Study on occupant comfort evaluation mode of tall buildings in wind excitation based on fuzzy probability method

Occupant comfort mode in wind‐induced vibration was proposed and studied based on fuzzy probability method (FPM). First, the predictions of the comfort mode were compared with the studies of other researchers to verify the reliability of the method proposed in this paper. Second, vibration comfort of 4 types of buildings was investigated and assessed respectively with the proposed mode. Third, parameters of influencing the occupant comfort, such as coefficient of variation and membership function (MF), were discussed, and optimal results were found. Finally, application of the comfort mode was investigated with a true super tall building. This study shows that the FPM is a feasible and reliable way of establishing the occupant comfort mode, and good predictions can be obtained, especially for FPM with MF1 and MF2. The quantitative story and total comfort ratios can be evaluated effectively for tall buildings in wind excitation. The proposed occupant comfort mode based on FPM provides a new and reliable way of investigating the comfort ratio of tall buildings quantifying vibration comfort and guiding structural comfort design.     

The wind‐induced response characteristics of atypical tall buildings

A tall building reacts sensitively to winds because the wind force increases according to the height and shape of the building. Various shapes of tall buildings and their aerodynamic characteristics have been studied extensively. For structural design and occupant comfort, the dynamic displacement of a tall building must be maintained within the criteria for acceptable levels of wind‐induced motion. An aerodynamically appropriate building shape needs to be selected at the design stage of a tall building. In this study, wind‐induced vibration responses were investigated, according to the criteria for maximum acceptable displacement and acceleration. Copyright © 2007 John Wiley & Sons, Ltd.     

高层建筑钢结构中的水箱制振技术

本文通过以往的试验分析,简单介绍了三种形式的水箱对高层建筑结构风振反应的制振基本原理,及制振效果和制振特点。并以厦门九州大厦钢结构第28特设置的制振水箱为例,通过对结构受控风振反应的计算分析,表明了水箱制振技术是高层建筑抵御风力作用的有效于段。     

Unified dynamic absorber design formulas for wind-induced vibration control of tall buildings

The objective of this paper is to establish some unified design formulas for various kinds of passive dynamic absorber for wind-induced vibration control of tall buildings. A total of five different passive dynamic absorbers (TMD, TLCD, LCVA, C-TLD and R-TLD) are considered in this study. Firstly, unified equations of motion for the building–absorber system under wind-induced excitation are presented. A set of unified formulas for the optimal properties and the equivalent damping ratios for these five dynamic absorbers are then derived analytically. The Shanghai Central Plaza, which is a thirty-nine-story reinforced-concrete building, is used as an example to demonstrate the procedure and to verify the accuracy of the unified approach. The results show that these unified formulas provide direct performance evaluation and comparison between the five dynamic absorbers for the control of wind-induced vibration of tall buildings. © 1998 John Wiley & Sons, Ltd.     

考虑二阶振型的高层建筑顺风向风振响应简化计算

为评估高层建筑风振的舒适度,应建立简单实用的结构风振响应计算方法。而我国GB 50009—2012《建筑结构荷载规范》的高层建筑顺风向风振响应简化计算方法没有考虑二阶振型的贡献。基于准定常理论,采用频域法进行了考虑二阶振型贡献的高层建筑顺风向风致响应评估,并分析了二阶振型对结构风致响应的贡献。结果表明：二阶振型对高层建筑顺风向动力位移响应的贡献一般在2%以内,但对顺风向动力加速度响应的贡献最大能达到18%。在评估结构顺风向风振加速度响应时,二阶振型的贡献不能忽略。在此基础上,推导了考虑二阶振型的对称等截面高层建筑顺风向风振响应简化计算方法。将此简化方法得到的结果与频域法和规范公式得到的结果进行对比,其误差在5%以内,表明简化公式具有较好的精度和适用性。     

