provide cheap temporary housing for the small damaged ... between 4 and 6 floors hosting most of the ... interest windows should be oriented mostly to south ...
RESHAPING CITIES AFTER A NATURAL DISASTER
Fig 1: Plan of L’Aquila with the proposed development
WHICH ARE YOUR ARCHITECTURAL (R)SOLUTIONS TO THE SOCIAL, ENVIRONMENTAL AND ECONOMIC CHALLENGES OF TODAY? Research summary The paper presents a methodology for the building of permanent neighbourhoods following a natural disaster. The case of the 2009 earthquake in L’Aquila, Italy is taken as an example for illustrating the approach. The historical centre of the city was destroyed and new towns were built away from the centre following the catastrophe. The research project conducted by the author assessed the new developments looking at both the urban and dwelling scales focusing on environmental performance and social sustainability. It resulted in a set of generative rules for new urban patterns based on environmental design principles and closely following the context (climate and topography). The paper will present the alternative design proposals put forward by the study. These draw upon the traditional features of Italian hills town, -the narrow streets, small squares, and mixed-use building typologies-, aiming to provide good environments, indoors and outdoors, maintaining the high density of dwellings and activities. Keywords: Earthquake, Housing Emergency, Sustainable Development, fast urbanism
1. Introduction Over the past fifty years the number of natural disasters has risen worldwide. In Italy, following this trend, there has been an increase in seismic activities. These events have had a large impact on the economy of the country with public money spent to respond to the immediate housing crisis. A common solution for managing emergencies is to provide temporary housing accommodation until the affected area is restored. The state of emergency applies notwithstanding urban regulations. For long-term solutions there is no clear strategy of how to approach the design process. Built examples lack urbanity, being designed for an immediate need without consideration to future integration with the existing urban form. On the 6th April 2009 an earthquake registering 5.8 on the Richter scale hit the city of L’Aquila and its surroundings. It was the peak of a seismic wave that had started some months earlier and is still active. The event was catastrophic, causing 309 deaths and damaging more than 23,000 buildings (almost 40% of which were listed). The Italian Government estimated damages of a gross total of over 10 billion euros. Three weeks after the earthquake two design competitions were launched in order to respond to re-housing needs: the first competition, “Progetto M.A.P.” aimed to provide cheap temporary housing for the small damaged villages around the city. The second one, “Progetto C.A.S.E.” proposed a permanent solution due to the complexity of the reconstruction of the historical centre. Construction started at the end of April. The first buildings were delivered to the population in November 2009 and by February 2010 all the works were concluded. In March 2010 the government allocated funds for the reconstruction of the town centre. This process
will take at least 20 years due to the complexity of the built environment and the building regulations that protect it. 2. Research methods and objectives The paper illustrates a design process that could be applied in post-disaster situations taking the case of L’Aquila as a case study. “Progetto C.A.S.E.” is an example of how high energy efficiency in buildings (more than 50% of the development is rated “Class A” under the Italian EPC) can be achieved meeting one of many requirements for creating a sustainable and balanced environment. However, the scheme’s wide street canyons, though useful for solar access, lead to low density residential neighbourhoods that have little in common with Italian culture in promoting social interaction or street life. Moreover, the historical centre of L’Aquila was mostly a pedestrian zone due to its narrow streets and its shops and public activities. By contrast in the reconstructed settlement, shopping and central urban facilities are scattered thus forcing inhabitants to use the car for any commute. The research project on which this paper is based (Scofone 2014) focused on the inhabitants’ experience, the changes that local people in L’Aquila experienced after the earthquake in both the historical town and the new settlements. A combination of qualitative and quantitative assessments was applied to investigate alternatives that recall and retain the key features of a typical Italian town. 3. L’Aquila Case Study: Analytical Work 3.1 The Old Town Centre The Old city centre sits on top of a hill. It has limited vehicular traffic allowing good pedestrian access. Self-sufficient, walkable, dense and diverse were qualities that made the
reached by direct sun are N-S oriented squares and streets, in which most of commercial and public activities are concentrated. Due to the high density environment, wind velocity is very low. This dense layout offers a variety of microclimates within short distances giving choices to pedestrians to use different paths, along with a variety of functions at ground level that provide a street life. Fig 2: Axonometric view of the old city centre
