When cities reach their breaking point, life must be moved beneath the surface. China’s subterranean-development expert speaks.
FOR THE FIRST TIME in human history, more people live in cities than outside them. As metropolises blossom throughout the world, and as existing urban centers struggle to cope with influxes of immigrants, more and more governments are turning to the underground. Developments beneath the earth’s surface aim to ease congestion, salvage open spaces aboveground, and provide some reprieve for cities in search of solutions to the problems posed by teeming populations and inadequate infrastructure.
Shu Yu has been at the forefront of underground urban planning for decades. He spent many years studying in Japan, the home of modern subterranean development, before bringing his expertise to bear on his homeland, China. He currently lives in Shanghai, where he is a professor at Tongji University, vice director of the Tongji University Underground Space Research Center, and president of the Shanghai-Tongji Underground Space Planning and Design Research Institute. He is extensively involved in the planning of the myriad southern Chinese cities where populations have exploded over the past half century, and has been charged with designing the underground portion of the 2010 World Expo in Shanghai.
What follows is an exposition of the history and current uses of underground urban space, as told to Tong Zhen. It is excerpted from a longer interview with Shu Yu that was published last year in Urban China magazine and translated from Chinese by John Thompson.
“URBAN UNDERGROUND SPACE” simply refers to space below a city’s surface: either man-made spaces formed through excavation or caves formed by natural processes. Besides being a geologic fact, the realm under the earth’s surface can be seen as a potential space for development.
Mankind has a long-standing history of developing underground space. Consider, for instance, the Peking Man site at Zhoukoudian, and the dwellings in the Loess Plateau of western China. People lived in the caves and planted crops in the ground overhead. In response to environmental pollution and energy crises, modern cities have employed eco-friendly architecture like green roofing, which essentially derives from Chinese cave dwellings.
If we want to resolve urban problems related to population density and limited surface space, we must turn to underground development. It’s a matter of “ascending to the sky and reaching into the earth.” Today, underground space is still used primarily for disaster protection. During World War II, Paris turned abandoned caves into ammunition depots, secret outposts, and arsenals. London used subways. Now China plans to construct integrated civil-defense projects designed to prepare for military conflict and protect against natural disasters. For instance, rain from torrential downpours cannot adequately be drained through sewer systems and often produces flooding. Constructing underground rivers is a relatively easy solution to this problem, and it creates a sustainable way of dealing with rainwater.
There are also significant stores of energy underground. Shanghai’s average annual temperature is about 16 degrees Celsius; underground, it’s a little bit lower, and without much seasonal fluctuation. By exchanging energy between the surface and the underground in accordance with the laws of stratigraphic temperature differences, we can cool the surface in the summer and warm it up in the winter. At the 2010 Shanghai World Expo, the main hall’s air-conditioning system will get about 80 percent of its energy from geothermal and hydrothermal heat pumps.
Of course, underground space is also used for transportation, storage, infrastructure, and shopping. Japan is planning to build underground shopping districts connecting subway stops. They will be two to three levels, with the first level for shops and public walkways, and the second floor on down for parking garages and subway stations. It’s convenient and cozy, and the profits are remarkable.
But this kind of development is only possible when the cost of surface expropriation and demolition exceeds that of underground construction, which generally has two to three times the start-up costs of surface construction. Our research shows that once a city’s per capita GDP tops $3,000, underground development becomes economical. Many Chinese cities now reach or surpass this threshold; in the cities that have over one million people, surface transportation is inefficient, unpunctual, and uncomfortable. Forty cities in China currently have plans in place to build subway and rail lines to remedy these problems. The experience of other countries shows us that the key to developing underground space in China is the intensive development of rail transport.
Foreign businesses with experience in developed nations have begun building underground in the downtowns of Chinese cities. Shanghai already has in use 30 million square meters of underground facilities. For the Shanghai World Expo, I’m working on underground integrated government facilities, energy-source centers, a series of high-tech guidance systems, and an underground safety-evaluation system. All of these efforts serve the expo’s theme: “Better City, Better Life.”
Promotional video for the 2010 Shanghai World Expo.
