A new methodology to detect corrosion on steel truss railway bridges exploiting local strain gauges: Analytical, numerical, and experimental validation

Steel truss bridges suffer from ageing deterioration phenomena, among which corrosion is the most critical. Several works in the literature proved strain gauges effective in assessing corrosion effects over bridge truss elements. This paper proposes a novel diagnostic methodology based on measurements performed by resistive micro-strain gauges applied to end diagonals and midspan lower chords of a Warren truss bridge. Data were collected from a permanent monitoring system in normal operating conditions. The authors introduce a new damage-sensitive feature (DSF), independent from operational variables, to enhance performance of corrosion damage detection. The proposed index consists of the normalised area of the strain time series recorded on instrumented bridge members. The proposed DSF is robust to noise and independent of train characteristics (speed, weight, number of axles, etc.). The normalisation is realised by exploiting some strain gauges on the track segment, whose records are...