三山大橋橫跨媯河，是2022北京冬季奧林匹克運動會基礎設施的組成部分，將市中心和張家口聯(lián)系起來。三山的文字意思是指三座山，這也說明了從側面看時橋梁的造型，即：三個拱形結構連接了起伏的山巒。大橋地處北京高密度的市區(qū)與城市北側跌宕河谷之間的門戶位置。大橋周邊地區(qū)作為休閑場所，在居民和游客中的人氣指數快速上升。在前往北京冬奧會的所有主要室外賽事舉辦地張家口的途中，這座大橋在山巒層疊的景觀中成為一座引人入勝的雕塑。緊鄰三山大橋的是2019年北京園博會用地。由國際級建筑大師設計的重點開發(fā)項目將把這一地區(qū)打造為一個展覽中心，展會結束后再改造成為市民的休閑娛樂區(qū)。大橋連接各重要節(jié)點場所，成為更廣泛的北京擴展區(qū)總體規(guī)劃中不可或缺的公共聯(lián)系紐帶，從形式上把新區(qū)與北京的城市肌理融為一體。
The San Shan Bridge spans across the Gui River and will be an integral part of the infrastructure program for the Olympic Winter Games 2022 in Beijing and connects the city center with Zhangjiakou. The english translation of “San Shan” is 3 Mountains and describes the form of the bridge seen from the side with its 3 arches connecting to its hilly backdrop.? The location for the Bridge is a gateway between the density of the city and the undulating river valleys in the North of Beijing. The area around the bridge is rapidly growing in popularity with both residents and tourists as a recreational area. There，the bridge forms an inviting sculpture to a more mountainous scenery on the way to Zhangjiakou，where all major outdoor competitions at the Beijing Olympics are being held. Right next to the San Shan Bridge is an area designated to the Beijing Horticultural Expo 2019. Major developments by international architects will turn this region into an exhibition hub，which afterwards will transform into a get-away，recreational district for the citizens. Connecting all these important locations，the bridge forms an essential public link for a wider Beijing Expansion Masterplan and will formally integrate the new territories into Beijings urban fabric.
形式設計理念，Formal Thoughts
三山大橋形式設計結合并考慮了項目周邊起伏的山巒環(huán)境、以及由尺寸相同、相互交織的五環(huán)構成的奧林匹克標志的含義。圓環(huán)表示五大洲團結融洽。大橋的主要結構設計為一系列在最高和最低點處相連的圓環(huán)。圓環(huán)構成主要結構元素，并在圓環(huán)和橋面之間設 置鋼索將橋面吊起。在前往奧運會賽事的途中“駛入圓環(huán)”可成為奧運會的標志性場景。從側面看時，大橋仿似一系列山峰和山谷，與臨近的蔥郁山坡形成了和諧的對話，將人造結構與周邊自然環(huán)境融為一體；從頂部看，大橋通過類似DNA的雙螺旋結構將媯河兩岸連接起來。對于不斷靠近媯河的奧運會觀眾而言，大橋宛如一座多層面的標志，跟隨人們朝向大橋的角度而不斷呈現出不同的形象。
The formal inspiration for the San Shan Bridge is a conjunction of its undulating surrounding and the meaning of the Olympic symbol，which consists of five interlaced rings of equal dimensions. A union of the five continents is represented within the rings. The main structure of the bridge is conceived as a series of rings，which connect at their highest and lowest points. The rings perform as a main structural element and suspend the bridge deck with steel cables in-between them. ‘Entering the rings’ on the way to the Olympic competitions，should be seen as an contextual icon for the Games. From its side，the bridge is seen as a sequence of mountains and valleys and is in an harmonious dialog with its neighbouring green hillsides，blurring the manmade structure with the natural surrounding. Seen from the top，the bridge connects the two shores of Gui River through a DNA string-like dual helix. Visitors of the Olympic Games，who are approaching the river are introduced to a multifaceted icon that changes its appearance based on ones perspective towards the bridge.
結構設計理念，Structural Thoughts
三山大橋橋面長452米，橫跨媯河兩岸，由三套交叉相連的拱形鋼結構組成，最大跨度95米。拱結構序列形成了一個預應力雙螺旋，在各自頂部和底部互為交叉支撐。螺旋結構盡可能地采用了細長造型，其設置位置可發(fā)揮最佳的結構性能。橋面通過高強度鋼索懸吊于橋梁結構，鋼索和拱結構互為交叉聯(lián)系。空間拱結構的造型類似過山車，采用管狀不銹鋼支柱打造，在連接上形成了較強 的側向抗力。每個拱結構組件都由五個利用綴板連接的鋼管組成，通過這些鋼管將荷載傳遞到穩(wěn)固的基礎承臺上。雖然拱結構的每個組件都采用扭曲造型，但鋼索的預張力可確保這些組件的穩(wěn)定性，避免其在壓縮荷載下發(fā)生變形。交叉連接的鋼索進一步強化了大橋的縱剛性，使其得以承受車輛的動荷載。鋼索構成的波狀表面圍合成大橋的內部空間。大橋采用的雙螺旋結構使其比傳統(tǒng)箱型梁橋節(jié)省了5倍的用鋼量。
The structure of San Shan Bridge connects the shores of Gui River through a 452 meter long bridge deck and is divided in three sets of cross-connected arch-like steel structures with a maximum span of 95 Meters. The sequence of arches form a prestressed double- helix，which intersects and supports each other on their bottom and top. The helix is designed and engineered to be as slender as possible and positioned to offer the best structural performance. The bridge deck is suspended from the structure by high-strength steel-cables，that connect to the arches in a cross-weaving way. Similar than a structure of a rollercoaster，the form of the spatial arch is built from tubular stainless-steel struts and strong in lateral resistance through its connections. Each member of the arch is composed of five steel tubes that are connected by batten plates and carry the loads to its solid foundation platforms. Although each member of the arch is twisted，it is stabilised by the pre-tension of the cable from buckling under compressive loads. The longitudinal stiffness of the bridge is largely enhanced by the cross-connected nature of the cables to resist the dynamic load of the vehicles. The undulated surface formed by the cables define and enclose the interior space of the bridge.Based on its dual helix structure，the bridge utilises 5 times less steel than a conventional box girder bridge.
園林式大橋，Beijing Garden Bridge
天然綠籬和樹木帶將大橋的機動車道和人行道分隔開來，并連接了橋跨上方兩側 的綠化河岸，進一步強化了大橋的“公共空間”屬性，同時實現人車分流。三山大橋由建筑設計方槃達和工程團隊合作完成，雙方在結合造型原則和結構創(chuàng) 新的基礎上進行了設計梳理。在雙方努力下，三山大橋以其獨一無二的結構造型，成為奧運精神的動人象征，并進一步打造北京連接全球的城市形象。
The transportation lanes and the pedestrian lanes are divided by a natural stripe of hedges and trees，which connect the 2 green shores over the span of the bridge. This enhances the bridge as a “public space” and separates the visitors from the traffic. The San Shan Bridge is an outcome of a combined effort between Penda as an architect and the engineering team to streamline a design which is based on a connection of formal principles and structural innovations.Through this shared effort it is possible to design a unique structural form，that can become a symbol for an inviting spirit of the Olympic Games and beyond can promote Beijing’s identity to be globally connected city.
