Abstract: The Italian earthquakes of recent decades created an emergency situation that required immediate post-earthquake reconstruction policies, which led to an increase in the demand for construction minerals. In particular, extraction in active quarries has been intensified, and new quarries opened according to extraordinary procedures notwithstanding current regulations. The objective of this work is to investigate the consequences that a seismic event may produce on both the built-up environment, i.e. the totality of urban and suburban settlements and infrastructure, and the natural environment, which is often compromised by hasty emergency procedures aimed at mineral extraction. As a result, correct evaluation of the demand for minerals and the recycling of earthquake debris are the fundamental elements of coherent post seismic reconstruction, by means of which post-earthquake policies could be reconciled with environmental protection.
Key words: Reconstruction, construction and demolition, waste, debris, recycling, earthquake.
1. Introduction
Italy is one of the European countries with the highest risk of earthquakes, the areas potentially affected extending throughout the country: in particular, the region of Friuli-Venezia Giulia, the central-southern Apennines, the Calabrian and Tyrrhenian margin and south-eastern Sicily [1]. Some 23 million Italians out of a population of 60 million(38%) reside in areas of high seismic risk, and 4,610 municipalities out of 8,112 (56.8%) are located in seismic zones [2]. The earthquakes occurring in Italy usually create extensive damage, due to both geomorphological conformation and incorrect use of the territory, characterized by an excessively high concentration of urban settlements.
The procedures for post-earthquake reconstruction, i.e. the removal of debris, the demolition of unsafe buildings, and their reconstruction [3], lead to an inexorable increase in the requirements for construction minerals. In particular, the demand for aggregates (sand, gravel and crushed stone) intensifies, because they can be used either in road filling, railway ballast or armour stones, or in the production of glass(quartz sands), ready-mixed concrete (made of 80% aggregates), pre-cast products, asphalt (made of 95% aggregates), etc.. Such structures are all examples of the urban and suburban settlement and infrastructure usually needed to rebuild after a seismic event.
By the recycling process, the part of the materials needed for reconstruction activities can be obtained. Therefore, the extraction of natural minerals could be reduced. Recycling of C&D (construction and demolition) waste is becoming a significant resource in some countries. For example, the Netherlands and Japan recover almost all the concrete from their construction waste; in 2007 Germany recycled 89.2% of C&D waste [4]. As regards European recycling policies, while in some countries the market for recycled aggregates is on the increase, in other EU states C&D waste is rarely re-used. According to the European Aggregates Association [5], nearly 6% of the European aggregates demand is covered by recycled aggregates. Recycled aggregates are generally composed of crushed asphalt pavement, originating from road paving and construction activity, and crushed portland cement concrete, from C&D debris[6]. By more extensive use of recycled aggregates, greater environmental conservation and protection could be attained, reducing the extraction of natural aggregates and thus limiting the opening of new quarries. In order to achieve this objective, the debris from catastrophic events may be included in a recycling process, becoming a resource. Review of the literature on the subject identifies the major benefits of recycling disaster waste [7], including:
reduction in landfill space used;
reduction in the amount of minerals used in reconstruction;
revenue from recycled aggregates;
reduction in transportation costs for both natural materials and debris;
job creation (for developing countries in particular).
Several case studies document this recent attention to the recovery of debris after catastrophic events, e.g. the deconstruction (the hand dismantling of buildings) in post-Katrina New Orleans [8]. This case aimed at reclaiming building materials from some of the 275,000 destroyed homes after the US Gulf Coast hurricane season of 2005. The results of the deconstruction program showed salvage rates varying from 28% to 62% of individual building weight, reaching a total project recovery rate of 48%. Moreover, the program demonstrated that it was possible to salvage enough material to build three new homes out of four destroyed ones.
In this context, our work aims to investigate how the emergency situation could be managed in order to mitigate the potential damage caused by a seismic event and the subsequent recovery and rebuilding process. Therefore, the amount of the waste resulting from specific Italian earthquakes has been assessed, with suggestions regarding potential recycling.
2. Emergency Management
2.1 Legislation and the Role of the Authorities
In Italy emergency management is entrusted to an organization called the National Civil Defence, whose responsibilities for forecasting, prevention, rescue and return to normal living conditions are stipulated by Law 225, published in 1992. Following the Constitutional Law No. 3 (2001), the state establishes the guidelines for civil defence, whereas local authorities (the Regions, the Provinces, the Prefect, the Mayor and the Municipalities) draft the programs for the prediction and the prevention of risks and the practicalities in cases of emergency. However, the ability of ordinance is provided by Law 225 as an operational tool, which may derogate from both local and national legislation, except for EU procurement procedures for public works contracts. The ability of ordinance is attributed to the Prime Minister or the Minister of the Interior, or commissioners delegated by them. By using accelerated procedures, such ordinances may allow an intensification of quarrying activity owing to the increased demand for building materials. In addition, the ordinances follow extraordinary procedures under the responsibility of the Prime Minister or his delegates instead of the usual formal procedures related to mining, which would normally be a regional responsibility. In this specific context, waste recycling is an initiative of great value which aims to mitigate environmental risks and to increase sensitivity to environmental protection.
