Photo © Adam Mork
3XN建筑事务改造并扩建了一座悉尼过时的20世纪70年代建造的摩天大楼“Quay Quarter Tower”
3XN’s Quay Quarter Tower in Sydney Transforms and Expands an Outmoded 1970s Skyscraper
由专筑网江鹏，小R编译
从这座50层的Quay Quarter Tower（QQT）摩天大厦可以俯瞰悉尼举世闻名的海港，这显然是当代建筑的风格。这座676英尺高的办公大楼有着扭曲的几何形状、似乎伸向水面的悬挑平台，以及其灵动的网格立面，成为这座快速变化中的城市的天际线中最为显著的建筑。
The 50-story Quay Quarter Tower (QQT) overlooking Sydney’s world-famous harbor is clearly contemporary. With its twisting geometry, its cantilevering blocks that appear to reach toward the water, and its jazzy gridded facade, the 676-foot-tall office building stands out as a distinctly recent addition to the city’s quickly changing skyline.
Quay Quarter Tower从中央商务区的一个主要港口处拔地而起（页面上方和顶部）。
Quay Quarter Tower rises from a prime harborside Central Business District site (above and top of page). Photo © Adam Mork, click to enlarge
然而，尽管拥有这令人惊奇的一面，QQT大厦并非完全新建，这座摩天大楼是由1976年在中央商务区（CBD）黄金地段建成的一座46层大楼改造和扩建而成，由于其标准层面积太小，对租户不再具有吸引力。最近由丹麦的3XN建筑事务所进行改扩建，耗资6亿美元的改造项目几乎保留了所有现有的塔楼结构，重新利用了95%的核心筒和65%的梁、柱和板结构体系。该改造项目是与BVN建筑师事务所合作开发的，可用建筑面积增加了一倍多，达到110万平方英尺。但是，最值得注意的是，至少从气候的角度来看，大楼的升级改造策略确实减少了1.2万吨的碳温室气体排放，相当于悉尼和哥本哈根之间8800次航班的排放量。
对于AMP Capital（3XN建筑事务所的客户和QQT大厦的所有者和主要租户）来说，保留尽可能多的旧结构是一项要求，这一点在其2014年设计竞赛简报中有所概述。然而，AMP对建筑再利用的兴趣并不是出于潜在的环境效益，而是出于经济考虑。3XN驻悉尼合伙人Fred Holt估计，这种方法将施工进度缩短了9到12个月，节省了约1亿美元。他说：“循环经济就是经济。”当然，一个不小的因素是，如果现有的大楼被拆除，上位规划也限制了新大楼的高度。
However, despite this aura of newness, QQT is not new, or not entirely so. The skyscraper is the product of the adaptation and expansion of a 46-story tower completed on the prime Central Business District (CBD) site in 1976 and no longer considered attractive to tenants, due to its too-small floor plates. The recent $600 million transformation—designed by Danish firm 3XN—retains nearly all the existing tower’s structure, reusing 95 percent of its core and 65 percent of its beams, columns, and slabs. The scheme, developed in partnership with architect of record BVN, more than doubles usable floor area, to 1.1 million square feet. But, most notably, at least from a climate perspective, the upcycling strategy saved 12,000 metric tons of embodied carbon—greenhouse-gas emissions equal to those produced, the architects say, by 8,800 flights between Sydney and Copenhagen.
For AMP Capital, 3XN’s client and QQT’s owner and anchor tenant, retaining as much of the older structure as possible was a requirement, one outlined in its 2014 design competition brief. However, AMP’s interest in building reuse was not prompted by the potential environmental benefits, but instead by economics. The approach shaved nine to 12 months off the construction schedule and saved about $100 million, estimates Fred Holt, a 3XN partner based in Sydney. “Circular economy is about economy,” he says. No small factor, of course, were planning restrictions that limited the height of a new tower, had the existing one been demolished.
