High rise buildings: is it wise to continue to explore such building typology?

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1 High rise buildings: is it wise to continue to explore such building typology? Sattler, M. Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil Abstract: NORIE (Núcleo Orientado para a Inovação da Edificação), the Construction Sector of the Postgraduate Program on Civil Engineering, at UFRGS, Brazil, has been studying, for nearly twenty year, a broad spectrum of topics related to buildings and communities sustainability. This paper aims at discussing some of the challenges related to tall buildings, particularly of those already built and that are nearly to reach the end of their life cycle expectancy. The study makes a literature review and discusses some case studies associated to the Brazilian reality. The analysis of future scenarios and of the stock of existing buildings that are approaching the end of their life expectancy points to the necessity of taking steps towards the search for solutions to what is being forecast as inevitable (end of fossil fuels availability; the growing degradation of urban spaces; etc.), so to offer a less blight perspective to our children. Keywords: Sustainability; life expectancy of buildings; high rise buildings. Introduction The world population has been growing and the rate of this growth has increased considerably in the last fifty years. Following this growth, urban population represents today more than 50% of the total world population. The way humans allocate their different activities in urban areas varies, and has resulted, mostly in its sprawl over large areas, but also in its vertical growth, sometimes in an impressive way. One could say that is of upmost importance to limit sprawling and increase density. No doubt about that, but should we worry about the hight of building or that does not matter? In this paper some considerations will be made that are important to the process of decision making when forecasting the future of cities some 30 years ahead. Firstly, one must recognize that, in both cases sprawling or growing in height those who support one or other usually only consider some specific aspects related to the issue, not realizing that the city performs like a complex system and, as a result, being innumerous the factors that contribute, or not, to its sustainability, health, security, resilience, It is common, thus, to find supporters of the thesis that, when concerning to urban settletments, the larger, the better [1]. Thus, with basis on economical arguments, mostly, some point out that some megaregions contribute with more than 66% of all economic activity and with more than 85% of the technological and cientific innovation, and as being so they announce the potencials for the consolidation and diffusion of this model of land use in the future. They also add that some city plans results in higher or lower costs, in accordance to favorable relations of use and to land use; adequation to topography; mobility and other 1

2 infrastructure components that are vital as design constrains and determinants. According to those in support to these arguments, paving and drainage are the more costly urban infrastructures, being responsible for 55% to 60% of the cost of all urban infrastructures. As such, being urban density determinant of infrastructure costs, the multifamily housing model is more advantageous than the single family model, for being denser [2]. It is undeniable the necessity of densifying urban areas, due to its associated social, cultural and economic benefits and to avoid, for example, the American model of suburbia, that determine an extreme scenery of sprawl cities. Nevertheless, even aligned with this option, many much more sensible models of densification exist [3], that have been proposing, since the 80 s, new alternatives for urban dinamics; diversification and intensification of uses and functions for urban land; density increase and social cohesion, among other aspects. The second remark is that in the analysis found and arguments presented favorable to denser cities, rarely future scenarios are discussed, as recommended by Sustainable Cities International [4]. This institution is used to work with future scenarios and makes use of the concepts of forecasting and backcasting. Forecasting is a method that allows translating past and present tendencies in future estimates. Instead SCI prefers using the concept of backcasting, that departs from the definition of a desired future (often referred as a vision) and then assess what is necessary to get to this future. They explain the problem associated with forecasting by asking the following question: But if the present tendencies are part of the problem? They explain that urban sprawl is an example that illustrates well this tendency of urban growth, where, if forecasting is applied, it will predict a larger urban sprawl! They further add that as tool for understanding what will be possible in the future, forecasting allows little divergence in perspective, when talking about the future of each city, and that backcasting allows to planners the introduction of new and creative ideas broadening the dialogue on the future we intend to create, versus another one, that is purely predictive and based on past tendencies and behaviour. At NORIE [5], we aim at creating guidelines for the development of small municipalities (identified as those with less than 20 thousand inhabitants), analyzing both urban and rural areas, with the aid of a systemic approach and in such a way of contributing to the construction of a more sustainable and healthy future. In the search for models of resilience for such communities, we try to identify complex systems that are oriented by the principles of sustainability in its broad sense (environmental, economic, social, cultural, political etc), under the lenses of a technical focus, trying to harmonize issues like: energy; land use; urban morphology; waste water treatment; solid wastes management; urban mobility and accessibility; water and air quality preservation and local production of food. This work makes a reflection on some challenges identified by NORIE, to be faced by the several actors in the civil construction production chain, in special by those associated to the production of buildings and, in particular, to urban morphology, questioning the option increasingly adopted, of tall buildings, in the face of the present challenges and of those that can be anticipated when analysing future scenarios. 2