In Fig. 1, the location of the Italian case studies analysed is reported.
2.2 Case Studies
2.2.1 Friuli-Venezia Giulia Earthquake (1976)
On Thursday, May 6, 1976, a quake measuring 6.4 on the Richter scale and on September 15, 1976, another strong quake struck the Friuli-Venezia Giulia region. The emergency management was entrusted to a special commissioner who had the ability to take whatever measures were deemed appropriate and necessary (Law 730, 1976), notwithstanding the rules in force. During the rebuilding process, the “new town”solutions (the reconstruction of houses in new areas) were not welcomed by the population, who preferred urban solutions more similar to those already existing. For example, for the reconstruction of the Cathedral of Venzone (Province of Udine, Friuli-Venezia Giulia), while civil engineers wanted to build a new church, the inhabitants insisted on restoration according to the original configuration.
Thus, they recovered 7,650 stones of the Cathedral and re-used them for its reconstruction, thus demonstrating the feasibility of converting debris into a resource. Because of the length of time since the event, quantification of debris resulting from the earthquake shown in Table 1 is difficult and underestimated. Moreover, from the comparison between the number of destroyed houses with those rebuilt, it can be noted that 12,000 new homes were built. This indicates that many damaged buildings were demolished instead of being scheduled for renovation works. In fact, demolitions originated from commercial interests, because the building firms charged the standard price for the removal of debris of 1,900 lire/m3 [9], corresponding to about 2.3 $/m3, according to 1976 yearly average exchange rates.
2.2.2 Irpinia Earthquake (1980)
On November 23, 1980, a quake of 6.8 on the Richter Scale took place in a zone encompassing the Campania, Basilicata and Puglia regions. Due to the vastness of the area affected and to the large number of municipalities involved (687), the commissioner appointed a special emergency structure subdivided into four hierarchical levels up to the municipal level. Law 219 (1981) set out all the arrangements for the reconstruction. The amount of earthquake debris is difficult to assess due to the Camorra infiltration in the removal activities (Parliamentary Anti-Mafia Commission, 1993). Despite this, there were some interesting cases of recovery: the first concerns the town of Valva (Province of Salerno, Campania), in which the municipal government rebuilt the old town by expropriating buildings, providing a recovery plan and relocating the debris piece by piece. The second case, more recently, pertains to the Integrated Project“The Abbey of Goleto” (2005-2008). The renovation works involved the re-use of the debris, which consisted of both blocks and rubble, which were recycled for the production of lime and pozzolana used for mortar, plaster, concrete screed and flooring [10]. In this case the demolition of damaged buildings was again preferred: in particular, Law 219 established a family-unit contribution for the reconstruction of the houses to be demolished, encouraging demolitions rather than renovation works. This resulted in growing pressure on the environment: in fact, not only the amount of debris transported to landfill, but also the demand for building materials increased.
2.2.3 Abruzzo Earthquake (2009)
On April 6, 2009, an earth tremor measuring 5.8 on the Richter Scale shook the Abruzzo region, in particular the province of L’Aquila. To ensure rapid implementation, the emergency decree passed by the Italian Government (Decree No. 39 of 2009, “Abruzzo Decree”) gave the delegated Commissioner the tasks of identifying the areas where new houses, infrastructure and services should be built, and of overseeing their construction.
These areas were located by an emergency decree(Ordinance of the President of the Council of Ministers No. 3811, 2009) as an exception to the existing urban and landscape regulations. Some recent studies [11] show how the built-up area increased either in previously unbuildable areas (because of landscape and historical-architectural constraints), or in agricultural zones (reduced buildability). The zone also includes the National Park of Gran Sasso and Monti della Laga, which were previously subject to landscape constraints.
The Abruzzo Decree sets provisions for the management of the debris resulting from the collapse and the demolition of buildings: it has been assimilated to municipal waste, and the municipalities must deal with its removal, collection, transportation, recovery and disposal. However, the mayors could not proceed with the complete removal of debris because they said that they lacked the technical and economic resources.
Thus, there is still uncertainty in the quantification of debris and in its removal. Recently (February 1, 2010), the criterion of “solidarity redistribution”, which identifies debris storage sites in neighbouring territories, was proposed to the mayors.
A specific project has also been agreed that schedules in 24 months the definition of both the quantification and the treatment of the debris, in collaboration with the University of L’Aquila.
