建筑设计与景观界面e-Word-文档.docx

Design architecture and landscape interface

Abstract: As borders between buildings and their natural surroundings become more permeable, experts see green surfaces and related features as functional components of building systems, with evolving standards, clearer metrics, and definable benefitsNature has been prototyping designs far longer than humans have. And as architects strive to keep up with the rapidly evolving world of green-building standards, some of them are looking to exploit that experience by bridging the gap between nature and the built environment. The end goal: creating a functional interface between the two that improves building performance.
Key word: Design architecture, natural surroundings, Systematizing Interface Standards

In the second half of the 20th century, buildings and landscape became disconnected. Many architects saw nature as an unruly force to be excluded at all costs. Nonetheless, a small but vocal group maintained interest in the interplay of the built and natural environments. And today, architects increasingly see biomimetic and biophilic approaches as practical strategies.
Contemporary systems that exemplify this interplay include green and blue roofs, green façades, living green walls, porous pavements, and associated systems for managing water and soil. But putting these green machines to work isn’t plug-and-play; it calls for patient cost-benefit assessment. Well-deployed natural features can improve water management and thermal control and reduce operating costs, but they are not a panacea.
“We have to break it down three ways,” says Signe Nielsen, a principal at the New York landscape architecture firm Mathews Nielsen. “We’ve got the up-front capital costs, the long-term maintenance cost, and then the long-term benefit to society.” In communications with clients, she recommends, “you ought to be prepared for developing an opinion on all three and backing it up with facts and dollars.” Specific metrics exist for irrigation, stormwater control, energy modeling, and benefits produced by trees, among others.
Architects, Nielsen notes, can employ resources such as the National Tree Benefit Calculator, which takes location, species, tree size, and nearby land-use categories as inputs, and returns estimates of cost savings for stormwater control, electricity and natural-gas savings, air quality, property value, and carbon reduction as outputs. Related instruments exist for irrigation calculations in certain regions, but shading, thermal, and cost data require site-specific calculations.
These measurements can also be a reality check. Nielsen recalls writing a manual for green roofs in New York and noting that a 4,000-square-foot green roof with 6-inch-tall foliage does wonders for stormwater retention, but, because oxygen production is a function of leaf mass, the roof’s potential by that metric was equivalent to that of a single tree. “I remember trying to make my case to the city, and they said, ‘You know, if we just planted four trees, it would cost us a tenth the cost of a green roof,’” she says. And while the argument over including such features rarely rests on a single variable, it is important to know which will resonate with decision-makers.

Systematizing Interface Standards
The LEED system, says Frederick Steiner, Assoc. AIA, dean of the School of Architecture at the University of Texas at Austin, “did a pretty good job with buildings, but once you got outside the building envelope, there wasn’t much there. Basically it was ‘use native plantings; conserve water,’ both of which are worthwhile goals, but it doesn’t go into very much depth.” New site-scale standards are evolving. The American Society of Landscape Architects (ASLA), the University of Texas’s Lady Bird Johnson Wildflower Center, and the United States Botanic Garden have formed an interdisciplinary partnership, called the Sustainable Sites Initiative (known as SITES), with a complementary voluntary rating system for sustainable landscapes, with or without buildings.
“The USGBC, a stakeholder in the initiative, anticipates incorporating the SITES guidelines and performance benchmarks into future iterations of the LEED Green Building Rating System,” reports Mark Simmons, director of the Wildflower Center’s Ecosystem Design Group and a member of the SITES Technical Core Committee. SITES, Simmon’s colleague Steiner says, is organized around the idea of ecosystem services, the accounting of processes that nature provides gratis: clean water and air, oxygen, climatic mitigation, plant pollination. And there are other groups exploring these ideas as well. Jeffrey L. Bruce, the chair of Toronto-based Green Roofs for Healthy Cities—a group that increases awareness of the economic, social and environmental benefits of green roofs and green walls—also recommends the Cascadia Green Building Council’s Living Building Challenge, which is “projecting a standard that may take us decades to reach. They’re looking at net-zero energy, net-zero carbon, net-zero water,” he reports. “Totally off the grid.”
The trick is to determine which interfaces are appropriate. “Why do you want a green roof?” Simmons says. “What do you want your roof to do?” Beyond aesthetic appeal, choices involve thermal control, stormwater management, externality mitigation, and biodiversity. Extensive green roofs, with a light vegetative layer, differ from intensive roofs, with thicker soil, sturdier structures, and more ecological complexity. David R. Tilley, associate professor at the University of Maryland’s Department of Environmental Science and Technology, estimates that green roofs are “about five to eight years ahead of the greenwall industry in terms of market penetration, popularity, standards, and size.”
“Designers should ask clients, ‘Which of these do you want: just aesthetics, stormwater, biodiversity?’ ” Simmons says, then tailor designs to performance. “Then the onus is on the industry to say, ‘OK, you live in Atlanta, you’re limited to 100 pounds per square foot, you want to absorb a half-inch of rainwater, and you want to attract butterflies. OK, those are the specifications; thank you, we’ll go back and design it and give you a roof that can do that.’ Now, that implies a lot of accountability.”

