Study On Several Key Technologies Of Long-span Curved Steel Box Girder Bridges

The construction of steel box girder is often used in urban viaduct and interchange rampbridge because of its long span capacity, factory processing and little impact on traffic duringthe construction. But in the stage of construction and use of steel box girder bridges, there arestill several key problems to solve. So this article will use curved steel box girder bridges onTaizhou interchange ramp as an engineering background to discuss and analyze key points ofsteel box girder bridge design, expecting to provide technical support for design andconstruction of long-span curved steel box girder bridges.This paper’s detailed work is as follows:1. The dead load of the curved steel box girder bridge is lighter and partial load ispossible at the service stage, so anti-overturning stability has become the key to control thedesign of small radius curve steel box girder bridges. The frequent overturning accidents ofsteel box girder bridges are introduced. And the anti-overturning stability is analysised. Thenthe calculation principle of anti-overturning stability coefficient is expounded. The paper useMidas/Civil to build3D model for parametric analysis of the steel box girder bridge to get theeffecting factors of the lateral resistance of anti-overturning stability, and some measures aresuggested to improve the anti-overturning stability. Through calculation and analysis of theanti-overturning stability coefficient of Taizhou typical curved steel box girder bridges, somedesign measures of the anti-overturning stability are put forward.2. Fatigue probem of steel bridge deck is the focus in the design of steel box girderbridges. There is many fatigue details of diaphragm cutouts, which makes them easy tofatigue cracking. The3D finite element models were parametric analysis was carried out withdifferent cutouts of the orthotropic steel bridge decks. Then four forms of cutouts arecompared for fatigue performance. The influence of the crossbeam height and deck thicknessis analyzed.3. Steel box girder bridge deck pavement is easily damaged, which directly affect thedurability of the bridge and later maintenance costs. This thesis analyzed the stress differencesbetween bridge deck pavement and highway road wearing surface, as well as the mechanism reason of pavement disease formation. To against the pavement diseases, the compositepavement layer form is put forward to solve the common diseases. Finite element method isused to contrast three kinds of pavement on the orthotropic steel bridge deck. The resultsshowed that the composite pavement can significantly reduce the fatigue stress of orthotropicsteel bridge deck, prolong the service life of steel bridge deck, and solve the problem of steelbridge deck pavement vulnerability.4. Steel bridge corrosion problem is one of the bottle neck of steel box girder bridge. Theapplication of weathering steel will effectively effectively solve the problem of the corrosion.The fifth chapter of this paper probes the corrosion mechanism of weathering steel. Thecomparison and analysis on the weathering resistance ability of the weathering steel bridgewhich are produced in China has carried out. Combined with the engineering design examples,the coating methods, the design and construction essentials of weathering steel are analyzed.The engineering project proposal are summarized and put forward.