Full-scale measurements of wind effects on the Jin Mao building

The Jin Mao Building located in Pudong New Area, Shanghai, which has a height of 420.5 m and 88 floors, is currently the tallest building in Mainland China. This paper presents some selected results obtained from the full-scale measurements of wind effects on the Jin Mao Building during the passage of Typhoon Rananim in August, 2004. The field data including acceleration responses, wind speed and wind direction were simultaneously and continuously recorded during Typhoon Rananim. Detailed analysis of the field data was conducted to investigate wind effects on the super tall building. The characteristics of typhoon-generated wind and wind-induced responses of the 88-storey building are presented and discussed. Dynamic properties of the building are determined based on the field measurements, and comparison with those calculated from the finite element model of the building is made. The amplitude-dependent characteristics of damping that were obtained using the random decrement technique on the basis of the field measurements are investigated. Furthermore, wind tunnel experiment is conducted to study wind effects on the Jin Mao Building through force balance model test, and the full-scale measurements are compared with the wind tunnel test results for verification of wind tunnel test techniques. Finally, the serviceability of the super tall building under typhoon conditions is discussed.     

Large eddy simulation of wind effects on a long-span complex roof structure

This paper presents a combined study of numerical simulations and wind tunnel tests for the determinations of wind effects on a long-span complex roof of the Shenzhen New Railway Station Building. The main objective of this study is to present an effective approach for the estimations of wind effects on a complex roof by computational fluid dynamics (CFD) techniques. A new inflow turbulence generator called the discretizing and synthesizing random flow generation (DSRFG) approach was applied to simulate inflow boundary conditions of a turbulent flow field. A new one-equation dynamic subgrid scale (SGS) model was adopted for the large eddy simulations (LES) of wind effects on the station building. The wind-induced pressures on the roof and turbulent flow fields around the station building were thus calculated based upon the DSRFG approach and the new SGS model integrated with the FLUENT software. In parallel with the numerical investigation, simultaneous pressure measurements on the entire station building were made in a boundary layer wind tunnel to determine the mean, fluctuating, and peak pressure coefficient distributions. The numerically predicted results were found to be consistent with the wind tunnel test data. The comparative study demonstrated that the recommended inflow turbulence generation technique and the new SGS model as well as the associated numerical treatments are useful tools for structural engineers to assess wind effects on long-span complex roofs and irregularly shaped buildings at the design stage.     

Wind effects on the world’s longest spatial lattice structure: Loading characteristics and numerical prediction

The 486-m long roof structure of Shenzhen Citizens’ Centre is the world’s longest spatial lattice structure. This paper presents some selected results from a combined wind tunnel and numerical simulation study of wind effects on the extra-long-span roof structure. In this study, simultaneous pressure measurements on its entire roof are made in a boundary layer wind tunnel, and the measured wind pressures, such as mean, root-mean-square (rms) and peak pressure coefficient distributions on the roof are presented and discussed. Based on the measured data from a number of pressure taps, a numerical simulation approach using backpropagation neural networks (BPNN) is developed for the predictions of wind-induced pressure time series at other roof locations which are not covered in the wind tunnel measurements. The BPNN is trained with the pressure data time series measured from adjacent pressure taps. The good performance of the developed neural network is demonstrated by comparing the predictions with the model test results, illustrating that the BPNN approach can serve as an effective tool for the design and analysis of wind effects on large roof structures in conjunction with wind tunnel tests.     

