两串列方形高层建筑局部风压干扰特性分析

对2个完全相同的串列方形高层建筑模型进行了受扰建筑风压测量的风洞试验.根据试验结果,分析了施扰模型相对位置和高度变化对受扰模型局部风压的影响.结果显示,高度比固定,迎风面平均风压在间距比小于3时为负压,大于3时为正压,侧风和背风面平均负风压及各个面脉动风压均在间距比等于3时取得最大值.高度比变化,间距比小于3时,迎风面...     

The effect of plan ratios on wind interference of two tall buildings

Tall buildings are vulnerable to lateral loading. The facades of these buildings are susceptible to wind loads. It is very difficult to assess the wind condition around the tall building in the presence of other surrounding buildings due to the wind interference effect. An experiment is carried out in the Boundary Layer Wind Tunnel at Tokyo Polytechnic University, Japan, to study the wind interference effect on tall buildings with varying plan ratios. The maximum and minimum local peak pressure coefficient contours on front face of the principal building are plotted. The interference effect is quantified in terms of interference zone charts. It is observed that interference zones extend over a larger area as the building plan ratios increases. The minimum interference factor depends on the plan ratios of the interfering building especially along the oblique direction. The results of this study may be useful for the preliminary design of cladding of tall buildings with interfering buildings.     

群体高层建筑的峰值风压分布特征

基于同步测压技术,研究了不同宽度比和不同高度比（记为Br和Hr,分别表示施扰和受扰建筑的宽度与高度之比）的2个高层建筑在串列、斜列和并列布置时峰值风压干扰效应。结果表明：邻近施扰建筑的侧面峰值风压主要呈现放大效应,且宽度比越大（Br≤1时）,高度比越大,放大效应越明显,立面最高负风压系数绝对值可升高30%。迎风面放大效应区则主要集中在施扰建筑位于横风向间距为3b(b为受扰建筑的迎风宽度)的迎风区域内,立面最高正风压系数可升高40%。当串列间距较小且高度比小于1（Hr=0.8）时产生的三维绕流现象可使得受扰建筑侧面局部风压升高61%,迎风面边缘局部风压升高24%。并列布置时产生的峡谷效应引起足够的重视,试验测得最大干扰因子可达2.13且随并列间距的增大而减少,当并列间距超过9b时峡谷效应才渐趋消失。由试验结果回归得到的并列布置时的侧立面最大峰值风压干扰因子随并列间距变化的关系式具有较高可信度。     

任意排列两方形断面高层建筑风致干扰机理研究

风致干扰效应是高层建筑群抗风设计中的常见难点问题之一。采用刚性模型测压试验,研究了均匀层流和两种大气边界层风场条件下任意排列两方形断面高层建筑的风致干扰效应,通过平均和脉动基底弯矩系数的干扰因子、风力系数、风压系数分布以及风荷载功率谱的研究,解释了其风致干扰效应的机理。结果表明,任意排列的两方形断面高层建筑风致干扰中,至少存在横风向静力干扰、顺风向静力干扰和横风向动力干扰三个值得注意的干扰区域。 窄道形成的加速效应使受扰结构上形成指向施扰建筑横风向平均吸力和阻塞形成的受扰建筑的横风向平均推力;遮挡效应使得受扰建筑承受指向位于上游的施扰建筑的顺风向风力;漩涡叠加增强位于尾流区受扰建筑上的横风向脉动荷载。不同风场的试验结果表明,提高来流的紊流度有助于减弱上述干扰效应。     

超高层建筑表面风荷载数值模拟研究

该文通过计算流体力学数值模拟技术对某超高层建筑进行了表面风荷载分布的数值模拟。结果表明：由于漩涡脱落,在结构侧面边缘出现了较强烈的负压区;在周边建筑干扰高度范围内,结构表面风压分布较混乱,结构在干扰高度以上部分风压分布比较规律;局部部位的设计风压应参考各风向角下风压峰值。     

Mean force and moment coefficients for buildings in turbulent boundary layers

Mean force and moment coefficients for a series of flat-roofed rectangular buildings are presented for a range of wind directions. The coefficients were determined by integrating mean pressures measured on model structures immersed in thick turbulent boundary layers simulating four typical neutral atmospheric flow conditions (power-law exponents of 0.12, 0.27, 0.34, and 0.38). A series of thirteen different building geometries were studied. The ratios of adjacent sides were 1, 0.5, 0.25, and the aspect ratio, the ratio of the height to the smaller side, ranged from 1 to 8. The effects of side ratio, aspect ratio, incident turbulence intensity, longitudinal integral scale, and the ratio of building height to boundary-layer thickness are discussed.     

