某索网结构可开启式屋盖

结构中力的传递路径应该是清晰可见的，这也是结构工程师在设计中所希望展现的结构的可读性。只有当建筑用材与构件截面在形式上不被强制规定的时候，才可对结构体系进行发展，针对结构自身特性进行相应地设计与建造。

The force path in the structure should be clear and readable, which is also what sbp has been striving to do. Existing structure system could achieve great improvement only when there is not much compulsive boundary conditions for the materials and element sections.

© sbp / Marcus Bredt

本稿将向大家介绍由sbp公司首创而且不断在众多的体育场馆中设计中频繁采用，并结合不同项目环境条件下不断创新发展的典型轻型结构体系——环索屋盖结构体系及一些采用该结构体系的世界著名体育场。

  This time we are going to give a brief introduction about a typical light structure- Ring cable roof structure, which is originally created and further developed by schlaich bergermann partner, and has been frequently used in lots of stadiums. In this article you will also see how this structural system has been successfully applied in famous stadiums that are designed by sbp.

预应力钢索可以在耗费很少材料的情况下实现很大的结构跨度，但对于索网结构而言，其对应于索的锚固而产生的造价会很高。钢索端部的锚固是实现索网结构样式多样化的前提，但是这需要耗费大量的锚固基础，索网扣件、锚固件等。

Prestressed cable structures span wide with a minimum of materials, but are expensive if they are back-anchored and finely meshed. Back anchoring is a prerequisite for the variety of possible forms, but it requires gigantic foundations and the fine meshing involves numerous costly cable clamps and anchorages as well as covering. 

环索屋盖结构充分发挥了预应力钢拉索结构的优良特性且规避了其短处，其结构构造类似于轮辐。轮辐由截面较薄的轮辋结构，大量辐条和一个中央轮轴组合而成。刚度很小的轮辋在单独工作的时候很小的外力就可以让其产生屈曲。通过辐条的预张拉后，轮辋的刚度则得到了很大的加强。

The Ring cable roof structure maximizes the favourable structural performance and minimizes the unfavourable shortcoming of cable structure. It is working like a spoke wheel. A spoke wheel is composed of a rim with thin section, some spokes and a wheel spindle in the center. The rim would easily get buckling problem when it is bearing any external forces as a consequence of the small stiffness. But while the three components work as a integration, the stiffness is hugely strengthened as the spokes are prestressed and thus bring the rim into another internal force status. 

在环索屋盖结构中，结构外圈设置的封闭的压环担起了轮辋的角色，结构内圈的封闭预应力拉环则起着类似于中央轮轴的作用。压环和拉环之间通过按一定间距布置的径向拉索连接。拉环中的预应力在放射状分布的径向拉索上产生拉力。径向拉索内的拉力传递到外环上在外环内部产生压力。预应力在这一轻型结构中的的作用就是提高整个屋盖结构的刚度 ，从而减小屋顶结构的位移和屋顶的振动以及非均匀荷载下的抗压环弯曲变形。拉索不但可以向抗压环传递荷载而且能起到稳定抗压环的作用。最终拉环、压环与其间的钢拉索一道构成了该内力自平衡的“自锚”形式环索屋盖结构。

In a Ring cable roof structure, the compression ring which is usually placed at the perimeter of the stadium takes the role of the rim in the spoke wheel while the prestressed tension ring in working as the wheel spindle in the center. Radial cables were used to connect the compression the and the tension ring. Compression ring is applied in this system so that radial cables can be anchored to the compression ring, and thus the prestressing force will be balanced within the roof structure system. Likewise, tension ring is applied in this system so that the big opening in the middle of the roof is realized and the prestressing force in the tension ring stablizes this whole system. Thus the roof structure is a self-anchored system. The self-anchored spoked-wheel roof is placed on vertical support columns and forms the most economic structural system for wide-span stadium roofs. Furthermore, the slender cable can barely be seen and thus makes a light and elegant stable roof.

巴西马拉卡纳体育场是为1950年巴西世界杯而兴建的一座足球场，它在建成时能够容纳20万名观众观看球赛，是当时世界上最大的体育场。马拉卡纳的名气，不仅仅来源于它的规模，马拉卡纳同时见证了许多顶级赛事、顶级球员辉煌时刻以及足球史上的一些难忘瞬间。球王贝利在马拉卡纳体育场打进了他效力巴西国家队的第一个进球，也是在马拉卡纳体育场打进了他为国家队效力的第1000个进球。1950年7月16日，相当于里约热内卢1/10人口数量的观众涌入了马拉卡纳体育场，含泪在自己家门口见证了巴西队在世界杯决赛上以1:2输给了乌拉圭。

The stadium Maracanã was erected to host the World Cup in 1950 and was the largest stadium in the world with a capacity of 200,000 spectators. This is however,  not the only reason for its fame. Its mythical status can be attributed both to the legendary matches and players that it has hosted –Pelé scored his first goal for the nation here and,  years later, his thousandth goal as a professional player – as well as some of the most traumatic moments in Brazilian football it has witnessed: on July 16th, 1950, almost a tenth of Rio’s population was in the Maracanã and broke down in tears as Brazil lost the World Cup final 1:2 to Uruguay.

