São Paulo: dense city?

SÃO PAULO: A DENSE CITY?

Carolina dos Santos GUSSON, Arch.¹

Ângela Helena Yamaguishi MADEIRA, undergraduate student 3 Denise Helena Silva DUARTE, Dr. Eng. 1

2 3

2

Laboratory of Environment and Energy Studies (LABAUT), Department of Technology, Faculty of Architecture and Urbanism, University of São Paulo, São Paulo – SP, Brazil, carolinagusson@usp.br angela.madeira@usp.br dhduarte@terra.com.br

Summary Two major forces that are shaping our cities today are the population growth and the rising rates of urbanization. For many reasons, one of the current needs of urban settlements is a higher urban density, giving priority to the existing city, a topic that still causes some debate. Assuming that the densification is inevitable and desirable from the point of view of urban sustainability, the subject of this research is the relationship between built density and population density in São Paulo, Brazil, with a total city population of 11.253.503 inhabitants and a metropolitan population of 19.502.940 inhabitants (IBGE, 2011), and their relationship with the land use and main buildings typologies in some districts. The objective is to map quantitatively the built density and population density in all Sao Paulo´s districts and cross these surveys with the main buildings typologies in some districts which are interesting to the research. Existing data were compiled from the Municipal Secretariat of Urban Development (SMDU, 2009) and the 2010 Census of IBGE - Brazilian Institute of Geography and Statistics, and the primary data were obtained from photographic records of the main typologies of different districts. After crossing these data, the paper concluded that there is not a direct relationship between built density and population density in Sao Paulo, confirming that the extensive verticalization is not always associated with a higher population density. In some districts the divergence is quite significant, which is attributed to several factors, such as the pattern of land use and occupation and the existence of numerous mono-functional areas in the city.

Such divergence occurs, for example, on the huge underutilized building stock in the central neighborhoods which supports during the day around 1000 people/ha, with 700 jobs/ha and that are almost empty at night. While the average density in the city of São Paulo is 74 hab/ha, and the densest district, Bela Vista, has 243 hab/ha, there are previous studies showing that in the slums, density reaches 1000hab/ha, however, without livability conditions. The work also demonstrated that there is not a direct relationship between the land use and occupation patterns, as well as between the building typologies and a certain population density. On the contrary, it was found that a given typology can be found in districts with very different densities, just because the same maximum plot ratio determined by the local regulation has very different meanings depending on the average income of the population of that district, which reflects in the housing unit’s area.

Keywords: urban density, built density, population density, land use, building typologies

1. Introduction: It can be argued that two forces are shaping our cities today: population growth and increasing rates of urbanization. These two forces are relevant to the discourse of sustainability; with the growth of cities there is a decrease of natural spaces, an increase in spending on urban infrastructure, in the displacements made by car and, consequently, air pollution (Roaf, 2010). Therefore, one of current needs of urban areas is a higher density occupation.

There is now a big debate around the higher urban density. Many arguments are related to planning, aiming to minimize negative impacts of high density and maximize its benefits. Densely populated areas mean the optimization of urban infrastructure, mixed-used and less commuting. Well designed dense cities imply an increase of energy efficiency, with lower resources consumption, less pollution and thereby contribute to the maintenance of rural areas (Rogers, 2001). One question that arises is: are we oversimplifying a complex phenomenon, trying to find an ideal pattern of land use or an optimal density for cities? (Heng, Malone-Lee, 2010).

The definition of a viable or ideal density for each location and the strategies to achieve these results vary widely. Some authors are concerned about the negative impacts of high density such as traffic congestion, noise, pollution, negative perception by the population and lack of privacy. One of the situations in which the high density does not become a viable solution is when the urban infrastructure and transportation system are unable to manage the large concentration of people. Another disadvantage of density is the proximity between people that could generate social conflicts because the lack of privacy (Cheng, 2010).

However, the need for a higher urban density is inevitable in the 21st century. According to Roaf (2010), urbanization and high density are irreversible. The denser way of living will continue and will soon be the norm.

2. Literature review about population density and the city of São Paulo Urban density, according to Cheng (2010) is measured by physical density (population and built) and perceived density. Physical density is a numeric measure which represents the concentration of individuals or physical structures in a given geographical area. It is objective, quantitative and a neutral espacial indicative. The physical density can be divided into two categories: population density and built density.

The IBGE (Brazilian Institute of Geography and Statistics) considers population density as inhabitants per unit area, expressed by the term inhabitants/km², and the surface unit as the total area of the district, city or state, habitable or not (IBGE, 2010).The built density is defined by the ratio of built area constructed on a site or area for a certain type of development (Cheng, 2010), the measure is the "plot ratio” that is how much you verticalize or is possible to verticalize on a particular site. Another measure is "site coverage", defined by the ratio between the projection of the building in a site, e.g. the percentage of land occupied by the built area.

