当我们研究建筑时，
你总会发现，
任何新的或创新的想法实际上已经被反复尝试，
通常可以追溯到几十年前。
Building under construction with Obayashi’s ABCS system
大林的ABCS系统正在建设中
One interesting thing about the building construction productivity puzzle is that it’s a worldwide phenomenon. Unlike with say, healthcare, or transit, or car manufacturing, where we have examples of other countries with different systems that perform far better, in building construction, especially homebuilding, almost everyone seems to be in a pretty similar boat. Around the world we see different capital/labor tradeoffs, different levels of prefabrication, and different building systems, but they mostly get similar results in terms of costs.
关于建筑施工生产率的一个有趣的问题是，这是一个世界性的现象。不像医疗保健、交通运输或汽车制造业，我们有其他国家的例子，它们有不同的系统，表现得要好得多，在建筑建筑，尤其是住宅建筑，几乎每个人似乎都在一个相当相似的船上。在世界各地，我们可以看到不同的资本/劳动力权衡，不同的预制水平和不同的建筑系统，但它们在成本方面大多得到相似的结果。
The upshot is that there’s a huge number of examples of people around the world trying to solve the problem, which often look much different than the solutions that have been attempted in the US.
结果是，世界各地有大量的人试图解决这个问题的例子，它们通常看起来与美国尝试的解决方案大不相同。
One of these examples comes from Japan. Starting in the late 1970s, Japan’s large construction companies began investing huge amounts of time and money into construction robotics research, culminating in the creation of automated building factories designed to construct entire skyscrapers. Rather than the “conventional” industrialized building approach, where construction work is moved into an off-site factory, these systems moved the factory onto the jobsite. They thus avoided one of the fundamental challenges of off-site construction (though as we’ll see, they got a whole new set of challenges in exchange).
其中一个例子来自日本。从20世纪70年代末开始，日本的大型建筑企业投入大量的时间和资金进行建筑机器人的研究，最终出现了可以建造整个摩天大楼的自动化建筑工厂。传统的工业化建筑方法是将建筑工作转移到场外的工厂，而这些系统将工厂转移到工地上。因此，他们避免了场外建设的一个基本挑战(尽管我们将看到，他们得到了一个全新的挑战作为交换)。
Japan’s Construction RobotsRobots were first brought to Japan from the US in the late 60s, and they quickly took root in the manufacturing sector. Kawasaki began producing their first industrial robot (a licensed version of the Unimate) in 1969, and Toyota began using robots on their assembly lines as early as 1974. Starting in the late 1970s, Japan’s large construction contractors, with the assistance of MITI, began investing heavily in developing robots capable of performing construction tasks. Heavy construction in Japan was (and still is) dominated by a few large firms (known as the Big Five or Big Six), which all invested heavily in R&D as part of their normal operations. Japan had traditionally had high construction costs (driven largely by labor costs) and difficulty finding enough skilled labor, and they also observed the same trend of stagnating construction productivity that we’ve seen in the US. Construction robots seemed to offer a potential solution.
日本的建筑机器人
上世纪60年代末，机器人首次从美国引入日本，并迅速在制造业扎根。川崎重工在1969年开始生产他们的第一个工业机器人(Unimate的授权版本)，丰田早在1974年就开始在他们的装配线上使用机器人。20世纪70年代末，日本的大型建设企业在产业部的帮助下，开始大量投资开发可以执行建筑任务的机器人。日本的重工业行业过去(现在仍然)由几家大公司(被称为“五大”或“六大”)主导，它们都在R&D上大量投资，将其作为正常运营的一部分。传统上，日本的建筑成本很高(主要是劳动力成本)，很难找到足够的熟练劳动力，他们也观察到与我们在美国看到的相同的建筑生产率停滞的趋势。建筑机器人似乎提供了一个潜在的解决方案。
SSR-2, an update to the SSR-1, designed by Shimizu and Kobe Steel
SSR-2是SSR-1的升级版，由清水和神户制钢所设计
The result was the development of a series of construction robots, starting with the world’s first construction robot (the SSR-1, designed to spray fireproofing) in 1983. These initial robots were single-task construction robots, built to perform one specific function such as finishing concrete, inspecting tile, welding, or spray painting. By the 1990s over 100 different types of single task construction robots had been developed in Japan.
