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1.
In the southern part of Italy, along the National Road 163 (the Amalfi Coastal road), and particularly close to Positano, some stone formations are present with a cylindrical shape (pinnacles) due to the erosion of the rock and the presence of sub-vertical cracking planes in the rocky slope. The landscape beauty and the dangerousness of these pinnacles, more than 10 m in height, leaning on the underlying road, requested a vulnerability study. The dynamic behavior of these natural solids is influenced by the notable mechanical inhomogeneity due to the nature of the rock, to the presence of diffused crack patterns and to the position along the slope. Some inspections have been performed to have a detailed survey of the pinnacles, using the Laser Scanner 3D technique and with the collaboration of geologist-mountain climbers; some rock specimens have also been taken to be analyzed and tested. The specific weight, the tensile (for bending) strength and the compressive strength, as well as the Young Modulus, considering various directions with respect to cracking planes, were analyzed during laboratory tests on the specimens sampled on site. Different structural modeling to analyze the seismic vulnerability of the pinnacles have been performed and compared: starting from simplified mechanical models of rigid blocks, passing through elastic analyses and finally to finite element (FEM) analyses. Numerical dynamic and static analyses, particularly, the modal dynamic analyses for the elastic continuum and the non-linear static analyses, considering both cracking and plasticity behavior of the rock have been performed. The analyses concerned the pinnacles both under the actual in-situ conditions and according to some strengthening interventions to evaluate the effectiveness and safety of the design.  相似文献   

2.
Restoring cultural heritage is an extremely important job due to its immeasurable value. However, it also requires even greater attention in the case of a building. The actions taken on these constructions not only guarantee their preservation from the point of view of their historical value, but they also guarantee their stability as structures. The need to control historic buildings, analyzing their defects and their possible consequences, is decisive in preventing significant damage. This work demonstrates calculating the thickness of vaults in a church. It is easy to determine the interior and exterior 3D geometry of the church using scanner laser techniques. By combining both geometries, it is easy to determine the difference between the interior vaults and the roof of the church. However, the interior of both geometries is completely unknown, and it is not possible to act on their condition for structural consolidation purposes. This work shows the methods used to determine the interior sections of the vault thicknesses by referencing the internal geometry of both models with the interior of the church, using plumb line system scanning. The results obtained show accuracy better than 6 millimeters.  相似文献   

3.
This paper provides new insights into understanding the causes of deterioration of the Corbii de Piatra rupestrian church and shows the significance of studying the geological environment of historical rock-cut settlements when undertaking preservation and restoration actions. The Corbii de Piatra church is one of the few rupestrian churches remaining in Romania and is an important part of the country's heritage. The church is carved in a stratum of polymictic sandstone of Oligocene age, which is part of the Getic Depression, located in the southern part of the South Carpathians. In the 14th century the interior walls of the church were decorated with mural paintings of a high artistic value. Over the centuries, the church's walls and mural paintings have been negatively affected by a series of physicochemical processes. These processes were studied through field investigations and laboratory analyses carried out between October 2007 and November 2010. The investigations revealed that tectonic fissuring and the structural anisotropy of the rock facilitate the infiltration of meteoric water through the walls into the interior of the church, from north to south, maintaining a high-level of humidity in the northern wall and in the interior of the church. The most harmful effects observed were: (i) the partial hydrolysis of the feldspars through reaction with water from the pores, producing a friable mass of phyllosilicates which led to a superficial disaggregation of the rock and to a diminished cohesion between the rock and the mortar of the fresco, (ii) the reprecipitation of the gypsum as efflorescences on the northern wall and ceiling, covering the mural painting in localized areas, as a result of the transportation of the gypsum by water from the upper strata, (iii) the alteration of the cinnabar pigment, as a result of water penetration by diffusion through the fresco from the wet rock to the pictorial layer (the secondary effect observed being the formation of sulfuric acid, which further reacted with the carbonate from the fresco to form gypsum), (iv) the development of biotic crusts, predominately algal, on the interior wet walls, which, facilitated by the permanent high humidity and the semi-obscurity of the interior of the church, have covered large surfaces of the fresco. Compared to the interior, the exterior vertical walls have been exposed to prolonged daily and seasonal variations of temperature and humidity. These variations have caused repeated variations in the volume of the sandstone, leading to contraction fissuring and peeling of the vertical walls. Any future procedures that might be used to conserve the church should strive to reduce the humidity of the sandstone in the interior walls.  相似文献   

