钢箱梁斜拉桥风参数实测与研究

发布时间：2018-01-25 19:25

本文关键词： 风压测量系统风场绕流计算流体动力学风特性风压　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：国内外学者对大跨径钢箱梁斜拉桥风参数现场实测的研究较少,特别是台风天气下桥址处风特性的研究也较少。为此本文依托“十二五”交通运输重大科技专项——特大型桥梁风、雨作用监测与模拟技术研究之风、雨耦合作用观测及提取技术研究这一课题,在厦漳大桥上安装风压测量系统,利用大桥健康监测系统,提取分析风压及风参数数据,分析研究桥址处风场规律,并基于CFD进行建模分析桥梁周围风场绕流情况,为以后大跨径钢箱梁斜拉桥风参数现场实测提供有用的参考。本文通过此次实测及计算分析,主要得到了以下成果:①本项目成功的开发出了一整套钢箱梁外表面风压测量系统,包括测量系统原理的描述、测量系统的详细设计、测量系统的详细安装步骤、测量系统的调试方法。设计出的传感器进风口遮挡装置,解决了进风口容易受雨水侵袭及堵塞进风口这一难题;利用“过度坡面法”解决了风压管不能镶嵌在桥梁梁体这个矛盾;同时,本文通过室内实验给出了风压管参考直径及长度,验证了永磁铁对低频电信号无明显影响,也给出了确定初值的两种不同的方法。②通过对现场实测数据的分析发现,风经过桥梁梁体时会产生绕流效应,为找出这一绕流效应的规律,本文基于CFD的方法进行数值模拟分析。通过对模型结果的数据分析发现,远端来流风速与风速仪处的风速之间存在一个线性的关系,远端来流风攻角与风速仪处的风攻角也近似存在一个线性关系。三维风速仪的布置高度与所测得到的风攻角存在一个指数关系。当风速仪高度固定时,远端来流风攻角与风速仪所测风攻角之间存在线性关系,由于两者之间差值较大,故需要进行攻角修正;远端来流风速与风速仪所测风速之间存在一个与远端来流攻角相关的一个函数关系。同时发现,当风速大于25m/s时,风场中迎风侧风速仪位置处风攻角值趋于稳定。③通过对台风“麦德姆(Matmo)”风特性的分析发现,迎风侧风速、风攻角、风向角都相对稳定,背风侧则相对比较紊乱、波动性大。迎风侧一般都为正攻角,背风侧一般都为负攻角,印证了第二章所阐述的风场绕流效应。台风“麦德姆(Matmo)”的紊流强度实测平均值为Iu=0.146、Iv=0.140、Iw=0.090(Iu:Iv:Iw 1:0.96:0.62)与规范值相比偏大。两侧风速仪所测得的紊流强度和阵风系数相差较大,也说明了风经过桥梁梁体时风场特性发生了明显的变化,即风场绕流效应。④本次实测获得了真实可靠的钢箱梁周围风压分布规律,通过分析不同风速、风攻角、风偏角情况下钢箱梁周围风压分布情况可以发现,在钢箱梁断面拐角处风压最为敏感,梁底检修车轨道会造成风压的突变,梁底风压呈现线性变化趋势,背风侧风压相对不敏感。
[Abstract]:The researches on long-span steel cable-stayed bridge wind field parameters is less, especially the typhoon weather research at the bridge site wind characteristics are rare. This paper based on the "major science and technology projects -- 12th Five-Year" transportation bridge wind, rain monitoring and simulation technology research, research on this subject by observation and extraction technology of rain coupling, install wind pressure measurement system in Xiazhang bridge, the bridge health monitoring system, extraction and analysis of wind pressure and wind data at the bridge site analysis of wind field rules, and based on CFD modeling and analysis of wind flow around the bridge, provide a useful reference for the future large span the steel box girder cable-stayed bridge wind field parameters. In this paper, through the analysis of the measurement and calculation, we get the following results: 1. The success of this project has developed a set of steel surface pressure The measurement system, including the principle of measurement system is described, the detailed design of the measurement system, detailed installation steps of the measurement system, the debugging method of measurement system. The sensor designed air inlet shielding device solves the air inlet easily from the rain and the problem of plugging into the air; solve the pressure pipe can not be embedded in the bridge body the contradiction between the "excessive slope law"; at the same time, through indoor experiment provides the reference wind pressure tube diameter and length, verify the permanent magnet has no obvious effect on the low frequency signal, presents two different methods of determining the initial value. Through the analysis of field data found that wind through the bridge body when will produce flow effect, in order to find out the effect of the flow rule, the CFD method based on the numerical simulation. The results of the model data analysis found that the distal flow velocity and There is a linear relationship between the anemometer, wind attack angle distal wind attack angle and anemometer at approximately a linear relationship. There is an exponential relationship between 3D anemometer wind attack angle arrangement height and can be measured. When the anemometer height is fixed, distal to the wind the angle of attack and the speed of the linear relationship between the instrument wind angle of attack, because of the difference between the larger, so the need for the existence of a fixed angle; and the distal flow angle of attack of a function relationship between the distal flow velocity measured by wind speed and wind speed. At the same time, when the wind speed is greater than 25m/s, the value of the wind tends to be stable. In the field of wind speed instrument position crosswind wind attack angle. According to the typhoon "Medem (Matmo)" analysis of wind characteristics, windward wind speed, wind attack angle, wind direction angle is relatively stable, the leeward side is relatively disordered, the high volatility of the attack. The wind side generally positive angle of attack, the leeward side is generally negative angle of attack, confirms the second chapter of the wind flow. The effect of the typhoon "Medem (Matmo) the turbulence intensity measured average value of Iu=0.146, Iv=0.140, Iw=0.090 (Iu:Iv:Iw 1:0.96:0.62) and the standard values are larger than the wind speed measured by both sides. The turbulence intensity and the gust coefficient difference, also shows that the wind characteristics of bridge beams through the wind changes, namely wind flow. The effect of the measured wind pressure distribution around the steel box girder is reliable, through the analysis of the different wind speed, wind attack angle, the wind angle around the case of steel box girder the distribution of wind pressure can be found in the box corner pressure is most sensitive, repair car track beam bottom pressure will cause the mutation showed a linear trend of beam bottom pressure, the leeward side pressure is relatively insensitive.

【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U446

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