【作者】 潘盛山；

【导师】 张哲；

【作者基本信息】 大连理工大学 ， 结构工程， 2004， 博士

【摘要】 在公路和城市桥梁中,钢管混凝土拱桥以跨越能力大、承载能力高、工程造价低、养护维修费用少、造型美观和施工方便等特点,在国内外得到了广泛的应用。对于大跨径的钢管混凝土拱桥,特别是窄桥,其横向稳定性问题特别突出,通常成为设计的控制因素。本文在总结前人对圆弧拱横向稳定实用计算的研究成果基础上,对上承式、中承式、下承式X型双肋无铰拱桥的横向稳定性进行系统的分析研究,主要研究内容如下: 1、利用能量原理,以桥面高度处的拱肋中心距作为桥梁的宽度,考虑中承式拱桥中桥面位置的影响,首次建立了包含上承式、中承式和下承式的X型双肋拱在保向力和非保向力作用下横向稳定临界荷载的统一计算公式。分析了拱肋的抗扭刚度和竖向抗弯刚度、横系梁的抗弯刚度与数量、矢跨比、宽跨比、拱肋内倾角度、桥面位置、桥面横向抗弯刚度等结构参数对拱横向稳定性的影响,并给出相应的图表。提出了改进X型双肋拱桥稳定性的方法。研究结果表明:横系梁在拱切向平面内的抗弯刚度与拱肋的横向抗弯刚度之比宜取为0.5～3;对于中承式拱桥,无论是否考虑非保向力的影响,桥面在立面上的位置宜选择.f₀/f=0.7～0.9。 2、运用空间有限元数值分析,弥补了解析法中位移函数假设上缺陷所造成的结果偏差。分别对上承式、中承式和下承式X型双肋拱桥的合理拱肋内倾角度与各结构参数之间的关系进行系统的分析。通过回归方法得出下承式、中承式X型双肋拱桥合理内倾角度的近似表达式,可供工程设计参考。研究结果表明:不是所有的X型双肋拱桥都具有比平行拱桥更好的横向稳定性。拱肋内倾时能否提高拱的横向稳定性与拱系的宽跨比、横系梁在拱肋切向平面内的抗弯刚度、横系梁的数量及桥面在拱系立面上的位置等参数有关。在合理内倾角度下,拱肋内倾可以有效地提高拱的横向稳定性。对中承式和下承式拱桥,在合理内倾角度下可取得较好的经济效益,而上承式拱桥的拱肋内倾角度应慎重选取。 3、对常见的平式横撑进行简化分析,将之等效为一字撑,并得出其换算抗弯刚度。运用响应面法得出K撑换算抗弯刚度的近似表达式。通过有限元数值分析,对双肋拱桥横撑的合理布置位置及其型式进行优化分析。研究结果表明:当设置多根横撑时（即横撑根数N≥3）,在拱的各种结构参数下拱顶横撑在拱径向平面内的抗弯刚度对拱的横向稳定性影响不大。当拱的横向失稳屈曲模态为半波正对称时,在拱的0.21L～0.38L附近处对称设置平式横撑比较有效;当拱的横向失稳屈曲模态为半波反对称弯扭耦合时,在拱脚附近摘要和拱顶的部分区域内设置平式横撑可以有效提高拱的横向稳定性,即拱的0.08L一0.2lL和0.42L一0.5L处。对于X型双肋拱,由于其横向失稳模态通常为半波反对称,因此横撑布置应如后者。桥面以上部分横撑采用K撑结构即可得到足够的横撑抗弯刚度,而没有必要采用抗弯刚度更大的交叉撑和米字撑等平式横撑。立式横撑布置在拱的0.125L一0.ZL附近比较有效。 4、对铜瓦门大桥与丹东市月亮岛大桥的稳定性进行分析,并对设计与施工中的关键问题进行探讨,论证了单片析架式钢管混凝土拱桥在大跨度窄桥中应用的合理性。关键词:钢管混凝土拱桥,窄桥,X型双肋拱,横向稳定性,单片析架式,横 撑分布,合理内倾角度更多还原

【Abstract】 Concrete-filled steel tubular (CFST) arch bridge are widely used in the construction of city and highway arch bridge in the world, because of their advantages such as long-span, high load-carrying ability, low engineering cost, little maintenance cost, convenience construction and the unique shape. To long-span CFST arch bridge, especially the narrow bridge, the lateral stability of the structure is a key question, and it is an important control factor in the design. Based on the summary of current researches of lateral stability of arc rib curves, this paper gives the study of the lateral stability of deck, half-through and through X-type double ribs fixed-end arch bridge. The main research work covers the following aspects:1. With the energy principle, taken the ribs center distance of deck as the width of bridge, considered the deck position of the half-through arch, a uniform lateral stability calculation formula including deck, half-through and through X-type double ribs is established, subjected to the orientedly conservative loadings and non-orientedly conservative loadings. Meanwhile the structure parameters influencing on lateral stability, such as the torsional stiffness and vertical flexural rigidity of arch rib, the flexural rigidity and numbers of crossbeams, the rise-to-span of arch, the inclination of rib, the position of deck and the lateral flexural rigidity of the deck, are discussed. And the corresponding numerical charts are given. The methods to improve stability of X-type double ribs arch are presented. The results of the studies indicate that the ratio of the flexural rigidity at a tangent of crossbeam to the lateral flexural rigidity of rib should be selected as 0.5-3.As to half- through arch bridge, f0/f(the position of the deck in elevation)can be selected as 0.7~0.9.2. With spatial FEM analysis, the deviation of result created by defect of displacement function hypothesis in analysis can be covered. The relationship between optimum arch ribs included angle and other parameters of deck, half-through and through X-type double ribs arch bridge are systematically analyzed. By the regression methods, optimum arch rib included angle approximate expression of deck, half-through and through X-type double ribs arch bridge are gained, which can be referenced by engineering practice. The results of the studies indicate that not all of the X-type double ribs arch bridge’s lateral stability is better than that of the parallel arch bridge. It depends on some parameters whether theinclination of rib can improve the lateral stability of arch, such as the width-span ratio of arch, the flexural rigidity of crossbeams in arch rib tangential plane, and the number of crossbeams, the position of the deck in elevation, etc. With the reasonable included angle, the inclination of ribs can improve the lateral stability of arch efficiently. To half-through and through arch, reasonable included angle can bring economic benefit. But to deck arch bridge, the inclination of ribs must be chosen carefully.3. The common horizontal type lateral bracing is simply analyzed and equaled as straight brace, then conversion flexural rigidity is drawn. Approximate expression of K-shaped brace’s conversion flexural rigidity is deduced by means of the response surface method. The layout and type of double ribs arch bridge’s lateral bracing are optimizing analyzed by means of the FEM numerical analysis. The results of the studies indicate as the following: First, when the brace numbers are over 3, the vertical flexural rigidity of brace at arch crown can’t influence the lateral stability of arch a lot. Second, when the lateral buckling mode of arch is half-wave symmetry, it will be helpful to position the plan type bracing symmetrically at 0.2 L~0.38 L. When the lateral buckling mode of arch is half-wave antisymmetry, the effective layouts of the plan type brace are at 0.08L-0.21 L and 0.42L -0.5L. To X-type double ribs arch, because the lateral buckling mode is usually half-wave antisymmetry , the layouts o更多还原