A robotic and automatic solution for identifying frequencies and high- resolution mode shapes of bridge structures – an experimental study

This study presents an automated robotic solution for identifying frequencies and high-resolution mode shapes of bridge structures. In this solution, a programmable wheeled robot, whose movement can be precisely and remotely controlled, acts as the mobile platform that carries an accelerometer, and another accelerometer is deployed on the tested structure as a stationary reference. By exploiting a mobile modal identification scheme, this study adopts an output-only frequency domain decomposition technique to extract frequencies and high-resolution mode shapes from the acceleration signals captured by both the mobile and stationary accelerometers. To validate the solution, a field test is conducted on a footbridge, where the frequencies and high- resolution shapes of the first two structural modes are successfully identified, using only two wireless accelerometers. This confirms the effectiveness and efficiency of the proposed solution.