钢筋混凝土箱形梁极限承载力的计算

Computation of ultimate capacity of reinforced concrete box girders

针对钢筋混凝土箱形梁极限承载力的计算问题,提出采用三维实体退化虚拟层合单元的分析方法.考虑结构的几何非线性和材料非线性,利用该类单元编制了钢筋混凝土结构极限承载力的计算程序,并将其应用于钢筋混凝土箱形梁极限承载力的分析.计算中,混凝土本构关系采用多轴强化塑性模型在应变空间中构建的三维本构关系;混凝土开裂采用正交分布裂缝模型模拟;钢筋按实际情况模拟,并考虑为理想弹塑性材料.通过分析,计算结果与试验结果能很好吻合,表明了计算理论及其程序的有效性和正确性.由于该方法能克服壳体单元或梁段单元法的缺陷,在计算钢筋混凝土箱形梁极限承载力方面非常有优势.

The ultimate capacity of reinforced concrete box girders was calculated by degenerated three dimensional solid virtual laminate elements. Considering the influence of geometrical and material non-linearity, the computation of ultimate capacity of reinforced concrete structures was programmed by the elements. During the course of numerical computation, the three-dimensional constitutive equations of concrete in the strain space which were set up by the multi-strengthening plastic model were employed; the orthogonally distributing crack model was applied to simulate the concrete crack; the steel bar was treated as an element segment, and assumed to be a perfectly-elastic plastic body. The computational results tally very well with the experimental results. Numerical results proved the validity and efficiency of the method and the program. Because the limitation of shell elements or beam segment elements is overcome, the method applied to analyze the ultimate capacity of reinforced concrete box girders has great advantages.