PC箱梁墩顶块数值模型分析方法

针对目前大跨径桥梁墩项块数值模型建立及分析方法上的不足,研究了大跨径桥梁墩顶块数值分析的单元选择、网格划分、网格密度、模型简化、预应力孔道影响及子模型选取范围等关键问题。通过与实测数据对比分析得出,在分析墩顶块这种复杂结构时,高阶四面体单元及自由网格划分模拟精度较高;将预应力孔道简化为方形孔道时,距离2倍孔道半径范围以外,正应力和主压应力基本相同,距离3倍孔道半径范围以外,主拉应力也基本趋于一致;空间模型选取长度在2倍0号块梁高以上时,各关键点的应力基本趋于一致等结论。本文分析方法为目前墩顶块空间应力分布特点的研究提供了一种重要的分析手段。

Analysis Method of Numerical Model for Top Block of PC Box Girder Pier

To counter the insufficiency of numerical analysis for long-span bridge pier top block,study of key factors of the numerical analysis such as unit selection,mesh generation,mesh density,model simplification, prestressed duct effects,and submodel selection scope was carried out.Compared with the test data,the conclusion is drawn that,the simulating accuracy of the higher order tetrahedron unit and the free mesh dividing are higher; when the prestressed duct is simplified to square-shaped duct,the normal stress is consistent with the principal compressive stress beyond the scope of 2 times of the radius range of the duct,and the principal tension stress is consistent with them beyond the scope of 3 times of the radius range of the duct;various key points stress tends to be consistent when length of the models is adopted twice 0 blocks high.The analysis method provides an important analysis method to the research of the spatial stress distribution in the bridge pier top block.