高层建筑钢结构基于风振响应和动力特性的优化设计

高层建筑的风致响应和等效静力荷载虽然可以通过风洞试验和动力分析有效的加以确定,在结构设计的整个过程中这些等效风力却往往被当作常数来应用。本文提出了一个结合气动风力分析和结构刚度优化的自动化技术。在结构设计中利用这个技术,可以在优化结构刚度和最小化结构造价的同时,实时检查和更新作用在建筑结构上的等效风荷载。一个几何尺度与航空研究共同顾问理事会(CAARC)建议的建筑模型一致的钢框架结构被用来进行风力分析和结构优化的例子。结果表明这个技术不但能在满足位移设计要求的情况下优化结构刚度降低造价,而且也降低了作用在结构上的等效风力。     

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。     

Sopite syndrome in wind-excited buildings: productivity and wellbeing impacts

Tall buildings vibrate in response to strong winds at frequencies below 1?Hz, which can cause motion sickness and sopite syndrome in humans. Sopite syndrome is characterized by sleepiness, low motivation and low mood that can reduce productivity in office workers. This paper uses recent multidisciplinary research to estimate the cost of building motion on organizations in tall buildings, and provides a framework for future research. The potential costs of wind-induced building motion to organizations are highly variable, depending on the local weather climate, but are likely to be significant in the long-term. It is argued that wind-induced building motion is a negative externality, a cost of inadequate design passed to building users. A three-factor approach towards reducing adverse impacts of wind-induced building motion is discussed: (1) further research investigating the characteristics of motion that provoke sopite syndrome, (2) create a new generation of serviceability criteria, and (3) regulations setting the maximum acceptable motion dose for office workers. This three-factor approach will likely produce comprehensive, yet usable, guidelines to develop strategies that reduce the adverse effects of motion on occupants in both new and existing buildings.     

基于风洞试验的超高层建筑结构风振时程分析

目前超高层建筑结构风振分析常采用的是规范的简化理论方法和基于风洞试验方法频域方法．随着结构体型的复杂化或周边建筑对风场有明显干扰时，进行结构风振时程分析是更为简单直接有效的方法。本文通过编程实现生成风洞试验中风荷载时程数据并导入有限元分析软件进行结构的时程分析，获得整体结构位移、内力以及加速度时程等重要数据，为规范方法不适用的超高层建筑结构风振响应分析及舒适度评估提供了可行的方法。     

调频减振系统和黏滞阻尼系统在超高层结构中风振控制性能的对比研究

超高层建筑中常用的风振控制措施主要包括调频减振系统和黏滞阻尼系统。系统地阐述了两种方案的基本原理、工程适用性以及参数取值,并结合实际项目较为全面地对比了其抗风性能。虽然调频减振系统在建筑功能的适应度上和施工可实施性上都存在一定的不足,但作为结构风振控制措施仍不失为一种可取方案。黏滞阻尼系统不但可以提升结构在风荷载下的舒适度,还能提升结构在风荷载和地震作用下的刚度和强度,适应了结构应对不同抗风设防水准的性能需求。结合高效的连接形式,黏滞阻尼系统是一种适用于高层、超高层建筑抗风的高性能且经济的减振控制措施。     

高层建筑风致振动控制的研究

随着高层以及超高层建筑结构不断向更高和更柔的方向发展,强风作用下这类建筑的传统设计方法有时已经无法完全满足结构的抗风设计要求。因此,提出了采用振动控制来抑制结构风致振动控制的新方法。论文首先概述了高层建筑中风振控制的方法及其国内外的研究现状,然后对其中的调谐质量阻尼器(TMD)、主动调谐质量阻尼器(ATMD),以及摩擦阻尼器这3种控制方法详加评述,最后进一步指出我国风振控制研究的发展方向。     

Case study of the dynamic response of a medium-height building to wind-gust loading

Increasing attention has been paid in recent years to the criterion of perception by the occupants of tall buildings of motion caused by high winds. Attention has, however, been focused on very tall buildings, predominantly in North America. This paper presents the results of observations of wind-induced motion of a building of relatively modest size, and of accompanying studies including the use of a mechanical shaker.

