When the city center is no longer the center of the city Decio Rigatti

Transcription

When the city center is no longer the center of the city Decio Rigatti
When the city center is no longer the center of the city
Decio Rigatti
Universidade Federal do Rio Grande do Sul, Brazil
[email protected]
Abstract
This paper aims to bring to discussion some of the impacts produced by the urban transformations in several contemporary cities. The growth of the urban grid overtime towards
the periphery produces a process of changes in the role of the different areas of the city,
depending in the way new parts are added to the previous urban area.
In the case study of Porto Alegre City, these features can be seen both in terms of the
transformations in its global urban structure and the production of new centralities, as
well as in terms of changes produced in the role of the city center over the past 30 years. As
a chain reaction, loss of centrality is followed by a loss of globally important attractors,
which is followed by their substitution by new typologies of business activities, which
characterizes new forms of social demand in this area. At the same time, permanencies
in terms of urban structure, built stock, especially that related to the city history and
memory, and some of the functions are superimposed in this changing space as part of the
process.
As a result, the same space that once used to be the space for the entire city now
tends to be used by few. What once used to be the space of a heterogeneous field of
social encounters and land use patterns now tends to be much more homogeneous, loosing
complexity. This paper will deal with this problem in two ways. The first one, using
space syntax tools, will explain the process of the Porto Alegre City urban growth, the
production of moving centralities and the syntactic role of the city center at the present
time. The second one, through a database about today’s land use pattern in the city
center, it will be possible to understand the degree in which loss of centrality is linked
to loss and/or change of attractors, how this process reduces the role of the area for the
entire city and how this entire process impose limits to the public policies that would like
to recover the previous role of the city center as an area for all.
1. Introduction
The processes of deterioration in urban centres which have recently happened in a large
number of Brazilian cities have shared some characteristics in different parts of the country
allowing us to assume that, despite the peculiarities that set them apart, they also undergo
common processes.
On the one hand it is possible to identify an increase in urban problems resulting
from the structural difficulties undergone by the Brazilian society as a whole originated
by the global redefinition of new capitalist build-up patterns and also, in the case of a
peripherical country such as Brazil, reflected in terms of a gradual loss of income by the
population, the increase of structural unemployment, exacerbation of social conflicts in
the countryside and in the cities. On the other hand and from an internal perspective
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Decio Rigatti
Table 7: Population Growth in the City Centre District in Porto Alegre. Source: IBGE,
Demographic Census.
Year Population in the City Centre District
1980
48,896
1991
43,252
1996
38,663
2000
36,862
to the urban areas, these structural and general problems happen simultaneously with a
process of spatial transformation and urban growth that still characterizes many of our
cities, even in inferior levels when compared to what happened during the 1970’s.
However the phenomenon of deterioration of historic centres seems to be more recent,
considering that the urban growth is one of the distinctive features of the constituency
of the Brazilian urban network, mainly from the second half of the twentieth century
onwards still produced this type of problems.
If we examine the scientific production presented in recent events, both national, such
as ANPUR 1 2003, and international, as NUTAU2 2004, we see that the treatment given
to the issue of city centre deterioration is a frequent issue. The treatment to the topic,
also given by the press, together with the necessary interventions by the public sector,
which must face a new but significative range of problems to the city as a whole, justify
the concerns linked to the theme and to which we hope to contribute from a specific point
of view. On the other hand and to reinforce the importance of the problem, specific public
policies aiming at the renewal of historic centres has been part of recent actions of local
governments.
One must try to understand the reasons why under certain circumstances the historic
centres can retain their vivacity unaffected, even under profound spatial transformations
and in others the very same changes have led to a decline of their relative importance in
the city as a whole and a physical deterioration that usually follows it. In the specific case
of Porto Alegre/RS, which will serve as a case study, the deterioration of its central area
can be roughly outlined as:
• A gradual loss of absolute population over the last decades;
• A large under utilization of the built stocks, comprising both buildings with many
empty units not used in the market as well as entire abandoned buildings;
• A lowering in the patterns of the activities installed, as we may see;
• A lowering in rent values, according to the data provided by Secovi;
• A large increase in the numbers of informal street vendors, taking control of public
spaces and also compromising the private sector activities (figure 101);
In that regard the present piece of work will attempt to discuss the problem through
the study of the Porto Alegre/RS case from two complementary perspectives: on the one
1
ANPUR - Urban Planning National Association for Teaching and Research.