其结果是一系列建筑机器人的发展，从1983年世界上第一个建筑机器人(SSR-1，设计用于喷涂防火)开始。这些最初的机器人是单一任务的建筑机器人，被建造来执行一种特定的功能，如整理混凝土、检查瓷砖、焊接或喷涂。到20世纪90年代，日本已经开发了100多种不同类型的单任务建筑机器人。
Boardman-100, a wallboard-placing robot
Boardman-100，一个放置墙板的机器人
Results from these efforts were mixed. Though the robots could often perform their tasks extremely efficiently, they required a great deal of setup and teardown time, and often encountered difficulties in buildings that hadn’t been specifically designed to accommodate them (such as narrow spaces that the robots couldn’t reach). They also had trouble dealing with the somewhat unpredictable nature of a conventional construction site - their need to work uninterrupted, combined with safety limits on how closely workers could approach, tended to constrain the rest of the construction process. And even when tasks could be completed faster, it often meant that the bottleneck just shifted to some other part of the process, limiting the overall benefit.
这些努力的结果好坏参半。虽然机器人通常可以非常高效地完成任务，但它们需要大量的设置和拆卸时间，并且经常在没有专门设计容纳它们的建筑中遇到困难(例如机器人无法到达的狭窄空间)。他们在处理传统建筑工地不可预测的特性时也遇到了麻烦——他们需要不间断地工作，再加上工人可以接近多近的安全限制，这往往会限制施工过程的其他部分。即使任务可以更快地完成，这也常常意味着瓶颈转移到了过程的其他部分，从而限制了整体效益。
The response to this was to lean further into robotics and automation - if robots couldn’t function effectively in a conventional construction environment, then the entire construction process would be changed to accommodate them. Starting in the mid 1980s, Japan’s construction robot development shifted away from individual robots, and towards creating an entire robotic construction site. Instead of a series of isolated tasks, individual robotic workstations would be linked and integrated into a single unified production system - an automated factory capable of spitting out an entire building.
对此的回应是进一步向机器人和自动化倾斜——如果机器人不能在传统的建筑环境中有效地工作，那么整个建筑过程将改变以适应它们。从20世纪80年代中期开始，日本的建筑机器人的发展从单个机器人转向创建一个完整的机器人建筑工地。取代了一系列孤立的任务，独立的机器人工作站将被连接并集成到一个单一的统一生产系统中——一个自动化工厂能够生产出一整栋建筑。
Concept sketches for a building factory, by Obayashi
建筑工厂的概念草图，由大林设计
The Skyscraper FactoriesThough they were developed by many different companies, these building factories all used the same basic group of technologies. They all featured some type of automated conveying system, usually a series of hoists and rail-mounted cranes that could raise material and components up to the “factory floor”, and then move them into position. These systems were designed to allow material to be supplied and moved in a “just-in-time” manner, to avoid large volumes of inventory.
高空造楼机
虽然它们是由许多不同的公司开发的，但这些建筑工厂都使用了相同的基本技术。它们都采用了某种类型的自动化输送系统，通常是一系列起重机和轨道式起重机，可以将材料和部件提升到“工厂车间”，然后将它们移动到指定位置。这些系统的设计是为了让材料以“即时”的方式供应和移动，以避免大量库存。
Buildings would generally be constructed from prefabricated components, such as precast floor panels or pre-built façade panels. Once moved into position, additional work would be done with the help of single task construction robots - most systems for instance had robotic welders for splicing steel columns together.
