摩天大楼设计背后的故事.doc

.摩天大楼设计背后的故事 在2018年，建筑师几乎摆脱了技术限制，而超高层建筑的设计和施工需要考虑的因素成千上万，包括大量的客观因素（成本、结构、力学、方案组合及构造）和主观因素（例如，美观度、文化、舒适度）。超高层建筑设计师必须留意变换所产生的影响。外立面一个细节的改变可能造成施工整体预算跃升10%。基底面积每增加1米，建筑的静负荷也许急剧增加，超出结构的承受范围。高度每增加12米，钢或混凝土的成本也许会飙升，最终导致项目停滞。成功并不仅仅是伟大设计的结果，而是“建筑师的能力实现最复杂的建筑形式和施工过程” 的结果。上海环球金融中心中国，上海当时，森大厦株式会社计划建设全球第一高楼上海环球金融中心，委托KPF承担设计。KPF用了两年的时间进行设计和规划，以确保项目在破土动工后的10年内平稳推进。200根基础桩打下去以后，森大厦提出了变更要求，他们希望增加建筑高度，也就是说，建筑的重量会增加。虽然建筑师可以改变大楼的高度，但已经做好的基础没法支撑多出来的重量。大楼其他方面的效率都非常高。大部分超高层大厦不住人的虚高比例可高达30%，而上海环球金融中心的这一数值仅为4%。如同埃菲尔铁塔或金字塔，上海环球金融中心的独特外形与众不同。尽管世界第一高楼的称号没保留几年，但大楼礼品店中作为旅游纪念品热销的大楼模型表明上海环球金融中心仍然是上海最受欢迎的地标和目的地之一。智慧城市密度20世纪初，世界人口总数只有16亿，仅为当前70亿人口的20%。在城市迁移热潮中，新居民涌向基础设施和服务最完善的热门地区，城市变得越来越拥挤。人们对城市有生活成本高、环境脏乱、舒适度差的负面印象。哈佛城市经济学家Edward Glaeser认为密度不是坏事。事实上，“密度很重要，因为人是社会动物，互相学习是本性。”Glaeser表示，我们不能低估当面接触的价值；跟着聪明人学让我们变得聪明，“这是城市繁荣的原因所在”。世界上大部分地区的密度在不断增加，向上延伸而非四散开来的摩天大楼也许是不断变密的城市解决不断增长的人口问题的最佳方法。联合国的统计数据显示，每天有 20万人 进入城市。从现实的角度来看，摩天大楼能增加地球上的可居住表面积。一样的地块，高层建筑能为更多的人提供生活、工作和娱乐空间。虽然人们对住所的需求未曾改变，但人口和社会特征改变了我们建造房屋的原因。在世界上增长和密集化速度最快的地区，“保有一级城市不是问题，问题是如何加快发展三级城市。”因此，超高层建筑是城市的稳定器；上海环球金融中心是上海众多著名建筑组成的天际线中最著名的建筑。超高层建筑的崛起不仅会改变城市的视觉效果，还会带来新的人口和企业，促进城市发展。香港环球贸易广场中国，香港超高层建筑有着跟小城市一样的问题和需求。2010年竣工的香港环球贸易广场承载着3万人的活动和功能需求。每天3万人同时涌入大楼。假如没有精心设计的动线和升降系统，那么大楼内的人也许一天都到不了目的地。大楼无缝连接下面的九龙站，行人能自由出入地上地下，建筑各层。畅通无阻的环球贸易广场状态良好，在香港的城市肌理中填上了浓墨重彩的一笔。环球贸易广场大楼，底部楼层全部住满，中间是临时施工准备区，顶部在建International Commerce Centre building with the bottom floors fully occupied, the middle a temporary construction staging zone, and the top still建筑的垂直动线系统、分区The buildings vertical circulation system, zoning香港环球贸易广场 / ICC，HK，China在吹过维多利亚港的大风中，大楼造型在不增加风阻的情况下最大程度地提高可出租建筑面积。大楼的凹角使建筑的风效率与圆形楼层相同，却无需采用难以使用的圆形楼层布局。维多利亚港吹来的劲风对大楼的风效率提出了很高的要求。环球贸易广场的分期施工跟动线系统和实际形态一样，力求最大程度地降低阻力。超高大楼的建设周期一般是五年，需要大量的前期投资，这些投资直到楼层出租才能取得回报。为了缩短建设周期，大楼的垂直组织一方面先安排低区入住，一方面开展中区和高区的装修准备和建设工作。超高层大楼在迪拜（低密度）、中国（高密度）和纽约（高密度，高建设成本）的建设完全不可同日而语。即使一栋大楼的设计看上去卓而不凡，但能否经受住使用和入住的压力，正常运转才是大楼成功的标志。随着天际线的日益密集，超高层向上的趋势是什么？1996年，全世界只有四栋超高层大楼（高度超过300米）。此后20年，超高层大楼如雨后春笋般涌现。现在，全世界的超高层大楼超过100栋，跟20年前的4栋相比，增加了30倍。不管是50层还是100层，摩天大楼的居民所面临的生活和工作环境与以往截然不同。超高层大楼是最有魅力的建筑形式之一，一次又一次地激发地区活力。几十上百亿的钱花出去；全民都投入到了超高层大楼的建造中去。鉴于旺盛的需求，超高层大楼设计需要很好地预计并满足未来入住者和数代人的需求。在KPF的建筑师看来，超高层大楼的品质衡量指标不仅仅是外观，还包括性能和使用者们的反应。作为超高层大楼的衡量指标，更加重要的是，设计要致力于为大楼所在的社会提供最好的服务。拥有多栋高层和超高层大楼设计经验的KPF预测超高层不光只是会往上走。KPF的总裁Jamie von Klemperer是中央车站附近的摩天大楼范德比尔特广场大楼的设计负责人，目前正在投入大量的精力在塔楼底部的设计和城市空间网络的营造。地面不是简单的平面，而是交通系统、信息系统和商业系统的综合体，摩天大楼和地面的接合是超高层大楼建设中最重要的环节，是超高层大楼超越其昭示性角色，给城市贡献价值的关键。MAKING A SUPERTALLIn 2018, when architects face very few technical constraints, the design and construction of a supertall building requires the consideration of hundreds and thousands of factors. These factors represent a multitude of objective considerations (such as cost, structure, mechanics, program mix, and construction) and subjective considerations (such as aesthetics, culture, and comfort).As an architect designs a super tall building, s/he must anticipate the effects of every small permutation. Change one detail of the fa?ade, and the buildings overall construction budget could jump by ten percent. Increase the footprint by one meter, and the buildings dead load grows beyond what the structure can withstand. Minor increase of typical floor height, and escalating steel or concrete costs will keep the building on the drawing board.Success isnt just the result of a great design; its also the outcome of the architects mastery of the most complex building type and construction process.SHANGHAI WORLD FINANCIAL CENTERThe plan was to build the tallest building in the world. Commissioned by the Mori Building Company to design the Shanghai World Financial Center, KPF would spend a minimum of two years in the design and planning phase. It would take all that time to make sure that once the building started construction, the nearly ten-year process would continue smoothly.The change request came after the two hundred foundation piles had been tendered driven in place. The Mori Building Company wanted the building to be taller, which meant a heavier building. Though the architects could make the building taller, the already-built foundation wouldnt be able to support it.The building is extremely efficient in other ways. Unlike many supertalls which lose as much as thirty percent of their floors to unoccupied vanity height, the Shanghai World Financial Center surrenders just four.Like the Eiffel Tower or the pyramids, the silhouette of the Shanghai World Financial Center is impossible to mistake. Although it was the worlds tallest building for only a few years, the building endures as one of the citys most beloved landmarks and destinations, as evidenced by its reincarnation as a popular tourist souvenir, which can be purchased in the buildings gift shop.SMART