基于CQC算法的大跨屋盖结构风致响应研究

笔者以大跨屋盖结构的风洞测压数据为基础,基于CQC快速算法理论编写了Matlab风致响应计算程序。计算风致响应时同时考虑了风荷载谱的实部和虚部对风致响应的贡献,能够有效准确的判定参振模态数、模态耦合项、以及背景共振相关系数。     

深圳湾体育中心风洞试验及风振分析研究

对深圳湾体育中心进行了测压试验、风环境试验和风振响应分析。着重研究了屋盖悬挑部分上、下表面脉动风压的相关性,指出相关系数对合压力脉动强度有重要影响。并通过对比测压试验,评估了周边建筑对屋盖平均风压和脉动风压分布的影响。周边建筑的存在使得平均风压幅值降低,而脉动风压明显增大。根据风环境试验结果,分析了体育场内部风场的分布,对当地主导风向进行评价,并提出针对性建议。最后,基于同步测压试验结果,对屋盖结构进行了基于时程方法的风致响应计算,得到了动力风荷载作用下的位移响应特征。     

大跨结构屋盖风致响应状态Newmark法

本文运用状态空间Newmark法,推导了大跨屋盖结构在时域内的随机风致响应和风振系数的计算方法。通过对一大跨平面空间网架结构的建模分析,计算得到了屋盖的随机风致动力响应时程,研究了屋盖的荷载风振系数和位移风振系数,分析比较了表面两种风振系数的分布特性和变化规律,研究结果可以作为大跨度网架屋盖风荷载设计的一种参考。     

某骨架支承式膜结构屋盖的等效静力风荷载研究

以郑州大上海步行街中心广场膜结构屋盖为工程背景,进行了刚性模型的同步测压试验。研究了屋盖表面风荷载分布规律和屋盖的风致响应;采用阵风荷载因子法和荷载响应相关法,研究了屋盖的等效静力风荷载,并分析了两种方法的优缺点。结果表明,城市中心的开敞式大跨度屋盖结构的风荷载以脉动风荷载为主;其风致响应也以脉动响应为主;阵风荷载因子法在以脉动响应为主的情况下定义等效静力风荷载存在困难,荷载响应相关法能克服阵风荷载因子法的这些缺点。     

大跨度铁路站房屋盖结构风洞试验与等效静风荷载研究

以哈尔滨西客站站房屋盖结构为研究对象,采用刚性模型同步测压风洞试验对建筑表面的平均及脉动风荷载进行测定,结合本征正交分解技术对风压场进行重构及预测,解决了风压测点与结构有限元模型节点的不匹配问题。分别建立整体结构和屋盖结构有限元模型,利用时程分析方法考察了下部结构对风致响应的影响,研究表明下部结构会导致屋盖结构的刚度弱化,建模中忽略下部结构可能导致对屋盖结构位移和内力响应的低估。引入多目标等效静风荷载分析方法,以结构在风荷载作用下的最大动力响应为控制指标获得针对多个等效目标的静风荷载分布,并对等效结果进行了验证,结果表明该方法可以实现以少量静风荷载分布形式实现所有响应均与动力极值响应等效。     

越南广宁体育场悬挑屋盖多振型和交叉项对风振响应的影响

在风洞试验同步测压的基础上,拟合了越南广宁体育场悬挑屋盖脉动风压自谱和相干函数经验表达式,采用准确的屋盖随机风振计算方法分析了上、下风向下悬挑屋盖结构的风致动力响应,重点分析了竖向动位移根方差响应随参振振型数的变化,研究了多振型和振型交叉项对其响应的影响规律。研究表明,越南广宁体育场双侧悬挑屋盖可只考虑前5阶振型,无需考虑振型交叉项的影响。     

基于CQC方法的大跨屋盖结构随机风振响应计算

本从线性结构随机振动响应计算的CQC方法出发，推导出适合于大跨屋盖结构随机风振响应统计量精细计算的算式，式中考虑了不同振型响应之间互相关的影响；同时指出，如需按CQC方法进行精细计算，就必须首先获得结构各点风荷载之间互功率谱密度函数的实部和虚部。     

POD在大跨屋盖风致响应计算中的应用

根据风洞试验同步多点压力扫描技术和本征正交分解方法重构作用于圆拱顶屋盖的脉动风力。对重构的脉动风荷载的时间历程曲线及其统计性质与实测风荷载进行比较。计算部分测压点上重构的风荷载的自功率谱、互功率谱及相干函数,并用实测荷载的功率谱作了检查。提出一种采用缩阶技术用完全二次型组合法计算大跨屋盖的风致响应的方法,这种方法利用少量本征模态计算缩阶的主坐标功率谱而得到脉动风荷载功率谱。为检验方法的效率,给出采用不同数目主坐标的圆拱顶屋盖部分节点竖向均方根位移的计算时间和计算误差,以及采用不同数目主坐标的缩阶技术得到的全部节点的竖向均方根位移响应的误差分布。     

国家海洋博物馆风洞试验与等效静风荷载研究

以国家海洋博物馆钢结构屋盖为研究对象,采用刚性模型同步测压风洞试验对建筑表面的平均及脉动风荷载进行测定,考察了典型风向下屋盖表面风荷载特性。建立结构整体有限元模型,利用时程分析方法获得结构在风荷载作用下的最大节点位移和杆件应力。引入多目标等效静风荷载分析方法,以结构在风荷载作用下的最大动力响应为控制指标,获得针对多个等效目标的静力风荷载分布并对等效结果进行了验证。结果表明,该方法可以实现以少量静力风荷载分布形式实现所有响应均与动力极值响应等效。     

