连续梁桥桥墩顺桥向计算长度系数研究

Research on Effective Length Factor of Continuous-beam Pier along Bridge

为准确研究连续梁桥桥墩的屈曲失稳问题,本文取三联连续梁桥中的1联,用位移法建立了连续梁桥桥墩失稳通用平衡方程组以求得计算长度系数。该平衡方程组中,不仅考虑了线位移刚度和转角刚度的耦合影响,而且考虑了支座刚度、邻联抗推刚度和全桥地基刚度对计算长度系数的影响;不仅考虑了单墩在轴向力作用下刚度的影响,而且考虑了其余墩在轴向力作用下的整体屈曲反应。同时推导了邻联对桥墩的抗推刚度,给出了地基刚度的计算方法。并通过与有限元分析对比,验证了理论推导解析解的正确性。最后,给出了各因素作用下计算长度系数的对比结果。

In order to investigate the buckling of continuous-beam piers more exactly, taking one segment of a three-segment continuous beam bridge for example, a general balance equations set of continuous beam bridge pier buckling is derived by displacement method for calculation of the effective length factor. The equations set considers not only the coupling influence of linear displacement and rotation rigidities, but also the influence of support rigidity, anti-push rigidity of adjacent segments and bridge foundation rigidity on effective length factor. Furthermore, the equations set not only considers the effect of axial force on the rigidity of investigated pier, but also the effect of axial forces of other piers on the buckling behavior of the whole bridge. The anti-push rigidity of adjacent segments to the investigated pier and the computing method of foundation rigidity are derived. Through comparison with finite element analysis, the correctness of the theoretical derivation is verified. Finally, the comparison of effective length factors based on different influencing parameters is given.