Failure Mode Prognosis of Highway Grillage Girder Bridge Considering Shear Resistance of Diaphragms

This paper presents a study on failure mode prognosis for a highway grillage girder bridge consider- ing the shear resistance capacity of diaphragms. The bridge concerned is composed of 5 main gird- ers and 3 diaphragms. The plastic yielding of the main girders considering their moment capacity and the diaphragms considering their shear capacity is concerned. The incremental analyses are conducted to evaluate bridge vehicle-carrying capacity. During the incremental analysis, the ductile or brittle shear failures of the diaphragm are considered. The results tell that the shear resistance capacity of diaphragm will induce the variation of structure failure mode under the traffic loads and should be designed to be of more redundancy to avoid the local failure, especially if uncertainty is considered.