historical centre a good social environment. Clearly high built density as encountered here can limit winter solar access to buildings and outdoor spaces. The urban morphology of the old town centre is illustrated in the axonometric view and typical street sections of Fig.2 . The residential street is narrow and has E-W orientation, with 2-3 storey high buildings facing north and south and sharing courtyards. The height to width ratio (H/W) of the street is higher than 2.0 and does not allow solar penetration during the cold period either indoors or outdoors. The shopping area features a N-S oriented street with H/W ranging from 1.7 to 2.0. The “piazza” is a large E-W oriented open space (H/W=0.25), where the heights of surrounding buildings vary between 4 and 6 floors hosting most of the public events in the town. Outdoor furniture allows people to enjoy the benefits of sunshine thanks to the geometric proportions of the space. Arcades (Fig.3) provide a valuable architectural device protecting from rain and snow in the winter and from sun in the summer. Except for churches, all the buildings are mixed-use with shops at street level, offices up to third floor and residential spaces on upper floors. Figure 4 shows the number of hours sunshine reaches the ground on typical winter days; the areas
Fig 3: Section of a typical residential street (A) and commercial street
3.2 “Progetto C.A.S.E.” “Progetto C.A.S.E.” comprises 185 buildings distributed across 18 sites outside the city of L’Aquila. The local authority decided to spread these over a 20km radius to avoid densifying the suburbs thus leaving space for future expansions.
spaces, path walks and road (Fig 7). The complete absence of services forces people to drive to malls leaving the streets of these settlements empty, with no activities on the street to promote social interaction. The microclimatic conditions created by the built from are homogenous: as showed in figure 8 in the warm period there is no outdoor space sheltered from solar radiation. A pedestrian can find no protection from direct solar radiation.
Fig 4: Microclimate in a typical winter day
Fig 6: Settlement’s layout
Fig 5: “Progetto C.A.S.E.” settlements’ location
Fig 7: Typical section
One of the most typical of the 18 new developments was studied further. This has a plot of 300m by 280m comprising 18 buildings and a total of 576 dwellings. The layout adopted (fig 6) is simple and easy to develop build, allows solar penetration into the flats and provides views to the surrounding landscape. The street level is an untypical sequence of open field with dirt path, parking
3.3 Building scale L’Aquila is in Italy’s climatic zone E, the second coldest. The U-values stipulated by the regulations were assumed as a starting point for thermal simulations performed with the dynamic thermal simulation software Tas (EDSL 2014). A typical flat on the first floor of a 3storey building was modelled for this. The dwelling is a 2-bedroom apartment of 70 m2 in floor area with a window-to-floor ratio of 20%
distributed 60%-40% between the two orientations (the orientations were subsequently varied as part of parametric studies). The dwelling is assumed to have four occupants with fixed daily activity schedules. Space heating and cooling demands were calculated for different orientations (North, East, South-East, South, South-West and West) and for different levels of solar obstruction (H/W= 0.0, 0.5, 1.0, 1.7) and exposure (single or double aspect).
interest windows should be oriented mostly to south, with a deviation of up to 45 degrees to West or East.
Fig 8: Microclimate in a typical summer day
Fig 9: Heating loads per orientation, obstruction and exposure
As can be observed from figure 9, unobstructed single aspect flats facing S, SE and SW have lower annual heating demands of 7 to 10 kWh/m2 per year. However, when solar obstruction rises to the limiting value of H/W =1.7 the space heating energy demand doubles, rising to values that are close to those of West and East facing variants all else being equal. Dwellings with dual aspect were found to be less influenced by orientation and obstruction, even if the effect of direct solar gains can still be seen on those with a southern (resulting in lower heating demand by some 4kwh/m2 annum). It can be concluded that where space heating energy savings are of
The most significant result regarding summer cooling loads was the effect of cross ventilation. Double aspect flats performed better irrespective of orientation. It was also observed that south and west orientations might experience more overheating due to the combined effects of solar radiation and daytime peak temperature. East orientation is preferable to reduce the risk of overheating. In conclusion, dual aspect dwellings that have windows facing South, South-East and SouthWest represent better overall performances. 4. Design Proposals
Alternative proposals are discussed here for the redevelopment of L’Aquila following the earthquake. With the aim of providing continuity to the urban tissue so as to help better integration, a new site was chosen in the immediate proximity of the old town. The site is on a slope oriented mainly to the south-east with parts of the site oriented to the northeast, east, south and south-west. The site is sloped with a maximum inclination of 15 degrees.
