Search Results (314)

This article examines the seismic assessment and strengthening of a traditional load-bearing masonry structure subjected to strong motion data, with particular emphasis on the effects of soil–structure interaction (SSI). The case study is the Archaeological Museum of Lemnos (AML)—a three-storey building with a composite load-bearing system of timber-framed stone masonry. Over time, the structure has undergone irreversible modifications, primarily involving reinforced concrete (RC) interventions. The building’s seismic performance was evaluated using two finite element models developed in the SAP2000 software (v. 25.3.00). The first model simulates the original structure, strengthened by grout injections, while the second represents the current condition of the structural system following RC additions. Soil–structure interaction was also investigated, given that the local soil is classified as Category D according to Eurocode 8 (EC8). Each model was analyzed under two different support conditions: fixed-base and SSI-inclusive. A suite of appropriate accelerograms was applied to both models, in compliance with Eurocode 8 using the SeismoMatch software, and linear time-history analyses were conducted. The results underscore the significant impact of SSI on the increase of peak tensile stress and interstorey drift ratios (IDRs), and highlight the influence of different strengthening techniques on the seismic response of historic load-bearing masonry structures. Full article

Black crusts and biological colonisation are among the most common types of ‘diseases’, with diverse aetiologies and presentations, affecting masonry architectural heritage. Over the past decades, there has been an increase in the incidence of this degradation phenomena due to the increase in pollution and climate change, especially on the urban walls of ancient cities. In particular, the present research examines the state of conservation of the city walls of Perugia, which are divided into two main city walls dating back to the Etruscan and Medieval periods and are recognised as historical heritage of high identity and cultural value. The degradation reflects, in the mentioned cases, on the liminal public and green areas. A view is also reflected in local journalism and social media, where residents and visitors have framed the spontaneous growth of herbs and medicinal shrubs within the stone joints of historic walls as an apparently benign and aesthetically pleasing occurrence. This misleading interpretation, while rooted in a superficial aesthetic appreciation, nevertheless draws attention to a real and urgent issue: the pressing need for systematic maintenance and intervention strategies—coordinated between academics, students, designers and stakeholders—which are able to reposition the city walls as central agents of urban and cultural regeneration, rather than peripheral remnants of the past. Full article

This study evaluates the accuracy of ²²²Rn exhalation rates from building materials using two standard experimental protocols, thus addressing the increasing importance of rapid radon assessment due to health concerns and regulatory limits. In detail, six types of natural stones frequently employed for the construction of buildings of historical-artistic relevance were analyzed using the closed chamber method (CCM) combined with the Durridge Rad7 system, by using two experimental protocols that differed in the measurement duration: 10 days (Method 1) versus 24 h (Method 2). Obtained results revealed that the radon exhalation rates ranged from 0.004 to 0.072 Bq h⁻¹, which are moderate to low if compared to studies in other regions. Statistical comparison using the u-test confirmed equivalence between protocols (u-test ≤ 2), thus supporting the validity of the faster Method 2 for practical applications. Furthermore, to estimate the potential indoor radon levels and determine the associated radiological risks to human health, for the investigated natural stones, the Markkanen room model was employed. As a result, simulated indoor radon concentrations remained well below regulatory thresholds (maximum value: 37.3 Bq m⁻³), thus excluding any significant health concerns under typical indoor conditions. Full article

The restoration of gold leaf on sandstone sculptures requires structural stability, aesthetic considerations, and compliance with the principles of cultural heritage preservation. A primary issue is achieving visual and material compatibility between newly restored and original areas. Based on the “Diagnosis–Analysis–Selection–Restoration” methodology, the research team developed a targeted restoration approach for gilded stone sculptures, using the Shakyamuni sculpture at Erfo Temple in Chongqing as a case study. Assessment of the current situation revealed that over 70% of the sculpture’s surface exhibited gold leaf delamination. The composition and structure of the gold-sizing lacquer, lacquer plaster filler, ground layers, and pigments were investigated using SEM-EDS, XRD, Raman spectroscopy, and THM-Py-GC/MS techniques. The results confirmed that the sculpture featured a typical multilayer gilding structure with clear evidence of historical restorations. Considering both material performance and interfacial compatibility, an NHL2/SiO₂/SF016 composite emulsion and traditional lacquer plaster were selected as the optimal materials for reattachment and infill, respectively. A scientific restoration protocol was developed, encompassing gentle cleaning, targeted reattachment and reinforcement, and region-specific repair methods. Principal Component Analysis (PCA) was used to evaluate the influence of temperature and humidity on the curing behavior of lacquer layers. Additionally, a non-invasive gold leaf color-matching technique was developed by controlling the surface roughness of the gold-sizing lacquer, effectively avoiding the damage caused by traditional color-matching methods. Full article

