中國(guó)近期的步行橋設(shè)計(jì)：一種景觀學(xué)方法

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中國(guó)近期的步行橋設(shè)計(jì)：一種景觀學(xué)方法

“他們橋梁設(shè)計(jì)的多姿多彩與雄偉壯麗毫不遜于他們?cè)谄渌b飾設(shè)計(jì)方面的成就……其中一些平面呈弧線形或匍匐逶迤；還有一些則根據(jù)需要朝各個(gè)方向產(chǎn)生分支——有些筆直跨過(guò)河道，有些則位于河道或運(yùn)河交匯處，有些呈三角形、四邊形、圓形等不一而足；橋的各個(gè)轉(zhuǎn)角處都設(shè)有涼亭，中央設(shè)有水池，池中飾以大噴泉或各種其他類型的噴泉。”

—— 威廉·錢伯斯，《東方園林論》，1772

眾所周知，整個(gè)18世紀(jì)，在歐洲旅行家的報(bào)告中有諸多對(duì)于中國(guó)園林特色的描寫(xiě)，恰值當(dāng)時(shí)西方美學(xué)變化發(fā)展的時(shí)期，兩者交匯產(chǎn)生了豐富的成果，同時(shí)期還伴隨著英國(guó)景觀設(shè)計(jì)的革命?！暗?，園林只要采取了更適宜的風(fēng)格，就必定顯得更為自然，而無(wú)需模仿大自然的荒蠻景象；它們看起來(lái)新穎別致卻不流于造作，不同尋常又不過(guò)于夸張；園中景致不斷地吸引著觀賞者的注意，令人心曠神怡，不同的景色激發(fā)了人們的好奇心，并通過(guò)調(diào)動(dòng)各種對(duì)比的情緒讓人激動(dòng)不已；這些園林設(shè)計(jì)師必定具有強(qiáng)大的創(chuàng)造力、豐富的經(jīng)驗(yàn)和出色的判斷力；它們敏于感受、手法嫻熟、富于想象，并且熟稔人類所有的情感與喜好?！?/p>

今天，我們是否有可能拓展錢伯斯提出的“園林設(shè)計(jì)師”概念，把橋的設(shè)計(jì)者也涵蓋在內(nèi)？

本文研究的人行天橋設(shè)計(jì)涉及一些最近在中國(guó)建成的作品，橋的設(shè)計(jì)是一門與景觀學(xué)的自覺(jué)意識(shí)密切相關(guān)的學(xué)科——因此，這一研究范疇能讓我們暫時(shí)擺脫全球化進(jìn)程與傳統(tǒng)文化之間各類趨勢(shì)呈嚴(yán)重兩極分化的狀態(tài)，在其中找到替代性設(shè)計(jì)方法的發(fā)展空間[1]。

橋在中國(guó)古典園林中的象征意義與感受作用理所當(dāng)然地構(gòu)成了一個(gè)必要的參照點(diǎn)——即設(shè)計(jì)者意識(shí)到，橋本身并不僅僅是跨越障礙的通途，同時(shí)也是綜合的美學(xué)表達(dá)手段——它通過(guò)蜿蜒曲折或往復(fù)迂回的路徑帶領(lǐng)人們漸次發(fā)現(xiàn)一處處意外的景致。橋也常常是戲劇性效果中重要而生動(dòng)的組成部分——因?yàn)樗鼈兒苌俪手本€形布置，而常常延續(xù)了園林小徑原本左搖右擺的路線，或表現(xiàn)為高聳隆起的拱券，又或沿折線型在平面上展開(kāi)。它們限定了人們?cè)趫@中對(duì)水面的理解，又為欣賞花園中的美景提供了固定的觀賞點(diǎn)[2]。

除了繼承自古典園林的設(shè)計(jì)手法之外，我們也不妨提醒讀者另一種可供參考的中國(guó)傳統(tǒng)設(shè)計(jì)手法——即在中國(guó)許多地區(qū)發(fā)展形成的杰出的木構(gòu)屋頂橋梁遺產(chǎn)，在湖南、湖北、貴州、廣西、福建等地都有此類設(shè)計(jì)，橋的類型從建有若干座精致涼亭的所謂“風(fēng)雨廊橋”，到更簡(jiǎn)單的、僅用木檁條搭建而成的橋梁等等。它們都為人們提供了帶有遮蔽的空間，形成了可供會(huì)面的場(chǎng)所，成為具有紀(jì)念性意義的公共場(chǎng)所，是對(duì)農(nóng)村的街道和廣場(chǎng)空間的補(bǔ)充[3]。

