It is generally understood as the ability of a system and its components to anticipate, mitigate, adapt or recover from the effects of a major disaster, in a timely and efficient way; though in a more global vision it is opportune to understand it as the capacity of persons, communities, organisations or the countries exposed to disasters, crises and underlying vulnerabilities to anticipate, reduce the impact and face the effects of adversity, to later recover without compromising their long-term perspectives.
The strengthening of resilience based on all the local capacities is the most advanced focus of risk management in the constructed habitat, with the aim of achieving a sustainable development that makes it possible to face the challenges of climate change.
Cuba, located in the passageway of hurricanes and tropical storms coming from the Atlantic Ocean, suffers recurrently from severe damages and economic and social effects. In the attention to this problem there are two options: risk management based on the reduction of vulnerabilities and the response after the natural impact; or, in its place, applying a focus of resilience that makes it possible to develop local capacities to reduce the disaster in the communities and society as a whole.
The Centre for Research and Development of Structures and Materials (CIDEM) of the Marta Abreu Central University of Las Villas is developing several experiences with a view to proactively act toward the achievement of urban resilience, as the means to reduce the impact of disasters, especially in the scenario of the increasing effects of climate change.
The constructed environment, and especially urban settlements and homes, have experienced the most severe impact of the natural disasters. In light of this increase in the intensity and recurrence of these disasters, the classical focuses that interrelate the concepts of vulnerability, risk and disaster in the constructed environment can be summarised between the dialectical interaction between what could be called the state of vulnerability and the degree of resilience for a given context and under a group of acting political, economic and social circumstances. The developing countries are, with greater frequency, a recurrent scenario for these manifestations.
As Mansilla pointed out, the city as a target for disasters and propitious space for the generation and intensification of risk has been greatly confirmed already throughout the world and with special emphasis in the underdeveloped countries. A United Nations Development Programme world report clearly establishes the connection between the development processes and the consequences of natural disasters. The document argues that, while only 11 percent of the persons exposed to natural dangers lives in countries with a low human development index, this represents more than 53 percent of the total of registered deaths.
A future of growing threat for the sustainable development of the developing countries can be perceived in the basic report of the World Conference on Disaster Reduction, held in 2005 en Hyogo, Japan, linking this to the persistence of certain demographic, technological and socioeconomic conditions, to unplanned urbanisation, to development in high-risk areas and to other consequences of underdevelopment.
The concept of resilience has imposed itself as an effective means to face the growing tendency of occurrence and negative effects of natural disasters in the constructed environment. It is generally understood as the ability of a system and its components to anticipate, mitigate, adapt or recover from the effects of a major disaster, in a timely and efficient way; though in a more global vision it is opportune to understand it as the capacity of persons, communities, organisations or the countries exposed to disasters, crises and underlying vulnerabilities to anticipate, reduce the impact and face the effects of adversity, to later recover without compromising their long-term perspectives.
Therefore, the strengthening of resilience based on all the local capacities is the most advanced focus of risk management in the constructed habitat, with the aim of achieving a sustainable development that makes it possible to face the challenges of climate change.
At the World Conference on Disaster Reduction held in Kobe, Hyogo, Japan, the interest of the countries in increasing resilience in the face of disasters was reaffirmed and was explicitly included in the 2005-2015 Hyogo Framework for Action.
These priorities, in addition to their integral focus on the issue of risk management, call for paying attention to the preference disaster reduction has and the important role played by the governments of every nation in decision-making and undertaking the different strategies and measures. International organisations, like the International Federation of Red Cross and Red Crescent Societies and the United Nations Development Programme, have established a strategy based on their work, oriented at achieving resilience, promoting the capacity of communities, organisations and countries exposed to disasters, crises and underlying vulnerabilities so they can anticipate, reduce the impact and face the effects of adversity to then recover without compromising their long-term perspectives (UNDP, 2004).
Maturana has specified the concept of resilience in the sense of the ability to anticipate, mitigate, adapt or recover from the effects of a major disaster, in an opportune and effective way. This means that a resilient community is well positioned to manage the threats, minimise their effects and recover rapidly from any negative impact. This derives in a similar or better state as compared to the position it had before the threat occurred. There are strong ties between resilience and the ability to adapt; therefore, resilience can also vary significantly between the different community groups.