强台风“黑格比”作用下低矮房屋风压特性

根据强台风"黑格比"登陆过程近地风场的实测结果及实测房屋表面测点在强台风登陆全过程监测获取的风压数据,分析了低矮房屋迎风屋面屋沿局部测点的平均、脉动及极值风压系数的变化规律,总结了其对应风场状况下的屋面体型系数。同时,利用等压线图分析了6种风场下的屋面平均、脉动及极值风压系数的分布规律。结果表明:在接近强台风"黑格比"风眼区域,由于明显交替变化的上升及下沉气流,导致低矮房屋迎风屋面屋沿及角部等局部区域形成强大的吸力及高压区,迎风屋面最小、最大体型系数值分别达到了-6.56、3.42;屋沿各测点风压谱相互吻合较好,当频率达到4Hz后,谱能急剧下降;迎风墙面测点在3/4墙高处压力最大,背风墙面各测点风压值基本一致,湍流积分尺度对平均风压系数的影响不大,但脉动风压系数和峰值风压系数随湍流积分尺度的增大而增大。     

Peak factor estimation method of non-Gaussian wind pressures on long-span tri-centered cylindrical roof structures

Claddings are susceptible to damage due to underestimation of extreme wind-induced surface pressures. Commonly accepted methods for estimating the peak factor (an input used to determine cladding design loads) involve complex calculation-intensive procedures. This research develops a four-parameter unified auto-spectral model of wind pressure to simplify peak factor estimation of wind-induced surface pressure via analysis of wind tunnel wind load data on tri-centered cylindrical roofs. Values of the model parameters were identified via statistical analysis of wind tunnel wind pressure measurement on two long-span tri-centered cylindrical roof structures with different curvatures. The study identified roof regions with non-Gaussian features by inspecting probabilistic density functions of the standardized wind-induced roof pressures and the third- and fourth-order statistical moments of wind pressure time histories. The paper ultimately proposed and evaluated a simplified method for estimating the peak factors in the non-Gaussian regions, the Three-parameter Hermite Model, derived through the moment-based Hermite Model, the Revised Hermite Model, and the parameter simplification accomplished in this study. The results show that the auto-spectral model of wind-induced roof pressures can accurately estimate the zero- and second-order spectral moments, which reflects the wind pressure fluctuating characteristics and geometric features of spectral curves. Compared with the peak factors of the moment-based Hermite Model and the Revised Hermite Model, the peak factor errors estimated by the Three-parameter Hermite Model are all less than 10%. These results suggest that the Three-parameter Hermite Model simplifies the calculation with acceptable accuracy.     

Time-frequency analysis of typhoon effects on a 79-storey tall building

Di Wang Tower located in Shenzhen, PR China, has a height of approximately 325 m and is a 79-storey tall building. This paper presents selected results of full-scale measurements of typhoon effects on Di Wang Tower. Wind speed, wind direction, wind-induced acceleration and displacement responses were simultaneously and continuously measured from the super tall building with anemometers, accelerometers and global position system (GPS) during a typhoon. The advanced data analysis method called Hilbert-Huang transform (HHT) was adopted in this study to analyze the non-stationary characteristics of wind speed and wind-induced responses of this building under typhoon condition. By using the empirical mode decomposition (EMD) method, the measured data were decomposed into several inherent intrinsic mode functions (IMFs). The probability density and power spectral density of fluctuating wind speed were obtained by traditional methods and were further analyzed by considering time-varying mean values of the measured data via the EMD method. The wind-induced responses with non-stationary features were studied by applying the HHT to each IMF for obtaining their instantaneous frequency and Hilbert-Huang composite spectrum. Meanwhile, the transient energy distributions of the wind-induced responses were analyzed in time-frequency domain, which were compared with the traditional power spectral densities obtained from the fast Fourier transform (FFT) method and those from the wavelet transform. Furthermore, the amplitude-dependent damping ratios were determined by combining the EMD and the random decrement technique (RDT) method. Through comprehensive analysis of the measured data, it was testified that the HHT method is a promising tool for the time-frequency analysis of random signal and can serve as a flexible and effective tool for analyzing field data of wind speed and wind-induced response with non-stationary features.     