2
NUTAU - Centre of Studies in Urban and Architecture Technologies.
When the city center is no longer the center of the city
231
Figure 101: Street Vendors in Porto Alegre City Centre, photo by author
hand we try to reconstruct the formation process of the urban structure of the city along
its history looking over the role of the morphological centrality presented by the city
centre over time. We hence try to grasp the impact of the physical transformations of the
urban growth process in the alterations to the levels of centrality in the historic centre.
On the other hand, we aim at understanding how the process of physical transformations
has been associated to the other, characterized by changes in patterns of urban activities
distribution and that produces a deep impact on the possibilities of space use and in the
types of social interfaces made possible by such patterns.
Based on such approach, the present study intends to contribute in a quite precise way
to the ongoing discussion about the deterioration of historic centres in three levels: firstly,
checking the impact of the urban growth as a general phenomenon; secondly, analysing the
land use patterns which can, together with the features of the urban morphology, explain
the potential use of the city; and, at last, bearing in mind what has been said, how public
policies focusing the city centre are conditioned and limited by such processes.
2. Porto Alegre, Growth and Transformation
Porto Alegre arose and grew from a peninsula, where it developed at least until the midnineteenth century, when its process of expansion beyond the peninsula started. In the
periods of large territorial expansion, such as during and immediately after the Second
World War, the urbanized area grew ever more, always using as matrix-routes (Caniggia
& Maffei, 1981) the radials that linked the city centre to other regions and areas already
occupied.
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Decio Rigatti
Figure 102: Evolution of the Integration Core Overtime in Porto Alegre
From an early stage, the occupation process with these characteristics reinforces the
role of the radials as important links in intra and inter urban connections, always having
the city centre as a focus. Therefore the connections of the different parts of the city to
the city centre are always privileged, to the detriment of the various areas among each
other.
The problem was faced for the first time with the proposal of building new ring roads
that would have the role of articulating the several radial roads and therefore modifying
the growth pattern existing so far. From the pioneering proposal which appeared in the
City Master Plan of 1959 and was built in the 1960’s until the second ring road, built
in the 1980’s and finally in the early twenty-first century, with the third ring road, the
process of urban growth was no longer a function of the radial roads, but also by the ring
roads, filling the existing gaps.
Besides the morphological transformations presented by the urban fabric, which affects
all the accessibility system, the process of city growth was also characterised by deep
changes in the forms of mobility, which has been increasingly centred in the individual
vehicle, as well as the patterns of consumption and social interactions, that produce new
types of spaces and uses within the dynamics of the city. Thus,
• the emergence of new important attractors, such as the shopping and administrative
centres, localized in areas peripherical to the city centre;
When the city center is no longer the center of the city
233
• the difficulties present in the city centre as to accessibility and mobility; as well as
the decline of life standards, a consequence of the real estate speculation;
• the construction of new locations and centralities in the interior of the urban fabric,
a result both from the growth process and the public investments,
produce a gradual process of loss of functions, roles, centrality and population in the
city centre, as seen above.
3. City Centre and Centrality
The analysis of the evolution of centrality in Porto Alegre (Rigatti, 2002) was based on
some methodological procedures developed in the Bartlett School of Architecture and
Planning of the University College London by Bill Hillier and Julienne Hanson. Using
such procedures it is possible to analyse the relative role of each space in a given urban
fabric in relation to the set of spaces that constitute it.
The spatial system of Porto Alegre is simplified and represented by its axial maps,
therefore allowing a simultaneous assessment to the relative role of the spaces altogether.
In figure 102 we can see the result of applying such procedures to the years of 1839, 1888,
1919, 1935, 1968 and 2000, considering that such moments represent the main stages of
transformation in the urban structure of the city. One can notice the evolution of the
spatial distribution of the spatial integration. In the picture the integration core of each
period is highlighted (figure 102).
