基于风洞试验的对称截面高层建筑三维等效静力风荷载研究

基于刚性模型表面测压风洞试验建立高层建筑三维风荷载模型,进而运用振型加速度法求解风振响应动力方程,得到了包含拟静力项和惯性力项的弹性力响应解,并推导了对称截面高层建筑顺风向、横风向和扭转向风致随机内力响应。在此基础上提出了基于内力响应等效的可考虑高阶振型贡献的对称截面高层建筑顺风向、横风向和扭转向等效静力风荷载计算方法。结合某一对称截面高层建筑工程实例,对采用上述方法计算得到的结构三维等效静力风荷载进行分析并与我国规范方法顺风向等效静力风荷载计算结果进行比较。结果表明,高层建筑结构抗风设计应该考虑三维等效静力风荷载,且二阶振型对高层建筑等效静力风荷载的贡献不可忽视。     

高层建筑结构在风荷载作用响应问题研究

随着社会经济的高速发展,城市低层建筑已不能满足人类的居住需求,高层建筑的出现应用满足了此方面的困难,在结构设计中,高层建筑相比于低层建筑承受更大的风荷载作用,而风荷载的不确定性因素导致结构设计的繁琐,同时基于低层建筑的荷载分析难以应用于高层建筑,因此研究高层建筑结构在风荷载作用下的响应是十分必要的。基于当前结构风工程的理论,对高层建筑结构下风荷载的研究方法进行了进一步探讨。     

浅议高层建筑抗风的技术问题及对策

高层建筑横风向、扭转向风荷载及群体建筑干扰效应可能引起较大的风致响应。本文综合分析了高层建筑受风荷载的特点,对不同的抗风要求提出了针对性的抗风措施。研究和工程实例表明,通过改变建筑外形或结构动力特性可有效改善高层建筑受风环境,从而降低建筑风致响应。     

实际工程中风荷载处理的主要方法及应用

介绍了实际工程中风荷载的主要确定及处理方法中的风洞试验和高频测力天平方法,阐述了高层建筑、体育场和塔架等建筑物的风荷载的处理及研究方法,以进一步完善结构抗风理论.     

基于风致响应的高层建筑等效静力风荷载优化设计研究

高层建筑风致响应目前需要一个等效静力风荷载优化。高层建筑风致响应等效静力风荷载优化能带来内外部规模的经济增长效应,提高企业自主创新能力,促进企业发展及风致响应竞争力形成。一定区域的建筑风致响应等效静力风荷载优化是在区域相关条件约束下形成的,有效的高层建筑风致响应等效静力风荷载优化应该是基于区域比较优势发展起来的。文章系统地介绍了高层建筑的定义及规模,然后又阐述了区位优势评价指标,最后介绍了等效静力风荷载优化的一系列的特征。     

中国建筑科学研究院风工程研究成果综述

回顾了中国建筑科学研究院近年来在风工程领域取得的重要研究进展。风荷载研究方面,在提出风振计算广义坐标合成法基础上,建立了基于响应时程的结构等效静风荷载计算体系,开展了复杂高层建筑风致振动的系统研究,探明了高层建筑弯扭耦合风振响应的基本规律,提出了高层建筑横风向响应的反应谱方法。风环境研究方面,提出了平衡边界层新的理论解释和数学模型,以及植被和绿化带数值模拟的附加源/汇数学模型。提出了考虑地貌修正的气象资料修正方法,建立了基于日最大风速记录的风环境评估体系,开展了列车风和烟囱效应等特殊风环境的研究。雪荷载研究方面,开展了雪荷载风洞试验和数值模拟技术的研究,提炼了雪荷载风洞试验模拟的核心相似参数,阐明了风致积雪飘移的流动机理,开发了CFD数值模拟的相关程序。团队研究成果在重大工程中得以广泛应用,部分成果被纳入国家和行业标准规范。     

高层建筑结构抗风分析的Pushover方法

以某高层建筑结构为例,进行了强风作用下结构的弹塑性风振响应时程分析,在此基础上,进行了将静力弹塑性Pushover方法用于结构抗风设计的可行性研究。通过动力时程分析、规范静力分析及Pushover抗风分析结果的对比发现:在风荷载较小的情况下,高层建筑结构处于弹性状态,由规范给出的静力等效风荷载方法计算得到的结构风振响应可以满足实际工程的需要。在强风作用下,高层建筑结构的部分构件进入塑性变形状态,用所提出的Pushover抗风分析方法计算得到的结构位移响应与时程响应分析结果吻合,而规范静力分析方法的结果偏小。     

