A new type of temperature-based sensor for monitoring of bridge scour

• The structure of heat transfer bridge is key of the sensor based on heat conduction.
• Internal structure design of sensor.
• Experimental procedure and results.
• Methods of data processing and analysis.

This paper introduces a sensor measuring the scour depth around the bridge based on the theory of heat conduction. The heat dissipation rate is different in different, heat losses faster in water environment than that in soil environment. Therefore, the position of mud surface can be judged by measuring the temperature change of the sensor in underwater environment. The sensor consists of a stainless steel cuboid shell, a heating piece and two probes of temperature sensor. The continuous power supply to the heating piece can make it heated, and the temperature statistics of two probes of temperature sensor is continuously measured during this process. Meanwhile, the temperature time-history curve in different environment can be drawn. The quantitative indicators Ke and R2 using for judging environment can be obtained by fitting the curve. The environment can be judged according to the environment coefficient Ke and the coefficient of determination R2. Also, the scour depth can be obtained. The laboratory experiment has proved that this sensor can distinguish environments such as air, flowing air, soil, sand, mud, water and flowing water.