The growth of Porto Alegre, from the edge of the peninsula, its initial core, to its
territorial limits to north, east and west and also southwards corresponds to a simultaneous
process of centrality transfer to territories that became privileged locals as regarding
their relative location in the system as a whole. In this process we can perceive a slow
displacement of the integration core from the peninsula ever more to east and today
concentrating largely in the area between the city centre district and the third ring road,
from east to west and between Avenida Ipiranga and Avenida 24 de Outubro, in the
north-south direction (figure 103). This gradual process is largely responsible for changes
that are sometimes deep in the character and relative importance to whole areas of the
city, affecting patterns of use and movement, land valuation or devaluation, real estate
speculation, prior to the physical changes presented by the city.
The specific type of growth verified in Porto Alegre is responsible for the fact that over
time its integration core, besides gradually moving eastwards from the city centre, also
expands in terms of the quantity of spaces that present good levels of relative accessibility
in relation to the whole spatial system of the city. Hence, the integration is distributed
through larger areas levelling off in terms of accessibility both the most structural roads
of the city and wide spaces in its interior. Therefore, besides the radial roads, the ring
roads also become important as spaces of good accessibility.
Nevertheless what one can notice in the growth process of Porto Alegre is that, according to the specific type of emphasis given to the urban reforms, these reinforce both
the displacement of centrality from the central area, as it was from the early stages of
the formation of the city to the decade of 1940 until 1968, when several projects focusing
the city centre were implemented, reinforcing once again the city centre as the main core
of the city. The loss of centrality in the central area of the city can also be verified by
the evolution in the participation of better integrated lines located in the city centre over
time.
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Decio Rigatti
Figure 103: Displacement of the Integration Core Overtime in Porto Alegre
When the city center is no longer the center of the city
Year
1839
1888
1919
1935
1968
2000
no. of
lines
(total)
122
227
530
2,272
3,471
11,366
Table 8:
no. of lines
no. of lines of
in the
the core in
integration core the city centre
12
10
23
5
53
7
227
14
347
53
1137
65
235
Percentage of
lines from the core
in the city centre
83.33
21.74
13.20
6.17
15.27
5.70
Participation of Spaces belonging to the Integration Core of the City of Porto Alegre
Located in the City Centre
Upon analysing the table one can perceive that, starting from a situation characterized by the massive presence of spaces globally important, as in 1839, there is a gradual
reduction in the participation of spaces better integrated into the city centre until 1935,
when it has one of the lowest values. In 1968 the physical changes implemented once again
valued the central area as a place globally relevant to the city as a whole, increasing its
participation by two and a half times when compared to the one of 1935, despite the great
increase in the extension of urbanization, which reflects on the total number of axis that
compose the spatial system. In the last period, due both to the densification and extension
of the urban fabric and the operations of urban reforms performed, there was once again
a decrease in the participation of the central area as a place to hold the relevant spaces
from the point of view of the entire city. This set of factors was the reason why in 2000
the city centre presents the lowest percentage of spaces that belong to the integration core
in all its history.
4. Attractors in the Central Area
The morphological transformations in the urban fabric and the new spatial relations verified - location of great attractors, conurbation etc. - added to the conditions of agglomeration in the city centre resulted that, from the late ’80s onwards, the central area of the
city goes through a process of disappearing of activities that characterized it, affecting
its functioning in a radical way. One of the main specificities of the central area was the
presence of exceptional functions, or as Cutini (2001) names it, of monopolistic functions:
the sitting of federal, state and municipal administrations; the headquarters of banks,
the sophisticated commerce, the specialized commerce, specialist’s health centres, among
others. These activities defined a dynamics of space use that put together dwellers, people
from other parts of the city and also people from the interior of the State that met there
their needs in terms of goods or services. The city centre more and more holds a cheaper
commerce, offices and the headquarters of banks. In this case doctors’ practices, clinics,
major lawyers’ and sales representative offices withdraw to the most expensive neighbourhoods. On the other hand and also increasing the problem, the public space is ever more
occupied by street vendors, increasingly jeopardizing the legalized activities located in the
buildings of the central area.
