建筑及结构工程师：Daiichi-Kobe事务所，Fujita公司
Architects and Structural Engineers:Daiichi-KobeAssociates,Fujita Corporation
空间构成的基本构想是用一个直径 125m的圆顶覆盖中心场地，并用不规则的结构覆盖周边自由安排的其他设施。这一构想否定了用一个大结构覆盖整个空间的设想，代之以许多适应内部空间形状的框架，然后使它们成为一个整体，形成一个室内运动场——“一个先进技术与创新观念的完美结合”、“一座利用自然能源的节能建筑”。为此，在设计的早期阶段就决定给予该建筑一个地球上浮云的形象。
为实现这个形象，决定在场地中央建造巨大的圆形双层充气膜结构屋顶，不规则的周边部分则用单层框架膜结构覆盖，全部室内空间保持正常压力。因为仅仅屋顶是充气膜结构，所以门窗可自由安排。为保持双层充气膜的厚度和形状。在屋顶中央部位设计了一个简单的锥台状框架，构成充气屋顶的中心环，这也使屋顶中央开口成为可能，对自然通风和采光极为有利。同时在声学上也是有效的。因为开口赋予天花表面一个自然的凸圆面形状，这就将声音朝四周分散，有效地降低了反射波。
双层充气膜形成了一个直径107m的、以锥台状框架为中央支撑的“浮云”。在中央的锥台状框架与外围的环形桁架之间，上、下各有48根辐射状的素相连。以带PTEE涂层的玻纤膜覆盖骨架和索，同时，双层膜间充气达30mm汞柱的气压（正常情况下）。这个庞大的外径125m的碟状屋顶被支撑在沿环形桁架的8个点上，每个点由“3—柱”型的组合柱支撑。由于充气膜有索支撑，即使跑气也不会有坠落损害的危险，从预防灾害及撤离的角度看，这种布置也是有利的。这种结构系统被称作“混合充气膜结构”，因为它结合了轮式索结构和充气结构的优点。这个工程是此种结构形式在世界上首次应用。
覆盖不规则周边部分的单层膜顶形成了一个简单的格构架结构——用直径350mm的球节点将钢管装配成网格。
建造圆屋顶花了大约20个月。建造主体结构的顺序如下：首先，同时立起8根组合柱；环形桁架及锥台状中心环在低位装配；连接上索和膜；连接下索和膜；往膜内注入空气；在环形桁架上安窗框和玻璃（重量大约2400t）；充气膜整体提升至 19m高度。在此过程中，“3—柱”组合柱的内柱充当导轨。最后，环形桁架和周边钢筋混凝土结构间连上不规则的单层膜顶。
西侧全景
双层充气膜上部
The basic idea in the organization of space was to cover the central field with a circle with a diameter of 125m, freely arrange the other facilities on the periphery an cover those facilities with an irregular form, Instead of enveloping the entire domed space with one large structure ,the idea was to create a number of frameworks, each adapted to the shape of an internal space and then integrate them. This was to be “an indoor playground”, “a work of originality that combines advanced technology and the latest thinking” and “an energy saving facility that, for example, uses natural energy.” For these reasons, it was decided at a fairly early stage in the design process to give the building the image of a cloud floating above the earth.
To achieve this image, it was decided to make the large circular roof a double-layered air-inflated membrane structure and to cover the irregular peripheral portion with a single-layered membrane structure. All indoor spaces including the field are at normal pressure and doors and windows can be freely arranged because only the roof is a air-inflated membrane structure. A simple frame in the form of a truncated cone is introduced in the center to maintain the thickness and configuration of the double-layered air-inflated membrane. The arrangement is also effective acoustically, because the opening gives to the ceiling surface a naturally convex shape that scatters sound toward the periphery and reduces echoes.
The double-layered air-inflated membrane forming a “floating cloud” with a diameter of 107m was built by linking a framework in the shape of a truncated cone in the center and a ring truss with 48 upper radial cables and as many lower radial cables, covering them with PTEE coated glass fiber membrane and introducing air into the double-layered membrane to achieve an internal pressure of 300mmHG(in normal circumstances). This enormous disc-shaped roof with an outer diameter of 128m is held up at eight points along the ring truss by supports, each made up of three columns. Since the air-inflated membrane is supported by cables, no damage through contact will occur even in the case of deflation. The arrangement is also advantageous from the point of view of disaster prevention and evacuation. This structural system is called a “hybrid double-layered air-inflated structure” because it combines the merits of a wheel-type cable structure and a air inflated membrane structure , and the project is the first application of the system in the world.
The framework of the single layered membrane covering the irregular peripheral portion was made a simple lattice shell structure in which steel pipes are assembled in a grid using ball joints with a diameter of 350mm.
Construction of the dome took approximately 20 months. The procedure followed for constructing the main structure was as follows. First, simultaneously with the erection of the eight 3-column supports , the ring truss and the truncated cone shaped central ring were assembled in a low position where it was easy to work and were joined by upper cable and membranes. Next, the lower cables and membranes were attached to these cables and air was introduced inside. After sash and glass had been installed in the ring truss [weight: approximately 2400t], lift up to a height of 19m was carried out. The inner columns of the 3-clumn supports served as guides in this process. Finally, the irregular, single-layered membrane connecting the ring truss to the reinforced concrete canopy of the peripheral portion, on which work had been proceeding simultaneously, was constructed.
西侧鸟瞰
充气膜内部
东侧夜景
圆屋顶内景
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