然而，我們必須避免在今天簡(jiǎn)單地照搬過(guò)去的設(shè)計(jì)理念。似乎可以謹(jǐn)慎地認(rèn)為，形成某一時(shí)期、某個(gè)社會(huì)文化、政治和經(jīng)濟(jì)狀況的環(huán)境其實(shí)也表達(dá)了某種景觀的理念。在這個(gè)意義上，至關(guān)重要的是需要考慮到20世紀(jì)末、多學(xué)科的交叉融合對(duì)景觀的概念所產(chǎn)生的影響——人們由此認(rèn)為，必須把景觀理解為人類集體文化轉(zhuǎn)型的結(jié)果，即“景觀是歷史上某種人們體驗(yàn)周圍世界的方式，其周圍世界由某些社會(huì)族群發(fā)展形成、且對(duì)他們具有特殊意義”，并正如地理學(xué)家丹尼斯·科斯格羅夫所寫(xiě)，景觀是“一種由某些階層的族群以他們想象中與自然形成的關(guān)系來(lái)定義自身身份及其所在世界的方式”[4]。

這就是為什么像瑪麗·帕多瓦這樣的學(xué)者會(huì)認(rèn)為當(dāng)代中國(guó)新建公園的設(shè)計(jì)過(guò)程表現(xiàn)出“混雜的現(xiàn)代性”，這一概念借自阿爾君·阿帕杜萊等文化社會(huì)人類學(xué)家提出的混合敘事概念——“替代的”現(xiàn)代性。當(dāng)代中國(guó)園林設(shè)計(jì)融入傳統(tǒng)要素的方式被認(rèn)為是借鑒了不同的設(shè)計(jì)理念，并“通過(guò)象征性設(shè)計(jì)元素的形式將全球化、國(guó)家層面和本土的影響”交織在一起，由此產(chǎn)生了新的意義[5]。

目前，中國(guó)正密集推動(dòng)的城市化進(jìn)程已經(jīng)拓展了各類傳統(tǒng)設(shè)計(jì)專題的疆界，從古典園林作為自然界縮影的概念，到貫穿20世紀(jì)的大眾公園的概念，直到目前新的景觀概念——即人們可以生活在其中的景觀，如水岸、濕地、湖畔、生態(tài)恢復(fù)后的棕地等。當(dāng)今對(duì)各類土地利用方式進(jìn)行轉(zhuǎn)變的過(guò)程所產(chǎn)生的影響已經(jīng)遠(yuǎn)超園林設(shè)計(jì)的單一領(lǐng)域——如果說(shuō)住宅用地的快速增長(zhǎng)使人們生活水平得到改善的需求變得更為迫切，各類人行步道的建設(shè)也應(yīng)在中國(guó)各類以步行為主導(dǎo)的設(shè)計(jì)策略中獲得相應(yīng)的地位，以便在恢復(fù)曾被忽視的城市肌理、修復(fù)各種工業(yè)區(qū)、城市邊緣地區(qū)和自然空間等區(qū)域的過(guò)程中，尋求更為人性化的尺度。

在這個(gè)意義上，研究橋如何一直保持著園林中作為感知和象征核心手段的地位，探索設(shè)計(jì)師們?nèi)绾瓮ㄟ^(guò)優(yōu)美而富于戲劇性的環(huán)境促進(jìn)使用者對(duì)植物、水體及其他景觀要素的體驗(yàn)，是很有建設(shè)性的。

例如，荷蘭West 8城市規(guī)劃與景觀設(shè)計(jì)事務(wù)所（與多義景觀規(guī)劃設(shè)計(jì)事務(wù)所合作）的“萬(wàn)橋之園”項(xiàng)目的象征意象即與此吻合（圖1）。這個(gè)項(xiàng)目是2011年西安國(guó)際園藝博覽會(huì)的一部分，園中蜿蜒迂回的小徑引導(dǎo)參觀者穿過(guò)茂密如森林的竹園，地面只在5處地點(diǎn)有所抬高。人們爬上這5座半圓拱形的橋之后，在繼續(xù)沿拱橋下行之前，會(huì)驚喜地見(jiàn)到開(kāi)闊的景觀。這條小徑在人們游移不定與興高采烈的情緒之間產(chǎn)生的鮮明對(duì)比，有意識(shí)地象征了人生的軌跡。紅色混凝土光滑的表面在一片綠意盎然中脫穎而出，凸顯了橋作為表達(dá)情緒的媒介的原型作用。

在多義景觀事務(wù)所的許多項(xiàng)目中，一些人行天橋蜿蜒著跨過(guò)水面或濕地，形成了最為密集的路徑分布格局，營(yíng)造了生動(dòng)活潑的親水體系。北京中關(guān)村軟件園中央公園（2004年）的設(shè)計(jì)即是如此，園中相互交織的路徑圍繞著湖面分布，產(chǎn)生了連續(xù)不斷的空間形態(tài)變化，并以折線的方式穿過(guò)水面（ 圖2）。同樣，在無(wú)錫長(zhǎng)廣溪國(guó)家濕地公園（2011年）項(xiàng)目中，非直線形的步行道穿過(guò)幾片濕地，形成了真正的探索之路，讓人們能夠親身體驗(yàn)大自然鬼斧神工形成的各種水體形式與豐富的植被類型（圖3） 。

