【作者】 黄弘读；

【导师】 徐兴；

【作者基本信息】 浙江大学 ， 结构工程， 2001， 博士

【摘要】 本文用虚拟层合退化梁、板单元分析桥梁的极限承载力。先通过对深梁和短梁的极限承载力分析并与试验结果对比进行考题，而后将此法运用到分析七星桥的极限承载力上去，得到此桥破坏的全过程。研究结果表明用虚拟层合单元对结构进行极限承载力分析方法简单而有效。 用虚拟层合单元可以简单而有效地对结构的极限承载力进行分析，由于单元内部可以分块，每个分块可以有不同的材料性质，而单元的刚度由分块的刚度迭加得到。在分析结构极限承载力时，先划分单元，然后对危险截面上的单元进行内部分块。外荷载分级加上去，在每一级荷载下，对单元内的每一分块进行应变分析，根据混凝土和钢筋的破坏准则判断分块是否达到破坏。我们令破坏块模量为零，则单元的刚度相应发生变化，然后进入下一轮数值计算。因此，我们可以方便地考虑结构破坏过程中的材料非线性。结合TL法考虑几何非线性，我们可以求解结构的极限承载力，而且可以跟踪结构破坏的整个过程，而在破坏的过程中单元的划分和单元的形状保持不变。 虚拟层合单元法为我们提供了一个合适的评价结构极限承载力的方法，避免了大量的实验。特别是对于成桥，意义更加明显，因为对成桥不可能做极限承载力实验，对于复杂截面（箱梁）和复杂结构则本法更能显出它的优势。因为虚拟层合单元可以把一个复杂的截面如箱形截面整个划为少数几个单元，这样就大大提高了计算效率。更多还原

【Abstract】 When virtual laminated element were used to analyze the ultimate load capacity of bridge, it is found that the number of elements is so small that the calculation efficiency is very high. During the analysis process, the shape of the elements remained unchanged. We can obtain the ultimate load capacity easily as well as the whole process of the damage of a bridge. Firstly, the ultimate load capacity of deep and short beams is analyzed and calculated, using 20梟ode virtual laminated beam element, and the results were found agree well with the experiments. Then we used the virtual laminated element to analyze another two simple supporting beams and the results also agreed well with the experiments. Finally,virtual laminated element was used to analyze a box梘irder bridge named QIXING BRIDGE. Again we tracked the whole process of the damage and obtained the ultimate load capacity. The method of virtual laminated element provides us an feasible way to analyze the ultimate load capacity of a bridge as well as the damage process.更多还原