Abstract
Fatigue cracks in orthotropic steel decks (OSDs) have been a serious problem of steel bridges for a long time. The structural stress approach is an important approach for fatigue life evaluation of welded structures. Firstly, two parameters and the mesh sensitivity of the stress-based integration equivalent structural stress approach (stress integration approach for short) are analyzed in this paper. Then, the applicability of the master S-N curve is verified based on experimental data of the deck-rib welding details in OSDs. Finally, the multi-scale finite element model (FEM) of Jiangyin Bridge is established, and the bridge fatigue life calculation steps based on the stress integration approach are given. The influence of the slope of the master S-N curve at high cycles on the bridge fatigue life is discussed. Further, the weld parameter influences on the bridge fatigue life are analyzed, as including the following: (1) The determination of the influence of the weld size changes caused by weld manufacturing errors on the bridge fatigue life; (2) the proposal of a new grinding treatment type, and the analysis of influence of the grinding radius on fatigue life; and (3) a comparison of the fatigue life of the deck-rib welding details under 80% partial penetration and 100% full penetration. The results show that the structural stress calculated by the stress integration approach does not change significantly with the parameters of the isolation body width w and the distance δ between the crack propagation surface and the reference surface. To simplify the calculation, δ is set as 0, and w can be set as the mesh size along the weld length direction. The mesh size of the stress integration approach is recommended as 0.25 times the deck thickness. The slope of the master S-N curve at high cycles significantly affects the bridge fatigue life, and a slope of 5 is reasonable. The weld parameter studies for the deck-rib welding details in the OSD of Jiangyin Bridge show that the change of weld size caused by manufacturing errors can obviously affect the bridge fatigue life, and the fatigue life of five different weld types varies from 51 years to 113 years. The new grinding treatment type, without weakening the deck, is beneficial to improving the bridge fatigue life. The fatigue life increases by approximately 5% with an increase of the grinding radius of 2 mm. The fatigue life of 80% partial penetration is slightly higher than that of 100% full penetration.
Highlights
The findings showed that as the penetration depth in thickened edge U-ribs (TEUs) specimens decreased from 12 to 4 mm, the maximum notch stress was only increased by 2.8%
The influence of the weld size differences caused by weld manufacturing errors on the fatigue performance of the deck-rib welding details in the orthotropic steel steel decks (OSDs) of Jiangyin Bridge is discussed based on the stress integration approach
The structural stress approach was verified based on the experimental data of the deck-rib weld details influence of the slope of the master S-N curve at high cycles on the bridge fatigue life is discussed
Summary
Due to to their their light light weight, weight, high high bearing bearing capacity capacity and and short short installation installation time, time, orthotropic orthotropic steel steel decks (OSDs) have been widely used in long-span steel bridges, suspension bridges, and cable-stayed decks (OSDs) have been widely used in long-span steel bridges, suspension bridges, and bridges [1,2].bridges. The influence of the weld size differences caused by weld manufacturing errors on the fatigue performance of the deck-rib welding details in the OSD of Jiangyin Bridge is discussed based on the stress integration approach. The structural stress approach was verified based on the experimental data of the deck-rib weld details influence of the slope of the master S-N curve at high cycles on the bridge fatigue life is discussed. Influence of the weld size change caused by weld manufacturing errors on the bridge fatigue life is Further, influence ofmeasured the weld parameters onthe theexperiment; fatigue life of(2)deck-rib welding details in the OSD analyzedthe based on the weld size in a new grinding treatment type is of Bridge was analyzed based on the stress integration approach, including:. Penetration based on the measured weld size in the experiment; (2) a new grinding treatment type is proposed, and the influence of the grinding radius on fatigue life is analyzed; and (3) the fatigue life of deck-rib
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