With recent demand increase of high-rise buildings, crowing of these has been realized within the downtown. Urban crowing lowers the penetration of wind into the downtown and worsens air circulation. In addition, inflowed wind into the downtown makes a variety of building winds causing the users’ inconvenience.
To lower this climate disaster, the methods to develop ‘wind way’ which facilitates the air flow using building allocation or open space in the downtown have been suggested. To utilize pilotis which is one of the using open spaces can increase the wind speed by facilitating air flow. Increased wind speed makes the ventilation effect higher to decline the level of air pollution so as to provide the users with pleasant environment upon improving wind environment surrounding buildings with flowing the stagnant air flow. Hence, installations of open public spaces for large scale buildings are mandatory in the Korean regulations on the constructions, which induces to secure open public spaces using by pilotis.
However, pilotis has not only benefits. Pilotis wind, one of building winds, generates gust by sudden wind inflow inside pilotis due to ‘Venturi effect.’ Pilotis are used actively in Korea, while not many wind-resistant designs were prepared for exteriors against gust generated by pilotis inside. Especially, pilotis has been used in a variety of spaces to generate the floating population, when casualties and users’ inconveniences are occurred by detachments of exteriors due to strong wind. To prevent detachments of exterior materials inside pilotis, the studies are required on the characteristics of air flow inside pilotis due to building wind.
Most of the existing studies were related to the characteristics or wind speed of air flow inside pilotis and their methods relied mainly on CFD analysis. In addition, excellent case studies and exterior performance tests were performed in overseas while few were conducted in Korea.
Wind tunnel test was performed upon selecting 3 types of pilotis and total 18 models each according to the heights of pilotis and buildings. Characteristics of wind pressure coefficient distribution generated inside pilotis were confirmed by investigating the effects of wind direction according to the types of pilotis.
As the height to width ratio of a building increases, the peak wind pressure coefficient increases. Also, as piloti height increases, positive pressure increases. maximum peak wind pressure coefficient appears wind direction with larger contact surface. conversely, minimum peak wind pressure coefficient occurs smaller contact surface. therefore, Design of exterior for buildings requires that take account of wind direction and piloti type, height and the surroundings environment of building.