The local contexts develop different policies by investing in the formation of resilient communities that adapt to the conditions that define it as such. Therefore, they focus on seeking transformation variants to reduce the vulnerabilities and direct their local development toward the resilience that allows them to build a safer habitat with a view to sustainable development.
The development of suitable technologies, with local and participatory sense, especially at a local level and in small communities, is included in the Decalogue for Resilient Communities (UNISDR, 2011; 2012) on which the United Nations is working to extend climate change confrontation.
In the last 10 years studies and applications have been carried out on a local scale at the Centre for Research and Development of Structures and Materials (CIDEM) of the Marta Abreu Central University of Las Villas, in the introduction of suitable technologies for the development of local resilience. The present work summarises the results obtained as part of these studies and applies them in the specific context of the barrio of El Martillo, located in a small city that is the administrative centre of a Cuban rural municipality, but its conclusions have a reproductive and methodological adaptation potential in other communities.
URBAN RESILIENCE AND CLIMATE CHANGE
Natural disasters have doubled in the decade of 2000-2009 as compared to the 1980s, with a pronounced tendency toward an increase in the annual average of hydro meteorological and geological disasters (257 in the 1990s as compared to 382 in the last decade). Climate change has a clear influence on these tendencies, since disasters due to hurricanes, typhoons, tropical storms and other related phenomena constitute more than 75 percent of those that took place in the last decade.
In the midst of the growing urbanisation prevailing on the planet, the impact is evidenced in the cities. In the last four decades, almost 8,900 natural disasters caused the death of three million persons, affected some two billion and caused 1.8 trillion dollars’ worth of loses.
The adverse effect of climate change will be particularly intense in the developing nations due to their geographic and climatic conditions, to their high dependence on natural resources and to their limited ability to adapt to a changing climate.
The development of urban resilience requires a change of paradigms centred on local focuses that allow for the development of capacities that go beyond achieving safety and resistance in the material elements exposed to the threats but the political, economic, social, institutional and other types of aspects that take place in society and the community are also of interest.
In this context, the so-called ecotechnologies are gaining ground as a means to achieve resilient communities and thus reduce the impact of disasters on homes and the constructed environment, while contributing to sustainable development and the creation of safe environments.
ECOMATERIALS AND ECOTECHNOLOGIES
The state of the art of manufacturing construction materials underscores the development of models in which the capital costs are high, while those of production are reduced to a minimum, a very convenient scheme for countries that have solid finances and low capital interests. In those countries the income of experienced and semi-experienced personnel is high, as a result of a higher degree of capitalisation. When this model is applied to the developing countries it brings unemployment in the short term, while it raises the dependence on foreign technology and imported raw materials.
The cost of construction materials represents a high percentage of the total construction. Some authors estimate it at more than 40 percent for homes in the developing countries. In such studies it has been determined that the imported raw materials represent a significant part of the cost of the materials in the traditional buildings. Examples like the undulating metal sheets, in which the local added value is insignificant, increases the dependence on imports. Other materials – like Portland cement, which represents around 15 percent of the total cost of building a home in the developing world – concentrate extreme dependence on technology and energy aspects, while the rest of the raw materials are locally supplied.
If the construction materials have been produced with raw materials available in the local surroundings of the workshops, the resulting products could be economical for a larger sector of the population, especially those who normally do not have access to traditional construction materials. Such productions could be capable of competing, in quality and price, with the traditional materials, and could also have a good environmental profile, based on the fact that local raw materials frequently come from agricultural and industrial waste.
This type of small-scale production is an incentive for the local economy through the creation of new job opportunities. Moreover, the environment is protected from potential threats coming from waste. The amount of energy incorporated in the new products is lower, compared to traditional products, given that the cost of transport is reduced to a minimum and the technological processes are rather simple.
