the modular design, subsystem framework, and advanced features of the monitoring system. Preliminary monitoring results, such as high spatial resolution distributed temperature/strain measurement, global heat-transfer analysis, pedestrian traffic analysis, dynamic characteristics, and GNSS measurements, are introduced. A fire accident is employed to demonstrate the function and value of the monitoring system and provided a rare opportunity to detect damages in a real structure. The monitoring system not only monitors the performance of the bridge in real-time but also provides a multifunctional platform, including an Internet-based software for research and teaching and a touchscreen visualization platform for public education.