Bridge condition monitoring system

System Overview:
Bridges crossing valleys, roads, rivers, or other obstacles are artificial channels that are elevated above the water or ground, and their reliability and safety are particularly important. Due to the enormous destructive power of bridge accidents, they not only cause traffic interruptions and affect the development of the national economy, but also bring huge economic losses and casualties, which will have a very negative social and political impact.
In 2006, the State Council issued the "National Medium - and Long Term Science and Technology Development Plan Outline", which required focused research on monitoring, early warning, and prevention technologies for production accidents such as bridges and coal mines, sudden social security incidents and natural disasters, nuclear safety, and biological safety. Therefore, the country attaches great importance to the development of safety monitoring and early warning technologies for large public facilities such as bridges.
In response to the aforementioned requirements, Hangzhou Shanghang has launched the SH-BRID2001 series bridge condition online monitoring system, which is specifically designed for bridge conditions, based on years of experience in earthquake prevention and disaster reduction monitoring. This system is an online monitoring system independently developed by the company, providing a good solution for continuous monitoring of bridge status.
Scheme composition:
In this scheme, the bridge condition monitoring system mainly consists of a monitoring host, system software, data transmission interface, data acquisition substation, various sensors, lightning arresters, and transmission network. The monitoring system is shown in Figure 1.


The monitoring host communicates with the data acquisition substation and is responsible for tasks such as analyzing and processing system monitoring data, real-time display, statistical storage, screen display, query and printing; The system software completes the data collection, processing, processing, display, storage, query, and report printing of various measuring points on the bridge; The communication network mainly completes the transmission and communication functions of measurement data; Various sensors are used to monitor and collect data on the on-site environmental parameters of each monitoring point, display them on site, and transmit information.
The system uses two monitoring hosts to achieve dual machine hot backup, and all monitoring data uploaded by the data collection substation is simultaneously written to the monitoring host and backup machine databases. By using the RS485 communication bus, the monitoring center station is connected to various data acquisition sub stations, and the entire system can form a distributed tree network data acquisition system. The transmission distance of the RS485 bus connected to each node can reach 1200m. Sensors are arranged according to the bridge structure diagram; After arranging the sensors, connect them to the corresponding signal acquisition module. The main detection items and the sensors used are shown in Table 1.
Table 1: Main Monitoring Items

serial number	monitoring project	sensor	Installation location
1	Structural stress and deformation monitoring	Vibrating wire surface strain gauge	The upper and lower surfaces of the box girder at the junction of the tower and beam, mid span, 1/4 mid span, and 3/4 mid span.
		Vibrating string rock stress meter
		Temperature transmitter (temperature compensation)
2	Temperature distribution monitoring	Surface temperature transmitter	The structural temperature is installed at the junction of the tower and beam, mid span, 1/4 span of the main span, and 1/2 height of the cable tower; The air temperature is installed outside the tower beam joint and inside and outside the mid span box beam
		Embedded temperature transmitter
3	Steel cable stress monitoring	Steel cable force transmitter	Edge rope, middle rope
4	Gap monitoring	Vibrating wire seam gauge	expansion joint
5	Pile foundation monitoring	Static level	Pile foundation and its surrounding environment
		Vibrating wire surface strain gauge
6	Bridge vibration monitoring	Accelerometer	Sota, main beam

System performance:
1) Key indicators can be automatically monitored and alarmed online;
2) Using waterproof aviation joints, easy installation and maintenance, good waterproof and dustproof performance;
3) Powerful software processing capabilities: Real time display, storage, over limit alarm, SMS alarm, data analysis, and print output of various monitoring data have been achieved;
4) Single bus real-time data transmission, simple wiring, low maintenance cost, and high system stability;
5) Fault self check, dual machine hot backup, and backup power supply ensure the stability and reliability of system operation;
6) Distributed network structure, some instrument failures do not affect system operation, and the system has good scalability.
(Editor in charge: admin)