Bridge damage detection using operating deflection shape ratios obtained from a passing vehicle

Large scale monitoring of bridge structures poses a significant challenge for infrastructure managers. This challenge could be overcome by using passing vehicles to monitor bridge condition. The operating deflection shapes of a bridge can theoretically be detected from in-vehicle measurements. This paper proposes a novel approach which introduces the concept of operating deflection shape ratios (ODSRs) from the responses measured on two following axles on a bridge. Unlike operating deflection shapes derived from drive-by measurements, ODSRs are nondimensional values and are not a function of the bridge excitation level. This means that ODSRs are always constant for various vehicles passages. It is theoretically demonstrated in this study that ODSRs corresponding to each mode of bridge vibration can be approximately extracted from the responses of two following axles. Finite element modelling is employed to validate the feasibility of using ODSRs for bridge monitoring. The sensitivity of the ODSRs to damage is demonstrated numerically for damage at various locations, different vehicle speeds and different pavement roughness values. Laboratory experiments are then used to verify the theory in a practical environment. It is confirmed that the ODSR can be calculated from in-vehicle vibration measurements and can be used to detect changes in the structural behaviour of the bridge. The results of the study indicate that the ODSR represents a useful feature for drive-by bridge monitoring.

Automated summary

This paper proposes a novel approach to monitor the condition of bridge structures using passing vehicles. It introduces the concept of operating deflection shape ratios (ODSRs) derived from in-vehicle measurements. The feasibility of using ODSRs for bridge monitoring is validated through finite element modeling and laboratory experiments. The results demonstrate that ODSRs are sensitive to damage and can be used to detect changes in the structural behavior of the bridge. Overall, the ODSR represents a useful feature for drive-by bridge monitoring.