不同地貌下几个典型屋盖的风压特性

在均匀流场、市郊地貌及城市地貌中对包括双坡、球壳及柱壳的几个典型屋盖进行了风洞试验,利用同步多点压力扫描技术得到屋盖的风压数据。将分布于屋盖的局部体型系数与建筑结构荷载规范进行了比较,讨论了不同地貌及风向角对屋盖风压的影响,分析了各风向角下的绝对值最大的负局部体型系数及出现的位置。发现位于双坡屋盖的屋角、屋檐及屋脊区域的风压远大于其它区域的风压,均匀流中这些屋盖的平均风压是市郊地貌屋盖的2至3倍,而市郊地貌屋盖的平均风压又是城市地貌屋盖的2至3倍。     

Effects of grid curtains on the wind loads of a high‐rise building

The effects of grid curtains on the local and overall wind loads of a high‐rise building are investigated in detail according to a series of wind pressure and wind force tests on rigid model in a wind tunnel. The effects of grid curtains on the mean and fluctuating wind pressures on windward and sideward walls when the wind direction is parallel to the geometrical axes are investigated, along with the effects of the most unfavorable wind pressures for all wind directions. Furthermore, the effects of grid curtains on the mean and fluctuating aerodynamic forces on the entire building are also analyzed for various wind directions, along with the effects of grid curtains on the aerodynamic force spectra when the wind direction is parallel to the geometric axes. The test results indicate that grid curtains affect the mean and fluctuating windward pressure slightly but greatly influence the large sideward negative pressures. Grid curtains increase the mean and fluctuating windward aerodynamic forces and reduce the fluctuating aerodynamic torsions. According to the aerodynamic force spectra, grid curtains can mainly affect the wind forces in the low‐frequency range. Copyright © 2015 John Wiley & Sons, Ltd.     

受扰高层建筑的风致响应分析

受扰状态下高层建筑的静动力响应明显不同于单体建筑。以一实际姊妹塔楼为研究对象,根据风洞试验中获得的风压分布结果,计算塔楼结构的风致响应。风洞试验及结构响应计算不仅考虑了两栋塔楼同时存在的情况,还考虑一栋塔楼先期建成,另一塔楼尚未建造的情况。细致分析了不同风向下结构的平均及脉动位移响应、静动力干扰因子的特点。结果表明,施扰建筑位于受扰建筑正前方时具有最大的干扰效应,此时受扰塔楼的总位移峰值最小;而当受扰建筑处于施扰建筑下游时,在风向偏斜时,受扰塔楼的总位移峰值最大。     

武汉体育中心体育馆表面风压的风洞试验研究

介绍了武汉体育中心体育馆风洞试验模拟方法和试验结果,讨论了不同风向角下屋盖表面风压的分布,并得出风荷载的分布规律。在考虑了上游有建筑物影响的情况后,分析了周围建筑对屋盖表面风压的干扰效应。围护结构的设计风压分别由我国规范和基于随机振动理论的标准方法计算所得,通过两种方法的比较,得到了若干结论。     

