Incorporating measurement data to improve the fatigue assessment of steel bridges

Fatigue calculations of steel bridges are particularly vulnerable to inaccuracies in stress assessment. Their accurate evaluation ensures structural safety and can contribute to extending the remaining service life of many structures. The following study deals with the incorporation of measured data into fatigue assessment based on FE calculations using the trains operating on site. The bridge under study was equipped with a large number of strain gauges to capture the global and local effects of train passages. In addition, some strain gauges were placed on both rails to determine train speeds and axle forces. A detailed finite element model of the bridge was created and the strains caused by selected detected trains were blindly compared with measured values. Although a fairly good agreement was obtained for most strain gauges without the need for model updating, some sensors did not comply with the measured values. In order to achieve better agreement, a model update was performed. The authors concluded with a comparison of the original and updated models and the determined operating trains with regard to the fatigue calculations and discussed the added value.