LUNG LUNG DESIGN: 光學玻璃之屋／中村拓志　Optical Glass House／Hiroshi Nakamura

2015年12月7日星期一

光學玻璃之屋／中村拓志　Optical Glass House／Hiroshi Nakamura

這棟建築的選址位在廣島市中心的高層建築簇群中，沿街面有許多往來的車輛和輕軌電車。為了在這環境中獲得片刻的隱私和安靜，建築師把一個花園和光學玻璃的帷幕牆巧妙的安置在房子臨街面的一側。所有的房間都可以看到花園，以及往來的車輛與輕軌電車，無聲的風景賦予居家生活一種截然不同的寧靜。

陽光從房子的東邊透過玻璃折射在進入屋內，產生一片美麗的光景。雨水滴落在天窗，呈現出入口地板上波光粼粼的光與影。樹葉過濾了天光，閃爍在客廳的地板上，再濺射到金屬鍍膜的超輕量布幕，一起隨著風起舞。雖然這座房子座落在市中心，卻能讓住者享受不斷變化的光線和城市脈動，隨著四季變化而有著不同的景緻。

This house is sited among tall buildings in downtown Hiroshima, overlooking a street with many passing cars and trams. To obtain privacy and tranquility in these surroundings, we placed a garden and optical glass façade on the street side of the house. The garden is visible from all rooms, and the serene soundless scenery of the passing cars and trams imparts richness to life in the house.

Sunlight from the east, refracting through the glass, creates beautiful light patterns. Rain striking the water-basin skylight manifests water patterns on the entrance floor. Filtered light through the garden trees flickers on the living room floor, and a super lightweight curtain of sputter-coated metal dances in the wind. Although located downtown in a city, the house enables residents to enjoy the changing light and city moods, as the day passes, and live in awareness of the changing seasons.

光學玻璃幕牆
這棟建築的立面一共安置了大約 6,000 塊淨透的玻璃磚（尺寸為 50mm x 235mm × 50mm），這麼大面積的玻璃量體不僅有效地阻絕噪音，並同時創建出一個開放通透的花園，可一覽城市的風景。為了實現這樣的立面效果，玻璃磚的澆鑄應用了非常高透明性的硼矽酸鹽（硼珪酸ガラス），一種光學玻璃的原料。這種材料的鑄造是極其困難的，因為它需要兩階段緩慢冷卻才能除去殘留的應力，同時維持尺寸該有的精準度。

8.6m x 8.6ｍ如此巨大的外觀，使這些玻璃磚無法獨自堆疊站立，尤其玻璃磚的鋪排僅僅是 50mm 的深度。因此，建築師在細部設計上貫穿了玻璃磚，並以75不銹鋼螺栓串接起這些玻璃，形成一整面外牆帷幕。這樣結構的弱點在於側向的應力，因此建築師沿著玻璃磚，在 10cm 高度的間隔以不銹鋼扁桿（40mm × 4mm）作結構的加強。扁桿安置在 50mm 厚的玻璃磚內，並以一道道均質的 6mm 密封附蓋之間的接縫，做為玻璃磚之間的聯合。這些嘗試的結果，一堵透明的玻璃牆面不論從花園或是街上都可以清楚看見。這個建築物的立面看起來像是一道向下流動的瀑布，散射光線和空氣中滿滿的新鮮感。

Optical Glass Façade
A façade of some 6,000 pure-glass blocks (50mm x 235mm x 50mm) was employed. The pure-glass blocks, with their large mass-per-unit area, effectively shut out sound and enable the creation of an open, clearly articulated garden that admits the city scenery. To realize such a façade, glass casting was employed to produce glass of extremely high transparency from borosilicate, the raw material for optical glass. The casting process was exceedingly difficult, for it required both slow cooling to remove residual stress from within the glass, and high dimensional accuracy.

So large was the 8.6m x 8.6m façade, it could not stand independently if constructed by laying rows of glass blocks a mere 50mm deep. We therefore punctured the glass blocks with holes and strung them on 75 stainless steel bolts suspended from the beam above the façade. Such a structure would be vulnerable to lateral stress, however, so along with the glass blocks, we also strung on stainless steel flat bars (40mm x 4mm) at 10 centimeter intervals. The flat bar is seated within the 50mm-thick glass block to render it invisible, and thus a uniform 6mm sealing joint between the glass blocks was achieved. The result　—a transparent façade when seen from either the garden or the street. The façade appears like a waterfall flowing downward, scattering light and filling the air with freshness.