New procedures and materials for improving protection of archaeological areas (original) (raw)
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Shelters are encountered on many archaeological sites of the Mediterranean Their presence is mostly related to the need to protect specific architectural or decorative features exposed during excavation and believed to be too fragile to be left exposed. Consequently shelters tend to be isolated or randomly scattered within the archaeological site. The process of planning designing and building shelters usually follows the period immediately after excavation. If the area to be covered or the setting is particularly complex a provisional shelter is often provided while funds are raised for the design and construction of a permanent one. If these do not become available then provisional shelters themselves often become permanent. Sheltering on an archaeological site brings formidable challenges and contradictions. On the one hand a shelter should confer good protection to the archaeological remains below by reducing the rate of deterioration from environmental causes On the other it should impose the least possible aesthetic impact on the site and harmonize with the archaeological and natural landscape. It also needs to provide quality in the visitor experience in presenting the protected remains.
PROTECTIVE SHELTERS FOR ARCHAEOLOGICAL SITES - Approaches to the shelters at Herculaneum, Italy
Although Herculaneum emerged extremely well preserved at the time of excavation the archaeological site that can be seen today has been exposed to the elements for more than 60-80 years and in some cases for over a century (Insulae II and III). As is often the case, the incredible wealth of rediscovered heritage is extremely fragile: this is the case, for example, of carbonized timber left in situ, but also of frescoes, mosaic and beaten earth floors, which are continually trodden on by visitors. Site morphology is also a factor that contributes to exacerbating the conservation challenges posed by the preserved heritage: the street level of the ancient city is located approximately 10-20 m below that of the modern city, which itself was built on a ridge formed from successive eruptions of Vesuvius. This means both difficulty in ensuring that the excavated escarpments are structurally sound and maintained, as well as difficulties in draining rainwater and groundwater that accumulates within the site. Pesaresi and Massari provide examples of provisional shelters that have been trialled at Herculaneum (Italy) which were specifically designed to address immediate conservation issues but to last longer than ‘temporary’ shelters thereby reducing the additional risk that temporary shelters can cause to archaeology when left in situ too long. They contrast these with other shelter typologies at the site in particular early twentieth century reconstructions that used the original Roman floor slabs or roofs as protective shelters.
At the beginning of the st century the international conservation community gathered in the USA to take stock of the state of play with regard to protective shelters for archaeological sites to learn from a century long tradition of shelter building and draw conclusions that could be used at unsheltered archaeological sites. On the other side of the world conservation specialists wanting to assess conditions in a large Roman house in Herculaneum Italy could not safely access the building due to the risks presented by the corroded and cracked reinforced concrete beams supporting the modern roofs. Yet remedial work on the roof could not take place without first making safe the damaged mosaic floor on which scaffolding would need to rest. At around the same time an assessment of over mosaics under protective shelters within Israeli archaeological sites revealed that more than half those mosaics were deteriorating with many being entirely removed and other conservation approaches adopted. It was this context of ongoing connections and contrasts between conservation theory and site management practice together with the continuing challenge of sheltering archaeological sites that led to the Symposium on Protective Shelters for Archaeological Sites held a decade later in and with a specific focus on the Mediterranean region. This introductory chapter aims to capture within the structure that the event followed key insights from each case study brought to the symposium many of which emerged as their authors later reflected on the issues raised on return to their specific sites and further updated their papers Indeed this volume has become something more than just the proceedings of the symposium offering considerations matured over a greater period of time and through extended peer exchange something that has been at the heart of the MOSAIKON Programme since it began but also at the core of the approaches of the Herculaneum Conservation Project which hosted the symposium. It is hoped that the insights that emerge from this introductory overview from the papers themselves that follow and from the brief notes of the closing discussion session of the symposium will between them offer pointers for heritage practitioners in the field to approach sheltering at archaeological sites in a way that builds on progress to date and enhances future practice in the sector.
