Using Instrumented Quarter-Cars for ‘Drive By’ Bridge Inspection

This paper investigates the concept of ‘drive by’ bridge inspection, a low cost alternative to Structural Health Monitoring (SHM), involving no sensors on the bridge. The concept may be of particular value after an extreme event, such as an earthquake or a flood, where a rapid indication of bridge condition is needed. Vehicle/bridge dynamic interaction is modelled to test the effectiveness of the approach. Damage is simulated here as a change in the bridge damping ratio. Two quarter- cars are simulated crossing the bridge with accelerometers on board. A frequency domain analysis then illustrates changes in the Power Spectral Density of the accelerations as the bridge becomes damaged. The time-lagged difference in the accelerations is found to be effective in detecting damage. Results are compared to those with sensors on the bridge and found to be similar.