2.3 A Recycling Experience: The Activity of the Umbria Region
The earthquake that struck a zone between Umbria and Marche on September 26, 1997 is an interesting example of the management of the debris. There were 70,252 damaged buildings, and in the worst affected municipalities more than 1,580 demolition orders were issued [12]. The Umbria Region promulgated the Directive on “Removal of debris, demolition of buildings and materials recovery” (1998), which defined the role of the local authorities and set controlling the number of demolitions and the re-use of debris as targets. In addition, the region established that each municipality must re-use at least 50% of the materials recycled from the earthquake debris in the reconstruction of public and/or private civil works. The timeliness in undertaking these procedures was possible because a policy of recycling of C&D waste had been initiated by the Regional Government even before the earthquake, with the “Plan for waste management” (1987), which focused on the recovery of “mixed waste resulting from demolition”. In this perspective, the amount of aggregates coming from the debris was assessed, taking into account the quantities resulting from the reconstruction of the destroyed buildings. Methodologically, the estimate was obtained by making a first assessment of building types(masonry buildings, typical of medieval city centres). For each building the amount of debris expected from normal demolition operations is 20%-25% of the volume of the whole building, estimated at 700-750 cubic metres. Subsequently, a data check on some demolitions carried out in one of the municipalities affected, Nocera Umbra, was undertaken. An average of 300 cubic metres of debris for each building was then defined, a total of 474,000 cubic metres. Moreover, an estimate of the waste deriving from the reconstruction of the damaged buildings, for which planning permission had been given (until December 31, 2001), was made; this assessment amounts to 429,000 cubic metres. Consequently, the quantification of the earthquake waste is 903,000 cubic metres. Many entrepreneurial activities dedicated to recycling were undertaken. These activities, as a result, led three years after the earthquake (December 31, 2001) to the production of 189,362 cubic metres/year of recycled aggregates, among which 103,333 cubic metres/year or 55% of the total were sold. The recovery rate of the debris conferred consisted of inert materials and iron, with ranges from 96% to 98% [11].
3. Potential Waste Recycling in Abruzzo
3.1 Preliminary Comments
In order to evaluate in a recycling perspective the recent earthquake management in Abruzzo, the feasibility of the methodology applied in Umbria was investigated. The initial assumption was to consider that the construction typologies of the Umbrian towns affected by the earthquake are similar to those of the towns of Abruzzo, i.e. medieval town centres mostly composed of single-family buildings with load-bearing masonry.
In order to analyse the damages reported in the historic centre of L’Aquila, the area of the city that suffered major damage following the quake, the Seismic Engineering Operational Unit DISAT-UOIS on days April 24, 25 and 26, 2009 carried out an inspection which mainly showed three-storey edifices in load-bearing masonry as residential building typologies [13].
In addition, the 14th General Census of Population and Housing [14], subdividing the residential buildings into three typologies of one, two, three or more dwellings, also supports this hypothesis, as shown in Table 2.
3.2 Procedure for the Quantification of the C&D Debris Generated in the Seismic Event
Assuming that for the building typologies of the Abruzzo towns affected by the earthquake the amount of debris expected from ordinary demolition activities is 20% of the total volume of a typical building of the zone, estimated at 700 cubic metres, a first assessment of the debris was made, resulting in 3,405,500 cubic metres.
It is important to note that such evaluation only takes into account the 24,325 buildings destroyed by the earthquake, leaving out the estimation of debris from the damaged ones (certainly not zero) because of quantification difficulties. Another assessment quantifies the debris as 2,650,000 cubic metres [3]. Currently, this assessment is under redefinition by the University of L’Aquila.
In order to apply the “Umbria methodology” to Abruzzo, quantification of the recyclable waste is necessary.
In fact, because of the various origins of such waste, the differing local building techniques, the local availability of raw and building materials, etc., the composition of the C&D waste is rather changeable. In order to evaluate the amount of recyclable waste, the average percentage compositions of C&D waste in Italy is shown in Table 3 [15, 16].
Hence, in Italy the average recyclable fraction of C&D waste consists of a percentage varying from 90% to 95%. Review of the literature on the subject suggests that from such amounts all masonry and concrete waste can theoretically be recycled and re-used, in particular when the recycled materials satisfy the given technical specifications and the process is economically competitive [17]. In practice, especially through a stationary recycling plant which leads to products of higher quality and homogeneity, it is possible to reclaim about 90%-95% of C&D debris.
For instance, the Plan for Waste Management in Sicily (2002) indicates that the efficiency of these plants can reach about 95%. The remaining 5% consists of 4% of natural earth, separated before crushing, 1% of light fraction (paper, plastic, wood, etc.) which goes to disposal and 0.1% is ferrous material.
The case study of the recycling plant of Santo Stefano Magra in the Province of La Spezia, Liguria[18] confirms that stationary installations could reach 95% efficiency, as well.