大跨双层屋盖结构风洞试验与风振响应研究

对南太湖湿地奥体公园复杂体型体育场双层屋盖结构进行了风荷载的风洞试验与风致动力响应研究。屋盖由高低两个开口椭圆屋面叠合而成,两屋面之间设置观光走廊。利用风洞模型试验测定了双层屋盖上下表面的平均和脉动风压时程数据。通过计算分析得到了屋盖结构局部测点的极值风压以及平均风荷载整体合力与最不利风向角。然后基于有限元方法对该屋盖进行了风振响应的动力时程分析,获得了结构风振系数、等效静力风荷载的分布图以及考虑风振效应的最不利风向等数据和结论。     

某体育会展中心大跨屋盖系统风荷载试验研究

介绍了某体育会展中心会展馆和体育场的大跨屋盖系统模型风洞试验的概况和主要试验结果,通过分析典型测点方法详尽研究了挑篷上平均风压和脉动风压的分布,讨论了脉动风压对总设计风荷载的贡献,并对比了计算围护结构风荷载的规范方法和统计方法;结果表明,正面迎风时,体育会展馆和体育场屋盖边缘的平均风压和脉动风压系数均较大,采用规范方法算得的会展馆围护结构风荷载大部分小于采用统计方法算得的风荷载,而用规范方法算得的体育场围护结构风荷载均小于采用统计方法算得的风荷载,在大跨屋盖设计中应分区域选用两者中较大值作为风荷载设计标准值。     

Wind-tunnel investigation of point pressure on TTU test building

External point pressures at mid-plane and roof corner locations, measured during a wind tunnel study of a 1: 50 geometrical scale model of the TTU test building, are reported in the paper. The mid-plane laboratory pressures are compared with field and numerical results. The agreement/discrepancy between the compared results is discussed. The roof corner pressures acquired for a wider than previously reported range of the wind azimuth are presented and compared with the available field results. Type I and III extreme value distributions (EVDs) are fitted to peak suctions acquired at four locations in a roof corner region. For the mid-plane locations, a very good agreement between the model and full-scale pressures is attributed to a close matching of the laboratory and field approach flows. The laboratory-field comparison of the roof corner pressures revealed trends observed in previously reported investigations. The extreme value analysis showed that the field peak pressures in this region were bounded by the laboratory peak pressures (the lower bound) and by the asymptotic limit of the type III EVD fit of the laboratory peaks (the upper bound). Rapid convergence and other attributes make type I EVD a fit of choice for the reported extreme wind pressures.     

风荷载作用下超大跨度机库结构响应分析

文章对某大跨机库进行三维脉动风作用下的风振分析,给出了主要风向角作用下屋盖节点的位移均方根值分布与加速度均方根值分布,并分析了不同风向角对风振响应值的影响。通过平均风与脉动风作用下的节点响应值对比,发现影响屋盖风振系数分布的主要因素是机库本身的结构特性,对节点风致响应进行频谱分析的结果进一步表明了对于节点位移响应来说背景分量占主要比重,而共振分量则在节点加速度响应中占主要部分。     

Study on full-scale measurements of wind-induced response of the Shenzhen Kingkey 100 Tower

采用自主研发的LAC-I无线加速度传感器，对高度441.8m的深圳京基100 (KK100)的加速度响应进行了为期5年的连续监测。选取了2011年至2015年间的4次主要台风（纳沙、杜苏芮、维森特和天兔）经过时的加速度观测数据以及常态弱风和环境激励下的加速度数据，进行结构动力参数识别以及验证与风洞试验结果的一致性。结果表明：各工况下自振频率的识别结果具有很好的一致性，与其在设计阶段对结构进行有限元分析得到的相应结果约大21%；阻尼比的识别结果表现出一定的离散性，x、y 两个方向的阻尼比分别在0.6%~0.9%和0.33%~0.71%之间变化，但阻尼比与振幅并不存在明显的相关性；在风场条件基本一致的情况下，实测结果与风洞试验结果具有良好的一致性；在振幅较大的横风向，实测和风洞试验得到的结构顶部峰值加速度响应相差4.2%，说明了风洞试验的可靠性。同时近5年来的连续观测遇到了与深圳地区10年重现期风压相当的最大风速，测得的瞬时峰值加速度仅为0.123 m/s²，表明该建筑的舒适度能够满足要求。     