"Not are they less various and magnificent in their bridges than in their other decorations…Some of them are upon a curve or a serpentine plan; others branching out in various directions:some straight,and some at the conflux of rivers or canals,triangular,quadrilateral,and circular,as the situation requires; with pavilions at their angles,and basons of water in their centers,adorned with Jets d'eau,and fountains of many sorts"

——W.Chambers,A Dissertation on Oriental Gardening,1772

It is widely known that descriptions of Chinese gardens features from the reports of European travellers throughout the 18th century fruitfully met an ongoing development process in Western aesthetics,accompanying the English landscaping revolution."But wherever a better style is adopted and Gardens are to be natural,without resemblance to vulgar Nature; new without affectation,and extraordinary without extravagance; where the spectator is to be amused where his attention is constantly to be kept up,his curiosity excited,and his mind agitated by a great variety of opposite passions; these Gardeners must be men of genius,experience and judgement; quick in perception,rich in expedients,fertile in imagination,and thoroughly versed in all the affections of the human mind".

Is it possible,today,to widen Chambers' term "Gardener" in order to include bridge designers?

Footbridge design is here investigated with reference to recent realizations in China,as a discipline strongly related to landscape consciousness:a field of investigation that allows to leave behind a rigid polarization among the opposite tendencies of globalization/tradition and to make room for an alternative approach[1].

The bridge's symbolic and perceptive role in Chinese historical gardens constitutes–of course–a necessary reference point:the awareness that a bridge itself shouldn't be just a tool for crossing an obstacle,but part of a comprehensive aesthetic expression that makes people gradually discover a series of unexpected sceneries,by following twisting and meandering lines.Bridges are very often vivid components of the drama:as they are rarely straight,they continue the winding concept of the path,rising to high arches or following zigzag lines.They establish how water must be perceived and provide defined viewpoints of the garden[2].

1　西安國(guó)際園藝博覽會(huì)“萬(wàn)橋之園”/Garden of 10,000　Bridges,Xi'an International Horticulture Exhibition（圖片版權(quán)/Photo courtesy:?West 8）

2　北京中關(guān)村軟件園中央公園/Central Garden of Zhongguancun Software Park,Beijing

3　無(wú)錫長(zhǎng)廣溪國(guó)家濕地公園/Changguangxi Wetland Park,Wuxi（2,3圖片版權(quán)/2,3　Photo courtesy:?多義景觀/Atelier DYJG）

Besides the garden design legacy,it is possible to remind of another important reference in Chinese tradition:the remarkable heritage of the covered wooden bridges developed in many provinces such as Hunan,Hubei,Guizhou,Guangxi,and Fujian,from the so-called "Wind and Rain Bridges" with several exquisite pavilions to simpler woven timberframed bridges.They all offer people a shelter and a place to meet in,providing monumental public places which are complementary to village streets and squares[3].

But it is necessary to avoid the simple transplantation of concepts from the past to nowadays.It appears appropriate to carefully consider the cultural,political and economic circumstances from which a certain society,in a certain age,has expressed an idea of landscape.In this sense,it is fundamental to take into account the convergence of many disciplines,at the end of the 20th century,on the meaning of landscape:a point of view that necessarily conceives the landscape as a product of collective human transformation of nature,a "historically specific way of experiencing the world developed by,and meaningful to,certain social groups",in the words of geographer Denis Cosgrove,"a way in which certain classes of people have signified themselves and their world through their imagined relationship with nature"[4].

This is why scholars like Mary Padua look at the process of creation of new parks in contemporary China as a sphere revealing a "hybrid modernity",borrowing the conception of hybrid narrative of "alternative" modernities from social-cultural anthropologists such as Arjun Appadurai and others.The incorporation of design elements from tradition into contemporary Chinese gardens is seen as a set of references able to intertwine "global,national and local influences in the form of symbolic design elements" and produce a new meaning[5].

The ongoing intense urbanization process in China has been widening the boundaries of traditional design themes,from the concept of the classical garden–as a microcosm of the natural world–through the 20th-century's public park concept,to new landscapes to be lived,such as riverbanks,wetlands,lakeshores,recovered brownfields etc.Today territorial transformations oblige designers to go far beyond the unique field of garden design:if the quick growing of settlements makes even more urgent the need to improve living conditions,the construction of new footbridges should gain a relevant status in pedestrian-oriented strategies in China,in search for a more human scale in the recovery processes for neglected urban fabrics,industrial areas,marginal zones,and natural spaces.

In this sense it would be productive to investigate how bridges quite often keep on playing a central role as perceptive and iconic tools,exploring the way many designers drive users' experience of vegetation,of water and of the various elements through scenic and dynamic settings.