Photo © Adam Mork
大楼现在扩建的部分是从一个新的、具有混合用途的平台上建立起来的，平台上覆盖着悉尼砂岩，许多邻近的历史建筑都是用这种材料建造的。该平台在陡峭的场地上建立了一个水平的地面，因为它从大桥街的主要入口向北朝着港口急剧倾斜。平台上设置了一个空间动态的、阁楼式的多层大厅，并提供餐饮和零售选择，不仅针对QQT租户，也针对CBD周围的街区。在平台的屋顶上，冰岛-丹麦艺术家Olafur Eliasson设计了一个棚架结构。
The now-expanded building rises from a new mixed-use podium clad in Sydney sandstone, the material of many of the neighboring historic buildings. The platform establishes a level ground plane on the steep site as it slopes sharply from the primary entrance on Bridge Street northward, toward the harbor. The podium houses a spatially dynamic, loftlike multilevel lobby and offers dining and retail options, aimed not only at QQT tenants but at the surrounding blocks of the CBD. And on the podium’s roof, a publicly accessible park is sheltered under a trellis by Icelandic-Danish artist Olafur Eliasson.
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塔楼的裙楼从海港（1）向上倾斜，一直延伸到大桥街（3）的主入口，从而形成了一个多层大厅（2）。
The tower’s site slopes up from the harbor (1) to the main entry on Bridge Street (3), allowing for a multilevel lobby (2). Photos © Adam Mork
从这个基地出发，QQT大厦的办公楼层堆叠在五个街区中，每个街区都充分利用了最大限度的分层线，同时充分利用了海港大桥的桁架、Jørn Utzon歌剧院的“帆”以及从环形码头往返的渡轮的景观资源。这座大楼的楼板面积现在约为2.2万平方英尺(从1.3万平方英尺增加到现在)，在设计它的几何结构时，需要牺牲老建筑最北端的核心筒结构，这种结构之所以叫“筒中筒”，是因为它的周边柱子间隔很近，核心位置也很好。改造过程包括在新的地板上嫁接，然后将扩大的体积封闭在新的玻璃幕墙中，而玻璃幕墙又被包裹在一个铝制的遮阳板内。它的网格模式在交替的方向上交织，以区分不同楼层。
但网格不仅仅是为了美观。Holt打趣道：“它的设计是有依据的——不仅仅是形式主义。”根据立面的太阳光照方向，遮阳板叶片的深度和轮廓对应不同，可减少30%以上的热量增加，降低机械冷却要求，从而减少碳排放。此外，遮阳板不需要百叶窗，因为至少在一天的大部分时间里，百叶窗会挡住所有重要的风景。
在QQT大厦堆叠的街区中，办公空间被组织成一系列垂直的“社区”，每个社区都集中在建筑北部边缘的多层社交空间和每个体量堆叠底部的屋顶露台。Holt说：“租户和游客一出电梯就能看到中庭，它的作用是让人们可以更容易地欣赏到大楼令人惊叹的景色。”它们还能将日光引入到大楼的内部，并为办公空间提供一种通风、非正式的感觉，这显然吸引了租户：截至去年年底，这座于4月完工的大楼已经出租了95%——在这个随时随地工作的时代，这是令人印象深刻的表现。
From this base, QQT’s office levels are stacked in five blocks, each twisting to take full advantage of the maximum allowed envelope while making the most of views of the trusses of the Harbour Bridge, the “sails” of Jørn Utzon’s Opera House, and the ferries coming and going from Circular Quay. Creating the tower’s geometry, with floor plates that are now about 22,000 square feet (up from 13,000 square feet), involved sacrificing the northernmost portion of the older building’s square-in-plan “tube-in-tube” structure, so called because of its closely spaced perimeter columns and placement of its core. The revamp process included grafting on new floor plates and then enclosing the expanded volume in a new glass curtain wall, which is in turn wrapped within an aluminum brise-soleil. Its grid pattern steps in alternating directions to distinguish each stack of floors from the next.
