Wind Environment Around Tall Buildings

Tall buildings can deflect wind down towards the ground, producing unpleasantly high speeds in pedestrian areas. Studies at model-scale in wind tunnels and at full-scale around existing buildings have made it possible to estimate the ratios of these speeds to the free, undisturbed wind speed at critical positions for common layouts and shapes of buildings. It is suggested that a design should aim to keep the mean wind speed at pedestrian level below 5 m/s for as much of the time as possible. Some examples of wind speed ratios are given and the likely occurrence of wind speeds greater than 5 m/s is estimated for particular sites. Remedies used to eliminate high wind speeds from pedestrian areas near to tall buildings are described. Situations are specified under which high priority should be given to the wind environment in the planning of redevelopment schemes. Designs that help to protect pedestrian areas from the downflow from tall buildings are outlined.

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Since the 1960s, wind tunnel testing has become a commonly used tool in the design of tall buildings. It was pioneered, in large part, during the design of the World Trade Center Towers in New York. Since those early days of wind engineering, wind tunnel testing techniques have developed in sophistication, but these techniques are not widely understood by the designers using the results. As a direct result, the CTBUH Wind Engineering Working Group was formed to develop a concise guide for the non-specialist. The primary goal of this guide is to provide an overview of the wind tunnel testing process for design professionals. This knowledge allows readers to ask the correct questions of their wind engineering consultants throughout the design process. This is not an in-depth guide to the technical intricacies of wind tunnel testing, it focusses instead on the information the design community needs, including: a unique methodology for the presentation of wind tunnel results to allow straightforward comparison of results from different wind tunnel laboratories. advice on when a tall building is likely to be sufficiently sensitive to wind effects to benefit from a wind tunnel test background for assessing whether design codes and standards are applicable details of the types of tests that are commonly conducted descriptions of the fundamentals of wind climate and the interaction of wind and tall buildings This unique book is an essential guide for all designers of tall buildings, and anyone else interested in the process of wind tunnel testing for tall buildings.

This state-of-the-art report describes various facets of the human response to wind-induced motion in tall buildings and identifies design strategies to mitigate the effects of such motion on building occupants.

This book is highly suitable for advanced courses as it introduces state-of-the-art information and the latest research results on diverse problems in the environmental wind engineering field. The topics include indoor natural ventilation, pedestrian wind environment, pollutant dispersion, urban heat island phenomena, urban ventilation, indoor/outdoor thermal comfort, and experimental/numerical techniques to analyze those issues. Winds have a great influence on the outdoor environment, especially in urban areas. Problems that they cause can be attributed to either strong wind or weak wind issues. Strong winds around high-rise buildings can bring about unpleasant, and in some cases dangerous, situations for people in the outdoor environment. On the other hand, weak wind conditions can also cause problems such as air pollution and heat island phenomena in urban areas. Winds enhance urban ventilation and reduce those problems. They also enhance natural ventilation in buildings, which can reduce the energy consumption of mechanical ventilation fans and air conditioners for cooling. Moderate winds improve human thermal comfort in both indoor and outdoor environments in summer. Environmental wind engineering associated with wind tunnel experiments and numerical analysis can contribute to solutions to these issues.