This is a status to which refers,for instance,the symbolic image of the "Garden of 10,000 bridges"

當(dāng)一座廢棄工廠需要轉(zhuǎn)變?yōu)閳@林景觀時(shí)，如何進(jìn)入和如何穿越場(chǎng)地永遠(yuǎn)都是設(shè)計(jì)策略的關(guān)鍵所在。由北京清華同衡規(guī)劃設(shè)計(jì)研究院有限公司和清華大學(xué)建筑學(xué)院（建筑師朱育帆、姚玉君、孟凡玉）設(shè)計(jì)的上海辰山植物園的礦坑花園就是一個(gè)令人印象頗為深刻的案例。包裹在銹蝕鋼板中的陡峭臺(tái)階作為頂部花園和深水池之間的過(guò)渡，通過(guò)一個(gè)雙重橋梁體系帶領(lǐng)游客探索這座舊礦坑。人們順著曲線形的步行橋攀緣而下，途經(jīng)崎嶇的崖壁，橋兩側(cè)的鋼板一面銹蝕，另一面則光潔如新（圖4）；然后，他們陡然來(lái)到一座巖洞下方，發(fā)現(xiàn)自己正站在一座浮橋上，曲折的步道則繼續(xù)引領(lǐng)人們前進(jìn)，變化的景象令人嘆為觀止（圖5）。材料或堅(jiān)硬或柔軟的質(zhì)地形成了鮮明的對(duì)比，更強(qiáng)化了人們?cè)诮?jīng)過(guò)不同路段時(shí)的情緒感受——自巖石上懸挑下來(lái)的銹蝕金屬橋強(qiáng)調(diào)了向下“跳躍”的動(dòng)態(tài)；而浮橋上木質(zhì)甲板與扶手表面的光滑質(zhì)感，則可讓人輕松平和地欣賞周圍的景色。

4　上海辰山植物園礦坑花園/Quarry Garden in Shanghai Botanical Garden

5　上海辰山植物園礦坑花園木棧橋/Wooden Floating Bridge,Quarry Garden in Shanghai Botanical Garden（4,5攝影/Photos:陳堯/CHEN Yao）

在許多案例中，對(duì)水域的改造將傳統(tǒng)的園林范疇拓展到了地景的尺度——鑒于涉及到大面積地恢復(fù)退化的自然區(qū)域、逐漸荒廢的工業(yè)區(qū)、修復(fù)住宅區(qū)的邊界以及基礎(chǔ)設(shè)施，這不僅是規(guī)模上的變化，也是設(shè)計(jì)意義的變化。

土人景觀事務(wù)所設(shè)計(jì)的六盤水明湖濕地公園項(xiàng)目（2013年）拓寬了那里曾經(jīng)開(kāi)鑿過(guò)隧道的河堤，由此形成了流域盆地。梯田式的池塘、小島和林木線都被蜿蜒的步行系統(tǒng)銜接在一起——部分人行步道被設(shè)計(jì)為混凝土立柱的高架橋，在水面上形成了彎曲而細(xì)長(zhǎng)的道路（圖6）。

土人景觀事務(wù)所在徐州睢寧流云水袖橋（2010年）的設(shè)計(jì)中也采用了類似的手法（圖7，8）。它遠(yuǎn)看猶如一條碧綠的飄帶，從地面上緩慢地升起，在整個(gè)景觀范圍內(nèi)曲折蜿蜒了幾百米，其間越過(guò)了一條寬闊的快速道路和若干河道。這條彎曲的步行道共長(zhǎng)869m，另有4條平行的坡道與之銜接，可通往公園內(nèi)的其他幾處地點(diǎn)。步道曲折的線條強(qiáng)調(diào)了這個(gè)景觀的有機(jī)特征，并形成了一種動(dòng)態(tài)感——它是設(shè)計(jì)師之所以借鑒“中國(guó)京劇中舞動(dòng)的水袖所形成的光影，以其一氣呵成的效果和流動(dòng)的曲線形狀成了天然輪廓”的原因。各種細(xì)部的尺度似乎也恰如其分地呼應(yīng)了項(xiàng)目本身的大尺度——扶手并未采用纖細(xì)的形狀，而表現(xiàn)出厚重與堅(jiān)實(shí)的形態(tài)——也讓這座橋從遠(yuǎn)處就能為人們所見(jiàn)，也吸引了沿周邊道路快速經(jīng)過(guò)的游客的注意力。夜晚的人工照明展示系統(tǒng)則更突出了這種效果。這座步行橋不僅能供游客快速方便地抵達(dá)公園，其自身也成為公園的“主干”——既為人們提供了豐富多變的觀景角度，成為公園場(chǎng)地的向?qū)?，也?gòu)成了某種“地形上的點(diǎn)睛之筆”[6]。

