Masayoshi Nakai

Aerodynamic Characteristics of Tall Building Models with Various Unconventional Configurations

Tall buildings have been traditionally designed to be symmetric rectangular, triangular or circular in plan, in order to avoid excessive seismic-induced torsional vibrations due to eccentricity, especially in seismic prone regions like Japan. However, recent tall building design has been released from the spell of compulsory symmetric shape design, and free-style design is increasing. This is mainly due to architects’ and structural designers’ challenging demands for novel and unconventional expressions. Development of computer aided analytical techniques and of vibration control techniques using auxiliary devices has also contributed to this trend. Another important aspect is that rather complicated sectional shapes are basically good with regard to aerodynamic properties for crosswind responses, which is a key issue in tall-building wind-resistant design. A series of wind tunnel tests have been carried out to determine wind forces and wind pressures acting on 31 tall building models with various configurations: square plan, rectangular plan, elliptic plan, with corner cut, with corner chamfered, tilted, tapered, inverse tapered, with setbacks, helical, openings and so on. Dynamic wind-induced response analyses of these models have also been conducted. The results of these tests have led to comprehensive discussions on the aerodynamic characteristics of various tall building configurations, and studies on corresponding optimal structural systems.

Fukuoka Dome, Japan

Fukuoka Dome, Japan’s largest stadium with a retractable roof, is a multi-purpose facility which can be used for baseball and other sports, concerts, exhibitions, and trade shows, with equal effici...

Prada Boutique Aoyama, Japan

For the outer lattice of PRADA Boutique Aoyama, the aim was to create a design that was both symbolic and revolutionary, befitting the building’s role as a flagship PRADA Boutique. As shown in (Fig. 1), the building comprises a diagonal latticework frame with a façade consisting of rhombus-shaped units measuring approximately 3,2 m in width and 2,0 m in height, covered by a sash of flat and curved glass surfaces. The basic shape of the aboveground floors in plan view is a pentagon, with each side measuring approximately 10 to 22 m (Fig. 2). Each of the five vertical sides is set back at the top, so the plan view shape is gradually reduced at the 6th and 7th floors (Fig. 3). Floors 1 through 4 are for retail, floors 5 and 6 are offices, and the 7th floor houses the machine room.The B1F belowground floor, measuring approximately 33 m by 23 m, is almost perfectly rectangular in plan view, following the shape of the site. It is used both as a storeroom and as a continuation of retail space from the aboveground floors.

Structural design of Kaohsiung Stadium, Taiwan

Abstract This paper presents an outline description of the structural design of the main stadium for the World Games held in Kaohsiung City, Taiwan, in 2009. Three new design concepts, unseen in previous stadiums, were proposed and realized: “an open stadium”, “an urban park”, and “a spiral continuous form”. Based on the open stadium concept, simple cantilever trusses in the roof structure were arranged in a delicate rhythm, and a so-called oscillating hoop of steel tubes was wound around the top and bottom surfaces of a group of cantilever trusses to form a continuous spiral form. Also, at the same time by clearly grouping the structural elements of the roof structure, the dramatic effect of the urban park was highlighted by unifying the landscape and the spectator seating area to form the stadium facade. This paper specifically reports on the overview of the building, concepts of structural design, structural analysis of the roof, roof design, foundation design, and an outline of the construction.