范路/FAN Lu

作者單位：清華大學建筑學院/《世界建筑》

欄桿是最基本的建筑構件之一，也是具有豐富內(nèi)涵的建筑要素。而為了充分理解欄桿的多重內(nèi)涵及其在建筑設計中的意義，我們可以簡要考察其在英文中的名稱、釋義和詞源。

欄桿（闌干），也常稱作扶手和護欄，對應的英文則有“railing”“handrail”“balustrade”“baluster”“banister”和“parapet”1）。欄桿最直白的翻譯應該是railing，意指由桿件構成的護欄。其詞根rail大約在14世紀初，由古法語和民間拉丁語傳入英語，意指直桿。這充分體現(xiàn)了欄桿最簡單質(zhì)樸的形態(tài)。到了19世紀，隨著工業(yè)革命的到來，rail多了鐵軌和纖細的含義，railing也就更多指向現(xiàn)代建筑中由水平豎直的金屬細桿構成的欄桿。顧名思義，雖然扶手handrail常常等同于欄桿，但更強調(diào)其中的水平橫桿，及其對人手和身體的支撐。與railing的簡單直白形成對比，欄桿的另一組譯名baluster和balustrade則更具有古典的形式風格意味。欄桿柱baluster詞根最早則可以追溯到希臘語，意指野生石榴花。而到了17世紀初，該詞從法語和意大利語傳入英語，則用來表示具有石榴花萼曲線或里拉琴身曲線的、支撐橫桿的立柱。而balustrade則是由成排或一系列的baluster構成的樓梯或陽臺護欄。對形式風格的強調(diào)還產(chǎn)生了“欄桿柱式”，常采用古典柱式的微縮處理。還有一個近似的詞是banister，從17世紀下半葉到18世紀上半葉，常用來指稱設計粗俗的欄桿立柱。最后一個詞護欄parapet是16世紀末從中古法語或意大利語和拉丁語傳入英語，它最初是指城堡和城墻上具有防御性的矮墻和屏障，后來也指稱陽臺、橋梁、屋頂、平臺等處的護欄。

通過上述概念辨析，我們可以將欄桿設計的特色大致分為4類，而這也是本專輯案例選取的參考依據(jù)。

第一類，強調(diào)欄桿自身的材料和幾何構成。其中，純桿件和純墻體可算是這一類的兩極。然而這兩極在具體設計中又可以相互結合、相互轉(zhuǎn)化。例如貝聿銘建筑中常出現(xiàn)的在樓梯一側墻面上挖出凹槽的扶手處理，便可看作是墻體與虛體桿件的整合。在耐克MSK盒項目中，鋼框架不僅充當欄桿，更延伸為活動平臺的圍墻。而在丹麥海事博物館建筑中，玻璃護欄采用無框無柱處理。高透明度的玻璃板如同墻體一樣，既是圍護構件又發(fā)揮結構作用。遠遠望去，仿佛僅剩一根橫桿漂浮在空中。

第二類，突出欄桿與其他建筑構件的關系，并表現(xiàn)整體設計意圖。在建筑中，欄桿并不會單獨存在，它勢必與其他構件相結合，形成樓梯扶手、平臺護欄、門窗把手等大量形態(tài)獨特的建筑部件。而對此精心設計便會產(chǎn)生某種詩意，強化整體建筑秩序——前面提到的欄桿柱式便是很好的例證。而在現(xiàn)代建筑史中，盡管菲利普·約翰遜的玻璃自宅占得首次發(fā)布的先機，但玻璃墻上的護欄扶手卻使其成為一座“普通建筑”。反觀密斯·凡·德羅設計的范斯沃斯住宅，卻憑借超越重力的清晰建構和無欄桿的玻璃外墻，成為一個純粹的哲學性結構和范式經(jīng)典。而在當代的加爾西穆尼奧斯城堡改造項目中，加建的欄桿、天橋、隔柵等鋼和玻璃構件，與石材砌筑的城堡遺址交織在一起，共同形成了延續(xù)加泰羅尼亞文化氣質(zhì)的藝術空間。

第三類欄桿的設計特色是暗示內(nèi)外空間關系，參與建筑對地形與城市界面的定義。在空間中，欄桿是一種弱隔斷。它一方面提供防護，阻擋繼續(xù)前行以避免危險；另一方面它又讓視線越過，暗示空間和行為的可能性。同時，欄桿作為一種豎向構件，會成為樓板、墻體或立面的一部分，塑造建筑的對外姿態(tài)。在金牛山森林步道項目中，“懸浮”的步道隨地形起伏，避免破壞山體植被。而步道護欄采用豎向隔柵樣式，強調(diào)通透性以及與山林樹木的視覺融合。而對于挪威國家歌劇與芭蕾舞劇院項目，護欄的設計卻是強調(diào)水平延伸。其室外斜坡與護欄墻體沒有直接相交，而是留出下沉的凹槽。這些凹槽作為階梯或坡道，在邊緣形成了快捷路線。同時這也削弱了護欄圍墻的豎向尺度，帶來斜坡可以向四周延伸出去的意向。

