PLANNING SUPER CITIES ON COMMUNITY BASIS

Transcription

1 ITPI JOURNAL 5 : 2 (2008) I T P I JOURNAL ABSTRACT PLANNING SUPER CITIES ON COMMUNITY BASIS DR. REMI I. OBATERU Associate Lecturer, Department of Urban and Regional Planning, University of Ibadan, Nigeria Explaining the concept of Cellular City, the author highlights that these cities are made of semi-autonomous communities separated by traffic green belts (corridors) which are at least 120 mt. wide and spatial coverage (land areas) which will basically be the function of their physical features and residential densities and therefore will vary from one community to another. Each community will have the population of 500,000 with a Community Business Centre (CBC) and perform all the functions expected of a normal city of that population size. While concluding, the author narrates the merits of the Cellular City. 1. INTRODUCTION The present growing concentration of the populations of the countries of the Third World in large cities, especially in super cities of 10 to 20 million population, demands that serious consideration be accorded to their physical forms and structures. In 2006, for instance, each of the cities of Shanghai and New Mexico had populations of about 20 million and New Delhi about 15 million. Most of the Third World super cities are also sprawling amorphously. This situation needs to be addressed. Fig. 1 Past Urban Forms In this article, a proposal is made for the planning and development of large cities on community basis. This involves the division of cities into semiautonomous communities of 50,000 population separated by traffic greenbelts (corridors), which are at least 120 meters wide. This applies to both city expansion and the planning and development of new cities ab initio. For the purpose of this article, the strategy is characterized as the Cellular City Plan for want of a better term. Before delving into it, it is necessary to first outline the previous urban forms and structures advanced to address the problem of urban growth, especially of uncontrolled urban growth, since the industrial revolution of about 1750 to 1850 in Western Europe. 2. PREVIOUS FORMS OF URBAN GROWTH Since the last two decades of the 19th Century, several forms of urban growth have been purposed by social reformers and urban planners, the most notable of which are the following (refer Fig. 1).

2 2

3 respectively on the linear principle by Le Corbusier, a Swiss architect planner; The Linear Plan for Stalingrad prepared in the 1930s by N.A. Milytin; The Linear Plan for London prepared by the MARS Group of architects in 1937 and published in 1941; The Jose Sert s Plan for a group of towns with a total population of about 960,000; The Broadacre City prepared in 1940 by Frank Lloyd Wright and its versions suggested by Melvin Webber; The Dispersed Sheet and the Galaxy Plans of Kevin Lynch; and The Five Fingers Plan of Copenhagen and the Radial Plan of Stockholm. Most of these plans are liner in form. The linear disposition is explained by the importance attached to public transportation and communication in urban development. The radial city plans developed after the initial sets of linear plans were adaptations of the linear concept. Such were The La Ville Radieuse and City of Tomorrow, and the Five Fingers Plan of Copenhagen and the Radial Plan of Stockholm. The emphasis of the Broadacre City prepared in 1940 by Frank Lloyd Wright and its versions suggested by Melvin Webber; and the Dispersed Sheet and the Galaxy Plans of Kevin Lynch, which are American, emphasize on low density urban development and the dispersal of urban functions over the entire metropolis. The La Cuidad Lineal, a linear city of 30,000 population proposed near Madrid by Don Arturo Soria y Mata in 1882; The Garden City of 32,000 population advanced by Ebenezer Howard in 1898; The La Cite Industrielle, a partially linear industrial city of 35,000 population published in 1901 by Tony Garnier, a French architect; The La Ville Radieuse and City of Tomorrow designed for 1.5 and 3.0 million people 2. THE CELLULAR CITY The cellular city is made of semi-autonomous communities separated by traffic greenbelts (corridors). 2.1 Communities Each community will have a population of 500,000 with a Community Business Centre (CBC) and perform all the functions expected of a normal city of that population size. The Central Business District (CBD) of the city will be located in the community in its heartland or geographical centre. The spatial coverage (land areas) of the communities will basically be a function of their 3

4 physical features and residential densities. They will therefore vary from one community to community. It is for presentation purposes that their land areas are made equal (refer Fig. 2 to 5). Fig. 3 Cellular City A 2.2 Traffic Greenbelts The traffic greenbelts (corridors) will have a minimum width of 400 feet (120 meters) in the middle of which will be expressways (freeways or motorways) of two carriageways separated by a median strip of about 30 feet (10 meters). Each carriageway will have at least 2 to 3 lanes. Fig. 2 The Spatial Relations of the Urban Communities and Traffic Greenbelt Fig. 4 Cellular City B Shown in Fig. 2 are four adjacent communities within the city and traffic greenbelts that separated them. Within the traffic greenbelts are expressways which will facilitate access to all the communities of the city. In Fig. 3, the city is laid out on the pure grid system all of whose expressways intersect at right angles. It is characterized by 25 communities whose total population is 12.5 million. In the centre is the Central Business District (CBD) while each of the others 24 communities has a Community Business Centre (CBC). In Fig. 4, the city is also laid out on the grid plan. However, some of the intersections in Fig. 3 are replaced by 14 junctions to minimize traffic and accident problems. Fig. 4 has the same land area (size) as Fig. 3 but 23 communities instead of the 25 communities in 4

5 it. This is explained by the fact that the four corner communities in Fig. 4 are each one and half times larger than the others. As stated above, the communities do not have to be of the same land area. There may be variations in their spatial coverage dictated especially by physical features and residential densities. Fig. 5 is a radio-concentric plan of radial and circumferential expressways (ring roads). In all there are three ring roads the inner road, the intermediate road and the outer ring road. There are 12 radial expressways: 6 long ones and 6 shorts ones. Fig. 5 Cellular City C The city has 19 communities with the Central Business District (CBD) located in its centre. It is surrounded by 6 other communities accommodated between the inner and intermediate ring roads. The other 12 communities are laid out between the intermediate and outer ring roads. The 19 communities accommodate a population of 9.5 million. The cities in figures 3 to 5 are capable of expansion. For instance, if a fourth ring road is added to Fig. 5 beyond the outer one (ring road), another 24 communities would be added. This being the case, the super-city will have 43 communities each of 500,000 population and a total population of 21.5 million. 3. CONCLUSIONS Other factors being constant, the key merits of the cellular city will include the following: (a) The greenbelts expressways will make the city function efficiently as all its communities will be easily accessible. Each community will be able to function well within the entire city; (b) The problem of urban sprawl will be contained, if not solved; (c) The traffic greenbelts will prevent the communities from merging and therefore prevent the loss of their individual identity; (d) The traffic greenbelts will provide locations for the primary lines of public utilities; (e) The cellular city structure will make it possible to provide social infrastructures to the communities on equitable basis; (f) All the communities will have easy access to the traffic greenbelts for informal outdoor recreation; (g) The location of the expressways in the greenbelts will help to minimize traffic noise and air pollution within the communities; (h) Open spaces (green areas) will be integral elements of the city s structure; and (i) The traffic greenbelts will beatify the landscape of the city and make it aesthetically pleasant. REFERENCES McConnell, S. (1967) Urban Form in the Regional Context, Official Architecture and Planning, January 1967, p Ling, A. (1967) Journal of the Royal Town Planning Institute, March 1967, p. 88. Obateru, O.I (2005) Basic Elements of Physical Planning, Penthouse Publication, Ibadan, Chapter 9. 5