复杂山区高墩多塔斜拉桥桥位风特性及振动响应实测

发布时间：2018-10-12 20:07

【摘要】：随着我国交通基础设施的进一步发展,跨海湾、跨山区峡谷大跨桥梁将逐渐成为今后若干时期内大跨桥梁建设的重点。复杂山区地形大跨桥梁抗风设计具有风特性复杂、山区风对大跨桥梁作用效应复杂等特点,目前是桥梁风工程领域的研究的重点问题之一。本文以在建的湖南郴州赤石特大桥为工程依托,针对复杂山区地形风场特性以及高墩多塔斜拉桥的风振响应进行实测研究。得到了复杂山区地形主要风特性参数,包括平均风速、风向和风攻角,湍流度、阵风因子、湍流积分尺度和脉动风功率谱等;同时对大风时段结构风振响应情况进行研究,得到了结构加速度响应均方根与平均风速的关系,以及结构自振频率和阻尼比,并与结构有限元结果进行了比较。本文主要工作如下:(1)简要介绍了国内外风场实测和风振响应实测的研究现状,并提出了本文的研究内容。(2)拟定了赤石大桥桥位风特性实测与结构风振响应实测方案,并对实测系统进行了详细的介绍,最后给出了现场安装情况。(3)基于MATLAB软件编写数据处理程序,分析了赤石大桥桥位处风场特性。基于长期实测数据,首先得到了塔顶和桥面高度处的平均风速、风向和风攻角,分析了风向和风攻角的分布规律。然后统计得到了大风时段的脉动风特性,包括湍流度、阵风因子、湍流积分尺度和脉动风功率谱等风特性参数。给出了湍流度与阵风因子的关系以及实测脉动风功率谱。(4)基于加速度响应实测数据分析了结构的风振响应。首先是针对原始数据进行预处理,包括剔除野值、去趋势和滤波等。然后以10min为时距求出加速度响应均方根值,分析其与平均风速的关系。最后利用随机减量法和模态时域识别法分析结构动力特性,包括自振频率和阻尼比,并与结构有限元分析结果进行了比较。
[Abstract]:With the further development of the transportation infrastructure in our country, the long-span bridge across the gulf and mountain canyon will gradually become the focal point of the construction of the long-span bridge in the future. The wind-resistant design of long-span bridges in complex mountainous areas is characterized by complex wind characteristics and complex effects of wind on long-span bridges. At present, it is one of the key issues in the field of bridge wind engineering. Based on the Chenzhou Chishi Bridge under construction in Hunan Province, the wind field characteristics of the complex mountainous terrain and the wind-induced vibration response of the multi-tower cable-stayed bridge with high piers are studied in this paper. The main wind characteristic parameters of complex mountain terrain are obtained, including mean wind speed, wind direction and wind attack angle, turbulence degree, gust factor, turbulence integral scale and pulsating wind power spectrum, etc. At the same time, the wind-induced response of structure is studied. The relationship between the root mean square of the structural acceleration response and the average wind speed, the natural vibration frequency and damping ratio of the structure are obtained, and the results are compared with the finite element results of the structure. The main work of this paper is as follows: (1) the research status of wind field and wind vibration response at home and abroad is briefly introduced, and the research contents of this paper are put forward. Finally, the field installation is given. (3) based on MATLAB software, the data processing program is compiled to analyze the wind field characteristics at the bridge location of the Chishi Bridge. Based on the measured data for a long time, the average wind speed, wind direction and wind attack angle at the top of the tower and the height of the bridge deck are obtained, and the distribution of wind direction and attack angle is analyzed. Then, the characteristics of pulsating wind in gale period, including turbulence degree, gust factor, turbulence integral scale and pulsating wind power spectrum, are obtained statistically. The relation between turbulence degree and gust factor and the measured pulsating wind power spectrum are given. (4) based on the measured data of acceleration response, the wind-induced vibration response of the structure is analyzed. The first step is to preprocess the raw data, including eliminating outliers, de-trend and filtering, etc. Then, the root mean square value of acceleration response is obtained by 10min distance, and the relationship between the RMS value and the average wind speed is analyzed. Finally, the dynamic characteristics of the structure, including the natural frequency and damping ratio, are analyzed by using the stochastic decrement method and the modal time domain identification method, and the results are compared with the results of the finite element analysis of the structure.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3;U448.27

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