中文摘要：

针对大跨预应力混凝土桥梁极限承载力的计算问题,提出建立在三维实体退化虚拟层合单元理论基础上同时考虑结构双重非线性的空间分析计算方法,并对大跨预应力混凝土桥梁极限承载力计算中的一些关键问题进行了探索研究,包括三维空间预应力效应的模拟;成桥内力的正确考虑;正确计及加载历史等。最后以一座典型的预应力混凝土连续刚构桥为例,给出了其具体的计算结果。分析表明,本文为考虑空间效应和破坏形态的大跨预应力混凝土桥梁全桥极限承载力分析提供了一种合理有效的途径,且计算方法具有很强的通用性。

英文摘要：

The spatial analysis method for large-span P. C. bridge ultimate bearing capacity was presented from the structural dual nonlinearity,The method was based on the degenerated three-dimension （3D） solid virtual laminated element theory. Several detail treatments of some key problems in the ultimate bearing ca- pacity calculation of large-span P. C. bridge were investigated, such as the simulation of 3D pre-stress effect, the proper consideration for the established internal force and loading history etc. The computation of ultimate bearing capacity for large-span P. C. Bridge was programmed by the method. Accordingly, the program was used to analyze the ultimate bearing capacity for a classical P. C. continuous rigid frame bridge. The numerical results indicated that the method could provide a proper and effective routine to cal- culate the whole bridge ultimate bearing capacity for large-span P. C. Bridge, by considering the spatial effect and spatial failure modality. The method proved to have good universality.