EVALUATION OF FINITE ELEMENT ANALYSIS MODELS FOR FATIGUE STRESS AT RIB-TO-DECK WELDED JOINTS OF ORTHOTROPIC STEEL DECK

Based on the orthotropic steel deck of Haihe Bridge in Tanggu, Tianjin, three finite element analysis (FEA) models for the fatigue stress analysis of rib-to-deck welded joints are evaluated, where the three FEA models are a FEA model of a standard steel box girder segment, a simplified FEA model, and a submodel of a steel box girder. The results show that the deviation between the simplified FEA model results and the FEA model results of a standard steel box girder segment can be reduced by increasing the diaphragm depth and constraining the flanges at the bottom edges of the diaphragm when analyzing the fatigue stress of rib-to-deck joints far away from a longitudinal web. All the simplified FEA models are not applicable to the stress analysis of the rib-to-deck joints near a longitudinal web since the stresses given by all simplified FEA models are at least 23% lower than that given by a standard steel box girder segment model. The 3-span submodel based on a steel box girder can give accurate results for the fatigue stress of rib-to-deck joints at any position of an orthotropic steel deck. Therefore, the 3-span submodel proposed is an efficient and accurate FEA model for the fatigue stress analysis of rib-to-deck welded joints at any position of a orthotropic steel deck, because it has the computational accuracy of the FEA model of a standard steel box girder segment and the computational efficiency of the simplified FEA model.