URBAN DENSITYAt the start of the twentieth century, total global population was just 1.6 billion, twenty percent of the 7 billion people today.Coupled with urban migration, the worlds cities are densifying as new residents clustering in high-demand areas, those with the most robust infrastructure and services.Cities have a negative reputation for being expensive, dirty, and uncomfortable.Yet, according to Harvard urban economist Edward Glaeser, density isnt bad. In fact, “Density matters because were a social species geared to learn from people around us.”Glaeser argues that we cant underestimate the value of face-to-face contact; we become smarter by being around other smart people, “and thats why cities thrive.”With so much of the planet steadily densifying, vertical buildinggoing up instead of sprawling outmay be the best solution to accommodate growing populations and densifying cities. According to the UN, there are 200,000 people moving into cities every day. From a practical standpoint, skyscrapers increase the planets inhabitable surface area; stacked buildings allow more people to live, work, and play on the same piece of land. While our need for shelter hasnt changed, the character of our populations and our societies have changed the reasons why we build.In areas of the world with the highest growth and densification, “The challenge is not to hold down the first-tier cities, but to pick up the third-tier ones.” In light of this call, the supertall acts a ballast in the city; its the most notable building in a skyline of notable buildings. Its placement not only has visual impact, but where a supertall stands, can determine how a city grows because it will attract new populations and businesses.INTERNATIONAL COMMERCE CENTREA supertall is subject to the same concerns and demands as those of a small city. Completed in 2010, the International Commerce Centre in Hong Kong houses the activities and functions of thirty thousand people. Everyday these thirty thousand individuals enter the building all at once. Without the carefully designed circulation paths and lifting systems, getting to the right place would become an all-day journey. Because the building seamlessly connects to Kowloon Station below, the individual commuter feels no resistance when moving from underground, to ground, to the buildings upper levels. For such a significant addition to Hong Kongs city fabric, the building is at its best because it is frictionless.Set against the strong winds sweeping off Hong Kong Bay, the buildings profile maximizes leasable floor space without creating extra wind resistance. The buildings re-entrant (notched) corners provide the building with the same wind efficiency as circular floors, but without the hard-to-use round floor layouts. This wind efficiency is of particular importance given the strong gales coming off of Hong Kong Harbor. If the ICC were built in Beijing, the same building would only need to resist a fraction of the lateral loads. (A 100-story tower in Beijing would experience the same magnitude of wind as a 20-story building in Hong Kong.) In fact, if the ICC were in Beijing, it would cease to be the same building at all.Like its circulation system and physical form, the construction process of the ICC was staged to provide the least resistance possible. Clocked at a typical speed of five years, supertalls require a huge amount of upfront investment that will show no return until the buildings floors are leased. Curtailing this timespan, the towers vertical organization allowed full occupation of the lower zones, while the middle and upper zones were prepared for fit-out and still under construction.Building a supertall is a very different in Dubai (low density), China (high density), and New York (high density, high construction costs). Even though a building looks like it has a transcendent design, the true mark of a buildings timelessness should be measured by how well it functions under the pressures of use and occupancy.AS OUR SKYLINES FILL UP, TO WHAT END DO WE SURGE UPWARD?In 1996 there were only four supertall buildings (over 300-m tall) in existence. In the two decades since, the upward pace of supertall building has been swift and frequent. There are now over one hundred supertall buildings throughout the world, thirty times what it was twenty years ago, when there were only four.Whether fifty or one hundred stories above the ground, the skyscraper resident lives and works in a place that no one has lived or worked before. Supertall building are one of the most seductive of building types and havetime and time againenergized entire regions by their presence. Billions of dollars are spent; whole nations are