As time goes by and with the changes in the mobility patterns of the population,
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the reality in the central area also changes. The changes in the commercial typology, the
leaving of important businesses which worked as movement attractors and as inducers
of new locations changes the profile of use in the city centre. From a theoretical point
of view, it is interesting to observe a piece of work developed by Johnson (1998), where
he comments that the art of designing consists in knowing which things are laid out
with the correct relations among them. Evaluating the typical structure of the traditional
commercial street, characterized by the fact that any person, parking their car only once
can access a large set of establishments, and therefore, “...they mutually reinforce each
other: whichever combination of services you want, they are all within walking distance of
each other.” (Johnson, J., 1998: 59). He reminds us that the structure of the commercial
street, which represents each business as the vortex of a structure that attracts and at the
same time exploits the power of attraction of people from neighbouring establishments,
is very sensitive to the presence of hyperstores, which can absorb the client able to do
all their shopping in the same place at a cost usually lower. When the presence or the
effect of the existence of distinctive patterns of consumption starts to affect the structure
of a commercial street, as in the case of Rua da Praia in the centre of Porto Alegre,
establishments close their doors and their role as an attractor of movement is ended.
More than just being an individual phenomenon of the business that closes down or an
entrepreneurship that cannot cope with the competition or to adapt itself to new patterns
of consumption and mobility, this is a phenomenon that in the end affects the whole prior
structure of the commercial street. As Johnson puts it:
“As individual shops close, the structure becomes impoverished. If too many
vertices are lost the assembly may loose its emergent property of being a place
where people can access services conveniently, in a downward spiral of closures
and more closures: eventually the relational structure collapses and ‘The High
Street’ ceases to exist.” (Johnson, J., 1998:59).
That is exactly what is happening now with Rua da Praia. The closure of stores in the
end affects the whole street, resulting in more and more closures and additional losses of
attractors to itself and to other streets, as this is one of the basic principles of functioning
in commercial streets. In the case of Rua da Praia, normally, the closing of a establishment
is followed by the opening of another one, but not with the same hierarchy, considering
that the ones that go away look for advantages in location that may allow their business to
compete with others of the same level and the new establishments installed can do without
such advantages of location and basically focus their role in a stricter form of mobility of
their clientele, represented by the availability and given by the public transport routes.
Therefore, the main users are people with low mobility, as they reach shorter distances,
defined by the terminals of collective transport or by their routes, considering that there is
no individual choice as to where to go or how to go, as this choice is already been defined
in the pattern of general mobility offered by the system of public transport.
It is under this panorama that the transport terminals acquire an important role in
the functioning of this typology of activities. On the other hand, these are exactly the
characteristics that are exploited by the street vendors, which grows in the central streets,
always tending to install in the proximities of the public transport terminals, either urban
buses, intercity buses from the Great Porto Alegre, the metropolitan train or the public
vans, which are all distributed in the central area.
And today: what is the pattern of distribution of the urban activities in relation to the
process described above? A detailed land use survey in what was considered the centre
When the city center is no longer the center of the city
237
Figure 104: Porto Alegre City Centre
of Porto Alegre, that is the area comprised by the first ring road (figure 104) was carried
out to examine such issue. In the survey, besides identifying the land use itself, each use
was classified according to the pattern of activity, the area of influence according to the
prevailing users and the larger or smaller degree of scarcity both in the area and in the
city.
The collected data were organized in a database where, besides the information of
the activities, the height of the buildings, etc., was included configurational information,
as integration, connectivity of axis where the activities were placed and others. At the
same time a georeferenced basis has been organised having the lot as the spatial reference
unit. Therefore it will be possible to cross reference among all the available variables in
the database and to obtain the spatialization of the results. The database is still under
construction, but checking the primary information we can already make some important
remarks regarding the present features in the distribution of activities.
