Beitrag zur Optimierung von Hängeranschlüssen stählerner Stabbogenbrücken

Optimisation of hanger connections for steel tied arch bridges. Hangers in tied arch bridges are subjected to varying strains due to traffic loads. This can be dangerous in terms of fatigue failure, depending on stress magnitude and number of stress cycles. In this respect, the connections of the hanger bars to the arch and lower chord should be considered as critical, because alterations in the geometry and notch effects of connecting welds cause non‐uniform stress conditions. The maximum stress peak at the notch tip is determined by the depth of the notch and the notch tip sharpness. In order to provide sufficient security against fatigue failure it is necessary to minimise stress peaks that cause cracks and to ensure homogeneous stress distribution within the whole element. With the help of parameter‐based shape optimisation and subsequent topology adaptation the aim is to reduce the danger of fatigue failure. For the connection detail developed under these aspects, the notch effect – expressed by the stress concentration factor – is determined. Finally an analytic formula for K_f is developed to enable the application of the notch stress concept for hanger connections.