Sheltering archaeological sites in Malta: lessons learnt
The purpose of this paper is to review the performance of the protective shelters installed over three archaeological sites in Malta over the past decade, and to draw some key lessons learnt that may be useful to others when considering whether to adopt a similar solution. The conservation threats to the Megalithic Temples of Malta are introduced and defined—these range from material issues (loss of surface) to structural issues (cracking and dislodgement of stones leading to structural instability and collapses). Causes identified specifically included fluctuating environmental conditions: wetting and drying cycles and thermal fluctuations, combined with the salt-laden Mediterranean island environment. The recognition during the late twentieth century of these issues as key factors in the deterioration of these structures, and the strategy that was developed in response, are outlined. A key component of this strategy was the installation of protective shelters over three of the main megalithic sites. The process through which the design requirements for the shelters were defined is reviewed. The performance of the shelters is then examined, through a critical review of unpublished reports and published studies. An evidence-based summary of the beneficial effects of the shelters is provided, and the possibility of any harmful effects discussed. A number of lessons learnt through this process are then identified. One key lesson is that the microenvironment in a newly-sheltered site is at a transitional stage that does not necessarily reflect longer-term trends, which therefore require long-term monitoring to be understood. The choice and number of environmental parameters to be monitored need to be informed by a careful consideration of their sustainability, both in terms of equipment and human resources. Any monitoring programme, however well-designed, needs to be open to re-evaluation and revision where needed. As more experience and data are accumulated from different sheltering projects, it will become more feasible to establish performance indicators in advance of a sheltering intervention, on the basis of which to evaluate its performance. The experience of these projects is then used to inform a checklist of key considerations for anyone considering whether to shelter an archaeological site. The foremost consideration is that every site requires a site-specific strategy tailored to its needs. The decision whether a shelter is desirable, and what its performance requirements should be, may only be taken in the context of such a strategy. This paper should help define the parameters for such a decision to take place.
Ge - Conservación, 2020
Excavated archaeological sites are frequently exposed to damaging environmental conditions, which could lead to rapid decay especially for vulnerable heritage such as mosaics. One of the most common solutions is the construction of shelters; however, some may not behave as expected, either because they do not protect adequately or induce decay. An environmental monitoring programme was undertaken inside and outside the two types of shelters at the Roman archaeological site of Complutum (Alcala de Henares, Spain) from May to September in 2018 and 2019. Hourly temperature and relative humidity readings collected by data loggers, together with rainfall data from a local meteorological station, have been comparatively assessed to better understand the consequences of sheltering in dry and warm areas. The results indicate that both shelters are avoiding further decay by keeping a more stable environment in relation to outside, although the more enclosed structure would be the most suitable one.
Pompeii is the largest archaeological site in the world and one of the most visited as well. Villa dei Misteri is a great suburban villa just outside the ancient city. Every year, thousands of visitors are attracted by the superb frescoes from which the domus takes its name. In the course of excavations, the most significant rooms were roofed with the dual pur- pose of providing weather protection and returning the monument to its ancient state. The re- sults of the restoring interventions display a wide range of roof structure typologies: reinforced concrete frame, reinforced concrete-tiles mixed floor, timber and steel frame. The evaluation of their health status requires a detailed study by means of a multidisciplinary ap- proach, which should include historical research, geometrical and structural surveys, dam- age assessment based on both in situ and laboratory diagnostic tests, UAV (Unmanned Aerial Vehicles) remote sensing to inspect area and coverings not easy to reach in saf...
Shelters evaluation, monitoring and maintenance in the context of archaeological site management
Pesaresi, P. & Stewart, J. (2018) Shelters evaluation, monitoring and maintenance in the context of archaeological site management. In: Aslan, Z., Court, S., Teutonico, J.M. & Thompson, J. (eds) Protective Shelters for Archaeological Sites. Roma: British School at Rome: 58-82.
