Resensy’s wireless strain sensors (Strain SenSpot) and wireless tilt sensors (Tilt SenSpot) were used to monitor another fracture critical bridge in Maryland. The structural health monitoring based on Resensys SenSpot sensors system was deployed on bridge US522 over Tonoloway Creek and Potomac River. The system consists of 12 tilt and 12 strain SenSpot sensors and two SeniMax data logger and remote communication gateways. The main purpose of the installation is to monitor operation of the rocker bridge bearings as well as monitoring strain in the bridge’s steel girders. Correct tilting of bearings (resulted by temperature change) is a primarily monitored. When bearings are functional and responsive, the possibility of overstrain and fatigue crack formation is relatively small; however, non-functional bearings cause cyclic strain (caused by temperature), which in turn leads to fatigue crack formation. The strain sensors provide accurate monitoring of the bridge’s critical members. Formation of fatigue crack is accurate detected by the devices. In addition, each SenSpot is battery operated. The guaranteed battery life of SenSpot is 10 years.
Resensys Wireless SenSpot™ provides a versatile suite of remote sensing capabilities for cost effective, reliable, and long-term bridge monitoring. SenSpot™ sensors are capable of measuring a wide spectrum of structural parameters – including strain (stress), vibration, velocity, displacement, inclination, temperature, and humidity, – in real time. Resensys SenSpots are the world’s most energy efficient wireless monitoring sensors, and a SenSpot™ sensor provides a minimum of 10 years of monitoring using a small ½-AA battery.
Standard SenSpot sensors for monitoring strain in steel members have a resolution of 1.0 microstrain while the full-scale strain monitoring is ±4000 microstrain. Both range and resolution are customizable if desired.
For monitoring orientation (tilt, inclination), Resensys’ wireless precision tilt SenSpot sensors is used. Similar to strain SenSpot sensors, the orientation SenSpot sensors have a battery life of 10 years, making them ideal for long term monitoring for settling, foundation instability, deflection, deformation, etc.