Evaluation on root-deck fatigue of orthotropic steel bridge deck

Orthotropic steel decks are widely used in cable-supported bridges. The fatigue cracks in trough-deck welded joints have been detected in some bridges in China. In this paper, the finite element method (FEM) is applied to evaluate fatigue durability of the root-deck fatigue in the trough-deck welded joints over the diaphragms. The reference stress is defined and the mesh size of a shell model is checked. Stress ranges under wheel loads are analyzed, and the pavement-deck interaction is discussed. The durability of the root-deck fatigue is evaluated. Results of this study show that the reference stress defined in the shell model is not sensitive to mesh size. Equivalent stress ranges of multi-axles are close to that of a single axle with multi-cycles. Traffic flow can be simplified as an axle fatigue load model with equivalent fatigue damage. Stress range regardless of the pavement-deck interaction is over estimated and the pavement-deck interaction should be considered in the stress range analysis, especially in thin decks. The predicted life of the root-deck fatigue considering the pavement-deck interaction seems to explain the fatigue cracks of bridges in China. The durability of the root-deck fatigue will be improved if steel fiber reinforced concrete (SFRC) pavement is applied. (C) 2013 Elsevier Ltd. All rights reserved.