4.
An investigation has been undertaken at St Andrew’s church, Walpole St Andrew, Norfolk, to establish the underlying causes of the observed stone decay to the upper parts of the six stone piers. The stone decay was first recorded in the early 1930s. The salt-contaminated masonry within the church has been shown to undergo severe salt decay during the summer, with little damage occurring over the winter months. The south aisle piers have been shown to decay 2.5 times faster than the north aisle piers. Although crystallization–hydration cycles have been identified, the rate of decay is at its greatest when the cycling is relatively infrequent. This was not the expected trend. Furthermore, it has been shown that during extended periods where the ambient relative humidity is less than 75%, the rate of decay reaches a maximum. It is the length of this ‘drying’ period that apparently has the greatest influence on the rate of decay and could explain the significant difference in the rate of decay between the south and north aisle piers. The results have serious implications for passive conservation, where it is often recommended to lower the ambient relative humidity to well below the equilibrium relative humidity of the salt contaminant, to avoid crystallization–hydration cycles. Since, at the time of building, the church was situated on the coast, it is possible that the sodium chloride contamination occurred during the building process (1440–1520), particularly since the area was prone to sea-flooding at this time. Alternatively, the salt could have been applied as a treatment during the general restoration of 1897. Whatever the source of the salt, it seems likely that the ambient environment was changed by the insertion of a sealed floor in 1897, which could account for the onset of the salt decay.  相似文献   

5.
This work presents an account of the results of diagnostic analyses on the lesions that were first detected in Michelangelo's David in the mid-1800s. After summarizing the events that may have affected the statue's stability and the state of deformation, the authors present the results of the Finite Elements Method (FEM) tests conducted on the digital model of the statue's surface. The analysis of these results made it possible to identify the static conditions that generated the cracks in the lower part of the left leg and in the tree trunk of the David. Lastly, the current situation was analyzed from the perspective of both deformation and stresses, evaluating the statue's stability also as regards its structural response to the seismic activity at the level expected for the Florence area.  相似文献   

6.
Moisture in walls provides a key control on decay processes, but has proved difficult to measure. As part of a larger study investigating the ability of soft wall capping (soil and vegetation) to help conserve ruined monuments we have investigated moisture contents of walls at two ruined abbeys. Two methods of moisture measurement were used, i.e. a novel adaptation of 2D electrical resistivity surveys and the well-established wooden dowel method. Medical ECG electrodes were utilised to provide a completely non-destructive resistivity measurement. At Hailes Abbey wooden dowel and 2D resistivity measurements were made of soft capped vs. uncapped wall sections. The wooden dowels showed drier conditions in the core of the capped sections, although the resistivity surveys were influenced by a different stone structure in the wall core. At Byland Abbey, resistivity surveys indicated drier stone blocks and wetter mortar in the near-surface zone, and illustrated the success of the soft-capping technique in reducing water contents in the core of the wall in comparison with hard-capping with mortar. The 2D resistivity technique is shown to be a useful and fast non-destructive technique with the capacity to provide good spatial and temporal resolution information on moisture distribution in walls.  相似文献   

7.
The knowledge of the morphological and mechanical properties of masonry walls is very important for the refurbishment of ancient buildings, particularly when the requirements of both structural safety and historical preservation must be fulfilled. The masonry is not of homogenous material: its mechanical properties depend on stones, mortar, and texture which are very variable due to their dependence on the historical periods and the geographical area of the erection. For this reason, a deep knowledge of masonries built in different sites and historical periods is essential in order to evaluate both the capacities of bearing vertical load and the seismic vulnerability of the masonry structure. Three fundamental typologies of tuff masonry have been defined: they are the characteristics of different historical periods from the XVI to the XX century. The models are in full-scale in order to reproduce the three defined chronotypes. Original tuff stones quarried in the corresponding historical period, mortars similar to the original ones, reproduced according to ancient documents and original constructive techniques have been used for the construction of the specimens. Compression tests performed in displacement control have been carried out on the masonry models in order to determine the maximum resistance of the material and the corresponding strain, the ultimate strain and corresponding residual strength. In this paper, the procedure used for making the specimens and for experimentally evaluating the mechanical properties of post-medieval Neapolitan yellow tuff masonry are illustrated and the obtained results, even in terms of plastic capacity of these kinds of masonry, are reported.  相似文献   