Such productive activities consist in the underlying concept of this paper: the ecomaterials (“eco” represents ecology and economy) that have become an alternative for traditional construction materials. Though both are similar, their production processes are significantly different. The ecomaterials are produced on a small scale, with proven and certified technologies, and use local resources. They have become a source of decentralised development based on the employment of operators who do not have a lot of experience and the use of products purchased in the vicinity of the workshop, which saves on transport costs. In all cases, the technologies for producing such materials include flexible systems for ensuring quality based on field and lab tests, adapted to the local possibilities of the developing countries. Thus, a reasonably high standard can be obtained in the production of these products, which can compete on a local scale.
The concept of ecomaterials comprises a wide variety of construction materials, with different origins and useful purposes. However, the best experiences have been reported in the production of micro-concrete roofing (MRT) tiles, CP-40 puzolanic cement, hollow concrete blocks, non-stabilised adobe bricks and baked clay bricks of low energy and using alternative fuels.
If, moreover, a strategy is proposed for disaster prevention and mitigation that includes the possibility of locally producing the ecomaterials, the conditions for success and sustainability are intensified. The local capacities would be created that would allow the vulnerable communities to develop their own generating resource capacities for recovering from the damages caused by the disaster, or renovate and build homes that can resist storms and the impact of a hurricane.
In the future, this would be reflected in the reduction of the vulnerability of housing settlements, as well as helping the development of the local economy through the creation of jobs and sources of local wealth in normal times. If the construction materials have to be supplied from external sources to the settlement, the post-disaster mitigation could be resolved, but the sustainability could be exposed and, in the long run, could also contribute to the increase of the vulnerability of the constructed environment in the face of the disaster and would expand its dependence on external resources to mitigate it.
On the evening of November 4, 2001, Hurricane Michelle penetrated into terra firma to the south of Matanzas province, with sustained winds of 250 kilometres per hour. Twenty hours later it left the country through Villa Clara province and straitened its course toward the north through a point near the coastal town of Isabela de Sagua and the small city of Corralillo. The strong winds caused damages in a radius of approximately 500 kilometres. Homes and crops suffered the most. Approximately 55,000 homes were damaged just in the province of Matanzas.
The roofs of the homes suffered the most damage (75% of the total). The strong winds created an internal pressure that pushed the roof tiles upwards and destroyed them. The major part of the light elements of the roofs was not in a condition to withstand the pressure and they failed. Complete sections of some roofs also flew into the air. If the roofs of these homes had been built with heavier elements the damage could have been minimised.
Following are the projects for disaster response carried out in Cuba’s case after Hurricane Michelle’s passage, which will serve to illustrate the ideas taken into account in this work. The first case study describes a specific intervention made through close coordination between the local government of Quemado de Güines and the Swiss Agency for Development and Cooperation (COSUDE). The second case study consists in a regional intervention in the province of Matanzas, carried out through the National Housing Institute, with funds centrally provided by the Cuban State to repair the homes damaged by the havoc wreaked by the hurricane.
In both cases the aspects related to the strategy implemented for the production of construction materials and their contribution to the mitigation of the damages caused by the hurricane are discussed. Elements related to the sustainability of such actions are also dealt with.
Case 1. Municipality of Quemado de Güines, Villa Clara
The urban areas of the municipality of Quemado de Güines were literally devastated by Hurricane Michelle’s strong winds. Part of the population was transferred to temporary facilities created in the schools and other official buildings. As soon as the hurricane left the island, the local and central government bodies started the disaster response activities to preserve what could be saved and mitigate the damages caused. Prior to the passage of the hurricane, the efficient system of civil defence had sheltered the inhabitants and tried to protect all the possible material resources.
COSUDE offered financial support as humanitarian aid, mainly for the actions directed at providing support to those who lost their homes. In this context, representatives of COSUDE coordinated with the CIDEM to immediately set up an ecomaterials workshop and locally produce the principal construction materials needed to implement a disaster response programme.
The alternative was to use the fund contributed to purchase the means to improve the homeless population’s living conditions and materials and products to repair the material damages to buildings and the infrastructure. This could have implied the organisation of imports, a process that could be slow and problematic, especially in a country like Cuba, submitted to the ironclad U.S. blockade since 1962.
