1. Underground Urbanism
In 1974, Gunnar Birkerts has proposed citywide systems of underground conduits. The 300 meter wide and 60 meter deep elaborate grids of trenches would hold utility and distribution networks, central heating and cooling facilities, recycling and waste-treatment plants, and factories. Thus, the ground level would be used for less utility-related things such as parks, residential areas, and schools, etc. Greek urban planner Constantinos Doxiadis argued as well that the ground level be returned to the people for leisure and pleasure, and underground be arranged for factories and roads. That is, the concept is 'machines and utility below, nature and leisure above'. Paolo Soleri suggested a three dimensional city ‘arcology’ which is self-sufficient, highly complex, and highly efficient. Edward P. Bass built Biosphere2 in preparation for the nuclear winter.
On the other hand, the underground urbanism have widely been realized from Houston, America in 1950s to Montreal and Toronto, Canada. Japan began to develop unique underground passage systems in Tokyo and Osaka from the early 20th century, and Korea and China can also be called as advanced countries in underground development which uses urban underground space actively.
2. Urban Underground Space Development in Big Cities
(1) Toronto, Canada
The Toronto Underground Pedestrian Mall System is circumscribed within its urban center. But, it is not easy to grasp the system which extends like a labyrinth 5 blocks wide and 10 blocks long.
The system is a group of privately owned buildings which are connected with each other by underground passages. The system provides a variety of functions such as traffic, shopping, office work, and leisure. Here, the public part of underground space is used by contracts with the municipal authorities. The system networks have the open structure in which the ground level and the underground are connected organically.
When did the system start to be built? It goes back to 1900 when the headquarters of the Eoton Company on Yonge street and its annex next to it were connected underground. And, five underground pedestrian passages were built by 1917. When the Union Station opened in 1927, the underground pedestrian passage linking the station and the Royal York Hotel across the street was constructed. However, what we can see now as the final structure of it was built mainly in the 1970s.
The most important hints we can get from the Toronto urban underground space seem to be 'direction' and 'time'. A consistent ideal called the securing of the ambulatory right and the accumulated time at least for 50 years during which the ideal has been embodied to that direction seem to have made the system a history.
And the system shows that the real vitality of a city comes from the meticulous integral development of the ground and the underground. The system demonstrates how important it is to overcome the dichotomous thought on the ground and the underground.
Fig. 1. Toronto Underground Pedestrian Mall System
Fig. 2. Toronto Eaton Cent
Fig. 3. Urban underground space, Toronto
(2) Osaka, Japan
Once, I was shocked by the case presented by a Japanese professor at an international conference. The case was CrystaNagahori, in which the mass of the top light rising up to the center of the street rhythmically was the strong image to an unimaginable degree. A couple of years later, I could finally see with my own eyes the completed CrystaNagahori. I thought that even though the Korean underground shopping street was born by benchmarking that of Japan, the differences between the two were quite as big as possible.
Fig. 4. Diamor, Osaka
Fig. 5. CrystaNagahori, Osaka
3) Houston, USA
Houston already finished a tunnel in 1947, and managed to have a wide-range tunnel system by 1950s. The Downtown Houston Tunnel System which connects over 50 buildings and parking lots of the urban center is developed, owned, and managed by the private sector for the conveniences of office workers. The city government prescribes that the site boundary line is up to the center of the street (Houston confers the occupation right of street part to the site owner for 30 years.). Thus, if the site owner agrees with the owner of the site across the street, they can build a tunnel across or parallel to the street. The city government, conferring the street occupation rights, does only periodic checks on facilities. Privately owned tunnels of the city can be accessed from lobbies of buildings, and used only during daily working hours.
