【作者】 许志豪；

【导师】 项海帆； 陈艾荣；

【作者基本信息】 同济大学 ， 桥梁及隧道工程， 2006， 博士

【摘要】 本文通过昂船洲桥桥址风场实测及相应风洞试验获取了抖振响应分析参数，并在此基础上建立和发展了大跨度桥梁精细化频域抖振分析方法。为了准确地取得桥址紊流风场特性并以此作为昂船洲桥抗风设计的依据，特别于东桥塔处安装了一个紊流风参数监测系统。该系统由安装于50米高钢结构桅杆上的超声风速仪、机械风速仪、加速度计等相应传感设备所组成。同时为了更能准确地了解昂船洲桥桥身和桥塔的紊流风场特性，通过1比1500地貌模型风洞试验收集了桥址和桅杆位置的紊流风场特性的互相关信息。此外为了求取桥身断面的动力特性，还进行了一系列1比80缩尺节段模型风洞试验。本文在此基础上通过相应的数据分析以识别昂船洲桥抖振响应分析所需的相关参数，包括三分力系数，颤振导数，气动导纳函数和抖振力相干函数等。通过风特性的实测数据分析和地貌模型试验，取得了可靠的风特性参数，为抖振分析也为今后抖振响应实测对比奠定了坚实的基础。对于采用分体双箱这种新颖桥梁断面的气动性能有了新的想法，如槽宽对气动阻力，气动导纳函数，抖振力相干函数，颤振稳定性的影响，雷诺数效应等，对今后采用分体双箱断面的大跨度桥梁抗风设计具有重要参考价值。 昂船洲特大斜拉桥采用特殊的分体双箱梁结构形式，双箱梁间开槽达14.3米。由于目前国际上对这类特殊桥身的实际应用极为有限，因此进行相应的敏感度测试以确保全桥的气动特性不会因为分离体梁槽宽的改变而发生显着变化就显得尤为必要。为此通过一系列节段模型测压风洞试验取得了不同槽宽的桥身断面在不同紊流尺度下的抖振力模型。由此本文提出了分体双箱梁桥面阵风荷载的经验公式。在对基于风相关的传统抖振分析的基础上，本文提出了新的桥梁抖振响应的更多还原

【Abstract】 The refinement of buffeting analysis for long span bridges in the frequency domain based on parameters obtained from field measurement systems and wind tunnel experiments is the object of this thesis. As part of the aerodynamic investigation for the unprecedented 1018m span Stonecutters Bridge, a field measurement system for studying wind turbulence characteristics was installed at the bridge site. The system includes the installation of ultrasonic and mechanical anemometers, bi-axial accelerometers, etc. on a 50m high meteorological mast near the eastern pylon of the bridge. In order to work out the correlation of turbulence characteristics between the mast and the bridge line, 1:1500 scale terrain model wind tunnel experiments for the study of the flow field in the vicinity of the bridge site was conducted. Furthermore, a series of 1:80 scale sectional model experiments have been conducted to evaluate the steady state aerodynamic force coefficients, flutter derivatives and spatial distribution of the aerodynamic forces on deck section of Stonecutters Bridge, including the chord-wise aerodynamic admittance functions and span-wise root coherence functions of forces. Through the wind characteristics studies, a mathematical turbulence model suitable for the buffeting calculations was derived. This will serve as a good reference for other projects in the area and a firm background for further development of buffeting analysis methodology. The sectional model experiments have reinforced and enhanced the understanding of the aerodynamic characteristics of twin-girder deck sections. The effect of gap width on flutter derivatives, aerodynamic forces, chord-wise aerodynamic admittances and span-wise root coherence of forces has been looked at in detail. The effect of Reynolds number (Re) on the evaluation of steady state aerodynamic forces coefficients has also been studied in detail. The findings will be a useful reference for future projects employing a similar separated twin-girder deck section.Stonecutters Bridge has adopted a special separated twin-box aerodynamic deck section with a wide gap of 14.3m between the twin girders. This kind of deck section in real-life application is extremely limited. In order to test the sensitivity of this kind of deck section to aerodynamic forces, the pressure measurement experiments were organized in a parametric study that aimed at defining the influence of width of gap in relation to the scales of turbulence on the dynamic loading. Empirical models for the gust loading on the twin-box girder deck sections were proposed. In lifting the traditional approach based on wind coherences, a new buffeting response analysis method based on the directly measured root coherence functions of forces and aerodynamic admittance function is proposed. The analytical results obtained using the new methodology were found to match reasonably well with those obtained in the full bridge aeroelastic model experiment. The new method is therefore considered reliable更多还原