【作者】 邹存俊；

【导师】 谢肖礼；

【作者基本信息】 广西大学 ， 结构工程， 2004， 硕士

【摘要】 钢管混凝土应用于拱桥同时解决了拱桥材料高强化和拱圈施工轻型化的两大问题，使得拱桥的跨径得以增大，所以钢管混凝土拱桥近年来得到迅猛的发展，但随着跨度的增大，稳定极限承载力问题成为制约其发展的主要因素之一。由于受尺寸和空间效应的约束，模型试验很难真实地反映结构的极限承载力，而采用计算机仿真分析技术模拟钢管混凝土拱桥极限承载力的全过程则可以较好地反映其空间效应，反复进行足尺模拟，优化结构，预测极限承载力，因此，本文的研究具有非常重要的理论和指导工程实践的意义。 本文在前人对钢管混凝土组合材料进行大量试验所得的钢管混凝土统一理论的基础上，提出一种适合进行钢管混凝土极限承载力模拟的物理模型，该物理模型为多线性随动强化模型，它考虑了钢管对核心混凝土的紧箍力作用效应，能够反映拱的真实受力情况。利用该物理模型进行结构极限承载力模拟，结果表明与试验结果吻合良好。 在进行钢管混凝土拱桥极限承载力全过程模拟中，本文考虑双重非线性影响的同时也考虑结构初始几何缺陷的影响。理想的纯压拱在没有初始缺陷时，其临界力仅与轴力水平有关，而实际结构中，由于施工过程中的制作、安装等因素，初始缺陷时不可避免的。目前对拱的非线性有限元分析往往集中在几何非线性和材料非线性分析上，忽略了拱的初始缺陷对其极限承载力的影响，关于钢管混凝土拱桥初始缺陷方面的报厂西大学硕L学位论文摘要道至今尚未见到。本文通过施加不同大小和形式的初始几何缺陷来研究其对钢管混凝土拱桥极限承载力的影响，结果表明初始几何缺陷对承载力的影响是明显的，在实际工程中应予以重视。更多还原

【Abstract】 After Concrete-filled Steel Tubular (CFST) applied in arch bridges, the two problems-high strength arch bridge materials and lighten arch construction-were solved simultaneously, thus the span of arch bridge could be improved. Concrete-filled Steel Tubular arch bridges developed very quickly recent years. But with the increase of span, the problem of stability ultimate bearing capacity became one of the main factors that limiting the development of arch bridges. For the restrictions of size effect and spatial effect, model experiments were hard to reflect the true ultimate bearing capacity of structures. Using computer simulation technique simulating the whole process of ultimate bearing capacity of Concrete-filled Steel Tubular arch bridge can better reflect its spatial effect?simulate truly time and time?optimize structure and forecast ultimate bearing capacity. Therefore, the research of this paper has very important academic and practical engineering guide significance.Based on the unified theory of CFST that established by the people who did many experiments on Concrete-filled Steel Tubular material, a new kind of constitutive relations, which was fit for simulating the ultimate bearing capacity of Concrete-filled Steel Tubular, was put forward. This model was a multilinear kinematic hardening model. The model considered the bond stress effect that steel tube imposed on inner concrete and could reflect the true loading states of arch. Applying the model to simulate the ultimate bearing capacity of structures, the results obtained were much close to experimental results.During the whole computer simulation process for ultimate bearing capacity of Concrete-filled Steel Tubular arch bridges, this paper considered double nonlinear effect and initial structure geometry defect effect at the same time. If an arch has no initial defect receive pressure purely, its critical force only has something to do with axial force level. But in real structure, initial defect can’t be avoided because of facture and fixing factors. Presently, the finite element analysis on arch concentrates on geometry nonlinear and material nonlinear, neglects the effect of initial arch defect to the ultimate bearing capacity of arch. The report on the initial defect of CFST arch bridge has not appeared yet. By applying different scale and different form initial geometry defects on calculation model, the defect effect to the ultimate bearing capacity of CFST arch bridges had been researched. The results showed initial geometry defects could affect ultimate bearing capacity obviously. The conclusion of this paper should be regarded in practical engineering.更多还原