3 Critical aspects associated to tall buildings Energy A number of experts in the área of energy point out to the problems that are expected to occur simultaneously to the depletion of fossil energy resources. Richard Heinberg is a well known expert with several published books in the area. Among them, The Party s Over: Oil, War and the Fate of Industrial Societies [6] points out: the total dependence of modern industrial societies in fossil energy resources; the worrying lack of resilience of these societies in face of even minimal reductions in energy resources; the inevitability of fossil fuels depletion, among other topics. In a more recent book [7], the author reinforces many of his assertions, including that of our continued depence on fossil resources, but also points out to the descendent curve of its availability, as well as to the depletion of mineral resources and, also, to the decline of global economic activity, on several aspects. Other authors [8] also remind us that lifts consume a lot of electricity and have an expensive maintenance and have a high cost of acquisition and substitution. They, alone, might represent between 5% and 15% of the current costs of a building and, the taller the building, the higher these costs will be. As the depletion of energy should not occurr sudenly, the population as a whole will not be deprived at the same time. With the gradual reduction of energy resources, the estimates are such that its price also will increase gradually, in such a manner that the poorer fraction of the population will be the one to miss it most for their comfort. Solar energy should become the main source of energy in the future and its use should grow gradually, being that both for water and air heating and electricity generation, at the same time that the efficiency of equipments for such uses should grow. This will be required as the density of energy in sun rays reaching the planet is relatively low and solar energy can only supply the energy required by those inhabitants living in the just under the roof of a building. This is reinforced by [8] that explain that the geometrical characteristics of tall buildings make not viable the use of solar systems for water heating, energy generation or air heating for autosufficiency, as their surfaces are not enough to supply the needs of all users of such buildings. Furthermore, glazed tall buildings, mainly in the tropics, also suffer from huge solar gains. Skyscrapers, as a rule, require air cooling, as they have a large floor area, a requirement to make them economically viable, and that makes natural ventilation very difficult to be obtained. Mechanical heating and cooling, on their own, multiply by four the expenses on energy in these buildings [8]. Durability and maintenance 3

4 In a study developed at NORIE [9], a review of the international literature on life expectancy of the different layers of a building (structure, services, partitions and internal spaces) found no consensus with regard to the longevity associated to each one of the layes, although the average estimate for the life expectancy of the structure of reinforced concrete point out to something around 50 years and to a life expectancy considerably shorter for the other components, what also is in agreement with the estimates in NBR [10]. According to [10], the life expectancy is the period of time in which the building, service or component can be used, under satisfactory conditions of security, health and hygine and maintenance is the set of activities to be performed for the conservation or to restore the functional capacity of a building and its constituent parts in order to supply the necessities and security of the users of the building. It is well known that the performance of a building decreases with time. In the same way one could wonder about the income profile of the users of such buildings and how it may vary with time. Would not such profile follow the tendency of decrease shown by the performance of the building if this were shown on a graphic, thus making difficult the maintenance operations? And, in addition, if we were to draw on the same graphic showing the decaying line of performance another line, identifying the costs of maintenance, would this no be, differently from the previous two lines, an ascendant one? Thus, in face of such a situation, where maintenance costs would be requiring increasing financial resources and the users of such building would become more and poorer along the lifetime of the building, would not the users of such building be facing an accelerated process of degradation of the building? In order to ilustrate such a reality and to deepen such a line of discussion, Figure 1 shows two moments associated to life cycle of a building: the first one, showing the end of the life cycle of Edificio São Vito, in São Paulo, a residential building with 27 floors and 600 apartments. The second, shows its demolition residues, together with those of 36 other buildings (not as tall as São Vito) also demolished at the same time. One might ask: how many tall buildings around the planet, either existent or to be constructed, will count with the financial resources required for their demolition, as was the case of São Vito? No doubt that the demolition process requires a considera ble amount of money. One could wonder that the users of such a type of building, either due to a lack of resources or two a lack of interest, or even due to a lack of agreement among its owners will not be able to afford its demolition or dismantling. Even because the total value obtained with the sale of the plot where the building stands added to value of the sale of the residues resulting from the demolition, in most cases, would not be enough to cover the costs of demolition (or dismantling) plus the cost associated to the transportation of the resulting residues. In the same way, the public and private sector, for the same reason (cost), hardly would be willing to cover the cost of demolition. So, without such willingness, what will happen with tall buildings and the urban areas where they are located today? 4

