超高层建筑上实施风力发电可行性研究

珠江城商务写字楼高309.6m,在大楼中上部建造4个风洞(吸风口)并安装有4个风能发电机进行风能发电。通过大比例尺(1∶150)模型的风洞试验,研究吸风口内风速放大效应;利用全尺寸CFD数值模拟评估在3年重现期风速下风机运行及气流流经吸风口引起的噪声影响;通过CFD数值模拟获得来流为40m/s时风机切入绕流的风荷载,建立风机及其上下8个楼层范围内的结构有限元模型,并将CFD数值模拟获得的风荷载作为输入荷载评估了风机运行时对其连接的上下两个楼层振动的影响。研究结果表明:①建筑外形及吸风口的喇叭口形状对气流具有明显的加速作用;②受到周边建筑的干扰作用,出现明显的"峡谷风效应",有周边工况下吸风口的风速放大效应出现在2号吸风口(tunnel-2);③在绝大多数情况下,4个吸风口均能达到风机运行时所需的风速要求,风力发电基本能够正常运行;④在3年重现期风速下,风机运行及气流流经吸风口产生的噪声小于50分贝,满足城市2类地区的噪声限制要求;⑤在吸风口处的来流风速为40m/s情况下,风机运行产生的振动较小,满足高层建筑对结构振动舒适度的要求;⑥在超高层建筑上实施风力发电是可行的,乃利用可再生能源的一种创新策略。     

超高层建筑结构经济性探讨

超高层建筑投资巨大,结构造价占较大比例。基于超高层建筑结构的受力特点,对影响超高层建筑结构造价的若干因素进行探讨,如建筑体型、结构体系、结构材料等。此外,施工方案和施工周期也间接影响结构造价。最后,对部分已建或在建的高度300m以上超高层建筑的结构用钢量进行初步统计和分析,以期找到一些规律。结构造价受多因素影响,需要相互平衡,合理优化的结构设计是降低结构造价的必由之路。     

典型超高层建筑风荷载幅值特性研究

本文对10个典型的超高层建筑刚性模型进行了测量表面风压的风洞试验,获得了各测量层的阻力、升力和扭矩系数的平均值和根方差。讨论了各测量层风荷载系数随风向角的变化规律,以及高宽比和断面长宽比对方形及矩形建筑风荷载的影响。结果表明,倒角方形、Y形和三角形建筑的风荷载均小于方形与矩形建筑;方形建筑高宽比的增大导致升力系数的根方差明显增大;矩形建筑断面长宽比的增大则使阻力系数的平均值、根方差减少,而升力系数的根方差增大;D类和B类风场中的平均气动力系数相近,而D类风场中脉动气动力系数的根方差大于B类风场。     

设置透风孔的超高层建筑风荷载特性

采用同步测压技术,进行设置透风孔的超高层建筑刚性模型风洞试验,对该类建筑物的风荷载特征进行研究。结果表明:孔洞附近,顺风向阻力表现出一定涡激力特性,横风向升力功率谱的谱峰下降幅度较大,阻力与升力系数的根方差均减小,但扭转向扭矩系数根方差的减小幅度有限。受孔洞影响的区域,阻力系数与扭矩系数的自相关性减弱,但升力系数的自相关性增强,阻力系数、升力系数的相干函数衰减程度减弱,相干系数的数值减小。设置透风孔后,超高层建筑升力系数、扭矩系数与阻力系数的互相关性不能再忽略不计,但升力系数与扭矩系数之间的互相关性有所减弱。     

典型超高层建筑风荷载频域特性研究

在边界层风洞中对10个典型超高层建筑模型进行了测压试验,获得了测点层的顺风向、横风向和扭转风荷载,对风荷载的功率谱、相关系数和水平、竖向相干函数进行了细致分析。得出以下结论:方形建筑阻力系数谱的峰值频率基本上与来流纵向风谱保持一致,升力系数谱的频带随着地面粗糙度的增大而变宽,能量减小,扭矩系数功率谱的能量随紊流度的增加而增加;矩形建筑长边迎风时,升力和扭矩系数谱均表现出很强的旋涡脱落特征,斯特罗哈数约为0.11,短边迎风时,升力和扭矩系数谱的频带明显变宽,峰值频率降低;升力和扭矩系数的相关性比较强,而阻力系数和升力系数、扭矩系数之间的相关性则相对小些;在旋涡脱落频率附近,升力系数和扭矩系数的相干性都明显增强。     

青岛某超高层住宅的风洞试验研究

为了研究超高层建筑在使用阶段的抗风安全性,基于青岛某超高层住宅工程,对设计风速作用下结构的风荷载分布规律、结构的位移、加速度响应进行风洞实验研究,并根据风洞试验结果,对结构的抗风安全性、结构三维风振特性及舒适性进行分析,研究结果为该项目的结构设计提供了依据。     

