On the coherency of dynamic load estimates for vehicles on flexible structures

Abstract

This paper develops a novel form of a well-known signal processing technique, so as to be applicable to the interaction between a heavy truck and a supporting bridge structure. Motivated by the problem of structural health monitoring of bridges, a new modal coherency function is defined. This relates the input action of moving wheel loads to the dynamic response of the bridge, including the effects of unevenness of the road surface and the vertical dynamics of the truck suspension. The analysis here is specifically aimed at future experimental testing – the validation of axle load estimators obtained from sensors on the truck. It is applicable even when no independent ‘ground truth’ for the dynamic loads is available. The approach can be more widely used in the analysis of dynamic interactions involving suspended moving loads on deformable structures, e.g. for structural vibrations due to high-speed trains.

• vehicle–bridge interaction
• vehicle–infrastructure interaction
• modal analysis
• algorithms
• truck
• tyre dynamics

Acknowledgements

This work was supported by the U.S. Department of Commerce, National Institute of Standards and Technology (NIST) Technology Innovation Program (TIP) [Cooperative Agreement Number 70NANB9H9008].

Funding

The authors are extremely grateful to Dr Yun Hwa Hong for his assistance regarding displacement reconstruction using FIR filters. We also gratefully acknowledge the generous support offered by the US Department of Commerce, National Institute of Standards and Technology (NIST) Technology Innovation Program (TIP) and the assistance of Michigan Department of Transportation for providing access to a bridge and for collecting data.