The investigation confirmed that perceptible motions were to be expected rather frequently, although the building in question was found to have rather better than average values of the relevant dynamic structural properties. A conventional stochastoc model of excitation by gusts appeared to be adequate for prediction to the relatively coarse precision which is acceptable for this purpose. The high response levels were primarily a result of the exposure of the site. The implications for designers are discussed.     

Smart building management vs. intuitive human control—Lessons learnt from an office building in Hungary

Smart building management and control are adopted nowadays to achieve zero-net energy use in buildings. However, without considering the human dimension, technologies alone do not necessarily guarantee high performance in buildings. An office building was designed and built according to state-of-the-art design and energy management principles in 2008. Despite the expectations of high performance, the owner was facing high utility bills and low user comfort in the building located in Budapest, Hungary. The objective of the project was to evaluate the energy performance and comfort indices of the building, to identify the causes of malfunction and to elaborate a comprehensive energy concept. Firstly, current building conditions and operation parameters were evaluated. Our investigation found that the state-of-the-art building management system was in good conditions but it was operated by building operators and occupants who are not aware of the building management practice. The energy consumption patterns of the building were simulated with energy modelling software. The baseline model was calibrated to annual measured energy consumption, using actual occupant behaviour and presence, based on results of self-reported surveys, occupancy sensors and fan-coil usage data. Realistic occupant behaviour models can capture diversity of occupant behaviour and better represent the real energy use of the building. This way our findings and the effect of our proposed improvements could be more reliable. As part of our final comprehensive energy concept, we proposed intervention measures that would increase indoor thermal comfort and decrease energy consumption of the building. A parametric study was carried out to evaluate and quantify energy, comfort and return on investment of each measure. It was found that in the best case the building could save 23% of annual energy use. Future work includes the follow-up of: occupant reactions to intervention measures, the realized energy savings, the measurement of occupant satisfaction and behavioural changes.     

Life-cycle cost analysis and life-cycle assessment of the second-generation benchmark building subject to typhoon wind loads in Hong Kong

Tall buildings located in Hong Kong can suffer great damage caused by typhoon hazards throughout their lifetimes. In addition, the effect of wind hazards may be exacerbated due to increases in the typhoon intensity and frequency caused by the climate change effect. Therefore, developing a framework to evaluate and quantify the damage caused by wind hazards on tall buildings from the economic perspective is critical for engineers and building owners in designing a cost-effective tall building. In this study, an economic damage indicator, life-cycle cost, is measured by using a probabilistic method called life-cycle cost analysis (LCCA). Moreover, the building sector is one of the biggest contributors to greenhouse gas (GHG) emissions, and the environmental impact that may be generated in intervention activities after wind-induced damage occurs is analyzed. An environmental impact indicator, embodied carbon emission, is quantified by employing another probabilistic method called life-cycle assessment (LCA). Therefore, an integrated methodology combining the LCCA and LCA is proposed to evaluate potential damage costs and environmental impact caused by typhoon hazards on tall buildings.     

A comparison of the occupant comfort in a conventional high-rise office block and a contemporary environmentally-concerned building

A comparative study of the occupant comfort (neutral) in a conventional high-rise office block and a contemporary environmentally-concerned building for Sheffield UK climate conditions was carried out. A questionnaire was designed for occupants to rate their workplace environment in terms of the thermal, visual, acoustic and overall perception and satisfaction level. The basic physical parameters were measured at the same time, e.g. air temperature, humidity, illuminance and sound level. It is inferred that (1) There is a noticeable difference between the conventional building and environmentally-concerned building in terms of their thermal and visual environment. (2) A clear distinction of the occupant sensation and satisfaction level towards their thermal and visual environment is presented between these two buildings. (3) The effect of basic physical variables on the occupants’ perception and satisfaction level becomes less significant when minimal standards are attained. (4) The acoustic satisfaction level however, was not perceived differently by the occupants of the two building types.     

