Structural health monitoring of an iron bridge

Issue

Quick assessment of the structural health of an iron bridge reproducing the ordinary operating conditions through ad-hoc experimental tests.

Solution

A fully remote static and dynamic monitoring was performed by a Terrestrial Radar Interferometric station quickly and temporary installed below the deck, thus allowing the simultaneous high resolution and high sampling frequency displacement detection on the whole structure. Topographic and Terrestrial Laser Scanner surveys were also performed in order to provide the actual geometry of the structure. All tests were performed in one only working day.

Achievement

The main vibration modes of the bridge were identified and confirmed by all experimental tests performed. Calibration measurements by a velocimetric sensor in the centreline of the structure also confirmed the achieved results both in terms of vibration and of oscillation amplitude. Static tests performed in order to reproduce the maximum static load in ordinary conditions allowed to estimate the maximum vertical displacement of the structure, while by long term static monitoring the deformations induced by daily thermal variations have been assessed.

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