IoT-based System for Real-time Monitoring of Bridge Displacement – an Invisible Guard Against Disasters

At around 6:10 p.m. on October 10, a terrible scene occurred when the overpass deck on Xigang Road at K135 in the Shanghai direction of national highway 312 turned to one side and fell on three cars under it. This was not the first time when a bridge collapsed.Ten days ago (on October 1), the 21-year Nanfang’ao Bridge in Yilan, Taiwan collapsed suddenly, killing 6 and injuring many others. Further back, three bridges fellwithin five days in July 2011, namely Tongyu River Bridge on provincial highway 328 in Yancheng, Jiangsu on July 11, Gongguan Bridge in Wuyishan on July 14 and the approach deck of the Third Qianjiang Bridge in Hangzhou on July 15. What can we doto avoid frequent bridge collapse?

Transportation plays a huge role in rapid economic development and acceleration ofurbanization of a country. Bridges are the veins of modern transportation. It is important to ensure not only smooth trafficunder a bridge, but also safety of cars on it. However, any bridge is impacted by external factors during construction and service, which will lower its functionality and safety. Without prevention and maintenance, this will lead to bridge collapse and casualties. Traditional monitoring methods are time consuming, labor intensive and delayed. Negligence is another problem. Taking Nanfang’ao Bridge for example, the port authority found throughinvestigation that the bridge had not been maintained for 21 years. The tragedy on October 1 may not have happened if regularmaintenance had been performed and any risks thus revealed had been eliminated. Upon an accident, besidescareful investigation by experts to pin down the cause and learn the lesson and strict law enforcement by the authority, what can be done with bridges? The Internet of Things (IoT) is one solution.

With today’s IoT, the communication technology has gradually come to age and regulation has become more efficient. Similar solutions are often seen in many bridge members in Shanghai and Wuhan. By embedding several sensors in a bridge, for example, those for monitoring bridge displacement, in combination with wireless communication technology, data about the bridge status can be timely transmitted to a platform for central processing. Upon any risk, an alarm is automatically sent to alert related parties for quick repairs to prevent accidents. Working with Jiangsu Zhonglan Intelligent Technology Co., Ltd., SIMCom has launched sensors for monitoring bridge displacement equipped with LPWA and 3G and 4G communication modules, for real-time monitoring of bridges. Different types of sensing equipment are embedding in a bridge, a data acquisition node/gateway and a real-time monitoring platform are established, the monitoring data are collected by SIM7020G, a communication module based on the low-power wide area network, and then transmitted to the acquisition node. SIM7600CE, a 4G module, transmits the data to the platform layer for storage, processing and analysis. Quick response is thus made possible based on the analysis results.

SIM7020G is an NB-IoT wireless communication module that operates on multiple frequency bands. It is packaged in a 42 PIN LCC offering various hardware interfaces and high scalability, which greatly facilitates product development. Compared with GSM,SIM7020G has more gain and a wider coverage, making wireless communication possible in locations like a basement. The module is durable thanks to PSM and eDRX lower-power mode.SIM7020G hasbeen certified by ATEX and supports both NB1 and NB2. The sensors for monitoring bridge displacement withSIM7020G orSIM7080G can monitor the bridge status in real time and check whether the cushion works well by means of vibration frequency. The data are transmitted by the module to the acquisition node and further to the platform for storage and analysis. An alarm will be generated when the results of data processing exceed the pre-set threshold. Any potential hazard will be immediately reported to relevant personnel for repair. Through the data analysis, estimations on bridge tolerance and service life may also be obtained. For example, repairing ordemolishing may be required when the ultimate bearing capacity of a bridge is severed impaired. Automatic monitoring by the module can also reduce labor input, reduce costs and improve monitoring accuracy.

We should always be alert to risks concerning people safety. We hope occurrence of safety accidents will be minimized as technology develops.SIMCom will continuously develop our capabilities and contribute to safeguarding people’s life.