为了迎接2014年世界杯以及2016年夏季奥运会，马拉卡纳体育场于2010年3月开始重修工程。马拉卡纳体育场需要做出一系列的改造以满足国际足联对世界顶级赛事举办体育场的相关要求。体育场的上层观众席被进行了加固翻新，而下层的观众席则直接进行了拆除重建以确保更好的观赛视角。对于当时的马拉卡纳体育场重修工程，其中的一个主要问题是屋顶：其混凝土结构的悬挑屋盖只能够最大限度地为现场45%的坐席起到遮挡作用。

As is to host the World Cup in 2014 and the Summer Olympic Games in 2016, Maracanã started reconstruction to fulfill FIFA standards. The upper spectator tier was renewed and the lower tier completely rebuilt with improved sight lines. The main problem, however, was the roof: a concrete construction that cantilevered forward just enough to cover 45 percent of the seats.

一开始的时候，设计师打算保留既有的屋盖结构并将其向体育场内侧进行加固延伸。但是很快他们发现这些已经建造了半个世纪之久的混凝土悬挑梁既无法被加固，也无法继续提供足够强度满足当前结构需求。同时，原有结构上再建造新的屋盖结构也被否决了，因为这样会改变体育馆的外观，这是不被允许的。最终sbp的工程师提出一个环索屋盖结构解决方案，这个屋盖在结构高度是如此的小以至于它可以作为一个整体嵌入原混凝土结构而不改变这个世界闻名的足球场的外观轮廓。马拉卡纳球场的环索屋盖结构由一个外圈压环，三个拉环以及两者之间的径向拉索组成。为了放置该环索屋盖，旧的混凝土屋盖悬挑梁被移除。对应于下部混凝土结构环形布置的60根混凝土柱，环索屋盖结构也分成了60个单元，其截面尺寸为1m x 2m的外圈压环就放置于混凝土柱顶。这60个连接节点中有52个是不传递横向力的，风荷载等引起的水平力仅通过4对对角切向布置的锚固件传递给下部混凝土结构。

At first the planners pursued the strategy of extending the existing roof coverage inward, retaining the existing roof construction. But the existing concrete cantilevers, now more than half century old, could neither be strengthened nor were they capable of supporting the roof. It was not possible to add a new roof structure as it would have altered the stadium’s appearance. Finally the engineers at schlaich bergermann und partner developed a roof construction that was so flat that it could be inserted into the historical construction without altering its iconic silhouette. The approach applies a new variant of the spoke-wheel principle employing a compression ring around the perimeter, three inner tension ring and some radial connection cables as the spokes. The cantilever arms were removed as to make space for the newly introduced roof. The sixty columns of the existing structure correspond to the sixty segments of the roof, while the spoke-wheel roof lies like a rigid lid, the one by two meter cross-section hollow beam of the compression ring resting on the tops of the sixty columns, fifty-two of which do not produce transversal forces. Horizontal forces resulting from wind loads are dissipated only via four pairs of diagonally arranged tangential anchor points.

▲马拉卡纳体育场 – 改造前 before renovation (photo by: Reprodução)

▲马拉卡纳体育场 – 改造后 after renovation © sbp/Marcus Bredt

位于乌克兰的基辅国家奥林匹克体育场的前身叫做 “列夫托洛斯基红馆”。在20世纪20年代初，基辅当地建造了这座“红馆”用以举办第二届全乌克兰奥林匹克运动会。建造完成至20世纪末，这座体育馆几经改名和修整重建。2007年，波兰和乌克兰联合申办欧洲杯成功，并决定将决赛场地设置在乌克兰的首都基辅，于是基辅市在原体育场既有结构的基础上改造建设了基辅国家奥林匹克体育场。

At the beginning of the nineteen-twenties, the “Red stadium Lev Trotzky” was built to host the Second All-Ukrainian Olympic Games in 1923. This is the origin of the Olympic Stadium, Kiev. During the following 80 years  after the lifting up, it has been reconstructed and renamed for several times. In the year 2007, the decision to award the European football championship in 2012 to Poland and Ukraine presented the city of Kiev with a new challenge. The cup final was to take place in the Ukrainian capital, so the city reconstructed the sports complex and naming it as Olimpiysky.