热带风气候条件下风荷载研究的风暴路径法

风气候中风向角对结构风荷载和风振响应是非常重要的一个影响因素,在热带气候条件(如台风)下风向角随时间变化较快,作用在建筑物上的风荷载是非平稳随机过程,这导致了其抗风设计方法与季风的不同。详细的介绍了在考虑风向角的影响后,能用于热带气候条件的风暴路径方法。该方法用等效静力风荷载思想计算用于承载力极限状态设计的风荷载。并且提出了还需要进一步研究的问题,为高层建筑抗风设计研究提供参考。     

高层建筑风激励振动控制Benchmark问题研究

从历届的国际结构控制大会中可以看出,高层建筑风激励振动控制问题一直是结构工程师致力讨论和研究的重点课题.本文通过对风激励高层建筑模型进行自由度缩减和降阶处理,得到大大简化的评估模型.运用不同的控制方法和控制策略对基准问题高层建筑在脉动风荷载作用下的位移、速度和加速度响应量进行分析,提出基于随机分析的均方根响应和基于确定...     

高层建筑风荷载相干性研究

利用高层建筑刚性模型测压风洞试验结果,对顺风向风荷载竖向、水平相干性,迎背风面相干性以及横风向、扭转方向风荷载相干性的主要特征进行研究。利用算例说明了迎背风面相干性以及横-扭风荷载相干函数对于风振响应的影响。从计算结果来看,迎背风面全相干假定将使顺风向风振响应计算结果偏于保守;当结构刚心和质心偏离时,假定横扭风荷载相干性等于零会低估横风向和扭转方向风振响应。     

群体高层建筑风致干扰效应研究进展

在高层建筑抗风设计中,正确地评估邻近建筑对风荷载的影响具有重要的理论和实用价值。从干扰机理、基底荷载干扰以及风压干扰3个方面总结与评述了国内外风致干扰效应的研究进展,列举了各国风荷载规范对干扰效应的条文规定;结合作者所在研究团队近十多年来进行的群体高层建筑的研究成果,对GB 50009-2012《建筑结构荷载规范》的风致干扰条文进行了补充说明,重点介绍了群体建筑气动干扰的量化方法,并强调了干扰效应的适用条件为折算风速不大于7;根据前期研究存在的问题和实际工程需求,建议进一步开展对群体建筑干扰机理、结构顶部峰值加速度、扭转干扰响应以及不同方向荷载相关性等方面的系统性研究。     

Interference effects on wind loading of a row of closely spaced tall buildings

Interference effects on a row of square-plan tall buildings arranged in close proximity are investigated with wind tunnel experiments. Wind forces and moments on each building in the row are measured with the base balance under different wind incidence angles and different separation distances between buildings. As a result of sheltering, inner buildings inside the row are found to experience much reduced wind load components acting along direction of the row (x) at most wind angles, as compared to the isolated building situation. However, these load components may exhibit phenomena of upwind-acting force and even negative drag force. Increase in x-direction wind loads is observed on the upwind edge building when wind blows at an oblique angle to the row. Other interference effects on y-direction wind loads and torsion are described. Pressure measurements on building walls and numerical computation of wind flow are carried out at some flow cases to explore the interference mechanisms. At wind angle around 30° to the row, wind is visualized to flow through the narrow building gaps at high speeds, resulting in highly negative pressure on associated building walls. This negative pressure and the single-wake behavior of flow over the row of buildings provide explanations for the observed interference effects. Interference on fluctuating wind loads is also investigated. Across-wind load fluctuations are much smaller than the isolated building case with the disappearance of vortex shedding peak in the load spectra. Buildings in a row thus do not exhibit resonant across-wind response at reduced velocities around 10 as an isolated square-plan tall building.     

