小半径曲线钢箱梁桥顶推施工箱梁横向倾覆稳定性研究

Stability of Transverse Overturning of Steel Box Girder Bridge with Small Radius Curve

目前曲线箱梁桥顶推施工在工程实际中得到了广泛应用,相对于直线桥,顶推中小半径曲线桥的箱梁受力更为复杂,箱梁体易发生横向倾覆,应该加以高度重视。为此,以一小半径曲线钢箱梁桥为工程背景,应用箱梁横向倾覆稳定系数计算方法,针对施工中最不利工况,在顶推施工过程中的不同阶段悬臂长度与成桥跨数对箱梁稳定的影响,建立小半径曲线箱梁桥计算的有限元模型,初步探讨顶推施工中关键阶段的钢箱梁横向倾覆稳定性。计算结果表明:施工中的悬臂段长度对结构倾覆稳定性有较大的影响,悬臂段越长,稳定系数越小,结构抗倾覆稳定性能越差;随着成桥跨数的增加,远端支座荷载偏心距随之减小,梁体抗倾覆稳定系数增大。

The pushing construction of curved box girder bridges has been widely used in engineering practice.Compare to the straight-line bridge,the top push small radius curve bridge box beam force is more complex,because the box beam body is prone to horizontal overturning,which should be paid great attention.To this end,a steel box girder bridge with small radius curve was taken as an example,the box beam lateral overturning stability coefficient calculation method was adopted to construct the most adverse working conditions in the top push construction process in different stages of the cantilever length and bridge span on the stability of the box beam.A finite meta-model was adopted to simulate a small radius curve box beam bridge which is followed by a preliminary discussion on the steel box beam horizontal top-over stability.The calculation results show that the length of the cantilever section during construction has greater impacts on the overturning stability of the structure.When the cantilever section is longer,the smaller the stability coefficient,the worse the anti-overturning stability of the structure.As the number of bridge spans increases,the eccentricity decreases accordingly at the far-end bearing,and the beam's anti-overturning stability coefficient increases.