Light, Shade, and Energy
Shade is vegetated surfaces’ primary service to the ecosystem. “Once you have a full canopy developed that’s three to four years old, and it’s matured,” Tilley says, “you’re looking at probably a 95 percent reduction in the solar load.” Canopy is measured according to leaf-area-index (LAI) relative to wall area; for each unit of LAI, sunlight decreases by about half. Effects on interior temperatures depend heavily on insulation: If walls already have a high R-value, even dramatic reductions in LAI will cut temperature only slightly, but at low R-values, a dense canopy reduces cooling costs appreciably. Replacing black asphalt with vegetation raises rooftop albedo, and evapotranspiration can add humidity to an urban atmosphere; both help mitigate heat-island effect.
The converse benefit—reducing heating loads with passive solar energy through the use of green façade systems—calls for deciduous species, which lose their leaves and thus allow light to penetrate into the building during winter. Native plants known to thrive under local conditions (climate zones, pest resistance, and soil compatibility, for instance) are preferable; consulting with local botanists is advisable.
Every region has its success stories and its problem children with regard to the plant varieties installed in a project. Maryland-based Tilley warns against using English ivy (Hedera helix), which adheres tenaciously and is aggressive enough to move beyond its support structure and enter a building through windows. Nielsen, based in New York, identifies wisteria as another potential monster: attractive and fragrant, but capable of growing 70 feet tall and forming a woody trunk powerful enough to crush metal and tear roof leaders off a building.
In French botanist Patrick Blanc’s vertical gardens, mesh-supported systems of felt, pipes, and valves deliver hydroponic nutrients to roots by capillary action. Maintenance is considerable: soil dries out faster in containers than at grade. “Those are art pieces, effectively,” says Denise Hoffman Brandt, landscape architecture program director at the Bernard and Anne Spitzer School of Architecture, City College of New York (CCNY). “They’re extraordinarily expensive to install and maintain. A modular, low-maintenance greenwall system hasn’t hit the market yet.”
The alternative—green façade systems or lightweight trellises on or near a building’s exterior, with plants rooted in ground-level soil—offers thermal and other benefits with lower operating costs and fewer structural complications. These systems can also be deployed to integrate plantings when “you’re dealing with not as much available plan space to incorporate gardens or large specimen trees,” or when retrofitting an existing project, says James Sable, vice president of Los Angeles–based Greenscreen. On the whole, green façades are more reliable on lower stories or on roofs than on a full skyscraping scale: With a few exceptions in tropical climates (such as towers in Southeast Asia by Malaysian architect Kenneth Yeang, Hon. FAIA), wind loads can make vertical green structures above four or five stories problematic.