還有一類欄桿，其特色則突顯了欄桿與人身體、行為、記憶以及與情感的關系。欄桿扶手是充分體現(xiàn)人體尺度的建筑構件。它誘惑人在建筑中行進，促進建筑流線的形成。它還激發(fā)人的觸覺體驗和想象，塑造使用者的身體姿態(tài)，如中國傳統(tǒng)建筑中的“美人靠”。更進一層，就像米開朗基羅在西斯廷天頂畫中用手指的輕觸來象征賦予人類靈魂，用手握住扶手也有可能隱喻進入物質(zhì)空間之外的記憶與情感世界。當然也有表達反向意圖的設計。在法國國家圖書館項目中，建筑師變換了3種護欄樣式——極少桿件式的、T型鋼構的和高墻式的。但這些非常規(guī)的處理，都是要弱化欄桿的人體尺度特征，以超尺度的方式突出圖書館的紀念性。

上述4類劃分只是出于認識上的簡便，而在欄桿設計中，建筑師常常會有多重考慮，護欄也會具有多重涵義。例如在李&鄭住宅項目中，新置入的白色鋼架結構既是護欄扶手，也是連接樓板、讓綠植、光線和視線穿透的墻體。它還充當“懸空而透明”的看臺，并成為立面上頗具吸引力的構成元素。

最后，需要表達一下致謝。感謝李路珂、青鋒和古斯塔夫·安布羅西尼3位學者為本期撰寫主題文章。還需要感謝以下各位建筑師和學者——胡越、五十嵐太郎、龍灝、柳亦春、曹曉昕、葛明、胡恒、唐芃、魯安東、劉亦師、張昕楠，正是他們對于諸多精彩案例的介紹和點評，才使本期專輯得以完成?！?/p>

注釋

1）對于欄桿在英文中的名稱、釋義和詞源的辨析，綜合參考了以下資料來源：《朗文當代高級英語辭典》《柯林斯英漢雙解大詞典》《牛津建筑與景觀詞典》和EtymOnline。

The railing is one of the most fundamental architectural components and has rich meanings. To understand sufficiently those multiple meanings in architectural design, we could make a brief review of the synonyms in English of railing, and their connotations and etymologies.

In English, railing is synonymous with handrail,balustrade, baluster, banister and parapet1), while the connotations of those words are of subtle difference. The railing is a fence made of bars, and its etyma, rail, was from old French and vulgar Latin in the beginning of the 14th century and meant bar or straight stick. In the 19th century, with the coming of Industrial Revolution,it was used figuratively for thinness and railroads. And then the railing usually referred to a fence with horizontal and upright metal bars which was applied in modern architecture. The handrail is frequently used instead of the railing, but it emphasises a little more about the long horizontal bar and its relationship with human hands and the support for peoples. The other two words, baluster and balustrade, are with more decorative implications.Baluster originated from Greek and came from French and Italian in the beginning of the 17th century. It means uprights with lyre-like double curves or shapes like the calyx tube of the pomegranate flower. The balustrade is a row or a series of balusters supporting a handrail of a stair or forming a type of parapet. And the balustrade order or the orders of balustrade columns are the design with the miniature versions from the Classical orders. There is another similar word, banister, which was often used to indicate the corruptive and vulgar baluster from the first half of the 17th century to the second half of the 18th century. The last word to be discussed is parapet which in the end of the 16th century came from Middle French or directly from Italian and Latin. It originally means a low wall or barriers at the top edge of defensive buildings such as castles and town-walls, but later it also implies a low wall along the edge of a balcony, a bridge, roofs, a terrace,etc.

Through the connotational analysis above, we could roughly recognise four categories of features in architectural railing design. And those are also the reference standard for us to select projects in this special issue.

The first category emphasises materials and geometrical composition of the railing itself.Constructions of pure bars or low walls are the two extremes in this category. While in specific designs, the bar style and the wall style could be integrated or mutual transformed, such as the railing disposition usually found in I.M. Pei's buildings could be regarded as the combination of wall and void bar.

The second category highlights the relationship between the railing and other architectural elements,and between railing design and the expression of overall intention. In the Farnsworth House designed by Mies Van der Rohe, railings are deliberately removed from the glass walls, which intensify the idea that it should appear as a philosophical structure.

In the third category, railings located in roof terrace,entrance and exterior space of a construction play an important role in connecting inside and outside and in architectural definition of the topography or urban interface. As in the project of Jin Niu Shan Trans-Urban Connector, "floating" walkways undulate with the mountain landform, and grating plates are used as walkway parapets which brings about a sense of visual fusion of walkways and mountain forest.

Furthermore, in the fourth category, the handrail has a close relationship with users' subjective feelings.It brings about tactile experience and imagination for users, shaping their body gestures, and promotes the formation of circulation by tempting users to walk through a building. The "Meirenkao" in traditional Chinese garden pavilions – railing with the curves echoing the beauty's resting-gesture, are typical of this kind.Generally speaking, the classification is made just for epistemological purpose, while in practical design, railings are considered to be with multi-category connotations.

Finally, we would like to appreciate the help of many scholars and architects. Without their contributions,this issue wouldn't come out. We'd like to thank LI Luke,QING Feng, Gustavo Ambrosini, who wrote articles specially for this issue. We'd also like to thank HU Yue,Igarashi Taro, LONG Hao, LIU Yichun, CAO Xiaoxin,GE Ming, HU Heng, TANG Peng, LU Andong, LIU Yishi,ZHANG Xinnan, who made enlightening reviews of railing design.□