Fortunately, COSUDE decided on the local alternative, giving rise to the birth of the humanitarian aid project that was presented, which later on evolved into a local development project. This was possible because the local government provided temporary shelter for the displaced families, with all the hygienic-environmental conditions, with food, medical, educational and psychological care and other facilities, with which it reduced the social and humanitarian pressure of that difficult situation.
Twelve days after the signing of official contracts, in late December 2001, the ecomaterials workshop started operating in Quemado de Güines. The CIDEM provided the machinery, advice and the training of the operators, who came from the affected community. The workshop was equipped to produce the MRT tiles, the CP-40 puzolanic cement and the hollow concrete blocks, all of which was in high demand to repair the damages of the homes affected by the disaster.
In the first six months the workshop was able to produce more than 80,000 concrete blocks, in which half of the amount of Portland cement was replaced by the locally produced puzolanic cement; as well as 12,000 units of MRT tiles. During 2002, 160 families were able to repair their homes with materials produced in the municipality.
The persons who headed the project made a firm commitment to employ materials resistant to climate phenomena associated to hurricanes, such as the hollow concrete blocks and the MRT tiles, the latter with a very good effectiveness demonstrated in the face of strong winds (RHYNER, 1989), probably because the small roof tiles can rise and ease the internal pressure created by the force of the wind, like a valve. In fact, some townspeople have said that the MRT tiles move in place during the action of the winds and hurricane gusts, but do not fail.
The MRT tiles offer a better alternative for roofs in hurricane risk areas, compared to the asbestos-cement sheets commonly used. The MRT roofs are heavier than the sheets, have a greater resistance against the concentrated dynamic load and their reduced size avoids the concentration of local tensions.
On the other hand, the MRT tiles are locally produced in the ecomaterials workshop, while the asbestos-cement sheets are produced in the eastern tip of the country, which is why it is necessary to transport them and travel from 600-900 kilometres before placing them on a home. Statistics indicate that through the intervention on the roofs, to replace traditional materials with the MRT tiles, their vulnerability decreases in the face of strong winds. Moreover, the walls built with hollow concrete blocks are stronger and can better resist the strong winds, as compared to wooden walls.
The problem with the MRT tiles in Cuba is that they require a support structure that is normally built with wood, a material that is very scarce and expensive in the country. Two important decisions were adopted in that direction: some wood should be imported to enable a fast intervention in the most damaged homes and undertake actions to develop a concrete support system. Both decisions yielded favourable results: the first 23 tiled roofs repaired during February and May 2002 were built with imported wood, as support for the MRT tiles. On the other hand, there are currently two workshops that are operating where elements of the so-called SIPRET concrete prefabricated system, developed by the CIDEM, are produced.
The ecomaterials produced in the local workshop during that period represented approximately 60 percent of the total amount of materials provided for the post-disaster actions in the municipality. After the disaster mitigation actions concluded, the workshop continued active and currently the ecomaterials produced are being used for the new housing construction plans the country has initiated on a municipal level.
This action is a good example of an integrated effort that involved different actors in a common objective: disaster mitigation. All the participating institutions contributed with resources, which were basically managed by the local government in a decentralised way.
Case 2. Ecomaterials for the province of Matanzas
This project was conceived as a large-scale mitigation action, organised by the National Housing Institute in an effort to recover from the damages caused by Hurricane Michelle in the entire province. The plan included the production of wall elements, mainly hollow concrete blocks, to be distributed among the affected municipalities. The mass production of undulated asbestos-cement sheets to replace the roofs that had been blown away was organised outside the province. The construction activities were assumed by special brigades created for that purpose.
The initial idea was to produce all the concrete blocks (four million units) in the large production installations to the east of Havana, at a distance of around 300 kilometres from Matanzas. The date was established for the handing over of the produced blocks during the first six months after the disaster. However, the shortage of resources, especially energy, led the leadership to seek local alternatives for the production of the wall elements. Thus the CIDEM project emerged to explore the possibilities of reproducing the ecomaterials workshops in Matanzas, with the aim of making hollow concrete blocks.