五种被动动力减振器对高层建筑脉动风振反应控制的实用设计方法

本文在建立了五种被动的动力减振器 (TMD, TLCD, LCVA, C TLD, R TLD)对高层建筑结构脉动风振反应控制的统一方程的基础上,导出了被动动力减振器对高层建筑脉动风振反应控制效果的等效结构阻尼比的统一计算公式和被动动力减振器优化参数的设计方法。在此基础上,文中依据我国《建筑结构荷载规范》,对设置被动动力减振器的高层建筑提出了抗风设计的荷载风振系数和脉动增大系数的修正公式,从而使被动动力减振器对高层建筑脉动风振反应控制的设计计算可采用常规的规范方法进行,大大方便了广大结构工程师的应用。     

我国高层建筑结构综述(上)

本文介绍我国高层建筑的发展概况、一些结构体系的特点和适用范围(包括楼板体系)。文中还扼要介绍了高层建筑结构的一些科研成果和设计经验,其中包括:剪力墙的形式及其设计,地震区底层大空间剪力墙结构,框架一剪力墙结构中剪力墙的合理数量及柱截面的选定,楼板变形对高层建筑结构内力的影响,筒体结构的试验研究,高层建筑结构动力特性,高层建筑风荷载体型系数及沿高度分布的研究。     

用高频动态天平方法研究金茂大厦的动力风荷载和风振响应

上海金茂大厦的总高度为４２０．５ｍ,风荷载是这一超高层建筑的控制荷载。采用目前国际上应用最广泛的高频动态天平方法对这一超高层建筑的模型进行了风洞试验,根据试验结果计算分析了该塔楼在风作用下的动力响应和等效风荷载,并将主要结果和其他有关试验的响应结果进行了对比。     

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.     

高层建筑静风荷载的干扰效应研究

在相邻建筑物的干扰下,受扰高层建筑的风荷载与其在孤立状态下相比会有较大的变化。本文采用测力天平模型风洞试验研究了两个高层建筑间的静力干扰效应,得到了两个相同的方形截面建筑在不同相对位置时的静力干扰因子IFm。并且首次引入了正交试验法设计试验方案,研究了施扰建筑高度、截面尺寸和外形对顺风向静力干扰因子IFm的影响。应用人工神经网络方法对试验结果进行了模拟和推广,给出了IFm的等值线图,可供规范应用和参考。     

Dynamic wind response of tall buildings using artificial neural network

This paper presents an alternative approach for predicting the dynamic wind response of tall buildings using artificial neural network (ANN). The ANN model was developed, trained, and validated based on the data generated in the context of Indian Wind Code (IWC), IS 875 (Part 3):2015. According to the IWC, dynamic wind responses can be calculated for a specific configuration of buildings. The dynamic wind loads and their corresponding responses of structures other than the specified configurations in IWC have to be estimated by wind tunnel tests or computational techniques, which are expensive and time intensive. Alternatively, ANN is an efficient and economical computational analysis tool that can be implemented to estimate the dynamic wind response of a building. In this paper, ANN models were developed to predict base shear and base bending moment of a tall building in along‐ and across‐wind direction by giving the input as the configuration of the building, wind velocity, and terrain category. Multilayer perceptron ANN models with back‐propagation training algorithm was adopted. On comparison of results, it was found that the predicted values obtained from the ANN models and the calculated responses acquired using IWC standards are almost similar. Using the best fit model of ANN, an extensive parametric study was performed to predict the dynamic wind response of tall buildings for the configurations on which IWC is silent. Based on the results obtained from this study, design charts are developed for the prediction of dynamic wind response of tall buildings.     

Interference excitation of twin tall buildings

The enhanced dynamic response of a tall square building under interference excitation from neighbouring tall buildings has been studied in a series of wind-tunnel model tests. In a low-turbulence wind environment and under normal strong wind conditions, the dynamic loads on the upstream of an identical pair of tall buildings may increase by a factor of up to 4.4. The dynamic loads on the downstream building of the pair may increase by a factor of up to 3.2 due to “resonant buffeting”. Measurements of along-wind and cross-wind force spectra and a number of wake spectra provide an explanation for the observed behaviour. Possible excitation mechanisms are discussed and critical building arrangements presented. The large interference loads found in this study indicate that interference excitation should be carefully considered in the design of tall buildings.     

群体风效应下高层建筑等效风荷载及舒适度分析

基于某复杂群体高层建筑项目风洞试验结果,采用覆面积分计算方法,对该项目最高塔楼进行了风荷载及风振响应分析,结构由于受到周围建筑的干扰影响,其实际风荷载与规范估算结果差异较大,计算还分析了不同风向下结构的等效基底倾覆力矩及其顶部峰值加速度,其结果可用于此结构的抗风设计。