A temporal monitoring of monumental buildings in calcarenite, exposed outdoors in the considered Mediterranean environment of Southern Italy, was performed using XPS, the surface-specific technique. The methodology adopted to monitor the surfaces interacting with atmospheric agents and biotic/abiotic pollutants involved progressive sampling, extended to about five years, from the walls of a new building, specifically installed in the immediate vicinity of an ancient farmhouse in an advanced state of degradation. Taking the ancient building as the final temporal reference, the aim was to obtain adequate information on the degradation processes of calcarenitic stones, from the initial and evolving phases of the new building towards those representative of the old reference. A large set of XPS data was obtained by resolving, through curve-fitting, the acquired spectra into component peaks, identified as ‘indicator’ chemical groups, which trend as a function of time, supported by PCA, demonstrates a close compositional similarity between the samples of the new building analyzed after 52 months from its installation and those of the ancient building dating back to over a century ago. The results obtained can be considered in the diagnostic strategy of the ongoing PNRR programs dedicated to the care of historical monuments and ecosystem sustainability. Full article

Civil structures carry significant service loads over long times but are prone to deterioration due to various natural impacts. Traditionally, these structures are inspected in situ by qualified engineers, a method that is high-cost, risky, time-consuming, and prone to error. Recently, researchers have explored innovative practices by using virtual reality (VR) technologies as inspection platforms. Despite such efforts, a critical question remains: can VR models accurately reflect real-world structural conditions? This study presents a comprehensive framework for assessing the visual fidelity of VR models for structural inspection. To make it viable, we first introduce a novel workflow that integrates UAV-based photogrammetry, computer graphics, and web-based VR editing to establish interactive VR user interfaces. We then propose a visual fidelity assessment methodology that quantitatively evaluates the accuracy of the VR models through image alignment, histogram matching, and pixel-level deviation mapping between rendered images from the VR models and UAV-captured images under matched viewpoints. The proposed frameworks are validated using two case studies: a historic stone arch bridge and a campus steel building. Overall, this study contributes to the growing body of knowledge on VR-based structural inspections, providing a foundation for our peers for their further research in this field. Full article

Processing ancient text images presents significant challenges due to severe visual degradation, missing glyph structures, and various types of noise caused by aging. These issues are particularly prominent in Chinese historical documents and stone inscriptions, where diverse writing styles, multi-angle capturing, uneven lighting, and low contrast further hinder the performance of traditional OCR techniques. In this paper, we propose a unified neural framework, UniText, for the detection, recognition, and glyph restoration of Chinese characters in images of historical documents and inscriptions. UniText operates at the character level and processes full-page inputs, making it robust to multi-scale, multi-oriented, and noise-corrupted text. The model adopts a multi-task architecture that integrates spatial localization, semantic recognition, and visual restoration through stroke-aware supervision and multi-scale feature aggregation. Experimental results on our curated dataset of ancient Chinese texts demonstrate that UniText achieves a competitive performance in detection and recognition while producing visually faithful restorations under challenging conditions. This work provides a technically scalable and generalizable framework for image-based document analysis, with potential applications in historical document processing, digital archiving, and broader tasks in text image understanding. Full article

Masonry industrial buildings, common in the 19th and 20th centuries, represent a significant architectural typology. These structures are crucial to the study of industrial archeology, which focuses on preserving and revitalizing historical industrial heritage. Often left neglected and deteriorating, they hold great potential for adaptive reuse, transforming into vibrant cultural, commercial, or residential spaces through well-planned restoration and consolidation efforts. This paper explores a case study of such industrial architecture: a decommissioned factory near Naples. The complex consists of multiple structures with vertical supports made of yellow tuff stone and roofs framed by wooden trusses. To improve the building’s seismic resilience, a comprehensive analysis was conducted, encompassing its historical, geometric, and structural characteristics. Using advanced computer software, the factory was modelled with a macro-element approach, allowing for a detailed assessment of its seismic vulnerability. This approach facilitated both a global analysis of the building’s overall behaviour and the identification of potential local collapse mechanisms. Non-linear analyses revealed a critical lack of seismic safety, particularly in the Y direction, with significant out-of-plane collapse risk due to weak connections among walls. Based on these findings, a restoration and consolidation plan was developed to enhance the structural integrity of the building and to ensure its long-term safety and functionality. This plan incorporated metal tie rods, masonry strengthening through injections, and roof reconstruction. The proposed interventions not only address immediate seismic risks but also contribute to the broader goal of preserving this industrial architectural heritage. This study introduces a novel multidisciplinary methodology—integrating seismic analysis, traditional retrofit techniques, and sustainable reuse—specifically tailored to the rarely addressed typology of masonry industrial structures. By transforming the factory into a functional urban space, the project presents a replicable model for preserving industrial heritage within contemporary cityscapes. Full article