矩形截面超高层建筑风致脉动扭矩的基本特征

利用刚性模型的同步测压风洞试验,研究了矩形截面超高层建筑脉动扭矩的基本特征。研究内容包括扭矩系数的根方差、功率谱密度、竖向相关性以及横风向脉动风力-扭矩相干函数,另外还考察了厚宽比和风场类别这两个参数对脉动扭矩的影响。研究结果表明,脉动扭矩系数随高度增加递减,随厚宽比增加而增加;脉动扭矩谱具有两个谱峰,谱峰形状随厚宽比改变发生很大变化;相对横风向风力,扭矩的竖向相关系数随距离衰减更快;脉动扭矩与横风向风力具有较强的相关性。     

矩形截面超高层建筑风致脉动扭矩的数学模型

利用风洞试验结果,对矩形截面超高层建筑风致脉动扭矩数学模型进行研究。以厚宽比和风场类别为基本变量,采用最小二乘法得到了风致脉动扭矩系数根方差、功率谱密度、竖向相关性系数以及横风向基底弯矩-基底扭矩相干函数闭合计算公式。这些公式的计算结果与原始试验数据吻合较好,说明计算公式具有较高精度。此外,利用结构随机振动方法,用提出的公式以及直接采用试验风压数据计算一栋实际超高层建筑的扭转动力响应,对比了扭转广义力谱、顶层扭转响应谱以及扭转响应根方差等计算结果,对比结果表明两者吻合较好,从而验证了公式的适用性。     

Influence of soilestructure interaction on seismic collapse resistanceof super-tall buildings

Numerous field tests indicate that the soilestructure interaction （SSI） has a significant impact on thedynamic characteristics of super-tall buildings, which may lead to unexpected structural seismic responsesand/or failure. Taking the Shanghai Tower with a total height of 632 m as the research object, thesubstructure approach is used to simulate the SSI effect on the seismic responses of Shanghai Tower. Therefined finite element （FE） model of the superstructure of Shanghai Tower and the simplified analyticalmodel of the foundation and adjacent soil are established. Subsequently, the collapse process of ShanghaiTower taking into account the SSI is predicted, as well as its final collapse mechanism. The influences ofthe SSI on the collapse resistance capacity and failure sequences are discussed. The results indicate that,when considering the SSI, the fundamental period of Shanghai Tower has been extended significantly,and the collapse margin ratio has been improved, with a corresponding decrease of the seismic demand.In addition, the SSI has some impact on the failure sequences of Shanghai Tower subjected to extremeearthquakes, but a negligible impact on the final failure modes.
2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.     

商用建筑面临的挑战

商用建筑是那些为公众易于接近的展示和销售商品的地方。商业建筑包括了从小零售店到货仓式零售商店。商业用房提出了复杂的消防和生命安全问题,解决这些问题需要进行特殊的考虑。商业用房所面临的火灾挑战起源于：     

控制超高层建筑桩筏基础筏板弯矩的方法

为保证超高层建筑桩筏基础的筏板弯矩设计能够控制在安全范围内,采用相对弯曲计算筏板弯矩法(简称反算弯矩法)与共同作用理论的解析-数值解混合法(简称共同作用混合法)分别对金茂大厦、上海环球金融中心两个实例进行分析。根据共同作用混合法计算上海中心大厦的地基变形,用以计算相对弯曲,求得相应弯矩,同时,分别采用共同作用混合法和共同作用数值解-迭代法(简称共同作用迭代法)计算上海中心大厦筏板弯矩并进行比较。利用上述计算的结果,分析上海中心大厦的筏板弯矩,确定控制其筏板弯矩的安全范围。     

上海的超高层超长桩超厚筏基础的现场测试研究(英文)

提供了宝贵的现场试验数据,论述了沉降、土压力、桩的荷载、巨型柱荷载和筏基的应力的分析结果,特别是结构刚度对筏基应力的影响和对基础的贡献层数以及刚度贡献的有限性。提出了一个实用的方法,以利于桩筏基础设计的新改革。此外,还提出一些预估沉降和群桩荷载的建议。     

谈某新建教学楼工程装饰施工技术

以某学院新建教学楼项目为例,结合工程概况,对主要施工方案进行了详细介绍,并对施工垂直运输、楼地面工程、吊顶工程等各工序进行了探讨,为类似工程的施工积累了经验。     

Wind flow patterns about buildings

A knowledge of building wake characteristics is useful in a variety of applications including dispersion of pollutants downwind of conventional or nuclear power plants, airport runway interference effect, take-off/landing limitations at heliports, pedestrian wind comfort, and wind loads on structures. Recent investigations have advanced both understanding of physical flow processes occurring in the near and far wake regions and theoretical predictive capability for flow and diffusion in the far wake region. These studies have shown, for example, that separation cavities immediately downwind are not enclosed by free streamlines as in two-dimensional separation/reattachment, that organized vortices can play an important role in wake development, and that theoretical solutions for some wake regions are possible.     