There are two ways to measure areas in population and built densities. The first one adopts the concept of net area, when is counted, as total area, only the buildable areas; and the gross area, when the total area is considered including roads, parks and other public areas. In this study plot ratio is adopted to represent the built density over the gross area. th

Until the early 20 century the city of São Paulo was essentially horizontal with one and two storey houses.

After that, due to population growth and better construction techniques, verticalization started. One big advantage was the reduction of production costs, in other words, the best use of urban land. However, many questions regarding the "harmful effects" of verticalization emerged as a concern with the quality of life, especially regarding the sanitary conditions of those buildings (Devecchi, 2010).

These discussions culminated with the municipal law 526, in 1957, which established a control over the height of buildings, setting the maximum plot ratio of four for residential use and six for commercial use and also established a maximum population density of 600 inhab/ha, by setting an ideal fraction of at least 35 m² per housing unit. As a consequence, two simultaneous and continuous controversial processes began: urban sprawl and a significant increase in the amount of vertical constructions. According to Devecchi (2010), this law consolidated the previous population density pattern of the terraced two storey houses, but with a vertical urban form. Taking this into account, which is the current relationship between population density, built density and building typologies in the city of São Paulo?

3. Methodology After literature review, existing data were collected in governmental institutions. Those related to population density were obtained in the Synopsis of the 2010 Demographic Census (IBGE, 2010) while those related to built density were found at the Municipal Secretariat of Urban Development (SMDU, 2009). The different building typologies were photographed in selected districts of interest for this research while a classification was done according to the predominant land use and occupation pattern, to buildings’ form and the average income of the population. The results were obtained crossing the photographic field survey, the classification of the building typologies and the existing data.

4. Results and Analysis Comparing the city of Sao Paulo´s population density with other cities in the world (Fig. 1), it is observed that even with an average density of about 74 inhabitants/ha, similar to other cities, the density of Sao Paulo´s densest district is one of the lowest. As the availability of transport and infrastructure should be directly linked to urban density, it would be possible think that there is an equitable distribution of these infrastructures throughout the city, which is definitely not true. São Paulo has some areas with reasonable availability of transport that does not necessarily have high values of population density and vice versa.

Figure 1

Big cities, their average density and densest districts

Sources: ¹IBGE (2011), ²Burdett and Sudjic (2011) and ³Hong Kong (Special Administrative Region) (2012)

Analyzing images of some of the densest districts of the cities mentioned above (Fig. 1), it can be seen that the densest areas do not follow the same occupation pattern, for example, tall buildings, or a predominant land use, or even a particular inhabitant’s income. Instead of that, what is found is the variety of typologies from high rates of population concentration in medium height extremely poor dwellings, with very little infrastructure, urban sanitation and public transport, in Mumbai, India, to values close to these in high standard residential buildings in Manhattan, New York, concluding that population density cannot be seen as synonymous of low quality of life (Fig. 2).

Kamathipura, Mumbai¹

Upper East Side, New York City2

Figure 2

Luwan, Shangai

Densest Districts´ Pictures

Sources: ¹Available at: <http://betacity.files.wordpress.com/2011/07/kamathipura-mud-boy.jpg>. Access in Feb, 2012 ² Available at: <http://www.nycondoblog.com/category/the-laurel-condominiums-400-east-67th-street>. Access in Feb, 2012 ³Available at: <http://www.travpl.com/forum/travel-china-27/shanghai-luwan-p10-258.html>. Access in Feb, 2012

Some slums may have a density higher than 1000 inhabitants/ha without quality of life. Figure 3 demonstrates this, showing the population density of the five most populated slums in São Paulo.

Figure 3

Population Density in São Paulo´s slums

Sources: Elaborated by the authors from IBGE (2011) slums´ inhabitants data and HABISP (2009) slum´s areas data

Analyzing the chart (Fig. 4), in general, the city of São Paulo does not have a high built density since its average plot ratio is 1. Higher values of up to plot ratio 5 can be found in the districts located in central areas. However, higher values of population density appear in peripheral districts, thus explaining a phenomenon quite pronounced in the last few years: the dispersion of the population. Recent data (IBGE, 2011) pointed that there was a general population increase in all districts, including the central ones, maintaining the different proportion of the population in central and peripheral districts.

Figure 4

Built and population density in the city of São Paulo (by districts)

According to the data, it is possible to highlight differences between the values of built and population density. A high built density not necessarily means a high population density and vice versa. There are cases where the plot ratio is under 2 and its population density is considerably higher than those of some central districts whose built density is much higher.

