FUNDAMENTAL STUDY ON WIRELESS MEASUREMENT IN STEEL BOX GIRDER BRIDGE USING LPWA

Abstract

 In steel bridge maintenance, it is important to measure the strain responses under live loads because fatigue damage in steel bridge is caused by repetitive high stress. However, the workability of the wired strain measurement systems which are usually used in the measurement of steel bridge are poor because they require wiring. Therefore, wireless strain measurement system are demanded.

 In the present study, a wireless strain measurement system using LoRa® which has recently become available on the unlicensed band was first developed. Then, by conducting field measurements of an in-service steel box girder bridge, the effectiveness of the developed system was verified. The field measurement results showed that the developed system could transfer the measurement data to about 130 meters away from the test bridge. The data transfer rate was about 96% of that in a place of good visibility. Finally, based on the measured strain responses, fatigue environments of two different cross sections in the test bridge were evaluated.