建筑物通常由预制构件建造而成，如预制地板面板或预制façade面板。一旦移动到位，额外的工作将在单一任务的施工机器人的帮助下完成——例如，大多数系统都有机器人焊工来将钢柱拼接在一起。
The systems also all included some sort of climbing mechanism. As floors were completed, the entire factory would be raised up, and construction would start on the next floor above (due to the expense of dismantling it, the factory structure would sometimes be incorporated into the final building). To protect the “shop floor” from the outside elements, the systems often incorporated a cover around the entire top of the building.
这些系统也都包含了某种爬升机制。随着楼层的完成，整个工厂将被抬高，并在上面的下一层开始施工(由于拆除费用，工厂结构有时会纳入最终的建筑)。为了保护“车间”不受外部元素的影响，该系统通常在建筑的整个顶部安装一个覆盖层。
To facilitate robotic assembly, the buildings would generally be designed to accommodate the robot’s capabilities - layouts were tweaked, connections were redesigned, assemblies were simplified, etc. The goal was to turn the entire construction site into a structured environment more conducive to robotic assembly.
为了便于机器人组装，建筑通常会被设计成适应机器人的能力——布局被调整，连接被重新设计，组装被简化，等等。我们的目标是将整个工地变成一个更有利于机器人组装的结构化环境。
For whatever reason (collusion? mimetic desire? bandwagon effect?) almost every large Japanese construction company developed some variation of this basic system. And they weren’t merely concepts or prototypes - they were all used to construct actual buildings. Let’s look at a few of them.
不管出于什么原因(勾结?模仿欲望?(从众效应?)几乎每一家日本大型建筑公司都开发了这种基本制度的一些变体。它们不仅仅是概念或原型——它们都被用来建造实际的建筑。让我们来看看其中的几个。
In many ways the SMART system is a fairly typical example of these sorts of building factories. SMART (Shimizu Manufacturing system by Advanced Robot Technology) consisted of a series of gantries and horizontal hoists that spanned the extents of the building, with vertical lifts at the edge for delivering material. Up to 25 vertical lifts could be installed, avoiding potential bottlenecks from vertical transportation without the expense of adding an entire crane.
在许多方面，SMART系统是这类建造工厂的一个相当典型的例子。SMART (Shimizu Manufacturing system by Advanced Robot Technology)由一系列跨越建筑范围的龙门架和水平升降机组成，在建筑边缘有用于运送材料的垂直升降机。最多可安装25台垂直升降机，避免了垂直运输的潜在瓶颈，而无需增加整个起重机的费用。
SMART-built buildings consisted of a structural steel frame, with precast concrete floor slabs and prefabricated façade panels, all of which could be moved into position by the automated horizontal hoists. Welding robots were used to connect the steel beams and columns after they were moved into position, with a laser measurement system ensuring placement accuracy. Each component was tracked with a barcode to measure overall construction progress and keep track of material.
smart建造的建筑包括钢结构框架，预制混凝土楼板和预制façade面板，所有这些都可以通过自动水平升降机移动到指定位置。在钢梁和立柱移动到位后，使用焊接机器人连接钢梁和立柱，激光测量系统确保放置精度。每个组件都用条形码进行跟踪，以衡量整体施工进度并跟踪材料。
The system was mounted to the top of the building, and covered the top four floors (the bottom several floors of the building had to be built by conventional methods). Once SMART was in place, all work was done inside the “factory” - work proceeded on multiple floors simultaneously, with structural framing being installed on the top floor while finishing work was completed below. When ready, the entire factory would be raised up using jacks, a completely finished floor would pop out beneath, and work would start on the next floor.