The crystallization of soluble salts is one of the most significant agents of deterioration affecting porous building materials in historical architecture. This process not only compromises the physical integrity of the materials but also results in considerable aesthetic, structural, and economic consequences. Soluble salts involved in these processes may originate from geogenic sources—including soil leachate, marine aerosols, and the natural weathering of parent rocks—or from anthropogenic factors such as air pollution, wastewater infiltration, and the use of incompatible restoration materials. This study examines the role of capillary rise as a primary mechanism responsible for the vertical migration of saline solutions from the soil profile into historic masonry structures, especially those constructed with calcareous stones. It describes how water retained or sustained within the soil matrix ascends via capillarity, carrying dissolved salts that eventually crystallize within the pore network of the stone. This phenomenon leads to a variety of damage types, ranging from superficial staining and efflorescence to more severe forms such as subflorescence, microfracturing, and progressive mass loss. By adopting a multidisciplinary approach that integrates concepts and methods from soil physics, hydrology, petrophysics, and conservation science, this paper examines the mechanisms that govern saline water movement, salt precipitation patterns, and their cumulative effects on stone durability. It highlights the influence of key variables such as soil texture and structure, matric potential, hydraulic conductivity, climatic conditions, and stone porosity on the severity and progression of deterioration. This paper also addresses regional considerations by focusing on the context of Spain, which holds one of the highest concentrations of World Heritage Sites globally and where many monuments are constructed from vulnerable calcareous materials such as fossiliferous calcarenites and marly limestones. Special attention is given to the types of salts most commonly encountered in Spanish soils—particularly chlorides and sulfates—and their thermodynamic behavior under fluctuating environmental conditions. Ultimately, this study underscores the pressing need for integrated, preventive conservation strategies. These include the implementation of drainage systems, capillary barriers, and the use of compatible materials in restoration, as well as the application of non-destructive diagnostic techniques such as electrical resistivity tomography and hyperspectral imaging. Understanding the interplay between soil moisture dynamics, salt crystallization, and material degradation is essential for safeguarding the cultural and structural value of historic buildings in the face of ongoing environmental challenges and climate variability. Full article

The impact of fire on natural stone structures is a critical concern, particularly for historical buildings. This study examines the residual mechanical properties of sandstone after exposure to high temperatures. Cylindrical sandstone samples were heated to temperatures up to 900 °C and subsequently tested under uniaxial compression. The results indicate that mechanical degradation becomes significant beyond 460 °C, with compressive strength decreasing by up to 43% at 900 °C. Young’s modulus also declined substantially, while axial strain increased, indicating progressive structural weakening. Additionally, visible colour changes suggest mineralogical transformations. These findings provide essential insights into the fire-induced deterioration of sandstone, offering valuable guidance for the preservation and restoration of historical stone structures. Full article

While archipelagos have a demonstrated role in the stepping-stone process of the global dissemination of Aedes-borne viruses, they are often neglected in epidemiological and modelling studies. Over the past 20 years, some Atlantic archipelagos have witnessed a series of Aedes-borne viral outbreaks, prompting inquiries into the local historical suitability for transmission. In this study, the climate-based suitability for transmission of Aedes-borne viruses between 1980 and 2019 across Madeira, the Canaries, Cape Verde, and São Tomé e Príncipe archipelagos was estimated. For each island, we characterized the seasonality of climate-based suitability, mapped the spatial landscape of suitability, and quantified the historical effects of climate change. Results show that both island-level suitability and the historical impact of climate change decrease with distance from the equator, while significant seasonality patterns are observed only in subtropical climates. This study provides a unique historical perspective on the role of climate in shaping Aedes-borne virus transmission potential in Atlantic archipelagos. The findings herein described can inform local public health initiatives, including human-based prevention, targeted viral surveillance, and mosquito control programs. Full article

For decades, in historical research, archeological vestiges have been linked with geomancy and cults of the mythical ancestors of a group of the population. This is particularly true in Eastern Asia and especially in China, Korea, and Japan. A fundamental problem of Japanese archeology is that few of the remnants were realized in stone. One of the most important parts of archeological sciences is the study of Necropolises or ancient interments. From the 1970s onwards, in the relatively “new” and promising land of Hokkaido, cemeteries were built with the concept of landscape in mind; this is also due to the lavish vegetation features of this northernmost island of Japan. In the case of the Takino cemetery on the plains of Sapporo, Hokkaido, whose construction began in 1982, solemnity and religiousness were incorporated by producing exact stone replicas of famous funerary landmarks from antiquity as such materials were inexistent in the Nipponese Isles. This trend to grant eternity included traditional Buddhist funereal monuments like the Stupa, Seokguram grotto, and Kamakura sites, but at a certain and exuberant point, under the influence of Isamu Noguchi, it reached Stonehenge in England and the Moai from Easter Island in Polynesia (being after all located in a remote isle of the Pacific Ocean). In this article we will outline such process of generation and overall conception, analyzing the inclusion and architectural assembly of the different compounds and the recent and extraordinary additions projected and built by the celebrity architect Tadao Ando. We expect, in this manner, to facilitate the comprehension of the significance of venerable landscape sublimated through archeology for the Nipponese modern civilization. Full article

