Radio-frequency identification triggering system for structural health monitoring of highway bridges

Abstract

One challenge with structural health monitoring (SHM) for highway bridges is managing large amounts of response data. This paper discusses a proposed SHM system that was developed to collect, store, and prioritize excitation data caused by traffic loads, especially overweight trucks. In the proposed system, a microcontroller is used to trigger the release of data. A radio-frequency identification (RFID) reader and antenna combinations are installed on the truck and at the bridge of interest. The truck information, including axle weights and configuration, is assigned to the RFID tag and placed on the windshield. The transponder at the bridge detects the approaching RFID tag and triggers the data acquisition system to release the response (strain) data from a sensor interrogator through a microcontroller to a network portal (such as a cellular modem or Ethernet radio) while the truck passes over the bridge. Field tests were conducted to validate the proposed system. The optimal position of the vehicle relative to the transponder, the height and horizontal position of the transponder, and the location of the RFID tag were investigated for a vehicle travelling at 105 kph (65 mph). The tests results indicated that the triggering system was successful, but it was sensitive to the position of the tag relative to the transponder.