在更小的尺度上，在日照的項(xiàng)目i中，一條條曲線型的白色鋼管形成了蜿蜒的橋身，銜接了城市與水岸線，它們看似是從河畔的植被中生長(zhǎng)出來(lái)的。這座長(zhǎng)達(dá)2km的步行橋坐落在日照山海天海濱的南側(cè)，毗鄰魯南海濱國(guó)家森林公園，是一個(gè)大型再開(kāi)發(fā)項(xiàng)目的一部分（圖9）。該項(xiàng)目涉及各類基礎(chǔ)設(shè)施和休閑區(qū)域，由HHDFUN事務(wù)所（王振飛，王鹿鳴）完成（2012年）。整個(gè)項(xiàng)目共同的設(shè)計(jì)思路是利用波浪起伏的有機(jī)形態(tài)、通過(guò)參數(shù)化的設(shè)計(jì)手段進(jìn)行圖紙表達(dá)。橋身有兩條主結(jié)構(gòu)的鋼管以非對(duì)稱的曲線形態(tài)從市區(qū)一側(cè)延伸出來(lái)，在步道中點(diǎn)的最高處匯合，之后又展開(kāi)為4個(gè)分支，朝海濱森林公園的方向延伸下去；豎琴般的鋼索構(gòu)成了透明而線條流暢的外立面。稍有彎曲的步行道在中部收窄，曲線形的鋼管則形成了動(dòng)感強(qiáng)烈的元素，它們?cè)谌谌胫車坝^的同時(shí)，吸引著游客積極地感受這里的自然環(huán)境。

在一些案例中，傳統(tǒng)的非直線形步道理念則已與某些結(jié)構(gòu)形式結(jié)合在一起。在上海青浦的項(xiàng)目中ii，文筑國(guó)際的設(shè)計(jì)總監(jiān)白德龍?jiān)O(shè)計(jì)了一座折線形的步行橋（2008年），形成的帶有頂棚的步道穿過(guò)了頗為迂回的淀浦河（圖10）。橋身曲折的結(jié)構(gòu)由3部分構(gòu)成——其中兩段較短的橋身在平面上與河岸相垂直，設(shè)有臺(tái)階，坡度較緩；另一段橋身則在平面上有些偏轉(zhuǎn)，平整的甲板在水面上形成了帶有遮蔽的廣場(chǎng)空間。由雙向彎曲產(chǎn)生的扭力通過(guò)三維立體結(jié)構(gòu)來(lái)支承——這是一種特別的桁架，其形狀與橋梁本身不對(duì)稱彎折的動(dòng)態(tài)趨勢(shì)相吻合。結(jié)構(gòu)體系則project by West 8 office(in partnership with Atelier DYJG)for the 2011 Xi'an International Horticulture Exhibition(Fig.1).A circuitous and winding trail leads the visitors though a dense,forest-like bamboo garden,rising up only at five points:five semi-circular bridges let people peak out over the vegetation and have a surprising wider view before climbing down again.The path is intended to represent a sort of trajectory of human life,marked by contrast between uncertainty and elation.The red smooth concrete surface brightly sticks out from the greenery,highlighting the archetype of the bridge as a medium for emotion.

In many projects of Atelier DYJG,some winding walkways rising over the water or wetlands constitute the most intense segments of the path layout,providing a vivid way to get in touch with the water system.This is the case of the Central Garden of Zhongguancun Software Park in Beijing(2004),where the interweaving paths create continuous spatial variations around a lake and zigzagging over the water(Fig.2).Also in Changguangxi Wetland Park in Wuxi(2011)the bending path establishes a real discovery trail across the wetlands,in order to let people experience the natural succession of diversified water and vegetation features(Fig.3).

When an abandoned worksite claims to be turned into a garden,the way to get in and to walk through it remains a key role in the design strategy.The Quarry Garden in Shanghai Botanical Garden(2009),designed by Beijing Tsinghua Tongheng Urban Planning and Design Institute Co.Ltd.+ School of Architecture of Tsinghua University(arch.Zhu Yufan,Yao Yujun,Meng Fanyu),is an impressive example.A steep stairway encapsulated in a rusty steel box acts as a threshold between the top gardens and the deep pool,taking visitors to discover the former quarry through a double bridge system.People climb down,dramatically brushing against the rocky hillside,along a curved bridge,which has one side made of rusted iron and the other of burnished steel(Fig.4); then,after having turned abruptly under a stone grotto,they find themselves on a floating bridge,eye-catching continuously changing views from the meandering path(Fig.5).The contrast among hard and soft materials strengthens the emotional feeling of the different phases of the route:rust metal suspended from the rocks is meant to highlight the "jump" down,while smooth wooden surfaces for the deck and the railings of the floating path are designed for peaceful appreciation of the landscape around.

In many cases,watersheds regeneration items widen the traditional scale of the garden to a landscape scale:not just a dimensional shift,but also a shift in meaning,whereas large areas to be recovered involve degraded natural zones as well as obsolescent industries,settlement borders and infrastructures.

In Liupanshui Minghu Wetland Park,designed by landscape office Turenscape(2013),the riverbed,previously channelled,has been re-enlarged and a drainage basin was created.Terraced pools,islands and tree lines are interwoven by a system of winding paths:some of them form elevated walkways,standing on concrete pillars,and create long twisting routes above the water(Fig.6).