5 Such a worry is expressed by [11], when they remind us that some of the taller, stronger and even more beautiful buildings from the beginning o the twentieth century, only now are approaching the end of their life cycle. And they ask: What will be the destiny of such buildings? (a) Figure 1: São Vito Building, in São Paulo: (a) Abandonned building. Source: (12); (b) Residues, at the end of the demolition process of buildings São Vito, Mercúrio e Herreras. Source: (13). On a similar way of thinking [8] refer, that many tall buildings deteriorate in a deplorable way as their owner cannot pay for their maintenance. They add that are many examples that show us that often it is easier do implode them, than to regenerate them. And they conclude that this alternative has cost implications in addition to environmental impacts. This situation certainly will be even more critical when one considers that the two panoramas above describe will coincide and that an enormous quantity of energy, not easily available in the future, also will be necessary for the demolition and residues transportation processes. Health and quality of life Some social and psychological issues also should be included in considerations about the height of buildings. Studies performed in tall buildings in the United Kingdom, pointed out to frequent cronic problems occurring with users of tall buildings, such as the delay of motor development in children that did not have the opportunity to descend to the ground level, without the presence and supervision of their parents [8]. Another study at NORIE [14] assessed the impact of the verticalization and densification process on the quality of residential space in a neighborhood of the city of Porto Alegre, Brazil. When the authors analised the impact determined by a 18 floor residential building, in a neighborhood occupied mainly by two and three storey buildings, they concluded that the tall building modifies not only the streetscape of the neighborhood. It reduces (or completely (b) 5

6 obstructs) the whole of the solar energy formerly incident on the plot; besides reducing or eliminating privacy; it adds considerably to population density and increases the demand for services and infrastructure, besides increasing traffic. It affects even the neighborhood relationships in the new buildings, life in gated communities are previledged and the resident rarely walks on the streets; neighbors do not know each other. One can ask, thus, how far, under such conditions, the cultural identity of the neighborhood can be sustained? How profoundly modified are such aspects that qualify the place of living of its inhabitants? Conclusion If we want to leave a more sustainable planet to our children there is no doubt that we have no alternative than reconsidering our way of living and to rethink the planet we are leaving to them. Forecasts with basis on our present actions, particularly on the way we have been intervening on nature to produce the built environment, is very worrying. One such worry has to do with the growing number of high rise buildings being produced, mainly those produced to become residential buildings. This paper briefly addressed a few of the issues (several others could be added) related to the life cycle of high rise buildings, including: energy; durability and maintenance; life expectancy; demolition costs; health and quality of life. With basis on a literature review and supported by adicional reflexions, considering the Brazilian reality, the following conclusions were considered to be pertinent, that, fundamentally, point out to some critical aspects associated to the production and living conditions in high rise buildings: With the gradual depletion of fossil energy resources, as pointed out by Heinberg, several aspects associated to our present comfort will become critical, among them: the vertical mobility of those living in tal buildings, as well as the vertical transport of heavy materials of any sort; Differently from old buildings, mainly in Europe, structure is growing in importance in tall buildings, both in terms of space and of materials and they have a relatively short life expectancy; With the end of the life cycle of this type of buildings, that can be shortened by the lack of resources of its users in their maintenance (simply because they cannot afford it), added to the difficulties inherent to the demolition process, a very worrying situation can be forecasted, that is the emergence of a growing number of dysfunctional and abandoned tall buildings (what happens to be already a reality in many cities in a number of countries); In addition to the above, several experts point out to the unhealthiness (mostly emotional) of living in tall buildings, mostly for those (elderly and children) that most are impacted by the problem of confinement in tall buildings. So, it becomes reinforced the importance of deepening and intensifying the practice of backcasting, as a way of contributing to the creation of a desired future, as far as the planning of urban areas is concerned, in the search of a more sustainable urban environment. 6