该系统安装在建筑的顶部，覆盖了建筑的顶部四层(建筑的底部几层必须用传统方法建造)。一旦SMART到位，所有的工作都在“工厂”内完成——工作在多个楼层同时进行，结构框架安装在顶层，而完成的工作在底层完成。一旦准备好，整个工厂就会用千斤顶升起，一层完工的地板就会从下面弹出来，然后下一层就会开始工作。
Shimizu was one of the first companies to develop construction robotics, and their SMART system was one of the first automated building systems to actually be used. Testing of it began in the late 80s, and in 1991 it was used to construct the Juroku Bank building. Shimizu also developed several variations on this system, such as one that was mounted to exterior steel masts rather than the building itself, and a version for building broadcast towers.
清水是最早开发建筑机器人的公司之一，他们的SMART系统是最早真正投入使用的自动化建筑系统之一。80年代末开始对它进行测试，1991年，它被用于建造Juroku银行大楼。清水开发了该系统的几个变体，比如一种是安装在外部的钢桅杆上而不是建筑本身，以及一种用于建造广播塔的版本。
Developed by a consortium of 5 companies, Akatuki-21 was in many ways similar to Shimizu’s SMART system. The main difference was that, in conjunction with the “sky factory” on top of the building, there was also a “ground factory” at the base. The ground-based factory would receive parts and materials, and assemble them into higher level-of-completion components (such as floor panels). These would then be transferred up to the “sky factory” above using lifts.
由5家公司联合开发的Akatuki-21在许多方面与清水公司的SMART系统相似。主要的区别在于，与建筑顶部的“天空工厂”相结合，在基地也有一个“地面工厂”。地面工厂将接收零件和材料，并将它们组装成更高水平的组件(如地板)。然后这些东西会被用电梯运到上面的“天空工厂”。
Like SMART, Akatuki was also based around a structural steel building assembled using automated lifts and robotic welding equipment. But instead of precast, Akatuki seems to have used cast-in-place concrete - its horizontal transport systems included attachments for the placing and leveling of concrete.
和SMART一样，Akatuki也是基于一个使用自动升降机和机器人焊接设备组装的钢结构建筑。但Akatuki似乎使用的不是预制混凝土，而是现浇混凝土——它的水平运输系统包括用于浇筑和找平混凝土的附件。
The Akatuki system was also designed for building deconstruction, running the assembly process in reverse for a building that needed to be torn down (though it’s unclear if it was ever actually used for this). Safely tearing down a building in Japan’s dense urban areas was apparently a significant challenge, and there were several other automated factory systems designed purely for building disassembly.
赤树系统也被设计用于建筑解构，将需要拆除的建筑的组装过程反向运行(尽管不清楚它是否真的用于此)。在日本人口密集的城市地区，安全拆除建筑物显然是一个重大挑战，而且还有其他几个自动化工厂系统纯粹是为建筑物拆卸而设计的。
Akatuki was first used in 1994 for the construction of the Shuyodan Headquarters building.
赤树在1994年首次用于建造疏代团总部大楼。
Unlike other systems (which almost always used structural steel or a hybrid of steel and concrete), Big Canopy was designed for use with precast concrete. It was a comparatively manual system, and consisted of 4 large steel masts that supported a platform-based gantry system, and thus was not mounted to the building itself. It was built to work with specially-designed precast concrete members, and was first used in 1995 on the Yachiyodai condominiums.
不像其他系统(几乎总是使用结构钢或钢和混凝土的混合)，大天篷设计使用预制混凝土。它是一个相对手动的系统，由4个大型钢桅杆组成，支撑着一个基于平台的龙门架系统，因此没有安装到建筑物本身。它的建造采用了特别设计的预制混凝土构件，并于1995年首次用于八喜代公寓。
In addition to Big Canopy, Obayashi also had a system very similar to Shimizu’s SMART called ABCS (Advanced Building Construction System).