Fig. 6. Downtown Houston Tunnel System Fig. 7. Cityscape on ground level
Fig. 8. Urban underground space, Houston
(4) Hanover, Germany
In the ground part of the urban center of Hanover, since there are many pedestrian-only spaces, and
sidewalks are wide, it is easy and pleasant to approach the center on foot. On the other hand, the more central
a place is, the narrower the carriageway becomes, which makes drivers inconvenient to use their cars. The
urban underground part takes care of pedestrians and promotes commercial activities. Especially, here, the
Choice and Focus strategy in underground development is being handsomely embodied by selecting the location
the underground development is most necessary, calculating its necessary scale, and building it as the
best underground space. The underground space called the Niki-de-Saint-Phalle Promenade has been built along
the street from the Bahnhof to the Kropck station. The characteristics of the Promenade evaluated by citizens as the good development are as follows.
Fig. 9. Plan of Niki-de-Saint-Phalle Promenade
The underground from the Bahnhof where all the mass transportations including train, subway, tram, and bus are concentrated, across the busiest commercial district, to the Kropck subway transfer station.
It adopts the concept of building additional pedestrian road on the existing ground level pedestrian road.
2) Pedestrian accessibility
Passing through the Bahnhof and extending to surrounding areas, it is accessible to pedestrians nearly as well as those in the station.
Located in the pedestrian-only district, people can access it without interference of vehicles.
Along with its shallowness, stairways and elevators in many places make people free of psychological and physical pressures.
Since it is space with the upper part of it open, people can see both of the inside and outside of it.
Since there is no entrance of it, physical and psychological boundary does not exist.
3) Matching with urban life of citizens
By arranging various shops in sunken space, it entices interests and curiosities, satisfying commercial activities along the street naturally.
Since its top part is open to the sky, it does not provide cover from climates completely. But, since there are ceilings in the middle of it, and it is connected with indoor spaces easily, it provides room for people to find cover from rain and snow.
Since the well-designed underground is visually connected with the ground level, people can sense the natural changes, experiencing a new urban space.
4) Disaster prevention and safety
With its top open, the structure does not need the connecting way with surrounding buildings, and there is no need for various protective measures for disasters.
There is no need for fireproof districting. But, in the indoor part of the pedestrian passage of the Bahnhof, sprinkler facilities are equipped with.
It is an open structure in which fire-fighting can be performed easily in emergency.
Crime prevention is naturally achieved because there are many people and shops together with CCTVs.
If the rain recycling facilities are installed, rainwater will be treated naturally.
Fig. 10. Niki-de-Saint-Phalle Promenade, Hanover
(5) Hangzhou, China
I discovered at Life Plaza of Hangzhou that something called the city can have a great cause. The great cause of the city means that, though it is not activated now, when it begins important activity called development, the city responds with enough ability to think of the future. Most cities are those of small-minded persons who, to avoid criticism of excessiveness, are accustomed to the praise of rationality, developing it piece by piece, and not bearing responsibility for the results.
Fig. 11. Plan of Life Plaza, Hangzhou
Can the construction of a city entice excitement in citizens' life? The people who live in the place where its architectures make hearts beat must be happy. In a hot afternoon in 2011, I was in such a thought at Hangzhou
Fig. 12. Life Plaza, Hangzhou
3. A Challenge of Korea : WSW in Seoul (Under Working)
Underground can be viewed as the symbol of human beings' old and proud search for truth, power, beauty, and safety through imagination and technological achievements. The future environment cannot avoid being less natural. The problem, though, is whether it will be less humanistic. Thus, the wide and deep approach to the underground is the attitude demanded to solve the problem. To reside in the underground is the multidisciplinary subject involving psychology, society, politics, culture, and health as well as technology, and, needless to say, the core of the subject is humanity.
О Lee, Gahng Ju, An Analytical Examination of Urban Underground Space Utilization in Montreal, Journal of
Architectural Institute of Korea V.24 N.5, 2008 О Lee, Gahng Ju, Developmental Process and Causes of the Toronto Underground Pedestrian Mall System:
1959-1990, Journal of Architectural Institute of Korea V.22 N.5, 2006 О Tarr, J.A., Dupuy, G., Technology and the Rise of the Networked City in Europe and America, Temple
University Press, 1988 О Tuan, Yi-Fu, Man and Nature, Association of American Geographers, 1971 О Williams, Rosalind H., Notes on the Underground, The MIT Press, 2008