Improvement of the vibration diagnostic method for soil-backfilled corrugated metal bridges
Abstract
A methodology for the quantitative assessment of the stress-strain state of buried corrugated metal bridges based on vibration diagnostics is proposed and experimentally verified. Unlike known approaches limited to the analysis of dynamic coefficients or decrements, the developed method provides a transition from recorded vibration accelerations to stresses. This is achieved by double numerical integration of vibration accelerations to obtain dynamic displacements, which are then recalculated into stresses using a validated finite element model. The algorithm requires static testing on only one object of a group (reference), after which only dynamic tests are applied to the remaining structures. Comprehensive tests on five similar overpasses, including static loading with dump trucks of known mass and synchronous recording of strains with strain gauges and vibration accelerations with triaxial accelerometers, confirmed a stable correlation between the stresses recovered from vibration diagnostics and those directly measured under static loading. The obtained results confirm the applicability of the method for assessing the technical condition of typical structures without repeating static tests. The developed methodology allows, after initial calibration, to perform operational monitoring of the technical condition of corrugated metal structures without traffic interruption, which significantly reduces survey costs and increases operational safety. In contrast to traditional static tests, which require traffic closure and significant time and financial costs, the proposed method ensures repeated use and high cost-effectiveness while maintaining the reliability of the assessment. The established correlation between dynamic and static stresses is characterized by a high correlation coefficient, confirming the reliability of the proposed approach. Thanks to the proposed method, monitoring of buried bridges becomes fast and cost-effective, which is especially important for regular surveys of a large number of similar structures.