8.
This paper analyses the market transformation in heritage tourism destinations when excessive tourism demand determines the emergence of a class of excursionists among visitors. Building on the approach of Keane (1997) and Shapiro (1983), some important dimensions of sustainable tourism development are highlighted. The lesser capacity of excursionists to learn the true quality of the tourist goods provides an opportunity for producers to cut back on quality. To serve high quality goods and keep up the reputation of the destination, producers need to gain a mark-up on price that might not be sustained in a competitive market. Hence the decline in ``high-paying' demand segments, increasingly substituted by visitors with lesser quality expectations, has significant consequences on the use and preservation of the heritage. The proposed formulation allows the identification of appropriate policy instruments to reverse this process.  相似文献   

9.
凤凰寺话古     
杭州凤凰寺古称“真教寺”“回回堂”，自古以来就是杭州穆斯林的礼拜堂、清真寺。清光绪重修后以其建筑形似凤凰展翅而名“凤凰寺”，是我国东南沿海四大清真古寺之一，与广州的怀圣寺（狮子寺）、泉州的清净寺（麒麟寺）、扬州的仙鹤寺齐名。  相似文献   

10.
Knowledge of the structural behaviour of existing masonry requires a multi-level approach, with the proper application of diagnostic and assessment methodologies. The structural performance of masonry wall structures can be understood provided that the history of their construction, their geometry, the characteristics of their masonry texture, and the characteristics of the masonry as a composite material are known. In order to obtain all these data, an effective on-site testing program, which can involve the application of different test methodologies as a combination of destructive tests (DT), minor destructive tests (MDT) and non-destructive tests (NDT), needs to be performed. Furthermore, the effectiveness of applied methodologies for the assessment of historical masonry structures strongly depends on the type of investigated structure, as well as on the appropriate numerical model for the analysis. However, the unclear aspects of any testing programme remain the same – how efficient is a particular testing technique, and how can it be assessed? Following the results of recently carried out EU and national research projects, a comprehensive set of data regarding the effectiveness of different testing methods, depending on the type of problem, have been collected and analyzed. Within this framework, several masonry heritage structures from Slovenia, which differ both from the historical and structural point of view (Pi?ece Castle, the Carthusian Monastery at ?i?e, and a typical stone-masonry house from the So?a Valley region), have been investigated by means of different techniques, and numerically analyzed. For this purpose, two different models were used: a push-over model based, on the structural element method, and FEM analysis. It was concluded that the effectiveness of any particular diagnostic technique for the investigation of masonry structures, and for the planning of their restoration, depends on numerous factors. An attempt to determine which of the techniques could be appropriate, depending on the problem, was made. No single test is self-sufficient for the solving of a particular problem, so a combination of different NDT, MDT and DT should be performed. Summarizing all the results, it can be said that, in the process of assessing the state of a structure, even a simple investigation technique is better than none. The effort will always be repaid - if not already in the planning stage of the restoration and retrofitting actions, then certainly in the execution stage of the revitalization works, on site.  相似文献   

11.
Mechanical behavior of leaning masonry Huzhu Pagoda   总被引：1，自引：0，他引：1  
The paper has been developed in the framework of a larger research program, in which the University of Rome “Tor Vergata” (Italy) and the Yangzhou University (China) are jointly involved to study and preserve historic towers. The research aims to evaluate the risk of collapse of the Huzhu Pagoda in Songjiang County, a leaning tower built in the XI century. Mechanical properties of the masonry material have been obtained by experimental tests on small specimen and the mechanical behaviour of the structure has been evaluated via numerical models. The static analysis of this ancient pagoda constitute a prerequisite base for the evaluation of its structural behavior leading to a suitable maintenance program. The architectural characteristics and damage conditions of the pagoda are key parameters in the preparation of a complex analytical model. The pagoda leans more than six and half degrees, and exhibits some bad structural conditions. Static analysis is carried out via finite-element method in order to establish a reliable numerical model and assess the static risk.  相似文献   

12.
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13.
The electrical resistivity tomography (ERT) represents one of the widely used geophysical techniques for the exploration of the subsurface. In the last few years, this method has been demonstrated to be an efficient reconnaissance tool not only for monitoring degradation status of walls and foundations of historical buildings, but also for imaging the spatial distribution of injected mortar, commonly employed for consolidation purposes. A 3D resistivity tomography survey was carried out on four selected wall portions of the historical church of Montepetriolo, Perugia, Central Italy. The obtained 3D resistivity distribution models before and after grouting provided suggestive images of the internal structure of the studied walls. Moreover, the spatial distribution of the zones being filled with mortar was determined quantitatively by scaling the post- to the preinjection resistivity values. Using a well known correlation between resistivity and porosity, established in the geophysical community, a further step towards a more quantitative assessment was attempted to indirectly determine the unit volumes of the injected mortar The obtained results were satisfactory and in some cases almost similar to the yard data. Furthermore, two flat-jack tests confirmed the local increment of the mechanical resistance of the studied left front (2) and right lateral (3) wall portions.  相似文献   