大跨屋盖结构风致抖振响应研究

建立基于非定常风荷载的大跨屋盖结构风致动力响应的试验和分析方法。该方法采用多通道测压系统扩大同步测压点的数目,更全面地获得屋盖表面风压的时空特性,为准确计算结构风致响应奠定了基础。在动力分析方法上应用CQC法计算屋盖结构的风振响应,考虑多模态及模态间的耦合影响,编制了结构风致动力效应计算程序SWDP。最后对上海铁路南站工程屋盖结构的抖振响应结果进行了计算和分析。结果表明,采用多通道测压系统可以有效地扩大同步测压点的数目;基于非定常风荷载的CQC方法是计算复杂大跨屋盖结构风振响应的有效方法;背景响应对于总响应的贡献通常是不可忽略的。     

台风风场作用下体育场罩棚风压分布风洞试验研究

通过刚性模型测压风洞试验研究了台风风场高湍流、强变异性等特征对大跨结构风压分布特性的影响。以某体育场罩棚为原型制作1∶300刚性模型,进行了常规B类风场和台风风场作用下的测压对比试验。基于试验数据,从测点风压和总体升力角度对两类风场作用下体育场罩棚结构的风压分布总体特性进行了分析,重点比较了典型测点在典型风向角下的风压分布规律及相互关系。结果表明：两类风场作用下平均风压的分布规律基本类似,但各风向角下台风风场中的屋盖总体升力比B类风场增大8%~25%;台风风场的高湍流特性导致基于极值负风压求得的各风向角下屋盖总体升力比B类风场大27%~46%,各测点的极值风压均明显高于常规B类风场作用下的对应值,比值约为1.13~1.70,因此对于台风多发地区的大型体育场屋盖设计,必须考虑台风风场高湍流所致的脉动风压增大效应。     

输电塔风振响应研究

本文基于Matlab采用Davenport风速谱对大气边界层的脉动风速进行了模拟,并通过一具体的工程实例,采用Ansys分析研究了不同风场湍流度和结构阻尼比对输电铁塔风振响应的影响,同时计算了结构的风振系数。计算结果表明,风场湍流度和结构阻尼比对输电塔的风振响应有不同程度的影响,计算时应考虑两者的综合效应;按我国规范计算的结构风振系数小于美日规范。     

台州体育中心屋盖的风振系数计算

针对大跨网架屋盖风致振动问题 ,采用时程分析方法 ,在有限元建模的基础上 ,直接采用风洞试验的数据 ,计算了台州市体育中心屋盖结构的竖向位移风振系数 ,得到了一些大跨屋盖位移风振系数的变化规律     

北大体育馆屋盖结构风荷载分布特性的试验研究

风荷载是控制大跨度钢屋盖结构设计的主要荷载之一。结合北京大学体育馆屋盖结构的风洞模拟试验,以屋盖上的平均风荷载和脉动风荷载为研究对象,对屋盖上的风荷载分布特性进行了详尽的分析。结果认为:整个屋盖所受风荷载主要以负压为主,屋盖悬挑部分在迎风时产生“上吸下顶”的叠加作用,其他风向为“上吸下吸”的抵消作用;屋盖角部的风荷载一般也很大,在结构设计时应采取必要的构造措施;脉动风荷载对于总的设计风荷载来说不能忽略,准定常理论不适合用来计算大跨度屋盖的风振响应。     

Study on full-scale measurements of wind effect on super high-rise buildings in Pearl River Delta region during super Typhoon Mangkhut

对超强台风“山竹”侵袭时珠三角地区数栋超高层建筑的风致响应实测结果进行分析和总结，开展内伶仃岛缩尺模型风洞试验，获取该岛对气象站点风速的影响系数，并依此对观测风速进行订正，结合实测和风洞试验分析和评价深圳湾壹号7号塔楼(T7)的抗风性能。结果表明：不同高度、平立面外形的超高层建筑实测风致最大峰值加速度均超过10 cm/s2，且超高层建筑风振响应和建筑高度不存在相关性；在所有被测的建筑中加速度响应最小的建筑为高度342 m的T7，其最大峰值加速度仅为13.2 cm/s2；参数识别得到T7的模态频率和阻尼比显示均具有明显的时变特征，最大风速时段识别的模态频率整体上较有限元数据模拟结果增大21%，前两阶模态阻尼比分别为2.1%和1.7%；优化的气动外形和合理的朝向是T7抗风性能优良的主要原因，对于一般矩形平面的超高层建筑应避免使其窄边面向所在地的强风主导风向；采用订正后的风速值和参数识别结果对风洞数据进行重分析，结果显示计算值和实测值吻合较好，验证了前期风洞试验的可靠性。     