除了Big Canopy，大林还有一个与清水的SMART非常相似的系统，叫做ABCS (Advanced Building Construction system)。
T-Up (Totally Mechanized Construction System for High-rise Buildings) was another system similar to SMART, but arranged in a slightly different configuration. Rather than building an entire floor at once, T-Up first constructed a steel-framed core, which a cantilevered platform (called a ‘hat truss’) was mounted too. The platform would climb the steel core, and then construct the rest of the floor below (using the now-familiar automated gantries). The platform eventually became the top floor of the building.
T-Up(高层建筑全机械化施工系统)是另一个类似于SMART的系统，但在配置上略有不同。T-Up没有一次建造整个楼层，而是首先建造了一个钢框架核心，其中还安装了一个悬臂平台(称为“帽架”)。平台将爬上钢芯，然后建造下面楼层的其余部分(使用现在熟悉的自动化龙门)。这个平台最终成为了大楼的顶层。
T-Up could also be supplemented with single-task construction robots for finishing work, material transportation, component manufacturing (for things like facade and floor panels), and a variety of other tasks.
T-Up还可以由单一任务的建筑机器人进行补充，用于完成整理工作、材料运输、组件制造(如立面和地板)以及各种其他任务。
T-Up was first used in 1992 on the Mitsubishi Heavy Industries building.
T-Up于1992年首次用于三菱重工大楼。
OthersThere were a variety of other systems. Some, like MCCS, FACES, and ABCS, were additional variations on the same basic concept: a covered climbing platform, automated material movement, and a series of single-task construction robots, all used to build a steel-framed building. Others used the same components in a different configuration - AMURAD, developed by the Kajima company, opted to keep the factory on the ground floor and instead raise up the entire building as each floor was completed. Some systems were designed to only erect a portion of the building in an automated fashion, with the rest built by conventional construction. Both Shimizu (Hybrid SMART) and Obayashi (Hybrid ABCS) had systems like this. And some, like HAT Down by the Takenaka Corporation, were designed purely for building deconstruction.
还有很多其他的系统。其中一些，如MCCS、FACES和ABCS，是相同基本概念的额外变体:有覆盖的攀爬平台、自动材料移动和一系列单任务建筑机器人，所有这些都用于建造钢框架建筑。其他公司在不同的配置中使用了相同的组件——鹿岛公司开发的AMURAD选择将工厂保留在一层，而是在每一层完成时将整栋建筑加高。一些系统被设计成只以自动方式建造建筑的一部分，其余部分由传统建筑建造。清水(Hybrid SMART)和大林(Hybrid ABCS)都有这样的系统。还有一些，比如竹中株式会社(Takenaka Corporation)设计的HAT Down，纯粹是为了建筑的解构。
Successes and Failures of the Automated Factories
During the 90s, these systems were widely deployed - it’s unclear how many buildings were built with them, but Bock 2013 documents at least 60 instances of their being used in some fashion. Some systems such as Akatuki 21, seem like they were only used on a single building. Others, like Shimizu’s SMART and Obayashi’s ABCS and Big Canopy, were used repeatedly.
在90年代，这些系统被广泛部署——不清楚有多少建筑使用了它们，但Bock 2013记录了至少60个以某种方式使用它们的实例。一些系统，如赤树21，看起来他们只在一个单一的建筑上使用。其他的，如清水的SMART和大林的ABCS和Big Canopy，被反复使用。
partial list of buildings built via automated factory in Japan
Considerable effort was spent on analyzing these systems' performance. Nearly all showed some degree of labor reduction, between 20% and 70% depending on the task being performed. Big Canopy required just 25% of the labor to erect a floor as a more traditional precast system, and T -Up required 70% fewer working-hours than conventional construction required.
在分析这些系统的性能上花费了大量的精力。几乎所有人都显示出一定程度的劳动减少，根据所执行的任务在20%到70%之间。作为一种更传统的预制系统，Big Canopy只需要25%的劳动力来架设地板，而T -Up需要的工作时间比传统建筑少70%。
Labor required for Big Canopy vs other systems
SMART, AMURAD, and ABCS also showed labor productivity improvements. Productivity improvements were also seen within single projects - as they progressed, and workers fell into a rhythm, performance would improve, with later floors being built faster than earlier floors (similar effects are seen on conventional construction sites).