The challenge of thermally upgrading traditional stone masonry buildings is addressed through the analysis of a representative example typical of regional rural architecture in central Poland, constructed using soft silica limestone and clay mortar. These buildings, which form an important part of the local cultural heritage, are increasingly becoming the subject of interdisciplinary research and conservation initiatives. This study presents a detailed characterization of the materials and architectural features specific to this building typology. Thermal transmittance calculations were performed and analyzed, with the use of THERM 7.6.1.0 software enabling precise modeling of the wall’s heterogeneous structure. The physical and thermal properties of natural materials—particularly soft silica limestone and clay—were taken into account. The analysis included evaluation of the heat transfer coefficient, temperature distribution, and heat flux density for a reference wall model, as well as for variants with both internal and external insulation layers. The study explores thermal comfort and energy performance within the broader context of preserving and reusing historic rural buildings. Furthermore, the findings are discussed in relation to current European energy efficiency regulations and heritage protection frameworks. The scientific value of this work lies in its context-specific, material-sensitive methodology and in providing practical insight into balancing energy retrofitting with architectural conservation. Full article

Bell towers, due to their slender geometry and structural configuration, are among the buildings most susceptible to deterioration from weathering and seismic events. These aspects influence the structural assessment of these historic towers, which is essential for their conservation and maintenance. The “Carmine Maggiore” bell tower in Naples (Italy) has been an important and prominent landmark of the city for centuries. It is square in plan and 72 m high. Over time, it suffered extensive damage and was severely damaged by the earthquake of 1456. Reconstruction began in the first decade of the 17th century and the original design was modified, adding two stories and changing the shape of the plan to octagonal. In the centuries that followed, the structure was damaged again and further interventions were carried out, adding tie-rods and replacing damaged elements. Today, the bell tower has very elaborate façades with mouldings and decorations, so that the supporting structure appears to be covered with plaster, stucco, and stone elements. This paper describes the results of FEM analyses of the bell tower, obtained from models with different levels of complexity to evaluate the influence of stone cladding elements on the seismic behaviour. In particular, the difference in the IS safety indices, calculated as the ratio of capacity to demand, exceeds 15%, due to the mechanical consistency of the cladding elements, which contribute significantly to both stiffness and strength. Full article

The Gobi Wall is a 321 km-long structure made of earth, stone, and wood, located in the Gobi highland desert of Mongolia. It is the least understood section of the medieval wall system that extends from China into Mongolia. This study aims to determine its builders, purpose, and chronology. Additionally, we seek to better understand the ecological implications of constructing such an extensive system of walls, trenches, garrisons, and fortresses in the remote and harsh environment of the Gobi Desert. Our field expedition combined remote sensing, pedestrian surveys, and targeted excavations at key sites. The results indicate that the garrison walls and main long wall were primarily constructed using rammed earth, with wood and stone reinforcements. Excavations of garrisons uncovered evidence of long-term occupation, including artifacts spanning from 2nd c. BCE to 19th c. CE. According to our findings, the main construction and usage phase of the wall and its associated structures occurred throughout the Xi Xia dynasty (1038–1227 CE), a period characterized by advanced frontier defense systems and significant geopolitical shifts. This study challenges the perception of such structures as being purely defensive, revealing the Gobi Wall’s multifunctional role as an imperial tool for demarcating boundaries, managing populations and resources, and consolidating territorial control. Furthermore, our spatial and ecological analysis demonstrates that the distribution of local resources, such as water and wood, was critical in determining the route of the wall and the placement of associated garrisons and forts. Other geographic factors, including the location of mountain passes and the spread of sand dunes, were strategically utilized to enhance the effectiveness of the wall system. The results of this study reshape our understanding of medieval Inner Asian imperial infrastructure and its lasting impact on geopolitical landscapes. By integrating historical and archeological evidence with geographical analysis of the locations of garrisons and fortifications, we underscore the Xi Xia kingdom’s strategic emphasis on regulating trade, securing transportation routes, and monitoring frontier movement. Full article