4.1. High Standard Commerce and Services
In the period preceding the process of decadence of the city centre, it grouped the main
high level stores with department stores, boutiques, jewellery stores, houseware stores
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Figure 105: High Standard Commerce and Service in Porto Alegre City Centre
and all sorts of specialised shops, besides services, especially liberal professionals such
as doctors, dentists, lawyers, etc. They tended to cluster along Rua da Praia, the main
commercial axis, a place of complex socialities and with one of the highest levels of accessibility in the city. The adjacent streets worked as extensions of locational qualities of the
main axis, presenting similar functional characteristics and maintaining a pattern where
the closer to Rua da Praia, the most similar in type and pattern to the existing activity.
A look at the distribution of the activities described above (figure 105) firstly shows
that today there is a great spatial dispersion and so it is very difficult to perceive an area
where such types of activities predominate. Secondly and as a consequence of the first,
there is not a very clear link between these activities and the levels of integration in the
spaces where they are located. Thirdly, it is also evident the small occurrence verified
today, when compared to their heyday.
4.2. Public Services
Until the seventies the city centre used to concentrate all the public services in the three
levels of government: the federal, the state and the municipal. In the surroundings of the
main squares in the central area, namely Montevideo, Alfândega and Matriz squares were
When the city center is no longer the center of the city
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Figure 106: Public Services in Porto Alegre City Centre
located the most part of those unique activities in the city, which worked as monopolistic
attractors. From the seventies on the building of the Centro Administrativo do Estado
(State Administrative Centre) started the occupation of the area reclaimed from the River
Guaı́ba towards the south that would later constitute the Parque da Harmonia, and after
that several Ministries local offices were installed along the south part of the first ring road,
as well as the new Câmara de Vereadores (City Council Building). Important state and
federal head offices also left the city centre to be installed along Av. Borges de Medeiros, in
the surroundings of Centro Administrativo do Estado. Under this process, a few agencies
remained in the city centre, such as the houses of the three state powers in the Praça da
Matriz, the City Hall in the Praça Montevideo and some municipal secretaries dispersed
in the city centre (figure 106).
It is clearly noticeable that the most important public service buildings, in terms of
number of users and also of civil servants moves from the city centre to peripheric areas,
which have in common good levels of accessibility in relation to the city as a whole.
4. Low Standard Commerce and Services
These activities seem to be the ones that have developed the most in the central area over
the last few years. This phenomenon can be analysed in two distinctive situations: first by
the unheard-of expansion of informal commercial activities over the public space (Rigatti,
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Decio Rigatti
Figure 107: Low Standard Commerce and Services in Porto Alegre City Centre
2003) and secondly by the expansion of low level commerce and services related to the
private sector located in the buildings of the area. In the latter it is particularly interesting
to take into account those activities located on the ground floor, i.e., those ones which are
more visible from the public spaces and which have a direct contact with the people in
movement (figure 107). Despite the availability of information on the activities developed
on other floors, here they will be limited to the direct interface between the public and
the private spheres.
One can observe in the city centre today that, besides the traditional areas which
concentrate low level commerce and services, such as those localised between the Mercado
Público (City Market) and the Estação Rodoviária (Central Bus Station), along Av. Júlio
de Castilhos and Rua Voluntários da Pátria, low level activities advance towards areas not
traditionally occupied by them, perhaps mainly because the land cost there was too high
for such uses. Even Rua da Praia, a traditional commercial street, which concentrated
most of the sophisticated and specialized shops in the city until the 80’s, has largely
been replacing those by lower standard shops, such as small houseware stores, “R$1,99
Stores”, cheap shoes and clothes shops and so on. The final part of the street, between
Rua Marechal Floriano and Rua Senhor dos Passos, is still an area characterized by a
middle level commerce, where there is little low level commerce as well as a high level one.
Another aspect that can be analysed by the spatial distribution of low level commerce
and services is their relation to the transport terminals (figure 108). This type of com-
When the city center is no longer the center of the city
241
Figure 108: Transport Terminals in Porto Alegre City Centre
merce has a clientele of people with low mobility, who depend mainly on public transport,
especially on buses.