大跨屋盖基于位移响应协方差等效静力风荷载计算方法

目前,频域内有多种等效静力风荷载求解方法,但每种方法都有其局限性;时域内也提出了风致响应的计算方法,却没有完整地提出求解等效静力风荷载的方法。本文基于位移响应协方差矩阵,提出了一种计算大跨屋盖结构等效静力风荷载的新方法。本方法的关键是获得位移响应的协方差矩阵,对于时域法,由于时程分析能得到位移响应时程,故可根据时程序列直接计算得到;对于频域法,也可由各阶模态响应推导得到,因而本方法既适用于时域法,也适用于频域法。最后,以某大跨屋盖结构作为工程实例,计算了等效静力风荷载,并将其与CQC方法计算结果进行了比较,验证了方法的有效性。     

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。     

Control of wind-induced vibration of long-span bridges and tall buildings

With the rapid increase in scales of structures, research on controlling wind-induced vibration of large-scale structures, such as long-span bridges and super-tall buildings, has been an issue of great concern. For wind-induced vibration of large-scale structures, vibration frequencies and damping modes vary with wind speed. Passive, semiactive, and active control strategies are developed to improve the wind-resistance performance of the structures in this paper. The multiple tuned mass damper (MTMD) system is applied to control vertical bending buffeting response. A new semiactive lever-type tuned mass damper (TMD) with an adjustable frequency is proposed to control vertical bending buffeting and torsional buffeting and flutter in the whole velocity range of bridge decks. A control strategy named sinusoidal reference strategy is developed for adaptive control of wind-induced vibration of super-tall buildings. Multiple degrees of freedom general building aeroelastic model with a square cross-section is tested in a wind tunnel. The results demonstrate that the proposed strategies can reduce vibration effectively, and can adapt to wind-induced vibration control of large-scale structures in the uncertain dynamic circumstance.     

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.     

Wind effects on a long-span beam string roof structure: Wind tunnel test, field measurement and numerical analysis

The Guangzhou International Convention & Exhibition Center (GICEC) with roof dimensions of 210 m wide and 457 m long is the largest exhibition center in Asia and the 2nd largest of this kind in the world. This paper presents results from a combined study of wind tunnel test, full-scale measurement, and numerical analysis of wind effects on the long-span beam string roof structure. In the wind tunnel test, wind-induced pressures including mean and fluctuating components were measured from the roof of a 1:300 scale GICEC model under suburban boundary layer wind flow configuration. The Proper Orthogonal Decomposition (POD) method and the quasi-steady approach as well as probability analysis were adopted to estimate the characteristics of the fluctuating wind pressures on the roof. On the other hand, full-scale measurements of wind actions and wind-induced structural responses of the roof were conducted during the passage of Typhoon Nuri. The field data such as wind speed, wind direction, and acceleration responses, etc., were continuously and simultaneously monitored from a wind and structural response monitoring system installed on the roof structure during the typhoon. Detailed analysis of the field data was performed to investigate the characteristics of the typhoon-generated wind and the wind-induced vibration of the long-span roof structure under typhoon condition. The dynamic characteristics of the roof were determined from the field measurements and comparisons with those calculated from the finite element model (FEM) of the structure were made. The damping ratios of the roof structure were estimated by means of the random decrement method and the amplitude-dependent damping characteristics were presented and discussed. Finally, the full-scale measurements were compared with the model test results to examine the accuracy of the wind tunnel test results and to identify possible modelling errors in the numerical study. The results presented in this paper are expected to be of considerable interest and of use to researchers and professionals involved in designing long-span roof structures.     

大跨度可开合空间网架屋盖风致效应

大跨度屋盖结构作为风敏感性较强的结构,风荷载是其控制荷载之一,可开合屋盖由于外形和结构的多变性,其风致效应更为复杂.以某大跨度可开合空间网架屋盖结构为研究对象,利用刚性测压风洞试验实测了屋盖内外表面的风压系数,对比了开合状态下屋盖表面风压的分布特征.基于本征正交分解(POD)及瞬态动力有限元分析,得到屋面节点的位移响应...     

基于风洞试验的双塔楼超高层建筑风荷载与风致响应

当超高层建筑的高度和间距都比较接近的时候,相互的干扰效应对结构的表面风荷载与结构的风致响应都会产生较大影响。基于刚性模型表面测压风洞试验,得到了双塔楼超高层建筑表面各测点的风压时程。在此基础上,通过数据处理,得到结构的三维动力风荷载模型,进而分别采用频域法进行结构动力响应分析。最后,通过分析结构表面风荷载与风致响应,研究了塔楼之间的干扰对结构风荷载的影响以及对结构风致响应的影响,结果表明:当双塔连线与来流方向平行时,三维风荷载和风致响应都会明显增大,干扰效应影响十分明显。     

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.     

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.     

屋面风荷载及风致破坏机理

随着建筑科技和施工工艺的进步,大量形式新颖、质量轻、柔度大的大跨度屋面结构不断涌现,风荷载成为这类结构的重要荷载。本文通过综合大量风洞试验成果和灾后实地调查结果,研究了平屋面、坡屋面、弧状屋面、柱壳和球壳屋面等各种屋面形式的风压分布特征,给出了可供设计和研究参考的屋面风压系数,并对屋面风压分布及屋面结构的风致破坏机理作了较为详细的论述,得出对屋面抗风设计颇有指导意义的结论。