The application of free-form grid shells as protective shelters in archaeological sites (original) (raw)
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Reciprocal structures or nexorade are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and re-used even by not specialized handcraft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. This paper proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and esthetical qualities. A paramet-ric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using CNC-cutting tested the structural feasibility of such a design approach.
With the construction of coverings in the Valle dei Templi of Agrigento, the management of the Park Agency is carrying out an experimental action which can produce innovation in the context of lightweight and temporary structures. The "Architecture X Acheology" workshop explored the state of the art in terms of works protecting archaeological landmarks, with the goal of identifying new modular and flexible structures which are adaptable to the diverse needs of archaeological sites. Parametric and computational strategies are the bases used for the design of the shelters.
Temporary shelters for archaeological excavations. An application in Kınık Höyük site (Turkey)
Structural Health Assessment of Timber Structures
Building temporary structures requires a change in the approach with respect to “ordinary” design. Some aspects (e.g. speed of construction, ease of disassembly) assume greater importance, others (e.g. durability) take second place. Temporary shelters for archaeological excavations also set further issues: the need to minimize construction time, in order to extend to the maximum the time available for excavation activities; the need to build in a complex plani-altimentric context and often in the absence of a definitive survey of the site; the impossibility of using usual construction machinery and to build “ordinary” foundation structures. Working in the Middle East requires you to interact with local workers who do not speak western languages and have a quite different technical culture; moreover, since excavations are often located in peripheral areas, the variety of materials available at affordable price and for prompt delivery is almost always limited. Together with general and methodological considerations, the paper illustrate the project of temporary shelters for the archaeological excavation at Kınık Höyük (South Cappadocia, Turkey). In relation to local technical and economic context, depending on the nature of the site, it was decided to build timber frame structures made of standardized locally-produced sawn beams, assembled by nailing. A fundamental requirement of the project was to ensure resistance to high winds that blow on the site from all directions: therefore the structure was braced using struts and X bracings, and suitable stabilizing masses have been set up to overcome the lightness of the structure.
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.
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.
Innovative steel 3D trusses for preservating archaeological sites: Design and preliminary results
Journal of Constructional Steel Research, 2019
Steel three-dimensional lattice trusses are highly efficient technical solutions to cover large spans, especially when single members are not provided with intermediate restraints able to prevent lateral-torsional buckling phenomena. In the present paper, a compound structure made of steel lattice beams and structural glass slabs is proposed for protection of monumental and archaeological sites. Due to both the risk exposure of monumental heritage to be protected and the use of structural glass, the definition of an appropriate design criterion is mandatory in order to avoid brittle collapse mechanisms. The attention is herein paid to the design procedure, with a brief description of basic ideas behind and the main focus on the parametric capacity design of the structure. The proposed procedure, whose validity is quite general, has been herein implemented by linear numerical analyses, which represent the basic step for further refined analysis aimed at erecting a full-scale prototype to be experimentally tested.
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.
Between the years 2003. and 2013. the Republic of Serbia allocated in its own budgets around one billion dinars for designing and construction of shelters on archaeological sites. This paper researches the main factors for decision making on different levels, resulting in certain designs and construction solutions, but in numerous problems also. Based on all so far performed works and their results, the general guidelines applicable to the range of professionals involved were given.
Journal of Architectural Engineering, 2009
The technical note describes a proposal to roof two internal courtyards of the main building of the Engineering Faculty at the University of Pisa by means of thin flat shells made of a quadrilateral mesh of steel bars supporting plane glass plates stiffened by a grid of steel cables. An exposure of the structural design concepts and of the geometrical genesis of the shells is presented accompanied by a stability analysis and a description of the technological solutions found to solve some crucial constructional problems.