【作者】 汪洁；

【导师】 刘健新；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2010， 博士

【摘要】 近几年,西部地区高速公路网大规模向黄土沟壑地区延伸,当公路线路穿越崇山峻岭和高原沟壑区时,高墩大跨的连续刚构桥常成为首选桥型。而且随着交通量的增大,大跨连续刚构桥除了具有墩高、跨度大的特点之外,还常采用上、下行的分离式布置,即采用双幅桥。对于双幅桥结构的高墩大跨连续刚构桥,在强风作用下有可能产生较大的尾流振动,因此考虑气流的遮挡和干扰,系统地研究双幅桥相互间的气动干扰效应,具有十分重要的意义。本文在研究单幅连续刚构桥梁对风反应特点的基础上,筛选了双幅桥之间的位置、风向角和攻角等各种影响双幅桥干扰效应的因素,设计了试验方案,首次系统全面地进行了连续刚构双幅桥的静力和动力干扰效应风洞试验研究,所采用的试验方法和试验结论对于研究类似桥梁结构的干扰效应有一定参考价值。通过双薄壁空心墩和不同主梁节段的测力风洞试验,并引入气动干扰因子来研究连续刚构双幅桥静力三分力系数的气动干扰问题。分析表明：上下游三分力系数与单桥的三分力系数相比均有所变化,且下游三分力系数变化明显,表现出遮挡效应和尾流干扰效应；不同的主梁断面形式、双幅桥之间的净间距、顺桥向错位、风攻角和风向角对双幅桥三分力系数干扰效应均有影响。试验得到的参数变化时桥墩和主梁三分力系数的一系列数据,将为工程技术人员在计算桥梁静风荷载时正确地估计双幅桥相互之间的影响提供理论参考和依据。在测力试验的基础上,进行静风响应干扰效应计算分析,分别对双幅桥施工阶段和成桥阶段的静风响应进行计算,并与单桥时的静风响应进行对比,定量的分析了干扰效应对位移响应和内力响应的具体影响。采用气动弹性模型试验方法研究了施工最大双悬臂状态动力气动干扰效应,得到了双幅桥不同净间距、顺桥向错位、高差、不同风向角和攻角等多种工况下的风致振动位移响应,分析了上述各因素对双幅桥间的动力干扰效应的影响,结果表明,双幅桥的水平振动响应与单幅桥相比,上游变化不大,下游响应都有不同程度的降低。更多还原

【Abstract】 In recent years, highway network in the western region is extended to loess gully region on a large-scale. When the highway routes pass through the mountains and highland region, the high-pier span continuous rigid frame bridge is often the preferred bridge type. And as traffic increases, the long-span continuous rigid-frame bridge pier besides the characteristics of high pier and large span, it also arranged has up and down separation arrangement, that is, parallel bridge. For the twin deck continuous rigid frame bridge with high-pier and long-span, the greater wake vibration will happens under the action of the strong wind, so it is obviously significant to study comprehensively the aerodynamic interference effect between pairs of bridge considering the airflow obstruction and interference.The factors of various interference effect such as position between parallel bridge, wind direction, attack angle are selected based on the characteristics of reaction to wind for single continuous rigid frame bridge. Test program is designed. The wind tunnel tests are conducted for the first time to study the static and dynamic interference effects of twin-deck continuous rigid frame bridge in Systematic and comprehensive manner. The test method and conclusion can help to study the interference effects of similar structure.Aerodynamic interference effect on aerostatic coefficient of the parallel continuous rigid frame bridge is studied by sectional model wind tunnel tests of double thin-walled hollow piers and different segments of the main beam, and by the introduction of factor. Analysis shows that:Aerodynamic interference of upper and lower has changed compared to the one of single bridge, and the lower aerodynamic interference changed significantly, showing a shielding effect and the wake interference effects; Different forms of the main beam section, the net distance and side-by-side interval between the two bridges, wind attack and direction angles all influent the aerodynamic interferences of aerostatic coefficients. The series aerostatic coefficients test data of the piers and the main beam when the parameters change will provide a theoretical reference for correct estimation the impact between parallel bridge by the designers in the calculation of the static wind loads.The interference effect of static wind response analysis is performed based on sectional model test, aerostatic response is analyzed respectively for the construction and bridge completion phase, and compared with single bridge. The specific impact of the interference effect on the displacement and internal forces response is analyzed quantitatively.Aerodynamic interference effects are studied by aeroelastic model test on construction of the largest double-cantilever state. The wind-induced vibration displacement response has been gotten under a variety of operating conditions such as different net distance between double bridge, cis-bridge dislocation, elevation difference, wind direction and attack angle. The above-mentioned factors of the dynamic interference effects are analyzed. Results showed that the horizontal vibration response of the double bridge, compared with the single bridge, the upstream response changes little and the downstream response reduces to varying degrees.更多还原