基辅国家奥林匹克体育场 – 改造前 (photo by: René Hoeflaak)

基辅国家奥林匹克体育场保留了大部分建于1968年的的原混凝土看台结构，屋盖结构则通过设置台结构外围的钢结构立柱进行支撑，这样避免了将屋盖结构的自重和承受的外力直接作用到原混凝土结构及其下部基础上去。钢结构立柱的数量以及空间布置遵循了原看台结构混凝土柱的布置原则，原结构的80条径向轴线上对应设置了80根支承屋盖的钢结构柱。在钢结构立柱上，采用了设置2个外圈压环和1个内圈拉环的轻型环索屋盖结构，屋盖顶部通过张拉膜进行覆盖。对于该体育场，由于设置了环绕足球场的跑道，且该跑道在长轴方向为长直线，在短轴方向为半圆弧，这样的设置在一定程度上定义了整个体育场的几何形状，而如此的几何形状对于拉压环结构来说较为不利，因为该几何形状的曲率变化较大，而拉压环的曲率对结构内力有很大的影响。对于这种情况，结构设计师将支承屋盖的钢结构柱设计成了在半柱高位置向内折的折线形式，且对于沿体育场长轴两侧布置的钢结构柱，其折角较小，而对于沿着体育场短轴两侧布置的钢结构柱，其折角则较大，如此一来，较之体育场内场的几何形状，钢结构柱的顶点闭合环和中间折点闭合环的在几何曲率上有了更好的连续性，而这两个闭合环即可以很好的作为屋盖结构的两个外圈压力环。

▲折线形钢结构梁以及上下两个压环 (图片来源：Jaeger F., Next 3 Stadia (p.100),2012)

The historically listed upper tier built in 1968 were retained till now in  Olimpiysky while the roof structure have to be built around the existing bowl of the stadium without touching it. For the design of the roof structure, the existing situation was similarly prescriptive as the number and spacing of the columns had to follow those of the construction of the historic upper tier of spectator stands. The eighty axes of the existing building correspond directly with the eighty columns of the new roof construction. The looped cable roof employs an inner tension ring and two outer compression rings arranged on above another, between which the bearing cables are spanned like the spokes of a bicycle wheel. The floor plan of the stadium is determined by the running track with long straight sides and semi-circular narrow sides, an arrangement that is not ideal for the compression and tension ring system. As a result, the bent portion of the columns above the elbow half-way up incline only slightly along the long sides and more distinctly around the ends, their tips describing an elliptical form in plan in turn creating more curvature. The resulting geometry benefits the building as a whole, lending it greater tension and character.

© gmp Architekten

© sbp/Marcus Bredt

© sbp/Marcus Bredt

建筑师：gmp- Von gerkan Mark und partner

业主方：National enterprise Olympic NSC

结构形式：轮辐式工作原理的环索屋盖

长度：306m                        宽度：236m

高度：65m                          座位：68,000个

竣工时间：2011年5月

加拿大卑诗省体育馆在1981年到1983年间建造完成并于1983年6月19日正式开放。其开始建造时是为了用作不列颠哥伦比亚雄狮队和温哥华白帽队的主场。建成时这座体育场的屋盖结构为气承式膜结构穹顶，在当时该穹顶屋盖是世界上最大的之一。该穹顶结构屋盖在2010年和2011年间的翻新工程中被环索屋盖结构替代。

BC Place was built between 1981 and 1983 and opened on the 19th of June 1983. It had been built to serve as a home for the BC Lions of the Canadian Football League and the Vancouver Whitecaps, who then still played in the North American Soccer League. Most characteristic feature of the stadium back then was its air-supported domed roof, the world’s largest of its kind. It however got replaced during an extensive renovation which took place in 2010 and 2011.

考虑到现有的下部看台结构以及业主希望翻新后的体育场成为温哥华市区的一个地标的想法，轮辐式环索屋盖结构的被选中做为了屋盖的替换方案。对于卑诗省体育馆的环索屋盖结构，径向钢索向外连接于36根巨型的立柱，而这些立柱则沿着体育馆外边线设置于原结构之上。整个屋盖结构由一个外压环和一个内拉环组成，整个结构可以提供足够的刚度以承受温哥华地区200 kg/m²的雪荷载。在该屋盖结构的内圈，还设置了另一个可开合式的膜结构屋顶，这个膜结构屋顶的开合用时约为10分钟。屋盖上铺设的透光率较大的面积达9500 m²的ETFE膜对建筑外观及建筑内部采光都有了很积极的影响。

Considering the structural performance of the existing stadium bowl and the desire for a landmark design in downtown Vancouver, a lightweight cable-membrane structure has been chosen for the roof which works according the spoked wheel principle. At the perimeter the cables are connected to 36 iconic masts located on top of the existing structure. The system is carefully balanced by an outside compression ring and an inner tension ring providing sufficient stiffness to carry the immense snow loads of up to 200 kg/m² in the Vancouver area. Besides the fixed membrane roof, the structure includes a retractable roof consisting of inflatable membrane cushions which unfold radially. The very transparent 9.500 m² ETFE perimeter facade has a significant influence on the architectural appearance and the interior light conditions. 

© Michael Elkan

建筑师： Stantec, Vancouver

业主方：BC Place, Vancouver

合作单位：Geiger Engineers (engineer of record: David Campbell)

长度：261m                                  宽度：220m

固定屋盖面积：32,500m2            可开合屋盖面积：8,500m2

座位：56,000个