Probabilistic Design of Composite Girders Considering the Degradation of the Shear Connection and the Redistribution of Forces

Abstract

Fatigue design of composite girders and in particular shear connectors according to Eurocode 4 is based on fatigue strength curves. Therefore, the lifetime of a girder can be limited by failure of a critical shear connector. The failure probability of a component is thus determined by the failure probability of one shear stud or composite dowel, although a composite girder is an internally highly statically indeterminate system with the possibility of redistributing forces in the shear connection. This paper outlines the positive effects on the lifetime of a girder by considering crack propagation and residual capacity of shear connectors with cracks as well as redistributing forces towards less stressed and damaged connectors. The failure probability of a girder is determined by a Monte Carlo simulation using a lamella model with incremental calculation of the degradation of the shear connection. The results show the economic potential of a future global safety concept for composite girders especially with composite dowels.