Modular, Adaptable Shelters for Environmentally Sensitive Archaeological Sites
The Valle dei Templi Park, located in the Italian island of Sicily, extends over a surface of 1,300 hectares and preserves an extraordinary monumental heritage and landscape, dating back to Greek times and a UNESCO World Heritage site since 1997. Though visited by millions of tourists, the archaeological sites are not appropriately equipped for tourist use: this is why the Park Agency is promoting actions to improve facilities that are appropriate for today's visitors and cultural standards. The "Architecture X Archaeology" workshop, that took place in 2013, explored the design and construction of lightweight, temporary structures to shelter archaeological sites and excavations otherwise exposed to the weather. The workshop was promoted by the Valle dei Templi Park Agency and was supported by the JSB programme, where Toyo Ito is one of the jury members. The interdisciplinary design of different types of shelters was based on locally available materials, but mixed the construction cultures of Italy and Japan through the participating universities. A Building and Information Modelling (BIM) process was adopted to control parameters related to the temporality of the shelters, their maintenance and their adaptability to the different local landscapes. The teams of Politecnico di Milano and the University of Tokyo developed two distinct solutions for specific applications. The "AkragaShelter" was designed to protect archaeological remains and, based on a mix of local stones, wood and plastic, is not intended to move, but can be dismantled in the future. The "Molecular Shelter" was instead designed around a single timber section to shelter temporary excavation sites, moving with the archaeologists in time; four persons are enough to displace the structure without dismantling it. The shelters were then constructed on site and they now represent the first step of a plan to introduce in the Valle dei Templi Park architectural elements that are at the same time contemporary and respectful of the sensitive heritage and landscape. The purpose is to prove that contemporary architecture, structure and archaeology can coexist harmoniously.
Conservation and Management of Archaeological Sites, 2002
Teutonico and Jane Thompson (open access from https://www.iccrom.org/news/protectiveshelters-archaeological-sites) has been published with the support of the Getty Foundation, in the context of the MOSAIKON, an international initiative dedicated to the interdisciplinary study of activities relating to the conservation and management of archaeological sites in the twenty-first century. A presentation of the volume was hosted by the British School at Rome on 4 March 2019. The introductory remarks (Forewords by Christopher Smith and Massimo Osanna) note that the symposium which took place at Herculaneum in 2013, and now published, was intended to provide an opportunity for free and open exchange among those responsible for archaeological sites and their protection, right across the Mediterranean region. Jeanne Marie Teutonico in her Preface, which opens with a brief reflection on the extraordinary heritage of pavements and mosaics across the Mediterranean in Classical antiquity, looks back to the use of protective shelters since the nineteenth century. (Although one might add that shelters had already been seen in antiquity, as attested to by the second-century geographer Pausanias, in relation to the House of Oenomaus at Olympia). Teutonico considers the pros and cons of such shelters, which are not always able to provide adequate protection for sites and instead frequently impact negatively on the landscape. Hence, the need for upfront reflection, on the appropriateness of the 'how' to protect mosaic heritage, and for careful management from different points of view: accessibility, finance, maintenance, technology, design, etc. In this respect, one might immediately think of the structure designed by architect Franco Minissi for the Villa del Casale at Piazza Armerina (Sicily), that was left to fall into disrepair in the absence of any sufficient routine or special maintenance: it was later replaced by other structures although it presented an important case study in this area. Teutonico highlights, therefore the importance of collaboration that is multidisciplinary, between archaeologists, conservators, architects, engineers, as well as environmental scientists, geotechnicians, geologists, etc. Such reflections underpinned the creation of the MOSAIKON network in 2008 to support the conservation, presentation, and management of mosaics in archaeological sites around the Mediterranean. And also informed the four key themes of the 2013 symposium: deciding whether or not to shelter; condition assessment and environmental issues; designing and improving shelters; issues of evaluation and maintenance. Chapters on these themes are supported by contributions illustrating specific case studies, only some of which can be mentioned here for questions of space. Overall the aim is to offer guiding principles on the subject in order to 'promote improved standards of conservation practice that will ensure a better future for our shared archaeological heritage' (p. viii). In reading the different parts of the volume, including the critical case studies that are included in Parts 2 and 3, one can see how the book delves into, repeatedly, all of the issues CONSERVATION AND MANAGEMENT OF ARCHAEOLOGICAL SITES