5. Conclusions
In regard to the first and second levels of discussion proposed to the present work, namely,
the impact on urban growth and the pattern of distribution of the urban activities, we
may say that as for the process of transformation that occurs in the centre of Porto Alegre,
there is a simultaneousness between the morphological transformations and the changes
in the patterns of location of the urban activities, both in the city and in the city centre
itself. The loss of locational qualities in the central area is deeply associated to the loss of
complexity levels verified in this area today. Complexity regarding city centres means a
space that carries significant aspects of the history and the memory of the entire city and
where the interface of different social categories made possible by and through the urban
layout can at least produce awareness of each other.
More than just a matter of market functioning, the deterioration of central areas as
the one in Porto Alegre represents a loss of collective spaces of social representation that
fragment, specialize and restrict the condition of social interfaces among different social
categories. In the present we can see a problem in Porto Alegre, which started to take
form in the early ’80s and is currently quite difficult to solve. The losses of accessibility
and functions are fundamental parts to understand the reality and to interfere on it and
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Decio Rigatti
such characteristics constitute very strong limits to the public policies which attempt at
renew the city centre, since the urban structure and the social use of space are interlinked
dimensions of the same reality. As we conclude from the formation process in the urban
structure of Porto Alegre, the reinforcement of the roles played by urban sectors in the
city as a whole depends on how the latter are articulated to the relative accessibility. In
that regard, the urban reforms implemented between the 40’s and the 70’s and described
above are a clear example of such relation. From the point of view of the public policies
that aim at the renewal of run-down urban centres, as the one of Porto Alegre, it is noticeable that the main goals set in the discourse, such as animation, beauty, comfort and
safety, which are in turn supporting actions and programmes as education for the environment, improvements in urban lighting, recovery of historic buildings and retrofitting
of abandoned buildings to be inhabit by low income dwellers, together with the policies
of enlarging the public transport terminals tackle the problem only superficially and, very
often with contradictions. Measures as the recovery of historic buildings help to keep an
urban identity and memory, maintaining the city centre as a focus of general interest and
may work out as monopolistic attractors. However, measures as the enlarging of public
transport terminals, which have resulted in a forced movement towards the centre by a
similar type of population and with a lower mobility pattern, and the programmes that
reinforce the city centre as a living area for a low income population redefine a new social
profile for the area, from which are excluded other segments of the population, socially
homogenizing the city centre.
As there are no projects to act directly on the accessibily issue, the public policies to the
city centre lack measures to recover it as a collective space, either from the point of view
of the monopolistic functions located there or from the point of view of its morphological
centrality, which would imply rediscussing and rearticulating the local and global relations
of the area with the whole city.
Recognizing the implications between urban morphology and social use of the space
represents a cornerstone in overcoming the restraints present in the functioning of a large
number of deteriorated central areas and, at the same time, functions as limits and yet
as potentialities to the development of public policies adequate to face the problem of
degradation of such areas.
Literature
X ANPUR, (2003) Anais do X Encontro Nacional da Anpur, Associação Nacional de
Pós-Graduação e Pesquisa em Planejamento Urbano e Regional, Belo Horizonte, em
CD rom.
Caniggia, G., Maffei, G. L. (1981) Compozizione architettonica e tipologia edilizia:
lettura dell’idilizzia di base, Venice, Marsı́lio Editori.
Cuttini, V. (2001) Configuration and centrality. Some evidences from two Italian case
studies, in: Proceedings Space Syntax. 3rd International Symposium Peponis J (ed.),
Georgia Tech, Atlanta, P. 32.1-32.11.
Johnson, J.H. (1998) Relational structure in planning and design, Environment and
Planning B: Planning and Design, 1998, , Anniversary Issue, 57 - 67.
NUTAU (2004) Seminário Internacional NUTAU 2004, Demandas Sociais, Inovações
Tecnológicas e a Cidade. São Paulo, USP, em CD rom.
When the city center is no longer the center of the city
243
Rigatti, D. (2003) Transformação espacial em Porto Alegre e dinâmica da centralidade,
Final research report for the Post Doctorate Project at the Università Degli Studi
di Firenze. Florença.
Rigatti, D. (2003) Camelôs, flanelinhas e os outros: Privatização de Espaços Públicos,
Paisagem e Ambiente Ensaios, FAUSP, São Paulo, Vol. 17, p. 41-67.

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