7 Acknowledgements The author expresses its gratitude to CNPq Conselho Nacional de Desenvolvimento Científico e Tecnológico, for the grant to him awarded (Bolsa de Produtividade em Pesquisa) that enabled the development of his research project on Materials and Urban Engineering Sustainable Strategies and the writing and presentation of this paper. References 1. GLAESER, E. (2011). Triumph of the City: How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier, and Happier. The Penguin Press. London. 2. SILVA, G. J. A. (2011). Cidades sustentáveis : uma nova condição urbana - estudo de caso : Cuiabá-MT. (In Portuguese). Tese de doutorado. Faculdade de Arquitetura e Urbanismo, Programa de Pesquisa e Pós-Graduação em Arquitetura e Urbanismo, Brasília. 3. FARR, D. (2008). Sustainable Urbanism: Urban Design with Nature. Wiley, New Jersey. 4. SUSTAINABLE CITIES INTERNATIONAL (2012). Infrastructure Costs and Urban Growth Management: A practical guide to understanding the impact of urban growth patterns on a city s infrastructure costs. SCI, Vancouver. 5. NORIE Núcleo Orientado para a Inovação da Edificação (2014). Available in: Accessed in: may HEINBERG, R. (2003). The Party s Over: Oil, War and the Fate of Industrial Societies. New Society Publishers. Canada. 7. HEINBERG, R. (2010). Peak Everything: Waking Up to the Century of Declines. New Society Publishers. Canada. 8. ROAF, S.; CRICHTON, D.; NICOL, F. (2009). Adapting Buildings and Cities for Climate Change. Architectural Press. Oxford. 9. ROCHA, C. G. (2008). Proposição de diretrizes para ampliação do reuso de componentes de edificações. (In Portuguese). Dissertação (Mestrado em Engenharia Civil) - Programa de Pós-Graduação em Engenharia Civil, UFRGS, Porto Alegre. 10. ABNT Associação Brasileira de Normas Técnicas (2010). Edifícios Habitacionais de até 5 pavimentos Desempenho, Parte 1: Requisitos gerais. NBR , Rio de Janeiro: ABNT. 11. SALINGAROS, N.; KUNSTLER, J. H. (set. 2001). The end of tall buildings. Available in: < Accessed in: jul EDIFÍCIO SÃO VITO (2013). Available in: pt.vikipedia.org/wiki/edificio_são_vito. Accessed in: fev ESTADÃO.COM.BR/BLOGS (2011). Demolição do Treme Treme. Photo: Hélvio Romero. Available in: blogs.estadao.com.br/olhar-sobre-o-mundo/demolição-do-tremetreme/. Accessed in: fev SCUSSEL, M. C. B.; SATTLER, M. A. (2010). Cidades em (trans)formação: impacto da verticalização e densificação na qualidade do espaço residencial. (In Portuguese). Ambiente Construído, Porto Alegre, v. 10, n. 3, p , jul./set

8 ATTACHED FIGURES Figure 1 (a) Figure 1 (B) 8