大跨混凝土斜拉桥成桥状态不闭合因素量化分析

Quantitative Analysis on the Completed State No-Closure Factors of the Long-Span Concrete Cable-Stayed Bridge

采用倒拆—前进分析法确定斜拉桥施工/成桥受力状态时,存在最终成桥状态与合理成桥状态不闭合现象。依托某主跨300m的大跨混凝土斜拉桥,在总结分析斜拉桥倒拆-前进分析不闭合成因基础上,利用Midas/Civil软件建立其倒拆与正装有限元模型,分别开展3个主要的成桥状态不闭合因素(结构体系转换因素、几何非线性因素、收缩徐变因素)的影响程度量化研究。针对各不闭合因素,基于'欧几里得范数',结合MATLAB程序,量化各不闭合因素影响程度。研究表明,收缩徐变效应对300m级大跨混凝土斜拉桥施工不闭合影响程度最大,结构体系转换次之,几何非线性影响最小。三种因素引起的目标状态与最终成桥状态的最大差值均为弯矩,且最大弯矩差值出现的位置均为塔梁固结处。

When the backward-forward analysis method is used to determine the stress state of the cable-stayed bridge during the construction phase and completed stage,there is a phenomenon that the final completed state and the reasonable completed state are not closed.Relying on a long-span concrete cable-stayed bridge with a span of 300 m,based on the summaries of the no-closure of the backwardforward analysis,the finite element software Midas/Civil is used to establish a three-dimensional model.The quantitative study on the three influential factors(the structural system transformation,geometric nonlinearity,shrinkage and creep)is conducted respectively.Based on the Euclid norm,the influential extent of every factor on the stress state is also quantified by the MATLAB software.The study shows that the shrinkage and creep has the most significant impact on the 300 m-span concrete cable-stayed bridge construction in all of the three factors.The structural system transformation is the second greatest influential factor and the geometric nonlinearity is the least.The maximum difference between the reasonable state and the final completed state which the three factors cause is the bending moment.Moreover,the position of the greatest bending moment difference is the tower beam consolidation.