| Because of the comprehensive advantages of orthotropic steel deck structure in bearing capacity, spanning capacity, mechanical performance and economy, are widely used in all kinds of bridges. At the same time of demenstrating a strong vitality, with the complexity of its structure, numerous cross welds, the local stress concentration caused by welding residual stress and the initial defects leads to lots of fatigue problems. Roughly accurate prediction of a new bridge’s fatigue life and a judgment about whether it can reach the design service life, is the inevitable requirement to ensure the safety during the design life period but also is the ultimate goal of fatigue design and assessment. The paper take the diaphragm-to-rib detail of orthotropic steel deck as research object, to calculate the fatigue life based on hot spot stress method.Full-scale model experiment was carried out with experimental data for validation and the finite element model is setted based on full-scale experiment model. It proves effective and superior for the hot spot stress method in fatigue life evaluation and fatigue assessment of complex orthotropic steel bridge deck structure through the finite element calculation by the nominal stress method and the hot spot stress method. The main works as follow:(1) The paper summarizes the development course, application situation, structure and mechanical characteristics of orthotropic steel deck structure, briefly describes the development course and present application of the fatigue, fatigue problems of orthotropic steel deck and hot spot stress method in the research of steel bridge fatigue;(2) The paper briefly describes the basic analysis theory and related fundamental concepts of the orthotropic steel deck structure fatigue, summarizes several main evaluation methods of the fatigue life;(3) The basic principle of hot spot stress method is introduced in detail and the sensitivity to the element type, the mesh size, the hot spot stress extrapolation method and other parameters is studied,through the finite element method and sub model technology;(4) Based on the engineering background of Hong Kong-Zhuhai-Macao Bridge, according to the existing traffic investigation report to calculate the standard fatigue vehicle load model and establish the corresponding finite element model, evaluate the most unfavorable loading conditions of the most unfavorable diaphragm-to-rib detail at the weld toe by the finite element analysis, corresponding position after loading combined cycle counting method to get the stress spectrum and to estimate the fatigue life based on the S-N curve of the hot spot stress method and Miner criterion;(5) The full-scale model test of the bridge and the corresponding established finite element model is to verify the accuracy of the calculated fatigue life based on hot spot stress method, whether it can meet the design requirement of 120 years service life and the effectiveness and superiority for assessment of fatigue life. The design principle, design scheme, loading plan and the effectiveness of the full scale model test for the validation can offer some references for related similar model tests in future. |
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