6　六盤水明湖濕地公園/Liupanshui Minghu Wetland Park

Turenscape has put in place a similar strategy in the design of Long Sleeve Skywalk in Suining County,Xuzhou City(2010,fig.7,8).Seen from a distance it appears as a long green ribbon,which gently rises from the ground and sinuously spreads over the landscape for many hundreds of meters over-passing a large fast road and several watercourses:it's a meandering walking path with a total length of 869m,reached by other four almost parallel long ramps connecting some points of the park.The sinuous line of the path stresses the organic character of the landscape,providing a sense of movement:that's why the designers refer to the memory of the "dancing shadows of long sleeves of Chinese operas,where seamless and flowing curves follow natural contours".The scale of the details–not thin railing elements,but thick and solid ones–seems to appropriately respond to the large scale of the project,allowing it to be seen even from a long distance,and to be caught in the eye by the fast traveller along the infrastructure too; this is accentuated at night by the artificial light display system.The walkway is not only an easy and safe way to reach the park,but it constitutes by itself the park's "backbone" as well:it offers a continuous change of viewpoints and gives orientation to the place,acting as a sort of "topographic eye"[6].

At a smaller scale,in Rizhao,several curved white steel tubes seem to grow out from the riverbank vegetation to shape a sinuous bridge that connects the city with the shoreline.Located in the southern part of the 2km-long Shanhaitian beach bordering the Lunan National Forest Park,the bridge is a part of a wide redevelopment project,concerning facilities and recreational areas,by HHD_FUN Architects(2012,fig.9).The common thread of the overall project is the use of waving organic forms,drawn through parametric design techniques.Two main steel tubes rise from the city's side,bend asymmetrically to converge at their highest point in the middle of the path,and then由外形規(guī)整的工字鋼形成的方形網(wǎng)格傾斜45°構(gòu)成，并根據(jù)剪力要求在需要的局部加密。

7　徐州睢寧流云水袖橋/Long Sleeve Skywalk,Suining,Xuzhou

8　徐州睢寧流云水袖橋模型/Model of Long Sleeve Skywalk （6-8圖片版權(quán)/6-8　Photo courtesy:?土人設(shè)計(jì)/Turenscape）

9　日照步行觀景橋/Rizhao Footbridge（圖片版權(quán)/Photo courtesy:?HHDFUN）

在這里，我們有可能找到一種對(duì)各類借鑒自傳統(tǒng)的獨(dú)特要素進(jìn)行現(xiàn)代式綜合的方法——一方面，橋作為媒介，提供了以非直線形路徑穿越水面的體驗(yàn)，形成了步移景易的效果；另一方面，橋的形象又為人們提供了一處場(chǎng)所，用設(shè)計(jì)師的話來(lái)說(shuō)，即一座“水上的房間”。

最后一個(gè)重要的議題是如何與一些植根于本土的技術(shù)手段進(jìn)行互動(dòng)。

在這方面，由馬克·曼朗建筑師事務(wù)所在揚(yáng)州設(shè)計(jì)的柳葉步行橋?qū)嵺`項(xiàng)目非常有意義（圖11）。這座橋位于舊城中心的西南角，其外觀是一個(gè)令人炫目的白色金屬符號(hào)，橫跨古老的大運(yùn)河；盡管在遠(yuǎn)處看，它可能讓人聯(lián)想起中國(guó)傳統(tǒng)的石拱橋，但從技術(shù)角度看，兩者卻有極大的差異——這座橋采用了剖面不斷變化的箱形梁結(jié)構(gòu)。利用現(xiàn)有高超的金屬板加工工藝進(jìn)行設(shè)計(jì)的能力讓設(shè)計(jì)師能夠避免來(lái)自外部的預(yù)設(shè)技術(shù)，并將本土的技藝作為珍貴的技術(shù)手段和認(rèn)同感的來(lái)源發(fā)揚(yáng)光大。

無(wú)止橋慈善基金會(huì)也在這方面進(jìn)行著一些值得關(guān)注的活動(dòng)。這個(gè)來(lái)自香港的基金會(huì)，在國(guó)家住房和城鄉(xiāng)建設(shè)部的支持下，在中國(guó)的偏遠(yuǎn)地區(qū)和不發(fā)達(dá)地區(qū)組織了許多橋梁（自2007年起建成了30座）和基礎(chǔ)設(shè)施的建設(shè)工程。這些項(xiàng)目通常都必須面對(duì)一些挑戰(zhàn)，包括來(lái)自具體場(chǎng)地條件限制（傾斜的水岸，有些是交通工具或電力設(shè)施無(wú)法到達(dá)的地方）和創(chuàng)造力匱乏的技術(shù)手段。

