01677705

Monograph

http://www.trb.org/Main/Blurbs/177995.aspx

This research focused on the development and implementation of contact-free, reference-free transverse bridge displacement measurements. Recent research had shown that transverse displacements of timber trestle bridges can capture critical changes in bridge serviceability as a function of railroad loading, speed, and direction. Measuring bridge movement under trains in the field is difficult and expensive because a fixed reference point is not normally available, thus creating the need to erect independent scaffolding to create good reference points near the bridge from where to measure. The research included a concept test for integrating unmanned aerial vehicles (UAVs) and laser technologies to assess the structural condition of simply supported spans of conforming steel railroad bridges, which can be instrumental in informing the subsequent prioritization of more detailed inspections. The primary tasks for developing this system was a robust integration of a Laser Doppler Vibrometer (LDV) sensor with a copter-type UAV, optimization of sensor data accuracy, optimization of UAV positioning and movement characteristics, and effective data analysis methods to measure displacements. Initial testing focused on characterizing constituent components of the system: the behavior of the copter UAV, the data from the LDV, and the expected data from current measurements of this type using conventional methods. Researchers compared the data of the LDV sensor to a common tool for linear displacement, the linear variable differential transformer (LVDT), to analyze the relative data outputs before mounting to the UAV. Subsequently, the researchers completed the characterization of the constituent components, and integrated the components into a preliminary testing platform. Finally, researchers collected data to determine their effects on data output of the LDV. The research team collected data outdoors for preliminary validation of the new technology. Results indicated that the prototype was able to monitor movements simulating the vibrations of a train crossing. The implementation of this technology allows for more efficient and effective measurements of displacement on railroad bridges during train crossing events, measuring bridges displacements without the need of installing sensors. This data is valuable for assessing safety of bridges at the network level and to inform bridge management prioritization.

This IDEA project was conducted by the University of New Mexico.

Rail Safety IDEA Project 32

English

34p

2018-7

Safety IDEA Program Project Final Report

Final Report

Digital/other

Figures; Photos; References; Tables

Drones; Inspection equipment; Laser radar; Maintenance; Prototypes; Railroad bridges; Sensors; Steel bridges; Strategic planning; Vibrometers

Innovations Deserving Exploratory Analysis (IDEA) (Program)

Displacement (Engineering); Laser scanning

Aviation; Data and Information Technology; Maintenance and Preservation; Railroads

TRIS, TRB, ATRI

Aug 14 2018 10:37AM