译文：

建筑设计和景观界面
摘要：随着建筑和自然环境之间的边界日益渗透，与之相连的标准不断发展，指标愈加明晰，效益更易定义，专家把绿色外观及其相关特征看作了建筑系统的功能构成部分。在人类进行原型设计之前，大自然很早就这样做了。当建筑师们努力跟上以绿色建筑标准构建的日新月异的世界时，他们中的一些人正努力缩小大自然和建筑环境之间差距。终极目标就是：创造一个连接自然和建筑的功能交界面提升建筑性能。
关键词：建筑设计，景观界面，界面标准系统化

20世纪下半叶，建筑脱离了景观。很多建筑师把自然看作一种难以驾驭的力量，千方百计地把它摒除掉。但一个规模弱小却声音响亮的群体保持着对建筑和自然环境相互影响的兴趣。时至今日，建筑师越来越把仿生和亲生方法当作实用性策略。

例证这类相互影响的当代系统包括绿色和蓝色屋顶，绿色正面，逼真的绿墙，透水的路面及搭配水和土壤的相关系统。但这些绿色机器投入到实际工作中却不是即插即用的；它需要耐心的成本效益评估。精心部署的自然特征能提高水管理和热控制并降低操作成本，但它们并不是包治百病的万能药。
“我们要用三种方式对其进行分解，”纽约建筑景观公司Mathews Nielsen的一位负责人Signe Nielsen说，“我们已经有了预付的资本费用，长期的维护费用及接下来的长期社会福利。”在和客户的交流中她建议说，“你在准备采纳一种观点时应该顾全这三方面并用事实和美元支持下去。”在其他方面，灌溉、雨水控制、能量模型和树木带来的利益都有具体指标。
Nielsen解释说建筑师可以利用多种资源如国家树木效益计算器，输入位置、种类、树木大小及附近土地利用类别，然后输出雨水控制、电力和天然气储存、空气质量、属性值及减碳的预估成本节余。某些地区还有用于灌溉计算的相关仪表，而阴凉、热量和成本数据需要因地制宜进行计算。
这些测量也可用作现状核实。Nielsen忆起曾给纽约一些建筑写过一本绿色屋顶手册，注解说一个带6英寸高树叶的4000平方英尺的绿色屋顶创造了雨水保留的奇迹。然而，由于氧气制造只有大量树叶才做得到，根据这一标准屋顶的制氧潜力只相当于一颗树。“我记得当时试着把自己的想法推向这个城市，他们回答说，‘你知道的，我们种四棵树的成本只需建造一个绿色屋顶的十分之一，’”她说。在争论这类特征很少取决于一个单一变量时，重要的是找到哪一点能与决策制定者产生共鸣。

界面标准系统化
奥斯汀的德克萨斯大学建筑学院的院长、美国建筑师联合协会成员Frederick Steiner说，LEED体系“在建筑上做得很好，然而一旦你走出建筑围护范围，就显得差强人意了。根本上来说，它就是‘使用当地植物；节约用水’，两者都是值得追求的目标，但考虑的深度都不够。”新景观-衡量标准正在发展演变中。美国景色美化设计师协会(ASLA)、德克萨斯大学的伯德约翰逊野花中心和美国植物园组成了一个跨学科的合作关系，命名为“可持续景观行动”（简称SITES），是带或者不带建筑的可持续景观美化的一个互补自愿评级系统。
注：（LEED是美国民间绿色建筑认证奖项，由非盈利组织美国绿色建筑协会（USGBC）于2003年开始运作，目前在世界各国的各类建筑环保评估、绿色建筑评估以及建筑可持续性评估标准中被认为是最完善、最有影响力的评估标准。LEED成功的商业运作和市场定位得到了世界范围内的认可和追随，如今它已经成为全球默认的主流绿色建筑评级体系，得到全球不同气候带国家的认可。）
“此次行动中一个举足轻重的机构USGBC（美国绿色建筑委员会）期望把SITES的指导方针和执行基准并入LEED绿色建筑评级系统未来更新的版本中，”Mark Simmons报告说，他是野花中心生态设计组的董事，也是SITES技术核心委员会的成员之一。Simmons的同事Steiner说，SITES是围绕着生态系统服务这一理念组织起来的，记录大自然无私奉献的过程：清洁的水和空气，氧气，气候调节，植物授粉。还有其他的一些团队开发着这些概念。Jeffrey L. Bruce，本部位于多伦多的“健康城市绿色屋顶”——一个致力于提高人们对绿色屋顶和墙体的经济、社会和环境效益意识的团体——的主席也推荐卡斯卡迪亚绿色建筑委员会的商住楼挑战。他说商住楼挑战“设计了一个我们需要几十年才能达到的标准。他们追求净零能源，净零碳，净零水。”完全脱离了这个圈子。
窍门是确定哪种界面恰当。“你为什么想要一个绿色屋顶？”Simmons说。“你想要你的屋顶做什么？”排除美观，人们的选择很多，包括热控制、雨水管理、外观缓和和生物多样性。有一个吸光植物层的开阔的绿色屋顶和用较厚的土壤较坚固的结构建造的密集型屋顶不同，它在生态上更复杂。马里兰大学环境科技学院副教授David R. Tilley估计绿色屋顶“领先于绿墙产业五到八年，从市场渗透、普及程度、标准和大小的角度来看。”
Simmons还说，“设计师应该询问客户，‘您想要的是什么效果？仅仅为了美观，还是考虑到雨水和生物多样性？’”，然后根据需求量身设计。“产业这一方有责任说，‘好的，您住在亚特兰大，有每平方英尺100英镑的限制，您想存留半英尺的雨水，您还想吸引蝴蝶过来。好，这些都是您的要求；谢谢您，我们回去会按照您的要求为您设计一个这样的屋顶。’现在，它意味着很大的责任心。”