THE USE OF UNDERGROUND SPACE varies from North America to Western Europe to Asia, according to differences in land, economy, society, culture, and climate. The United States has a very innovative, progressive model. When a city reaches the point at which the existence of overpasses becomes a restriction to urban development, they knock them down and take them underground. Boston had an overpass built in the 1970s that improved transportation in the city but weakened the vitality of the vibrant areas alongside the highway, turning it into a dead space. In order to revitalize the city center, the government decided to take the overpass underground and landscape the surface, revitalizing the area.
Canada is a northern country with five months or more of unrelenting winter cold, which makes living and working there inconvenient. Taking advantage of the 1967 World Expo in Montreal, the city built a subway system. A network of underground pedestrian walkways connected the basements of the major buildings around each stop. Underground plazas and common spaces were linked to commercial areas, forming a true underground city. The government gave companies the right to use the subterranean space, drew up technological standards, established design requirements that would satisfy the public’s
needs, stipulated opening and closing times, and encouraged commerce by paying for construction and providing security. This kind of experience—the city guiding private enterprise in the development of underground space—is worth learning from.
Europe’s exemplar is the Parisian “twin-level city” of La Defense. This modern underground business center integrates rail transport and roads, leaving nothing but open space on the surface. Buildings have six-level basements, so all kinds of facilities have been placed underground. The city’s lifeblood runs through these underground spaces, truly realizing the dream of a “twin-level city”! Paris has also seen the transformation of the shopping mall. As the city expanded in the middle of the century, its longtime central marketplace at Les Halles went into decline. In 1971, the city dismantled the market and began building a railway hub and mall on the site, using the construction of the rail lines as an opportunity for large-scale revitalization. The remaining structures were preserved, and the new project was rendered in an excellent combination of modern, contemporary, and ancient styles. It was christened in 1977 as Forum des Halles, a four-story underground shopping area with a recessed plaza, fountains, mosaics, and a wax museum.
In Asia, Japan has made the greatest strides in developing underground space. Following the construction of underground railways, Japan started building other facilities beneath its cities. Osaka has a completely integrated underground city center; urbanites can go about their daily business without ever setting foot on the surface. By the late ’50s, the reputation of Osaka’s underground street—translated into English as “underground shopping center”—had spread internationally and become known as a crystallization of theoretical approaches and building methods. The area occupied by this development was public, so the government held the land-use rights; it provided funds for transportation and let famous commercial brands open stores. This led to the founding of the cooperative Underground Street Company Limited. In 2001, Japan implemented the Underground Special Use Measures, which granted land-use rights to public services. This was a major breakthrough, as it resolved the problem of building public works underneath privately owned land. Previously, subway projects had been delayed for years because of objections by property owners. China should learn from this regulation.
FOR UNDERGROUND DEVELOPMENTS to be successful, you have to find a way to get around the problems of light, moisture, and noise. People associate the underground with tombs and bomb shelters. On the surface, the field of vision is broad: You can see light, trees, people going about their business. Underground, in a sealed space, you can’t; it’s difficult for people to see how they might escape if something happens. If the air quality isn’t sufficiently regulated, it will give off an “underground smell.” Generally, cramped, closed spaces make people agitated and uncomfortable. We are still researching the underground environment to determine the extent to which its characteristics affect physiology and psychology.
We need to make the bodily experience of being underground not feel like you’re underground. We should change the composition of the underground environment—the space’s lighting, shadows, colors, materials, shape, and texture—so that it matches what people are used to above ground. We should change the quality and flow of air. We are also thinking of ways to introduce key elements of the natural environment underground, such as sunlight, green plants, flowing water, and small animals. If we can’t do that, we can at least project images of surface life onto the walls underground.
Digital image collages by Natalie Labriola: Subterranean Mini-Mall; Guardians of the Fallout Shelter; Sleep-Away Bunker; Snow Day; Out of Business; Stalagmite Yoga Chamber; Tunnel Vision Quest. To the right: Shanghai World Expo mascot Haibao, who is rendered in the form of the Chinese character ren, which symbolizes human beings; his name means “treasure of the sea.”