SMART、AMURAD、ABCS的劳动生产率也有所提高。生产率的提高也体现在单个项目中——随着项目的推进，工人们进入了一个节奏，工作表现也会提高，较晚的楼层比较早的楼层建造得更快(传统建筑工地也有类似的效果)。
Construction time per floor for the AMURAD system (higher floors were constructed earlier)
AMURAD系统每层的施工时间(越高的楼层施工越早)
The other frequently cited benefit was in construction speed. Even with the initial factory setup time (typically 1 month, though in some cases it could take up to 2-3 months), the buildings could be built significantly faster than conventional construction. ABCS claimed a 2-3 month savings for a 20 story building, and a 6 months savings for a 40 story building:
另一个经常被提及的好处是建设速度。即使考虑到最初的建厂时间(通常是1个月，但在某些情况下可能需要2-3个月)，建筑的建造速度也会比传统建筑快得多。ABCS声称，20层的建筑可以节省2-3个月，40层的建筑可以节省6个月:
Shimizu found that a 15% savings in construction period with their SMART system, though this required a large enough building to overcome the initial long setup period for the factory:
清水公司发现，他们的SMART系统可以节省15%的建设周期，尽管这需要一个足够大的建筑来克服工厂最初较长的安装周期:
Time required for SMART construction vs conventional
Something similar was found with the MCCS system - when the building was too short (in their case 8 stories), no time savings was obtained.
在MCCS系统中也发现了类似的情况——当建筑太短时(在他们的案例中是8层)，没有节省时间。
Other benefits were found as well. Construction defects were apparently reduced (though I can’t find any specific data on it) The protective covering meant fewer days were lost to inclement weather. By some metrics the work environment was less taxing - Obayashi apparently measured the heart rates(!) of their workers on the Big Canopy system and found a noticeable decrease. There was also less construction waste - Shimizu documented a 70% decrease in waste on buildings using the SMART system.
研究还发现了其他好处。建筑缺陷明显减少了(虽然我找不到任何关于它的具体数据)，保护性的覆盖物意味着在恶劣天气下损失的天数减少了。从某些指标来看，工作环境更轻松了——大林显然在大冠系统上测量了他们员工的心率(!)，发现心率明显下降。建筑垃圾也减少了——清水记录说，使用SMART系统的建筑垃圾减少了70%。
However, there were drawbacks of the systems as well. The long factory setup time made them impractical for smaller buildings, and even on buildings that were large enough, extensive upfront design and coordination was required to design the building for robotic assembly. In some ways, the move from single-task construction robots to fully automated construction sites just shifted where the difficulties occurred - instead of a long setup (and takedown) time for each individual task, now you had one enormous and costly setup over the entire first portion of the project.
但是，这些制度也有缺点。工厂设置时间过长，这使得它们不适用于较小的建筑，即使是足够大的建筑，也需要大量的前期设计和协调来设计机器人组装的建筑。在某种程度上，从单一任务的施工机器人到完全自动化的施工现场，只是转移了困难发生的地方——不再是每个单独任务的长时间设置(和拆卸)，现在你有一个巨大的和昂贵的设置在整个项目的第一部分。
And the expense of the systems, combined with the relatively modest gains in construction time, meant they had significant payback periods. Kajima calculated that AMURAD would theoretically pay for itself in about 8 buildings, meaning it would take at best 20 years before a positive return on investment would be seen.
