外倾单肋下承式异形人行钢拱桥稳定性分析

发布时间：2018-05-16 19:23

本文选题：外倾单肋 + 钢拱桥　；参考：《苏州科技大学》2017年硕士论文

【摘要】：在中国桥梁史上,拱桥是最绚烂也是最值得骄傲的一笔。随着社会的进步、经济的发展以及材料性能的提升,常规样式的拱桥已不能满足人们对审美的要求,很多异形拱桥相继建成。本论文以张家港市某一已建成专用人行钢拱桥为工程背景,对外倾单肋下承式异形钢拱桥的稳定性能进行分析,本文用软件Midas Civil建立了三维有限元模型,针对结构所受荷载选择四种荷载工况(工况Ⅰ:恒载、工况Ⅱ:恒载+人群荷载、工况Ⅲ:恒载+风荷载和工况Ⅳ:恒载+人群荷载+风荷载)对桥梁的整体稳定性、几何非线性稳定、稳定性能的影响参数、桥梁的自振特性以及吊杆的张拉程序进行了详细分析,得出主要结论如下:(1)、对桥梁在四种荷载工况下的稳定性进行分析得到与荷载工况对应的一阶失稳临界荷载系数分别为144.71、54.13、347.21和47.67,结构的一阶失稳模态均为面外失稳,说明结构在设计荷载作用下不会发生屈曲破坏,而且具有较高富余度。(2)、考虑初始缺陷后对桥梁进行几何非线性稳定性分析得到的一阶失稳临界荷载系数分别为36.0、13.14、213.32和14.01,可知初始缺陷对桥梁稳定性能的影响非常大。(3)、对拱肋刚度和拱肋外倾角度两个参数进行分析,得出两参数的变化与桥梁的稳定性的关系:桥梁拱肋刚度的由0.6EI增加至1.5EI,四种工况下拱桥一阶失稳临界荷载系数呈线性增长趋势,随着拱肋外倾角度由5?增加至50?,Ⅰ、Ⅱ、Ⅳ三种工况下一阶失稳临界荷载系数呈减小趋势,工况Ⅲ下临界荷载系数随着拱肋外倾角度的增大而增大。(4)、利用子空间迭代法对桥梁的自振特性进行分析得出桥梁的前几阶阵型与频率,其中一阶自振频率为1.36Hz,与设计方计算结果一致。(5)、对吊杆的张拉程序进行优化,得到了使内力与变形最优的交替一次张拉至最终吊杆力的张拉程序。
[Abstract]:In the history of Chinese Bridge, arch bridge is the most magnificent and most proud. With the progress of the society, the development of economy and the improvement of material performance, the conventional arches can not meet the requirements of people's appreciation of the aesthetics. Many special arch bridges have been built one after another. This paper takes a steel arch bridge which has been built in Zhangjiagang as a project. Background, the stability performance of the external inclined single ribbed steel arch bridge is analyzed. In this paper, a three-dimensional finite element model is built with software Midas Civil to select four load conditions for the load under the structure (working condition I: constant load, working condition II: constant load + crowd load, working condition III: constant load + wind load and working condition IV: constant load + crowd load + wind load) The overall stability of the bridge, the geometric nonlinear stability, the influence parameters of the stability performance, the self vibration characteristics of the bridge and the tensioning program of the hanger are analyzed in detail. The main conclusions are as follows: (1) the stability of the bridge under the four load conditions is analyzed and the critical load coefficient of the first order instability corresponding to the load condition is obtained. For 144.71,54.13347.21 and 47.67, the first order instability modes of the structure are all out of plane instability, which shows that the structure will not have buckling failure under the design load, and has high redundancy. (2) the first order buckling critical load coefficient of the first order is 36.0,13.14213., considering the initial defect on the geometric nonlinear stability of the bridge. 32 and 14.01, we know that the initial defects have great influence on the stability of the bridge. (3) the stiffness of the arch rib and the angle of the arch rib extroversion are analyzed, and the relationship between the changes of the two parameters and the stability of the bridge is obtained: the stiffness of the bridge arch rib is increased from 0.6EI to 1.5EI, and the critical load coefficient of the first instable instability of the arch bridge is linearly increased under the four operating conditions. The trend, as the angle of arch rib extroverted from 5? To 50?, the critical load coefficient of first order instability in the three conditions of I, II, IV is reduced, and the critical load coefficient increases with the increase of the angle of the arch ribs. (4) the first several order forms and frequencies of bridge are obtained by the subspace iteration method. The first order self vibration frequency is 1.36Hz, which is in agreement with the design result. (5) the tension program of the hanger is optimized, and the tensile program that makes the internal force and deformation optimal one time stretching to the final hanger force is obtained.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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