三维脉动风模拟技术在大跨机库风振分析中的应用

风荷载在大跨度屋盖结构设计中往往起主要作用,这使得该类结构的风荷载及风致动力响应研究日益受到关注与重视。结合大跨度机库屋盖表面脉动风作用特点,依据改进的Iwatani线性回归滤波器法并结合中心采样定理,实现了基于Matlab的超大跨度网架结构三维空间相关脉动风速时程模拟。以Davenport谱为目标谱对首都机场六机位机库网架所有上弦节点位置处的随机脉动风速时程进行了模拟。进而结合风洞试验数据,依据屋盖各节点风压系数将模拟的风速时程加载于机库结构并进行风振响应时域分析,以研究三维脉动风作用下超大跨度机库屋盖结构的响应特点。分析结果表明本文模拟空间随机脉动风的方法可以较好地考虑大跨机库表面的脉动风特点,为结构的风振时域分析提供准确的荷载时程。     

超强台风“山竹”期间珠三角地区超高层建筑的风效应实测研究

对超强台风“山竹”侵袭时珠三角地区数栋超高层建筑的风致响应实测结果进行分析和总结,开展内伶仃岛缩尺模型风洞试验,获取该岛对气象站点风速的影响系数,并依此对观测风速进行订正,结合实测和风洞试验分析和评价深圳湾壹号7号塔楼(T7)的抗风性能。结果表明：不同高度、平立面外形的超高层建筑实测风致最大峰值加速度均超过10 cm/s2,且超高层建筑风振响应和建筑高度不存在相关性;在所有被测的建筑中加速度响应最小的建筑为高度342 m的T7,其最大峰值加速度仅为13.2 cm/s2;参数识别得到T7的模态频率和阻尼比显示均具有明显的时变特征,最大风速时段识别的模态频率整体上较有限元数据模拟结果增大21%,前两阶模态阻尼比分别为2.1%和1.7%;优化的气动外形和合理的朝向是T7抗风性能优良的主要原因,对于一般矩形平面的超高层建筑应避免使其窄边面向所在地的强风主导风向;采用订正后的风速值和参数识别结果对风洞数据进行重分析,结果显示计算值和实测值吻合较好,验证了前期风洞试验的可靠性。     

近地台风风场特性及低矮房屋风荷载现场实测研究

通过研制的可移动平坡屋面实验房风压及台风风场现场实测系统,研究近地台风风场特性和低矮房屋表面风荷载分布规律。基于实验房获取到的10余次近地台风风速和风压实测数据,对近地台风风场湍流特征参数如湍流强度、阵风因子、湍流积分尺度及脉动风速功率谱等,按来流不同方位地貌状况进行分类研究;同时分析了斜向强风最不利工况下,屋面角部区域风压分布特征。分析结果表明: A、B、C类地貌条件下,台风顺风向湍流强度均值分别为0.13, 0.21, 0.32;阵风因子同湍流强度正相关,湍流积分尺度随湍流强度增加而减少;与季风相比,台风眼壁区域的顺风向脉动风速功率谱密度值略大于季风的实测值,而横风向脉动风速功率谱密度值显著大于季风的实测值;在低频和惯性子区范围,台风眼壁区域的顺风向脉动风速von Karman和Harris谱拟合值与实测值吻合较好;在斜向风作用下迎风屋檐角部边缘测点区域具有较高峰值负压和脉动风压,峰值负压系数达-13.5。