But the grid is more than aesthetic. “Its design is informed—it isn’t just form,” quips Holt. Depending on the facade’s solar orientation, the depth and profile of the brise-soleil’s blades vary to cut heat gain by more than 30 percent, lowering mechanical cooling requirements and thereby reducing operational carbon. In addition, the brise-soleil dispenses with the need for blinds, which would—for at least part of the day—block the all-important views.
Within QQT’s stacked blocks, the office space is organized as a series of vertical “neighborhoods,” each focused on its own multistory social space at the building’s northern edge and a rooftop terrace at the base of each stack. The atria, which tenants and visitors see as soon as they get off the elevators, serve, says Holt, to democratize access to the tower’s stunning vistas. They also drive daylight deep into the tower’s footprint, and allow for workspaces with an airy, informal feel that clearly appeals to tenants: As of late last year, the tower, -completed in April, was already 95 percent leased—impressive performance in this work-from-anywhere era.
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扭曲和悬挑的平台布置为露台创造了可能（4和5）。
The arrangement of blocks of floors that twist and cantilever creates the opportunity for terraces (4 & 5). Photos © Adam Mork
QQT大厦被认为是世界上最大、最高的建筑改造项目。而且，正如人们所预料的那样，这种规模的适应性再利用会伴随着许多工程和构造的复杂性。主要的挑战是由钢管混凝土柱和钢梁组成的新建筑和混凝土框架的旧建筑之间的高差沉降。结构咨询公司BG&E的高级助理Tom Benn表示:“通常，我们只需要将塔楼与地面连接起来，但在这里，我们还必须连接到现有的结构。”人们担心的是，新建筑的扩建会把现有的核心筒和相邻的柱子向下拉，影响建筑的所有方面，包括电梯和立面。解决方案是在建筑的新旧部分之间留下一个临时的间隙，只有在新建筑基本稳定之后，才将两者永久地连接在一起。
QQT is believed to be the largest and tallest building-transformation project anywhere. And, as one might expect, adaptive reuse at such a scale comes with a host of engineering and construction complexities. Chief among the challenges was the differential settlement between the new construction, which consists of concrete-filled steel-tube columns and steel beams, and the old building, with its concrete frame. “Usually, we just have to connect a tower to the ground, but here we also had to connect to an existing structure,” says Tom Benn, a senior associate with structural consultant BG&E. The concern was that shrinkage of the new construction would pull the existing core and its adjacent columns downward, affecting all facets of construction, including the elevators and the facades. The solution was to leave a temporary gap between the building’s old and new portions, tying the two together permanently only after the new construction had substantially settled.
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新建部分与原来的20世纪70年代的塔楼（6）有紧密的间隔，阻碍视线的柱子，与QQT的垂直立面形成鲜明对比，它们拥有令人惊叹的港口景观。（7）
The original 1970s tower (6) had closely spaced, view-obstructing perimeter columns, in contrast to QQT’s vertical villages, with their stunning harbor vistas (7). Photos © Adam Mork
设计师和承包商不仅要考虑到垂直沉降，他们还必须考虑到在施工过程中完成的、扩建的新结构以及新旧交接部分的横向移动。然而，由于非常规的施工顺序，旧建筑自上而下的拆除与扩建部分的施工会同时进行，导致这一改造过程变得极其复杂。在整个过程中，工程师们用各种低技术和高科技仪器跟踪建筑物的运动，包括铅垂线、应变计、倾斜传感器和加速度计。这种“结构健康监测”可以验证工程师早期结构模拟的准确性和QQT数字数据的持续校准，并提供了对旧建筑改造需求的准确理解。除了从20世纪70年代的塔中采集的约1600个岩芯样本外，动态3D模型帮助工程师确定了需要加固的位置，添加了钢夹套以增加抗压能力，碳纤维层压板以加强张力。
The designers and contractors not only had to take vertical settlement into account—they also had to consider lateral movement, for the completed, expanded structure, and for the new and old portions during construction. Predicting this performance, however, was complicated by the unconventional construction sequence that entailed top-down demolition happening concurrently with new construction at the base. Throughout the process, the engineers tracked building movements with a variety of low- and high-tech instruments, including plumb bobs, strain gages, tilt sensors, and accelerometers. This “structural health monitoring” allowed verification of the accuracy of the engineers’ early structural simulations and constant calibration of QQT’s digital twin, and provided a keen understanding of the retrofit needs for the older building. Along with some 1,600 core samples taken from the 1970s tower, the dynamic 3D model helped engineers pinpoint places where reinforcement was needed, adding such elements as steel jackets to increase compressive capacity and carbon-fiber laminates to strengthen for tension.
