System reliability and the redundancy factor by simplified modeling

In this paper, the relationship between component and system reliability and the resulting redundancy factor by application of a simplified system modeling approach is investigated. The redundancy factors and the associated reliability indices of girders are studied using common steel girder bridges consisting of four to twelve girders. Different system models in which the system fails due to the failure of any girder, all girders, and any two or any three adjacent girders are developed and studied considering three correlation cases among the resistances of girders. The results show that the redundancy factors associated with different system models can be significantly different.