Wind excitation of neighbouring tall buildings

There is a growing concern about the importance of interaction effects between neighbouring tall buildings subjected to wind loading. Available results indicate that both the peak dynamic response as well as the mean wind loads may increase substantially due to building interaction.An extensive wind-tunnel study of the interaction between two square prisms with a height-to-base length equal to six was undertaken at the LAC, UFRGS. Fifteen relative prism positions were studied, for wind orientations at every 15°, under smooth-uniform as well as turbulent-shear wind. Mean force and torsional moment coefficients for uniform flow were reported in previous publications. Herein, complete results for turbulent wind are given. In addition, the most important interaction effects observed under both flow conditions are discussed in detail.     

强风作用下楔形外形超高层建筑横风效应试验研究

对正方形平面沿高度方向逐渐收缩的楔形外形超高层建筑进行同步测压试验,分析不同高度横风向气动荷载功率谱密度、相干特征、结构基底气动弯矩和相应的风振响应,在此基础上进一步考虑切角对结构气动荷载和响应的影响。研究结果表明：采用锥形外形可有效地消减作用于结构上的横风向气动荷载,并在一定条件下消减结构的风振响应;楔形外形可以抑制漩涡脱落的强度,但不能消除结构的漩涡脱落现象,且会升高结构的漩涡脱落频率并进而升高结构的风致响应;在楔形外形的基础上再进行切角处理可以基本消除结构的横风向漩涡脱落现象;经切角处理后,楔形外形结构的横风向风致峰值基底弯矩在结构1阶模态自振周期6.12~14.28 s范围内基本保持不变;对于锥度η为2.2%和 4.4%的高层建筑,切角处理后其100年重现期的峰值基底弯矩分别比未切角减少31.13%和14.58%。     

新型超高层结构体系的抗风设计研究

在大气边界层风洞进行了“珠江城”商务写字楼大比例尺（1：150）模型风洞实验,通过对风洞实验数据分析,获得了基础等效静风荷载及结构顶部风致加速度响应,并将其结果与其他较小比例尺的两个风洞实验结果相对比,分析了模型几何缩尺比、周边建筑及平均风剖面对实验结果的影响。     

Wind engineering in Africa

The International Association for Wind Engineering (IAWE) has very few contacts in Africa, the second-largest continent. This paper reviews important wind-related African issues. They all require data on wind climate, which are very sparse in Africa. Wind engineering in Africa can assist in collecting data on wind climate, developing wind energy, reducing the adverse effects of wind and related drifting sand in building activities and agriculture, and limiting other wind-related disasters, in environment and ecology, such as those caused by erosion and fire. The paper aims to encourage Africa-oriented supportive research, especially better data coverage; quality control of existing data; search of historical archives; generation of data by numerical weather analyses; and validation of extrapolation techniques. We envisage promising cooperation with Africa, despite the fact that African countries do not currently participate in the international exchange and cooperation in these fields. African priorities presently seem to be different, while funds and other facilities are lacking. Capacity building in wind engineering and support issues should be initiated by agencies such as UNEP, FAO, EU, WMO, NGOs, etc. The necessity of professional wind engineering input in these activities should also be recognized. Interaction of IAWE with these agencies is necessary.     

Wind environmental conditions in passages between buildings

Experimental measurements have been carried out in a boundary layer wind tunnel to determine wind velocity and turbulence conditions in a passage between two rectangular buildings. The experiments were done under simulated open country terrain conditions for a wide range of wind azimuths. Geometrical parameters included the height of two buildings and the passage width.Results show that the most critical wind velocity conditions occur for buildings of different heights and at a point near the passage entrance for a wind direction skewed by 30° from the passage centre line. Turbulence conditions, however, are found more critical for wind perpendicular to the passage centre line. Also, the larger the passage width, the lower the velocity amplifications and the higher the turbulence intensities in the passage. The paper demonstrates that different K parameters for the inclusion of wind gustiness in an equivalent effective wind speed make little difference in the comfort criteria evaluation.     

Fire safety engineering in timber buildings

The combustibility of timber is one of the main reasons that many building regulations strictly limit the use of timber as a building material. Fire safety is an important contribution to feeling safe, and an important criterion for the choice of building materials. Historically, the combustibility aspect of wood has been a disadvantage for using timber as a construction material. The main precondition for an increased use of timber in buildings is providing adequate fire safety. This paper reviews the opportunities and challenges to reach this goal by implementing Fire Safety Engineering and Performance Based Design principles.