光，影和能源影是植物覆盖着的表层对生态系统最大的贡献。“一旦你的整个雨棚用了三到四年，它就该寿终正寝了，”Tilley说，“你可能看到太阳负载减少了95%。”雨棚是根据相对于墙体面积的叶面积指数（LAI）来测量的；每单位LAI，日照减少约一半。内部温度效应严重依赖于保温系统：如果墙的R值（热阻值）高，即使LAI大幅减少也只能轻微降低温度，但如果R值低，茂密的雨棚能明显降低冷却成本。用植物代替黑沥青能增加屋顶漫反射系数，蒸散能增加城市大气层的湿度；二者都有助于缓和热导效应。
相反效益——通过使用绿色正面系统减少被动式太阳能供热量——需要落叶树种，它们的叶子在冬季脱落因而太阳光线能穿透到建筑内。在当地条件下即能茁壮生长的土生植物（气候带，抗虫和土壤兼容等）更合适；明智的做法是咨询当地的植物学家。
关于安装在一个项目中的植物品种，每个区域都有它的成功范例和问题案例。马里兰的Tilley提醒不要栽植英国常春藤（洋常春藤），它会顽强附在支撑结构上并凶猛地越过支撑结构从窗户进入到建筑物内。纽约的Nielsen把柴藤看作另一个潜在的怪兽：柴藤既赏心悦目又芳香扑鼻，但它能长到70英尺的高度，它强硬的木树干能压垮金属撕掉屋顶的雨水管。
在法国植物学家Patrick Blanc的垂直花园中，筛网支撑的油毡、管道和阀门系统通过毛细管向根部输送水培营养。维护相当可观：容器中的土壤远比地坪上的土壤干涸得快。“那些是艺术品，”纽约城市大学（CCNY）伯纳德和安妮斯皮策建筑学院的一位景观建筑项目总监Denise Hoffman Brandt说，“它们的安装和维护花费巨大。模块式、低维护的绿墙系统尚未投放到市场。”
一种可替代的方法——在一个建筑物外部上或者附近的绿色正面系统或轻型格子，植物根植在地面土壤里——以其较低运营成本和较少复杂结构提供了热量及其他方面的好处。当“你没有太多可利用的规划空间来合并花园或大园景树”时，或者当你在翻新原工程时，这些系统也可用来整合植物，总部位于洛杉矶的绿屏公司副总裁James Sable说。总的来说，在低楼层或屋面上应用绿色正面比在摩天大楼上可靠。但热带的一些少数情况例外（如马来西亚建筑师Kenneth Yeang Hon. FAIA[美国建筑师协会荣誉会员]在东南亚设计的塔），风载使得四五层以上的垂直绿色结构变得问题重重。