悬浇连续梁桥临时固结钢管混凝土柱稳定性分析

An Analysis of the Stability of a Temporarily-Consolidating Concrete-Filled Steel Tubular Column for a Cantilever Cast Continuous Beam Bridge

以福建省南平市某快速通道上跨铁路连续箱梁桥为例,对悬臂浇筑施工连续箱梁桥临时墩梁固结所用墩旁钢管混凝土柱进行了稳定性分析。计算了墩旁钢管混凝土柱第一类和第二类稳定安全系数,并分析了几何缺陷、边界条件变化、核心混凝土受约束情况对第一类和第二类稳定安全系数影响。结果表明,墩旁钢管混凝土柱第二类稳定安全系数为第一类稳定安全系数的0.323倍,核心混凝土无约束时降为0.235倍;几何缺陷对钢管混凝土柱第一类和第二类稳定安全系数影响均较小;柱端边界条件变化对墩旁钢管混凝土柱第一类稳定安全系数影响显著,对第二类稳定安全系数影响较小。采用墩旁钢管混凝土柱做临时固结时,应确保柱端构造安全可靠。

With the railway continuous box girder bridge over-crossing a certain expressway in Nanping of Fujian as a practical example,the stability of the temporarily-consolidating pier-side concrete-filled steel tubular column for a temporary pier and beam during cantilever casting the continuous girder is analyzed,upon the basis of which the first-class and the second-class stability-safety coefficients of the pier-side concrete-filled steel tubular column are calculated,with the geometric imperfections,the change in the boundary conditions,and the effects of the constraints of the core concrete on the 1 st-class and the 2 nd-class stability-safety coefficients analyzed.The result of our calculations shows that the 2 nd-class stability-safety coefficient of the pierside concrete-filled steel tubular column is 0.323 times the 1 st-class stability-safety coefficient,and it will be decreased to 0.235 times when there are no constraints happening to the core concrete;the geometric imperfections have comparatively small effect on both the 1 st-class and the 2 nd-class stability-safety coefficients of the concrete-filled steel tubular column;the change in the boundary conditions of the column end has remarkable effect on the 1 st-class stability-safety coefficients of the concrete-filled steel tubular column but has comparatively small effect on the 2 nd-class stability-safety coefficient.When the pier-side concretefilled steel tubular column is adopted for temporary consolidation,the structural security and reliability of the column end has to be ensured.