Typhoon effects on the Center in Hong Kong
Abstract: This paper presents selected results of wind characteristics and structural responses measured from the Center (350 m high, 79 floors) in Hong Kong, during the passages of three typhoons. The field data such as wind speed, wind direction and acceleration responses, etc., were continuously measured from the super-tall buildings during the typhoons. The simultaneously measured wind-induced acceleration was adopted to evaluate the dynamic characteristic and wind effect on this super tall building. The damping ratio with amplitude-dependent behavior was found by the random decrement method, and the serviceability performance level for different return period was estimated for this tall building. Furthermore, the full-scale measurements were compared with wind tunnel results to evaluate the accuracy of the model test results and the adequacy of the techniques used in the wind tunnel tests. The research output is expected to be of considerable interest and practical use to professionals and researchers involved in the design of super-tall buildings. Keywords: Wind effect; Tall building; Field measurements; Wind tunnel test;
In the present day we are experiencing an unprecedented level of activity in the design and construction of super-tall buildings. Many super-tall buildings (building height >300 m) have been or are being built throughout the world. As a consequence, the sensitivity of modern tall buildings to dynamic excitation by wind has increased. This has resulted in a greater emphasis on understanding the structural behavior of modern tall buildings under strong wind actions. Although there have been many advances in wind tunnel testing and numerical simulation techniques for investigating wind effects on buildings and structures, there are still many critical phenomena which can only be investigated by full-scale experiments. With the development of data acquisition techniques during the last three decades, a number of full-scale measurements of wind effects on tall buildings have been made throughout the world, including the measurement programs on three Chicago tall buildings undertaken by Notre Dame University and on several super-tall buildings in Hong Kong and mainland China. However, it has been widely recognized in wind engineering community that the chance to conduct full-scale measurements is quite rare, and obtained data are very important and valuable. This paper presents some selected field measurement results of wind effects on The Center (350 m high, 79 floors) in Hong Kong. The Center is located in the central districts of Hong Kong Island, which has an approximately square plan form, is a steel structure. The Center is situated very close to the coast in a typhoon-prone region, and as such the super-tall building may be subjected to severe wind forces under typhoon conditions. Hong Kong, located in the southeast coastal region of China which is one of the regions most seriously impacted by typhoons in the world, are idea test beds for investigating typhoon effects on super-tall buildings. Determination of structural dynamic characteristics is necessary in the design of tall buildings, since natural frequencies, mode shapes and damping ratios are basic data for wind or seismic-induced response analysis. Several analytical and numerical methods are available for evaluating the natural frequencies and mode shapes of a structure in design stage. It has been recognized that damping is a nonlinear parameter, and may increase with increasing amplitude. However, literature review reveals that the information on amplitude-dependent damping contained in the literature mostly concerns normal tall buildings in the vicinity of 40 stories or shorter. In this study, the amplitude-dependent damping ratios of the four super-tall buildings are determined by the random decrement technique based on the measurements of wind-induced responses....
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