钢管混凝土拱施工阶段抗风性能与成桥阶段稳定性能研究

发布时间：2018-05-21 13:56

  本文选题：钢管混凝土 + 抛物线拱　； 参考：《哈尔滨工业大学》2015年博士论文

【摘要】：随着钢管混凝土拱桥跨度的不断增大,拱肋在施工阶段和成桥阶段的稳定问题日益突出:在施工阶段,空钢管拱肋常采用缆索吊装法悬臂拼装,此时拱肋仅靠侧向设置的缆风维持面外稳定,结构的面外刚度较低。在风荷载的强烈作用下,拱肋可能发生大幅振动,并由此导致缆风的断裂和结构的破坏,故应对拱肋在悬臂拼装阶段的抗风性能进行研究;在成桥阶段,闭合的拱形结构已经形成,且风撑的设置使拱肋面外刚度大幅提高,其面外风致稳定问题不再突出,但使用荷载作用下拱肋承受较大轴压作用,其面内整体稳定问题较为突出,因此应对成桥阶段拱肋的面内稳定性能进行研究。本文选取常用的抛物线型钢管混凝土拱桥作为研究对象,对其悬臂施工阶段的空钢管拱肋抗风性能和成桥阶段的钢管混凝土拱肋面内稳定性能进行研究,具体研究内容如下:(1)针对钢管混凝土拱桥常用的截面类型和截面尺寸,开展了空钢管拱肋节段模型风洞试验,得到了四肢桁式截面和横哑铃桁式截面的三分力系数和气动导纳函数,为后文进行空钢管悬臂拱肋的抖振分析提供了基础。通过对试验测得的截面升力系数进行分析,得到了拱肋发生驰振的条件。(2)考虑曲线型拱轴线对抖振分析的影响,采用MATLAB编制了悬臂空钢管拱肋抖振分析程序,并利用经典理论分析结果和桥梁实测结果验证了程序的正确性和适用性。采用上述程序对不同参数下悬臂空钢管拱肋的风致响应进行了系统分析,提出了悬臂抛物线型空钢管拱肋阵风系数的建议取值。(3)开展了矢跨比为1/4.5、1/6和1/9的三组钢管混凝土抛物线拱平面内稳定承载力试验,研究了试件在轴压和压弯受力状态下的失稳破坏模式、稳定承载力和约束效应发展规律;通过试验得到了矢跨比和加载工况对钢管混凝土抛物线拱稳定承载力的影响规律。(4)建立并验证了轴压作用下钢管混凝土抛物线拱的ABAQUS有限元分析模型,对轴压作用下钢管混凝土抛物线拱的弹性和弹塑性稳定性能进行了研究,得到了矢跨比对抛物线拱稳定承载力的影响。引入矢跨比考虑屈曲前变形的影响,对现有规范采用的稳定系数进行修正,提出了轴压作用下钢管混凝土抛物线拱平面内稳定承载力计算公式。(5)建立并验证了压弯作用下钢管混凝土抛物线拱的ABAQUS有限元模型,对压弯作用下钢管混凝土抛物线拱的弹性及弹塑性稳定性能进行了研究,得到不同工况下轴力和弯矩分布规律。引入考虑矢跨比的稳定系数,考虑轴力和弯矩的不均匀分布情况,提出了压弯作用下钢管混凝土抛物线拱的弹塑性稳定承载力计算公式。
[Abstract]:With the increasing span of concrete-filled steel tube arch bridge, the stability of arch rib is becoming more and more serious in the construction stage and the completion stage. In the construction stage, the cable hoisting method is often used to assemble the hollow steel pipe arch rib. In this case, the arch rib is maintained out of plane stability only by the lateral cable wind, and the out-of-plane stiffness of the structure is low. Under the strong action of wind load, the arch rib may vibrate greatly, which will lead to the breakage of the cable wind and the destruction of the structure. Therefore, the wind-resistant performance of the arch rib in the cantilever assembly stage should be studied. The closed arch structure has been formed, and the installation of wind brace has greatly improved the out-of-plane stiffness of the arch rib, and the problem of the out-of-plane wind-induced stability is no longer prominent. However, under the action of load, the arch rib is subjected to greater axial compression, and the problem of overall in-plane stability is more prominent. Therefore, the in-plane stability of arch rib in bridge stage should be studied. In this paper, the common parabolic concrete-filled steel tube arch bridge is selected as the research object, and the wind-resistant performance of the hollow steel tube arch rib in the cantilever construction stage and the in-plane stability performance of the concrete filled steel tube arch rib in the completion stage are studied. The specific research contents are as follows: (1) aiming at the common section type and section size of concrete-filled steel tubular arch bridge, the model wind tunnel test of hollow steel tube arch rib section is carried out. The three-point force coefficient and aerodynamic admittance function of the truss section and the transverse dumbbell truss section are obtained, which provides the basis for the buffeting analysis of the cantilever arch rib of the hollow steel pipe. Based on the analysis of the lift coefficient of the section measured by the test, the condition of the arch rib galloping is obtained. The effect of the curve arch axis on the buffeting analysis is considered. The buffeting analysis program of the cantilever hollow steel pipe arch rib is compiled by MATLAB. The correctness and applicability of the program are verified by the results of classical theory analysis and bridge test. The wind-induced response of cantilever hollow steel pipe arch rib under different parameters is analyzed systematically by using the above program. Three groups of concrete filled steel tube (CFST) arch plane stability bearing capacity tests with a rise-span ratio of 1 / 4. 5 / 1 / 6 and 1 / 9 are carried out. The failure mode, stability bearing capacity and constraint effect of the specimens under axial compression and bending loading are studied. The influence of rise-span ratio and loading condition on the stable bearing capacity of concrete-filled steel tubular (CFST) parabola arch is obtained. (4) the ABAQUS finite element analysis model of CFST parabolic arch under axial compression is established and verified. The elastic and elastoplastic stability of concrete-filled steel tubular parabolic arch under axial compression is studied, and the influence of the ratio of rise-span to span on the stability capacity of parabolic arch is obtained. The influence of deformation before buckling is taken into account by introducing the rise-span ratio to modify the stability coefficient used in the existing codes. The calculation formula of in-plane stability bearing capacity of concrete-filled steel tubular (CFST) parabola arch under axial compression is presented. The ABAQUS finite element model of CFST parabolic arch under compression and bending is established and verified. The elastic and elastoplastic stability of concrete-filled steel tubular parabola arch under compression and bending is studied, and the distribution of axial force and bending moment under different working conditions is obtained. Taking into account the stability coefficient considering the rise-span ratio and considering the non-uniform distribution of axial force and bending moment, a formula for calculating the elastic-plastic stability bearing capacity of concrete-filled steel tubular parabolic arch under compression and bending is proposed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U448.22
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本文编号：1919466