To clarify the correlation between building typology and density, a group of districts was selected, among a total of 97 districts. They represent the largest discrepancies between population density and built density, as can be seen in figure 5.

Figure 5

Population and Built Density in the selected districts

Sources: elaborated by the authors after ¹IBGE (2011) and ²SMDU (2009) data

The districts of Bela Vista, Santa Cecilia and Moema have in common the predominance of vertical residential buildings. The values of built and population density, however, vary a lot (Fig. 6). According to the results, a high level of verticalization does not necessarily assume high values of built density. In Moema, for example, despite being a district where the predominant building typology is vertical high standard housing, gross plot ratio is no more than 2, corresponding to the same terraced 2 storey houses th density, founded in the beginning of the 20 century. The reasons for this are related to factors such as income, size of dwelling units and land occupation pattern.

Figure 6

Districts with the same typology and different densities (built and population) Sources: ¹SMDU (2009) and ²IBGE (2011)

The districts of República, Sé and Itaim Bibi are dominated by vertical commercial and services’ buildings.

However, they have different values of population and built densities (Fig. 6). Republica and Itaim are more mixed-used, as one can see in the almost coincident values of population and built densities in both districts; instead of that Sé has a more monofunctional use.

Factors such as income and site coverage associated with the plot ratio of the districts are crucial to the differences in built density values. In the districts of Santa Cecilia and Brasilândia, despite having the same values for population density, they have distinct prevailing typologies and different built density values (Fig. 7). In the case of Santa Cecilia, building typology is predominantly vertical middle standard residential use and its built density value is higher than in the case of Brasilândia, where the predominant typology is the horizontal low standard residential use (Fig. 8).

Figure 7

Districts with the same population density, but with different typologies and built density Sources: ¹SMDU, 2009 and ²IBGE, 2011

Santa Cecilia Average Standard Vertical Housing 29%

40%

High Standard Vertical Housing Commerce and Services Vertical Buildings

14% 17%

Others

Brasilandia Low Standard Horizontal Housing 11% 39%

21% 29%

Medium Standard Horizontal Housing Commerce and Services Horizontal Building Others

Figure 8

Santa Cecilia´s and Brasilandia’s main building typology Sources: ¹SMDU (2009) and ²Authors´picture (2012)

In the districts of Moema and Barra Funda the same built density is verified, but with divergences in both building typologies and population density (Fig. 9). Moema has a low built density if considering its predominant typology: vertical high standard residential use, remembering that this study adopted the gross area to calculate the built density (Fig. 10). In this particular case, Ibirapuera park´s area influences in the built density results for Moema as well as the railway area for Barra Funda district.

On the other hand, Barra Funda, where the predominance is of vertical and horizontal commerce and services and industrial buildings, the built density is equivalent to Moema, however presenting a low population density for a central region serviced by public transportation and infrastructure (Fig. 10).

Figure 9

Districts with the same built density, but with different typologies and population density Sources: ¹SMDU (2009) and ²IBGE (2011)

Barra Funda

22% 46%

17%

Vertical Commerce and Service Buildings Horizontal Commerce and Service Buildings Industrial Buildings

15% Others

Moema Higher Standard Vertical Housing 27% 43% 8% 22%

Figure 10

Medium Standard Vertical Housing Horizontal Commerce and Service Buildings Others

Barra Funda´s and Moema´s district main building typology Sources: ¹SMDU (2009) and ²Authors´picture (2012)

5. Discussion and conclusion After crossing these data, this research concluded that there is not a direct relationship between built density and population density in Sao Paulo, confirming that the extensive verticalization is not necessarily associated with a higher population density. This work also demonstrated that there is not a direct relationship between the land use and occupation patterns, as well as between the building typologies and a certain population density. On the contrary, it was found that a given typology can be found in districts with very different densities, just because the same maximum plot ratio determined by the local regulation has very different meanings depending on the average income of the population of that district, which is reflected in the housing unit’s area.

High urban density can be reached using different building typologies, not only vertical but also with medium height buildings. The built density in São Paulo is more concentrated in central areas with a population density similar to the poor peripheral areas, as Brasilandia district. However the central areas have higher availability of transport and infrastructure compared to the peripheral areas, which gives them a potential for higher population density. The slums, which have low quality of life and poor infrastructure, can reach more than 1000 inhabitants/ha; similar values could be reached in the central areas with a better environmental quality and adequate infrastructure. According to Glaeser (2011) “there is no such thing as a successful city without human capital […] our culture prosperity and freedom came from the fact that people are living, working and thinking together”. Thus, the urban density contributes to a living and diverse environment suitable for humans to reach their higher development.

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Cheng, Vicky Bo-Ki. 2010, Human perception of urban density. Department of Architecture, University of Cambridge, Cambridge, 264 p. (PhD Thesis).

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