节段施工体外预应力混凝土梁弯曲性能研究

ANALYSIS ON FLEXUAL BEHAVIOR OF SEGMENTAL EXTERNALLY PRE-STRESSED CONCRETE BEAMS

节段施工体外预应力混凝土梁接缝受力行为的模拟,是能否进行可靠的有限元分析的关键。根据接缝处不同部位混凝土和钢筋的受力特点,建立了能够模拟接缝工作的计算模型,开发出能够对体外预应力梁进行全过程仿真分析的非线性有限元程序。应用所编程序,对Angel C.Aparicio等人的节段式体外预应力混凝土试验梁,分别改变其相应参数,进行弯曲性能分析。分析结果表明:接缝位置处的单元与普通梁段的单元并没有本质不同,其差异在于决定梁单元刚度亦即参与工作的材料有所不同;普通钢筋配筋率对节段较短的体外预应力梁抗弯性能基本没有影响;体外索初始张拉力、布筋形式和节段划分数目对节段施工体外预应力梁的弯曲性能分别有不同程度的影响。

The simulation of the seam behavior is a key to analyze the segmental externally pre-stressed beam with finite element method.Based on the force characteristics of the reinforcements and concrete in different parts of the joint,a numerical model which can simulate the workings of the joint is presented and a nonlinear finite element program which can simulate the working process of externally pre-stressed concrete beams is developed.With the program,the factors of an experimental beam made by Angel C.Aparicio et al are altered and the flexural behavior of segmental externally pre-stressed beams is analyzed.The results show that the joint element has no essential distinction with the normal in the beam,the difference is only in the materials that work and define the rigidity of element;the ratio of ordinary steel bars has little effect on the flexural behavior of externally pre-stressed concrete beams with shorter segments;the initial prestress in external tendons,the shape of the tendons and the number of segments have effects on the flexural capability of the segmental externally pre-stressed beams.