14.
The concentrations of CO2, CO, formaldehyde (H2CO) and water vapour were simultaneously monitored in various sections of a mountain church situated in the village of Rocca Pietore in the Italian Alps. The performance of a conventional, hot-air heating system and a novel design for heating the church, consisting of low-temperature heating elements, such as electrically heated pews and carpets, were compared for the supply, transport and removal of gases, the deposition and/or transformation of which may affect the preservation of displayed works of art. Experiments with sulphur hexafluoride (SF6) tracer-gas showed a considerable influx of external air through the hot air carrier ducts of the old heating system, and also the leakage of the internal air mostly via the apertures of the doors. The ventilation rates for the total volume of the church with the hot-air heating system (on for 1.5 h), the new heating system (on for 2 h), and without heating were calculated to be 0.25, 0.18, and 0.13 h−1, respectively. Without heating, a nearly homogeneous distribution of gases has been observed along both the horizontal and the vertical cross-sections of the church. Immediately after switching on the hot-air heating system, the levels of CO2 and water vapour showed a sharp increase. After turning this system off, the levels of gases showed a slow fall and they developed a highly non-homogeneous spatial distribution indoors for many hours. In the upper region of the church, being airtight, higher concentrations of the pollutants could be detected. The low levels of CO and H2CO, mostly originating from incense burning during services, were correlated to that of CO2. The hot-air heating system has been proved to present a potential deterioration risk to artworks, as it increases the supply, transport and deposition probability of air pollutants. On the other hand, the novel, symmetrical heating system eliminates these undesirable effects, thus its application is advantageous to all churches involved in the preservation of works of art.  相似文献   

15.
The paper focuses on an interdisciplinary research project concerning the preservation of the XVII century monumental building of Monte di Pietà in Naples, Italy. The building underwent a series of restorations being the structural walls affected by humidity and cracks. The importance of this monumental building in the historical city center of Naples led to design an extensive surveying program to provide the designers of strengthening with a detailed investigation of the geometry of the entire structure, and particularly of the entrance façade, with great details on several materials, thicknesses and restraints. A preliminary investigation was performed on the historical phases of this monumental building to have a clear knowledge of its vicissitudes, and then in situ structural assessment included 3D laser scanner techniques probing radar, in situ stress measures. This surveying phase was crucial especially for the subsequent Finite Elements modeling (F.E.M.) of the façade. The scope of the numerical refined analyses was to evaluate the state of stress in the structural elements of the façade putting in evidence structural ‘weak points’ and finally to design a retrofit intervention having a detailed map of the ‘intervention areas’. The theoretical damage assessment has been compared with on-site assessment and in situ stress measures. The damage primarily concerned the entrance façade and its valuable decorations. Furthermore, the basic principles for the design of the strengthening have been discussed.  相似文献   

16.
This article presents the first study of a painting, possibly the Forty Martyrs of Sebaste, which has been concealed for over 500 years, and which has, this century only, re-emerged through plaster removal in the church of SS. Peter and Paul in Famagusta, N. Cyprus. Though very badly damaged the painting, which has remained undocumented and unstudied in the history and art history of Cyprus, may offer vital clues concerning internationalism and cultural interaction in Cyprus in the 14th and 15th centuries. It also offers specialists a rare glimpse at Italian ecclesiastical wall painting from this rich period in western art history, and makes clear the intellectual loss that might be felt if some basic conservation processes are not begun soon. Lastly, in the light of the changing political situation in that island it invites scholarship in a range of disciplines to the church and to other historic landmarks within the old city walls.  相似文献   

17.
The European project Friendly-Heating (FH): comfortable to people and compatible with conservation of artworks preserved in churches addressed the problems caused by the continuous or intermittent heating of historic churches, which disturbs the microclimatic conditions to which the building and the artworks preserved inside have acclimatised. As thermal comfort and the preservation of artworks often conflict with each other, a balance between the two needs is necessary. The proposed heating strategy is to provide a small amount of heat directly to people in the pew area while leaving the conditions in the church, as a whole, undisturbed. This novel heating system is based on some low-temperature radiant emitters mounted in a pew to provide a desirable distribution of heat to the feet, legs and hands of people occupying it. Due to little heat dispersion, this novel system not only significantly reduces the risk of mechanical stress in wooden artworks and panel or canvas paintings, fresco soiling and cyclic dissolution-recrystallization of soluble salts in the masonry, but is energy-efficient. The detailed environmental monitoring was conducted in the church of Santa Maria Maddalena in Rocca Pietore, Italy over a 3-year period to verify the performance of the novel heating system in comparison to the warm-air system that was active earlier in the church. The methodology and results of this comprehensive and multidisciplinary study were included in three draft standards of the European Committee for Standardisation intended for use in the study and control of environments of cultural heritage objects.  相似文献   