However, there was no interest in producing the MRT tiles, whereas it was decided to use the asbestos-cement sheets produced in a factory located in Santiago de Cuba, some 600-800 kilometres from the different localities of the province of Matanzas. Neither was the production of puzolanic cement thought of, since given the situation of the emergency, the central government placed at the disposition of the territory large amounts of Portland cement.
The concrete blocks workshops started operating in the different municipalities of the province of Matanzas with the idea of creating a production capacity of a million units (25% of the real demand) in the territories affected by the hurricane. The chosen municipalities were: Colón, Cárdenas, Jovellanos and Perico. In late March 2002, all the workshops were in full operation and in July 2002 the reported production was more than 250,000 units, reaching 450,000 units late that year, with which a production record was set in the province.
This effort demanded a logistical programme to organise the supply of dry goods and Portland cement as well as transporting what was produced to its destination. The aggregates were transported from a local quarry by train, at an amount of between 2,000 and 3,000 cubic metres a month of dry goods during the first half of 2002. The Portland cement was supplied from Havana, 250 kilometres away. The undulated asbestos-cement sheets were transported from Santiago de Cuba, in an expensive and complicated operation.
A while later, the state of emergency was lifted (another hurricane affected the country in another province), the flow of resources declined and production decreased. Some workshops had to close down because they did not receive materials and others were able to function locally, according to a reduced availability of materials. If the production of puzolanic cement had been undertaken it would have been possible to extend the use of available Portland cement and, at the same time, even to continue producing with small external support. The system that initially functioned very efficiently simply failed when the external resources were missing. The majority of the costly machines was conserved and stored for better times. Producers lost motivation and the elements and materials for walls were again locally in short supply.
In addition to the above, many of the new roofs demonstrated they were not safe against hurricanes and again failed under the strong winds of the hurricanes from 2003 to 2005. In late 2004, the National Housing Institute included the problems of vulnerability of the undulated asbestos-cement sheets in the face of the strong winds and discouraged their use in disaster mitigation projects. Among other solutions, the MRT tiles have emerged as a safe alternative in the face of hurricanes.
This analysed case has a different focus from the other. The actions were convened at a national level and the resources were provided centrally. While many of the problems created by the hurricanes were tackled, the invested resources did not contribute significantly to reducing the vulnerability of the province in the face of hurricanes given that there was a dependence on sources of external resources. This situation put at risk and in the long run affected the sustainability of the actions.
The results show the feasibility of the practical application of the principles and methods for the development of resilience in the face of disasters on a local scale. The major part of the economic losses, material and human damages due to natural disasters occur in the constructed habitat, especially in urban areas with the greatest concentration of population, which is why the promotion of resilience is one of the major long-term measures among those for risk management.
Decision-makers play a decisive role, in prevention as well as mitigation of disasters. An appropriate risk management strategy contributes to minimising the effects of disasters in human settlements, while also contributing to increased efficiency in the administration of resources for disaster prevention.
The presented case studies are proof that the local production of ecomaterials is a feasible and necessary means for achieving urban resilience in developing communities, as a way for the vulnerable population to be able to create safer environments in the face of climate change.
Cardona, D.: Gestión integral de riesgos y desastres. (Integral risk and disaster management), Bibliographical material for the Doctorate in Civil Engineering. Universidad Politécnica de Cataluña, 2003.
Mansilla, E.: Riesgo y ciudad (Risk and city). Universidad Nacional Autónoma de México, Department of Postgraduate Studies, Faculty of Architecture, Mexico, 2000.
Rhyner, K.: El Huracán “Gilbert” y la teja TMC (Hurricane Gilbert and the MRT tiles), FCR Bulletin, No. 5, September, Switzerland, 1989.
Salas, J.: “La importancia los materiales en la construcción de bajo costo” (Import of materials in low-cost construction), Revista Materiales de Construcción magazine, Vol. 42, No. 227, July/August/September 1992, Spain.
Martinera, F. – A. Olivera: Decreasing vulnerability against natural disasters through local manufacture of building materials. Open House International, 2005. (Accepted to be published in No. 1, March 2006)
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