单跨双坡工业厂房平均风压试验研究

通过一系列不同外形尺寸的单跨双坡厂房刚性模型风洞测压试验,研究不同风向角下结构表面的平均风压系数,重点讨论建筑结构外形参数和风场条件对单跨厂房主体承重结构风压系数的影响。研究发现,主体结构框架梁屋面平均风压系数受高跨比和风向角影响很大,而基本不受纵跨比和风场类型的影响。框架梁屋面的负风压随着高跨比的增大而增大,但中部和端部框架梁屋面的风压特性有很大差异;中部框架梁屋面的负风压随着风向角的增大不断增大,端部框架梁屋面的风压随着风向角的变化也很显著,但缺乏很好的规律性。主体承重结构框架柱墙面的平均风压分布较为均匀,风压系数可直接按美国金属建筑结构手册选取。根据试验数据采用阻尼最小二乘算法拟合框架梁屋面风压分布公式。经验证,公式计算出的风压系数能良好地反映分布规律,且具有较好的精度,可以为荷载规范的修订和补充提供参考。     

高层建筑群静力干扰效应的试验研究

采用力天平技术 ,用风洞试验方法研究了 5种不同高度和宽度比的一个和两个施扰建筑物在不同间距和地貌条件下对受扰建筑的静力干扰影响。分析中采用神经网络、统计分析等方法对不同影响因素进行分析和对比 ,采用了一种比较简洁的方式 ,描述三个建筑物间的风致干扰特性 ,解决了三个建筑物的静力干扰效应难以表示的难点。结果显示 :对于顺风向静力干扰而言 ,干扰因子基本都小于 1,呈现遮挡效应。但同时也发现 ,由于狭管效应 ,处于并列布置时的某些配置的最大干扰因子值可高达 1 2 ,即此时结构在受扰后的平均荷载有可能比其孤立状态增加 2 0 %。一般情况下 ,遮挡效应随施扰建筑物的宽度的增大而增大 ,但狭管效应也会随之增强。高度比小于 0 5的施扰建筑的影响可以忽略不计 ,对干扰效应有较明显影响的高度比在 0 5～ 1 0之间 ,高度比超过此范围的建筑物的遮挡影响基本和高度比为 1的一致 ,但狭管效应则会更为明显。     

Across‐wind dynamic response of high‐rise building under wind action with interference effects from one and two tall buildings

Systematic studies on the across‐wind dynamic interference effects on two and three tall buildings are presented in this paper. It is found that surrounding and upstream interfering building(s) can significantly affect the across‐wind load on the interfered principal building. Generally speaking, two interfering buildings can cause more adverse dynamic effects on the principal building than a single one does. The results show that the maximum interference factor (IF) among three buildings increases 80% over that between two buildings in terrain category B which has been defined in Chinese load code for design of building structures; a noticeable difference of 29% of IF is also observed in terrain category D. Vortex shedding from the upstream buildings can lead to vortex‐induced resonance, resulting in excessive across‐wind loads on the downstream building. Although interference effects in terrain category D are much smaller than those in exposure category B, the maximum IF is found to be 1·83 in the case of three buildings with the same size in terrain category D and 2·27 in other configurations. Copyright © 2007 John Wiley & Sons, Ltd.     

Aerodynamic interference effects of a proposed taller high‐rise building on wind pressures on existing tall buildings

When a large super high‐rise building taller than the surrounding tall buildings is built in a dense urban area, the aerodynamic interference effects of the surrounding buildings on the proposed building attract much attention, while the interference effects of the taller high‐rise building on the nearby existing buildings are often ignored. Based on a series of wind tunnel tests, the interference effects of a proposed taller high‐rise building, an adjacent equal‐height partner building, and relatively short background buildings on the target building's local wind pressures are analysed in this paper. Two‐dimensional numerical simulation are carried out to further understand the interference mechanism in some cases. The test results show that the influence of a nearby proposed taller high‐rise building may lead to wind‐induced damage on the interfered shorter buildings' envelopes. The envelope structures of other surrounding buildings facing the side of the proposed building need to be given more attention.     

