曲线钢箱梁稳定性分析与控制

Stability analysis and control of curved steel box girder

薄壁钢箱梁在顶推过程中结构受力复杂,此类问题在曲线钢箱梁顶推过程中尤其突出。基于此,本文通过建立钢箱梁的空间壳单元分析模型,对钢箱梁进行屈曲特征值分析,进而研究顶推过程中的最不利工况以及在各荷载工况下的安全储备。结果表明:在施工过程中曲线钢箱梁在横隔板处最容易发生失稳,少数发生在底板I肋或导梁腹板。为减小曲线钢箱梁发生失稳的风险,可通过控制顶推机在钢箱梁底部的相对位置,增强结构的稳定性。本文成果可为同类工程提供一定的借鉴与参考。

The structural stress of thin-walled steel box girder is complex during the jacking process,and such problems are especially prominent in the jacking process of curved steel box girder.Based on this,the buckling eigenvalues of the steel box girder is analyzed by establishing the spatial shell element analysis model of the steel box girder,and then the most unfavorable working conditions in the jacking process and the safety reserve under each load condition are studied.The results show that the curved steel box girder is most prone to instability at the diaphragm during the construction process,and a few occur in the I rib of the bottom plate or the sternum of the nose girder.In order to reduce the risk of instability of the curved steel box girder,the stability of the structure can be enhanced by controlling the relative position of the ejector at the bottom of the steel box girder.The results can provide a certain reference for similar projects.