Fig 10: Minimum height to with ratio to reach required solar access
development is placed on the top equidistant from the north and south site boundaries and closer to the town so as to facilitate connections. Figure 13 shows the master plan that embodies these strategies. The typical residential layout (Fig 14) is dense and compact, characterized by relatively narrow streets (Fig 14- point D), 5 to 8 metres wide depending on orientation, and slopes oriented east-west that are mainly pedestrian with limited car access to vehicles authorized by local regulations. Stairways (3-5 meters width) (Fig 14- point A) follow the slope designated for pedestrian movements only. The layout set up by solar access and pedestrian movement is interrupted by small squares that promote outdoor activities along with small shops. Pedestrian movements are the main mode of movement; inhabitants have a wide range of paths to choose from. The intensive network of paths crosses a set of squares with the following attributes:
Fig 12: View of a sunny square (Point B in Fig 14) Fig 11: Design process
Figure 9 shows how key environmental design rules can help generate different morphologies on the site. The master planning follows guidelines illustrated in figure 10 relating to distances between buildings to safeguard winter solar access. Orientation and slope provide the key for densifying the scheme. The core of the
Sunny squares are open spaces (Fig12/ Fig 14point B) that allow solar access all-year round. They are designed to be used mostly during cold periods and mid seasons, allowing occupants to feel as much as 8°C warmer than the ambient temperature. “Roofs with a view” (Fig 15 / Fig 14- point E) are public spaces designed on the rooftops in areas where the terrain is too steep (>12°).
Fig 13: Design proposal showing various features of the masterplan
Fig 14: Section through the site showing different outdoor spaces and building’s typologies
Fig 15: View of a roof with a view (Point 4 in Fig 14)
This kind of environment is accessible from two levels and due to the favourable position it offers a view of the surroundings mountains. Like the sunny square, it is an open space that allows solar access all year around. There are also protected squares (Fig 14- point C), that are in the shade most of the time overshadowed by adjacent buildings; these spaces are less frequent, but they provide additional options. They are suitable for more intense activities such as sports and in summer they provide cooler areas compared to other places. It can be seen that in winter only the narrow street that is oriented southeast-northwest, is reached by direct sun (Fig 14- point A), while the other street is in the shade throughout. In warm periods this is reversed. This confirms that accessing the new centre will be more comfortable thanks to this carefully designed microclimate in both seasons.
environment while using standardized buildings and construction methods. “Zona E”, the climatic region that applies to the town of L’Aquila, represents some 40% of the country. This suggests that the design process presented here could find applicability in other parts of the country. A similar approach could be used to generate new urban patterns in a different climate. 6. Acknowledgements We acknowledge the support of the MSc/MArch SED (Sustainable Environmental Design) teaching staff. We would also like to thank the people of L’Aquila for enriching this research with their active contribution and Camilo Diaz for his Support. 7. References Yannas, S. (1994) “solar and Housing Design” AA, London. Givoni, B. (1998) “Climate Considerations In Building And Urban Design” Van Nostrand Reinhold. VV/AA (2010) “L’Aquila Il Progetto C.A.S.E.” IUSS Padova.
5. Conclusions An approach to rapidly designing settlements to take account of both social and environmental issues was described. This generated a scheme that is strongly contextualised, respecting the physical and cultural attributes of the surrounding
Scofone A. (2014) “ Reshaping Cities After Natural Disasters ” Architectural Association School Of Architecture, London. EDSL (2014) Tas v9.3.1. Environmental Design Solution.
