曲线斜拉桥锚固点与支座偏移设计的分块法

Segment Method in Anchorage and Bearing Offset Design for Curved Cable-stayed Bridge

以结构部分与整体力学关系为基础,采用"分块法"计算曲线斜拉桥主梁锚固点和主墩支座偏移值,以使内外侧索力及主梁横梁内外侧负弯矩相等。将曲线主梁划分成若干矩形截面曲线梁,通过分块梁与整体梁段的力学关系来建立平衡方程,应用该方法推导了曲线斜拉桥主梁锚固点和主墩支座偏移值的计算公式。用有限元方法分析了2种偏移对龟韭沟大桥受力的影响,并绘制了偏移值对大桥受力的影响曲线,将曲线反应出的合理偏移值与公式计算结果进行了比较。结果表明:偏移主梁锚固点和主墩支座能较好地改善曲线斜拉桥受力,且公式计算结果与有限元分析结果吻合良好。

Based on the mechanical relationship of the segments with the whole structure,segment method was presented to calculate the reasonable offsets of the deck anchorages and the bearings of main piers on curved cable-stayed bridge to equalize the inside and outside cable tensions as well as the inside and outside negative moments of main crossbeam.As the curved main beam was subdivided into several curved beams with rectangular section,the balance equations were established via the relationship between the segments and the whole beam,and the formulas for calculating the abovementioned offsets were deduced.Then,taken Guijiugou Bridge for example,the influences of the two offsets on the bridge were analyzed using finite element method.The influencing curves were plotted and the reasonable offsets reflected by the curves were compared with those from calculating formulas.The result shows that deck anchorage and bearing offsets could improve the mechanical state of curved cable-stayed bridge effectively and the values calculated by formulas coincide with the outcome of finite element method.