设有外镂空装饰结构的扭转体型高层建筑风荷载研究

对设有外镂空装饰结构的扭转体型高层建筑的风荷载采用风洞试验方法进行研究,分析扭转体型高层建筑风压和风荷载合力的分布特征,研究装饰结构对主体结构风压分布的影响、装饰结构自身内外表面的风压分布特点,比较有无装饰结构的扭转体型高层建筑风荷载合力。结果表明：扭转体型对主体结构的局部风压和扭矩产生较大的影响,但对主体结构X向和Y向风荷载合力的影响不大;装饰结构对主体结构迎风面和背风面的风压影响较小,但能明显减小主体结构侧风面风压的平均值和脉动效应,使得主体结构的极值负压得到降低,有利于围护结构的抗风设计;装饰结构上同一位置内外表面的平均风压非常接近,合成的净压值很小;装饰结构对于主体结构的平均风荷载影响较小,但降低了主体结构风荷载的脉动效应,对主体结构的抗风有利。     

错列布置超高层建筑群的干扰效应研究

对实际超高层建筑群进行群体和单体塔楼两次同步测压风洞试验。通过两次试验测量结果,考察风向及塔楼位置对顺风向、横风向和扭转方向的主体结构承受风荷载以及围护结构的极值风压的影响,并结合风压试验结果及CFD流场计算结果对干扰机理进行说明。研究结果表明,处于中间位置的2号塔楼的扭转干扰放大作用非常显著,较为不利的风向为110°风向,该风向下扭转方向的静力干扰因子达到1.53;沿弱轴Y方向和扭转方向的动力放大因子达到1.32和1.37。     

大连市贝壳博物馆表面风压分布特性风洞试验研究

为了满足大连市贝壳博物馆的抗风安全需要,进行了刚性模型表面风压分布特性风洞试验研究。详细介绍了试验所采用的主要技术参数与基本的数据处理方法,给出了典型风向角下结构表面风压分布的等值线图和结构典型测点在不同风向角下的风压变化规律;分析了各风向角下绝对值最大的局部体型系数及其出现的位置,并将屋盖的局部体型系数与现行《建筑结构荷载规范》(GB 5009—2001)进行了对比。结果表明:屋面上表面的风荷载主要表现为负压,顶部迎风挑檐边缘较大,屋面的尾流区域较小或为正压。屋面两侧的悬挑部分及主入口处迎风时分布有大面积正压,以靠近拐角部分最大,且这部分屋面对风作用反应敏感,设计时应考虑体型系数的变号情况。     

Numerical simulation of the wind field around different building arrangements

A numerical model with the RNG κ−ε turbulence closure model and a pressure correction algorithm of SIMPLEC is used to examine three different building configuration effects on wind flow. Comparisons of computational results with experimental data have been carried out for the vertical velocity profiles at some measurement points. For the experimental study, the building arrangements were presented by 1:150 scale models and tested in a low-speed wind tunnel. It was found that the wind environment for two improved arrangements with lower interval-to-height ratio is better than that for the reference layout with higher aspect ratio in terms of the natural ventilation. The interference effect is more obvious for two improved arrangements than the reference one. The numerical results also show that changing wind direction from perpendicular to the building facades to a 45°-incidence angle has significant effect on the flow field for different configurations.     

球形建筑风荷载及风流场的数值模拟

采用数值模拟方法对一处于设计方案阶段的球形高层建筑的表面风压及周围风流场进行了计算分析,获得了该类建筑与典型钝体高层建筑所不同的风压分布特性及周围风流场特性,例如球面背风区下侧的对称涡漩脱落现象,背风区中心线附近的局部正压作用等。在对不同风向角下的风压分布规律进行分析的基础上,给出了建筑物在最不利风向角下的最不利截面上的风压系数分布曲线,为该建筑方案抗风性能的鉴定及最终方案的确定提供了依据。     

两平行面板组成的独柱支承广告牌的风荷载研究

借助计算流体动力学 (CFD)大型商业软件Fluent6 0 ,对大气边界层内由两平行面板组成的独柱支承广告牌的表面风压进行了研究 ,发现结构的雷诺数敏感性、地貌类别对结构风压和风致扭矩系数的影响可以忽略不计。在此基础上 ,采用实体和面板两种组合模式 ,以C类地貌边界层剪切流为来流条件 ,深入研究了这种广告牌在各种来流方向角下的表面风压分布 ,指出了两种模式下风荷载的差别 ,得到了结构的总体平均和局部风压系数 ,给出了风致剪力和扭矩的计算表达式。建议可供同类结构抗风设计时参考