4. Results and Discussion
Given the two previous evaluations of the C&D earthquake debris in Abruzzo, and assuming that the recyclable fraction is about 90% of all debris, from which the 5% of light fraction and ferrous material should be subtracted, the obtainable amount of recycled aggregates could be assessed. This amount in the first case consists of 2,911,703 cubic metres(estimated ex-Umbria methodology) and in the second of 2,265,750 cubic metres (estimated ex-ITC-CNR).
These recycled aggregates could be re-used directly in the reconstruction process. Although the extraordinary demand for building materials in the Abruzzo region following the seismic event is difficult to quantify, presumably it is higher than the ordinary annual requirements, estimated as 4 cubic metres/inhab [16].
The next step is to quantify the extraordinary demand for building materials due to the reconstruction process in the regional capital of Abruzzo, L’Aquila.
A review of the literature identifies several approaches that could be undertaken, among which it is possible to mention three main groups [19, 20]:
(1) the assessment of demand for aggregates based on statistical aggregates;
(2) the assessment of demand for aggregates in reference to the forecasts of the urban plans;
(3) the assessment of the consumption and the production of aggregates.
In post-earthquake reconstruction, the second approach seems to be the most appropriate. It is based on an evaluation of the possible consumption of mineral resources referring to the forecasts of planning instruments. In this specific case, appropriate planning tools are desirable to provide an assessment of the destroyed buildings and infrastructures, and therefore such urban plans can estimate how many of these need to be reconstructed. According to these forecasts, the quantification of the extraordinary demand for aggregates is then possible, and consequently the modalities to find the materials needed for reconstruction, partly deriving from natural resources and partly from the recycling of C&D debris, can be planned. However, presently there is a lack of urban plans which could allow us to make predictions and estimates of the requirements for the rebuilding process in the city of L’Aquila.
For this purpose, it would be useful for the municipalities located in seismic areas to establish plans for the recycling of debris involving:
analysis of building typologies, with information on materials and construction techniques, and indications of the buildings most at risk;
assessment of the extraordinary demand for building materials in the occurrence of seismic events;
the primary location of the storage, treatment and recovery facilities of the debris.
On an international scale, the need to plan for disaster debris can be traced back to the USEPA’s(United States Environmental Protection Agency’s)“Planning for Disaster Debris” [21], updated in 2008[22]. Although many other states outside the US have recognised the importance of planning disaster waste, few guidelines exist, and they are mostly based on the USEPA’s guidelines [7]. In the absence of such tools, observations on the re-use of recycled aggregates in the case of Abruzzo could be made, considering that they could be used to satisfy the ordinary annual demand for aggregates in the Abruzzo region, with percentages that vary from 44% to 56%, depending on the two different estimates, as shown in Table 4.
5. Conclusions
This paper studies the possibility of recycling the debris resulting from catastrophic events such as earthquakes. Since post-seismic reconstruction results in increased demand for building materials, the re-use and the recycling of C&D debris has interesting potential. In order to recycle the greatest quantity of debris in the shortest time, firstly proper quantification of the available C&D waste and secondly correct assessment of the demand for building materials are appropriate. The literature on the subject suggests the use of stationary recycling facilities, which guarantee a reclaim of up to 95% of the materials processed. The waste management methodology of the Umbria Region after the 1997 earthquake at first quantified the amounts of debris, basing on those from ordinary demolition activities, and then checked the data with the amounts obtained in some actual demolitions. This method allowed us to quantify the debris in the Abruzzo case study, and also the derived potential amount of recycled aggregates. In particular, it has been demonstrated that the recycled aggregates would be able to cover the ordinary annual demand for aggregates of the Abruzzo region, in a percentage varying from 44% to 56%.
In order to make a proper quantification of the extraordinary requirements for building materials due to the reconstruction process, further studies are required. In fact, the next step of the research is to quantify the extraordinary demand for building materials due to the reconstruction process in the regional capital of Abruzzo, L’Aquila. The assessment of demand for aggregates in reference to the forecasts of the urban plans seems to be the most appropriate approach. Since an updated urban plan for L’Aquila is still lacking, the estimation of the extraordinary requirements for minerals is difficult, but it assumes great relevance because it could allow the debris to be re-used directly in the reconstruction process. Acting in this way, the municipalities located in seismic areas would be equipped with plans for the recycling of the debris including preliminary assessment of the building typologies, predictions of the extraordinary demand for building materials for the reconstruction and the primary location of the treatment facilities of the debris.
Acknowledgments
This research was supported in part by the Autonomous Region of Sardinia with a grant financed by the “Sardinia PO FSE 2007-2013” funds and provided according to the Sardinian Regional Law 7/2007 “Promotion of Scientific Research and Technological Innovation in Sardinia”.
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