Simplified formulas for evaluation of wind-induced interference effects among three tall buildings

The base-bending moment (BBM) response and the mean BBM of grouped high-rise buildings are studied by a series of wind tunnel tests on typical tall building models using the high-frequency force balance technique. Interference excitations of two upwind buildings with various heights in different upwind terrains are considered. An effective method is proposed to represent the distribution of the envelope interference factor (EIF) among three tall buildings. The results show that two upstream buildings cause more adverse dynamic effects on the downstream building than a single upstream building does. Significant correlations are found in the distributions of the interference factors of different configurations and upwind terrains. Relevant regression equations are proposed to simplify the complexity of the multi-parameter wind-induced mean and dynamic interference effects among three tall buildings. Finally, an example of how to use the data provided in this paper and the proposed methodology is presented.     

Natural ventilation strategies for indoor thermal comfort in Mediterranean apartments

Natural ventilation strategies as effective low energy refurbishment solutions are identified within this research study, for an existing urban multi-storey apartment building in Athens, representative of over four-million Greek urban residential buildings. Retrofit strategies were evaluated using occupant comfort criteria and the existing ventilation strategy, for a single apartment using dynamic thermal simulations. These strategies included individual day and night ventilation, a wind-catcher and a dynamic façade. Suitable openings operation in response to environmental parameters provided sufficient day and night ventilation and occupant comfort. The inclusion of a wind-catcher yielded very little improvement to the ventilation performance. However, the combined operation of the wind-catcher and the dynamic façade delivered operative temperature reductions of up to 7 °C below the base-case strategy, and acceptable ventilation rates for up to 65% of the cooling period. The successful performance of the proposed strategies highlights their potential for reducing energy consumption and improving thermal comfort in a large number of buildings in hot climates.     

Dynamic characteristics and wind-induced response of two high-rise residential buildings during typhoons

Two high-rise residential buildings in Hong Kong, among the tallest in the world, were equipped to monitor their wind-induced dynamic response. The effects of typhoon Imbudo and typhoon Dujuan on the buildings are presented in detail. Upcrossing analyses performed on the acceleration data indicate the wind-induced response of the buildings during typhoons Imbudo and Dujuan follow a Gaussian distribution. Natural frequencies of vibration in two orthogonal translational and torsional directions are estimated by empirical, numerical, and experimental techniques. A comparison between these natural frequencies reveals that experimental values are higher than empirically or numerically predicted values. This finding suggests that tall, reinforced concrete (RC) buildings in Hong Kong are stiffer than similar buildings in other countries.     

Thermal comfort and workplace occupant satisfaction—Results of field studies in German low energy office buildings

The issues of comfort and workspace quality in buildings have gained much importance with the European “Energy Performance of Buildings Directive” of 2001. New energy efficient building concepts and technologies require a revision of comfort standards, which were developed for air-conditioned buildings only. Particularly, the question of recommendable upper indoor temperature limits needs further investigation. In addition, a broader approach to occupant satisfaction in buildings is necessary with respect to overall building performance.     

Wind-induced loading and dynamic responses of a row of tall buildings under strong interference

This paper studies wind-induced interference effects on a row of five square-plan tall buildings arranged in close proximity. Mean and fluctuating wind loads are measured on each building member and wind-induced dynamic responses of the building are estimated with the high-frequency force-balance technique. The modifications of building responses from interference over a practical range of reduced velocities are represented by an envelope interference factor. Wind tunnel experiments and response analysis are carried out under all possible angles of wind incidence, at four different building separation distances, and for two arrangement patterns of buildings in the row, that is the parallel and diamond patterns. It is found that building interference leads to amplified dynamic responses in many cases but reduction in responses also occurs at some wind incidence. For a building row of the parallel pattern, five distinct wind incidence sectors of different levels and mechanisms of interference effect can be identified. The largest values of envelope interference factors can reach 2.4 for the torsional responses. When the row of tall buildings is arranged in the diamond pattern, increase in wind excitation occurs at many wind angles due to a “wind catchment” effect. The interference factors have larger peak values, reaching 2.1 in the sway directions and above 4 in torsion. However, all large amplifications of building responses do not occur in the situations of peak resonant dynamic responses of the single isolated building. Thus, the design values of peak dynamic responses of a tall building are not significantly magnified when placed in a row.