由奧雅納工程咨詢(上海)有限公司和無(wú)止橋基金會(huì)共同合作完成的云南省咪霞村無(wú)止橋iii（2013年）就是一個(gè)杰出的案例（圖12）。這座橋身的每一個(gè)單獨(dú)構(gòu)件都不能超過(guò)一定的重量，否則無(wú)法由人工運(yùn)到山上。一些用當(dāng)?shù)夭杉氖瘔K填充的篾筐被用來(lái)作為兩岸基礎(chǔ)框架的重量平衡構(gòu)件。徑向和橫向的鍍鋅鋼梁構(gòu)成的結(jié)構(gòu)十分堅(jiān)固，鋼梁之間用手工擰牢的螺絲螺帽和螺栓連接固定。橋面甲板是透空的網(wǎng)格，扶手則是一些半圓形的條狀構(gòu)件。在現(xiàn)場(chǎng)以外通過(guò)測(cè)試之后，這些構(gòu)件被運(yùn)往當(dāng)?shù)?，?0位志愿者在12天里建造完成。當(dāng)時(shí)還利用了當(dāng)?shù)氐闹窦庸ぜ夹g(shù)——現(xiàn)場(chǎng)的臨時(shí)腳手架體系就由竹框架綁鋼筋、錨件、皮帶輪和繩索建成。這個(gè)項(xiàng)目清楚地表明如何能夠有效地利用高水平的專業(yè)知識(shí)理解和建造易于組裝的預(yù)制結(jié)構(gòu)，以適應(yīng)特殊的當(dāng)?shù)貤l件并同時(shí)在施工中利用當(dāng)?shù)丶夹g(shù)。

作為總結(jié)，通過(guò)不同案例的比較研究可以得出一些重要結(jié)論。其中一項(xiàng)關(guān)鍵的議題就是以創(chuàng)造性的方式借鑒傳統(tǒng)、并通過(guò)當(dāng)代形式滿足當(dāng)代社會(huì)需求的能力。本文案例涉及的設(shè)計(jì)師都避免了以膚淺或陳詞濫調(diào)的符號(hào)為基礎(chǔ)對(duì)過(guò)去經(jīng)驗(yàn)進(jìn)行轉(zhuǎn)譯（如類似塔形或龍形的樣式），并通過(guò)推動(dòng)主流的設(shè)計(jì)態(tài)度轉(zhuǎn)向以用戶感知體驗(yàn)為主導(dǎo)，重新闡釋了傳統(tǒng)觀念中關(guān)于移動(dòng)的概念——上文分析過(guò)的人行步道都能夠和諧融入周圍景觀，并同時(shí)提供了活潑的手段供人們理解景觀。不僅如此，在更微妙的意義上，對(duì)一種文化的轉(zhuǎn)譯進(jìn)行反思也意味著文化的外延得到拓展，由此將技術(shù)也納入其中——也就是有可能向本土技藝進(jìn)行學(xué)習(xí)并與之互動(dòng)——這種策略已在一些案例中取得了成功，并將研究對(duì)象拓展至富有成效的范圍。（致謝：筆者要特別感謝克里斯蒂亞妮·M·埃爾對(duì)于中國(guó)步行橋的結(jié)構(gòu)與造型問(wèn)題的探討。）

參考文獻(xiàn)/References:

[1] Rowe,P.G.,Kuan S.(2002),Architectural Encounters with Essence and Form in Modern China,Cambridge,Mass:MIT Press,2004.

[2] Chen,L.,Yu,S.(1986),The Garden Art of China,Portland:Timber Press; Tang,H.C.(1991),Philosophical Basis For Chinese Bridge Aesthetics,in Transportation Research Board,Bridge Aesthetics Around the World,Washington:Library of Congress; Rinaldi,B.M.(2011),The Chinese Garden:Garden Types for Contemporary Landscape Architecture,Basel:Birkh?user.

[3] Knapp,R.G.(2008),Chinese Bridges:Living Architecture from China's Past,Tuttle:Rutland.

[4] Cosgrove,D.E.(1984),Social Formation and Symbolic Landscape,University of Wisconsin Press.

[5] Appadurai,A.(1996),Modernity at Large:Cultural Dimensions of Globalization,Minneapolis:University of Minnesota Press; Padua,M.G.(2007),Hybrid Modernity:Framing the Public Park in Post-Mao China,in Negotiating Landscape,CELA.

[6] Saunders,W.S.(ed.)(2012),Designed Ecologies.The Landscape Architecture of Konjian Yu,Basel:Birkh?user.

譯注：

i 指日照步行景觀橋。

ii 指上海青浦步行橋。

iii 具體位置在云南省紅河州綠春縣平河鄉(xiāng)咪霞村。divide themselves into four lines spreading down towards the beach park; harp-like steel strings create a smooth,transparent exterior fa?ade.The combination of the slightly meandering path,narrowing in the middle,and the curved steel tubes generates a strong dynamic feature able to fit in the landscape and in the meantime to drive the users' attention to a vivid perception of nature.

10　上海青浦步行橋/Qingpu Footbridge（圖片版權(quán)/Photo courtesy:?文筑國(guó)際/CA-Design）

11　揚(yáng)州柳葉橋/Liu Ye Footbridge,Yangzhou（攝影/Photo:Agence Mimram Paris）

12　云南省咪霞村步行橋/Mixia Village Footbridge,Yunnan Province（圖片版權(quán)/Photo courtesy:?Arup）

In some cases,the traditional concept of bending walk has been combined with specific structural form.In Qingpu,Pedro Pablo Arroyo Alba of CA Design envisaged the creation of a zigzag bridge,hosting a covered path to cross somewhat obliquely the Dianpu River(2008,fig.10).Three segments give form to the bent structure:two short ones,orthogonal to the riverbanks in plan,provide gently stepped ramps,while the longer segment,oblique in plan,features a flat deck able to perform as a sort of covered square flying over the water.The torsion induced by the double bend is supported by a three-dimensional structure:a unique steel truss girder,shaped in accordance to the asymmetric diagram of bending momentum.It is made of regularly dimensioned H steel set as a 45°-rotated squared frame,denser when necessary according to the diagram of shear stress.

