Determination of Bridge Natural Frequencies Using a Moving Vehicle Instrumented with Accelerometers and GPS

An instrumented vehicle fitted with accelerometers and GPS allows recording frequencies with position. This information can be used to determine the main frequencies of a bridge as the vehicle traverses it. The accelerations, that contain the dynamic excitation result of the interaction between vehicle and bridge, can be processed using spectrum analysis. Numerical simulations are used to define the accuracy of the predicted frequency for a number of scenarios. Accuracy typically gets better as the bridge span increases, the vehicle speed decreases and the road gets smoother. Experimental data is also employed to test this measuring technique.