ABSTRACT
With the increasing popularity of twin I-girder bridges, lack of robustness of this bridge type has always been a major concern. Though the AASHTO (2012) specification considers all twin I-girder bridges as non-redundant and fracture critical structures, the robustness of these structures can be improved through design criteria updates and the addition of auxiliary members. This study aims to evaluate the robustness of simply supported twin I-girder bridges. Experimental testing was conducted on two scaled bridge specimens (intact and damaged) under asymmetric loading conditions, and the structural responses were analyzed. Obtained test data were used to validate the developed finite element model and non-linear analyses were performed for further investigation. In this study, the robustness of twin I-girder bridge is studied with different vertical positions of crossbeam, considering different damage locations. The results obtained indicate an enhanced system robustness when the crossbeams are positioned at the lower end of the girder.