18.
This paper aims to view the implications of an identification of wood species found during an archaeological excavation on a medieval church building and a surrounding graveyard at Thorarinsstadir in Seydisfjordur, east Iceland. The excavation in Seydisfjördur is a part of a project entitled ‘The transition from paganism to Christianity in Iceland’ sponsored by The East Iceland Heritage Museum, the Research Council of Iceland and The European Commission. It started in 1997 and from 1998 it has been a part of the PARABOW project, in the frame of the Raphael project. The project involves archaeological researches on pagan and Christian remains from the early medieval times in Iceland. The aim is to examine the origin and development of the Christian religion in Iceland. Furthermore, it is the intention to investigate how Christianity evolved alongside paganism assuming the conversion to Christianity was a long process, climaxing in the year 1000 when Christianity was adopted as a national religion. The wood identification uncovered evidence concerning church architecture, limiting actors for building traditions, Icelandersˈ ritual practices as well as their contacts with the foreign countries during the Viking Age and early medieval times. It did show that the native species were mainly used as fuel but drift timber was probably mainly used for construction purposes and for making coffins. According to the results from the wood identification, for instance, the excavation at Thorarinsstadir in Seydisfjördur revealed a wooden church made of drift timber.  相似文献   

19.
This study shows that the sandstone used in the construction of the Church of San Mateo in Tarifa (Cádiz, Spain) is highly sensitive to processes of decay because of a combination of factors that are intrinsic and extrinsic to the material. The mineralogy, texture and porous system of the sandstone and the proximity of the church to the sea all play a part in these processes. X-ray diffraction reveals that there are interstratified chlorite/smectite clays among the minerals that make up the rock. These mixed layer clays have been shown to undergo hydric expansion. This phenomenon may be accompanied and augmented by the presence of NaCl which acts as an electrolyte in osmotic swelling processes. Two varieties of sandstone were used in the construction of the church, namely grey sandstone and brown sandstone. The latter is more porous and undergoes greater hydric expansion, showing a higher degree of deterioration. Ultrasound analysis has demonstrated that both varieties are anisotropic because they contain bedding planes and are affected by the preferred orientation of the phyllosilicates in the rock. The anisotropic nature of these stones was confirmed by capillary suction tests. The capillary front reaches a relatively low height which means that when water is absorbed, the anisotropic textural properties combined with the presence of chlorite–smectite mixed layers in the sandstone result in mechanical (shear) stress between the first few centimetres of the wet stone and the dry area behind. The latter effect favours the development of flakes, so causing the decay of the ornamental stone and the church façade.  相似文献   

20.
The funeral monument of Maarten Tromp, in the Old Church of Delft (the Netherlands), is partially built with Tournai stone, a grey-blackish limestone from the Wallonia region (Belgium). This stone is suffering a severe delamination and scaling, which has, in the course of the centuries, led to a considerable material loss from the surface of some of the stone elements. In order to identify the damage process and define a sound basis for the conservation of the monument, a research plan was set-up including, next to the tests and analyses on the stone, a 1-year monitoring of the microclimate in the church and the investigation of the structure of the monument as well as its connections to the adjacent walls. First of all, the stone type was identified by macroscopic features and by thin section microscopy. The moisture distribution in the monument and in the adjacent walls was gravimetrically determined on samples taken at different height and depths. The content and type of salt in the Tournai stone from the monument were determined by X-ray diffraction and ion chromatography, and the results compared to those obtained for the fresh stone. The analyses showed the presence of considerable amount of gypsum, together with a low content of soluble salts (chlorides and nitrates). The SEM-EDS observations showed that gypsum is mainly crystallizing in cracks between the layers of the material. The damage mechanism and the influence of salt on the decay were further investigated by combining hygroscopic moisture uptake, hygric dilation (RH cycles between 50% and 95% RH) measurements and SEM-EDS observations; all measurements were performed both on stone sampled from the monument and, as comparison, on fresh stone specimens. The results show that gypsum is the main salt present, but its role in the damage is not significant. The naturally thin laminated structure of the stone together with the considerable hygric dilation seem to be the main causes of the delamination observed in this stone.  相似文献   

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