Here it is possible to find a modern synthesis of distinct characters borrowed from tradition:on the one hand,the idea of a bridge as a medium to provide a non-straight experience of crossing the water,offering changing viewpoints over the landscape; on the other hand,the image of a bridge offering people a place,in the designers' words,"a room over the water".

Finally,one significant topic is the interaction with specific locally-rooted technological skills.

In this regard,the Liu Ye Footbridge in Yangzhou designed by Marc Mimram(2010)is a meaningful realization(Fig.11).The bridge appears as a glowing white metallic sign spanning across the Old Grand Canal,on the West-South border of the historic city centre; although from the distance it might recall the image of traditional Chinese arch-type bridges,it is radically different from the technological point of view:a box girder with a continuously changing section.The capacity to take advantage of the existing high craftsmanship in working sheet metal allowed to avoid pre-defined technologies imposed from abroad,thus enhancing local savoir faire as a precious technical and identity resource.

A noteworthy activity in this respect is being carried out by Wu Zhi Qiao(Bridge to China)Charitable Foundation,a Hong Kong charity that has organised the building of many bridges(more than 30 completed from 2007)and village facilities in remote rural and underprivileged areas of China,with the support of the Ministry of Housing and Urban-Rural Development.Very often the projects need to confront with challenging specific site conditions(steep banks,sometimes no vehicle access or no electricity available onsite)and low innovative technological skills.

The bridge built in Mixia Village,Yunnan Province(2012),by a collaboration between Arup and Wu Zhi Qiao Foudation,is a significant example(Fig.12).No single component could have an excessive weight as it had to be hand-carried along the mountain path; some gabions,made of wire cages filled with locally sourced stones,were used to counterweight the base frame on each bank.Galvanised steel longitudinal beams and transversal components form a rigid structure,connected by hand with nuts and bolts; the decking is an open mesh,and the railing consists of a series of semicircular bars.After a previous offsite testing,the components were transported on site and built up in 12 days by a team of about 50 volunteers,taking advantage of the local skills in bamboo working as well:a temporary suspension cable system was built onsite,using bamboo frames holding steel wires,anchors,pulleys and ropes.The project clearly shows how a high level technical expertise can be usefully exploited to conceive and produce easy-to-assemble prefabricated structures,in order to fit with specific site conditions and in the meantime to make good use of local know-how for the construction.

In conclusion,significant items appear from the comparison of the different case studies.One of the key topics is the capability to make reference to tradition in an innovative way,and to fulfil contemporary needs through contemporary forms.The designers avoided an interpretation of the past based on trivial or clichéd icons(e.g.pagoda-like,dragon-like forms)and interpreted the traditional idea of movement by driving the main design attitude toward the perceptive experience of the users:the footbridges analysed above fit harmoniously in the landscape,becoming a part of it,and in the meantime offer a vivid way to perceive it.Furthermore,the reflection on interpretation of a culture in a more subtle way has meant to refer to a wider meaning of culture,thus including technical features as well:the possibility to learn from,and interact with,local know-how has been in some cases a successful strategy that opens the way to a fruitful field of investigation.(A special thanks to Christiane M.Herr for discussing structure and shape matters in Chinese footbridges.)

摘要：景觀意識(shí)是中國(guó)近期步行橋設(shè)計(jì)中的一個(gè)普遍特征，并以恢復(fù)水岸、濕地、湖畔、棕地生態(tài)以及城市肌理為目標(biāo)。以創(chuàng)造性的方式借鑒傳統(tǒng)元素，借助富有活力的優(yōu)美環(huán)境、通過(guò)與地方特征和技藝的互動(dòng)，調(diào)動(dòng)使用者的知覺(jué)體驗(yàn)，一同構(gòu)成了當(dāng)今中國(guó)步行橋設(shè)計(jì)的主要特點(diǎn)。

Recent Footbridge Design in China:A Landscape Approach

古斯塔夫·安布羅西尼/Gustavo Ambrosini徐知蘭 譯/Translated by XU Zhilan

Abstract:the landscape consciousness is investigated as one of the common features in many new footbridges recently built in China,aimed at recovering riverbanks,wetlands,lakeshores,brownfields,as well as urban fabrics.The incorporation of elements from tradition in an innovative way,the capacity to drive the perceptive experience of the users through scenic and dynamic settings and the interaction with local identities and know-how constitute some of the main items.

關(guān)鍵詞：步行橋，中國(guó)園林，傳統(tǒng)，創(chuàng)新

Keywords:footbridge,Chinese garden,tradition,innovation

收稿日期：2016-02-23

作者單位：都靈理工大學(xué)