Photo © Adam Mork
QQT大厦最巧妙的特点之一是它的“弹性楼板”——如果租户希望扩展他们的垂直社区范围，在中庭上下的楼层都被设计成可以拆卸的。这些连接主要是用螺栓连接的，而不是焊接的，类似宜家的部件套件中的元件都是按尺寸设计的，这样它们就可以在货梯中运出大楼，而不需要临时电梯或外部脚手架。目前没有这种填充层的楼层已经准备好了连接，如果租户愿意，可以插入它们。这证明了3XN事务所创造的办公空间的高质量，到目前为止还没有租户选择填充中庭，优先考虑采光、景观和社交空间，而不是更多占用平方英尺面积。
扩建后的塔楼在设计时考虑到了进一步改造的可能，这应该有助于它在未来保持良好的可行性。QQT大厦为全球许多20世纪中后期城市中过时的办公建筑提供了一个范例，表明它们可以被重新设计，而不是被完全拆除。该项目表明，旧的商业大厦可以被重新定义，以创造世界级的办公空间，而不需要建造新的建筑从而付出巨大的环境代价。
One of QQT’s most ingenious features is its “flex floors”—floors above and below the atria that have been configured to be removed, should tenants wish to extend their vertical neighborhood. The connections are primarily bolted, rather than welded, and the elements in the IKEA-like kit of parts are sized so they can be taken out of the building in the freight elevator without the need for temporary lifts or external scaffolding. Levels currently without such infill floors have connections ready that would allow their insertion if tenants so desired. It is a testament to the quality of the workspaces that 3XN has created that no tenant so far has chosen to fill in its atrium, prioritizing daylight, views, and social space over more occupiable square feet.
That the expanded tower has been designed with further transformation in mind should help keep it viable well into the future. QQT offers a model for the many outmoded mid- and late 20th-century office buildings in cities globally, demonstrating that they can be reimagined, rather than demolished. The project shows that aging commercial towers can be redefined to create world-class workspaces—without the huge environmental toll of new construction.
项目信息
建筑师：3XN-Kim Herforth Nielsen，创始人兼创意总监；Fred Holt，3XN澳大利亚负责合伙人；Jeanette Hansen, Audun Opdal，合伙人；Alyssa Murasaki Saltzgaber，项目经理
注册建筑师：BVN
顾问：BG&E和ADG（结构）；Arup（机电、消防、立面）；ASPECT Studios（景观）；Design Research Studio（大堂和市场大厅内部）；Studio Olafur Eliasson/Studio Other Spaces（公共艺术品）
总承包商：Multiplex
客户：AMP Capital
面积：110万平方英尺
费用：6亿美元
竣工日期：2022年4月
Credits
Architect: 3XN — Kim Herforth Nielsen, founder & creative director; Fred Holt, partner in charge, 3XN Australia; Jeanette Hansen, Audun Opdal, partners; Alyssa Murasaki Saltzgaber, project manager
Architect of Record: BVN
Consultants: BG&E and ADG (structure); Arup (m/e/p, fire, facades); ASPECT Studios (landscape); Design Research Studio (lobby and market hall interiors); Studio Olafur Eliasson/Studio Other Spaces (public artwork)
General Contractor: Multiplex
Client: AMP Capital
Size: 1.1 million square feet
Cost: $600 million
Completion Date: April 2022
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