而这些系统的成本，加上建造时间上相对有限的收益，意味着它们有显著的回收期。Kajima计算出AMURAD理论上可以用8栋楼来收回成本，这意味着它最多需要20年的时间才能看到投资的正回报。
The Automated Building Systems Today
Despite being relatively recent (many of these systems were in use in the early 2000s), and the amount of enthusiasm surrounding them, none of these building factory systems appear to currently be in use. I can’t find any recent examples of buildings built using any of these methods, and pictures of the factories in action all seem to be of the same several buildings. None of the systems seem to be mentioned in any of the companies’ annual reports (though both ABCS and Big Canopy are mentioned in Obayashi’s 2004 report), and I can’t find any mention of them on any company websites. A steady stream of publications can be found through the 1990s and into the early 2000s, and then stops.
尽管这些系统是最近才出现的(其中许多系统是在21世纪初才开始使用的)，以及围绕它们的大量热情，但这些建筑工厂系统目前似乎都没有投入使用。我找不到任何使用这些方法建造的建筑的最近的例子，而实际工厂的图片似乎都是相同的几栋建筑。虽然2004年大林社长的报告书中提到了ABCS和Big Canopy，但没有一个企业的年报中提到这些制度，而且在企业网站上也没有找到。”从20世纪90年代到21世纪初，出版物的数量一直稳定，然后就停止了。The one exception here is Shimizu, which seems to be continuing to develop construction robots, as well as a system for integrating them into an entire jobsite (the Shimizu Smart Site). They show what looks like some testing environments for a new generation of robots (doing many of the same tasks as previous construction robots), as well as an artist's rendering of the now-familiar-looking building factory. It’s unclear if this latest iteration has actually been used anywhere.
这里唯一的例外是清水，它似乎在继续开发建筑机器人，以及将它们整合到整个工地的系统(清水智能工地)。它们展示了新一代机器人的一些测试环境(和以前的建筑机器人做很多相同的任务)，以及一名艺术家对现在看起来熟悉的建筑工厂的渲染。目前还不清楚这一最新版本是否真的在任何地方使用过。
Concept sketch of Shimizu’s current automated building system
清水目前的自动化建筑系统的概念草图
Why Didn’t the Building Factories Succeed?
The building factories were an interesting angle on the problem of construction productivity, but they ultimately seemed to have similar limitations as off-site industrialized building systems. Namely, they had extremely high up-front costs (since they required a large amount of heavy, complex equipment) and comparatively low volumes (since each factory could build just a single building at a time). Construction speed was improved, but only on large enough buildings (screening off buildings that were just a few stories, the vast majority of construction), and only marginally.
建筑工厂是解决建筑生产率问题的一个有趣的角度，但它们最终似乎与非现场工业化建筑系统有类似的限制。也就是说，它们的前期成本非常高(因为它们需要大量笨重、复杂的设备)，而且产量相对较低(因为每个工厂一次只能建造一座建筑)。建造速度有所提高，但只适用于足够大的建筑(排除了只有几层楼高的建筑，这是绝大多数的建筑)，而且只提高了一点点。
And this created a vicious circle - the relatively modest productivity improvement meant buildings still took months or years to construct. This meant feedback on their performance came excruciatingly slowly, making it hard to iterate and improve on the systems. Low rates of improvement meant that the required payback period was high, which meant that it was hard to justify further development. It’s hard to iterate on an idea until it clicks when each iteration costs hundreds of millions of dollars to run, and your feedback trickles in over a period of months or years. It was only the huge size of the Japanese construction companies and their willingness to sink huge sums on R&D that allowed these experiments to be run at all.
这就造成了一个恶性循环——相对温和的生产率提高意味着建筑仍然需要数月或数年才能建成。这意味着对他们表现的反馈非常缓慢，使得系统难以迭代和改进。低的改进率意味着所需的回报期是高的，这意味着很难证明进一步的发展是合理的。
当每次迭代都要花费数亿美元来运行时，你很难对一个想法进行迭代，并且你的反馈会在几个月或几年的时间里慢慢产生。正是由于日本建筑公司的庞大规模，以及他们愿意在研发上投入巨额资金，才使得这些实验得以进行。
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