Heritage Structures Research Articles

A novel computer vision and point cloud-based approach for accurate structural analysis of a tall irregular timber structure

Wood material has been widely used in critical heritage structures such as pagodas, totem poles, and large-scale sculptures. Conducting rigorous structural analysis is crucial to protect these structures in high-seismic regions. Typically, these types of structures are modeled using an equivalent finite element (FE) model which used simple cylinder with a constant cross section equal to the average of the top and bottom cross section. However, simplified equivalent FE models may not accurately consider the irregularities and complexities of these structures. In this paper, advanced computer vision and point cloud techniques were adopted to accurately and rapidly construct a FE model of a 30-meter irregular timber sculpture. This was achieved using video scans, computer vision-aided 3D reconstruction, point cloud processing, and mesh to solid element conversion. The refined FE model was used to conduct capacity check, mesh sensitivity study, pushover analysis, and response spectrum analysis. The results of the refined FE model were compared to an equivalent FE model. The results show: 1) the proposed numerical modeling methodology for structural analysis can efficiently and accurately measure the dimension of the irregular sculpture up to 98.2 % accuracy; 2) the lateral stiffnesses of the 30-meter irregular sculpture vary significantly (up to 42.6 %) from one direction to the other; 3) the equivalent FE model overestimated the shear and moment capacities by 20.6 % and 13.2 %, respectively; 4) on average, the equivalent FE model overestimated the shear and moment demands by 8.9 % and 5.5 %, respectively. Overall, the proposed application has demonstrated a fast, economical and accurate method to conduct seismic evaluation and design for irregular structures.

Vibration vulnerability assessment of heritage structures in Lahore: a step towards sustainable conservation

Lahore is among the most important historical cities in Pakistan, and many cultural heritage structures, such as Shalamar Gardens and Lahore Fort, which are recognised as World Heritage Sites by UNESCO, are located there. The rapid increase in transit operations and infrastructure development in Lahore can increase the vulnerability of nearby heritage structures to ground-borne vibrations. In this study, a vibration vulnerability assessment of the heritage structures present in Lahore was performed with the help of the framework provided by the Federal Transit Administration (FTA), USA. A remote survey was carried out to gather valuable information regarding the distance between the heritage structures and potential vibrational sources, as well as the latitude and longitude of the heritage structures, via the web-based mapping tool Google Earth. A vibration vulnerability map of heritage structures was developed on the basis of a vibration vulnerability assessment to make it convenient for policymakers to visualise the present state of heritage structures with respect to vibration vulnerability. The performed vibration vulnerability assessment was validated by experimentally measuring vibrations at the Buddha’s Tomb (Buddha Ka Awa) heritage structure. The study revealed that 17% of the heritage structures present in Lahore are vulnerable to vibrations at present, with potential vibrational sources such as road traffic, metro trains, and rail traffic. The vibration vulnerability assessment revealed that 72% of the vibrationally vulnerable heritage structures in Lahore are most influenced by vibrations from road traffic. The results of this study can aid policymakers in creating intervention packages for vibrationally vulnerable heritage structures in Lahore in relation to their respective needs, which will make it possible to achieve the sustainable conservation of heritage structures.

Enhancing Preservation: Addressing Humidity Challenges in Indonesian Heritage Buildings Through Advanced Detection Methods Point Cloud Data

Heritage buildings are valuable assets that represent national cultural identity. Proper building maintenance is a major issue for preservation, as building monitoring aspects and preventive measures are often only taken after physical damage happens. In the context of Indonesian heritage buildings, high levels of humidity which may cause condensation and soil dampness are often overlooked. Early detection methods are urgently required to effectively detect potential risks of condensation. This study aims to investigate condensation risk for heritage building surfaces by calculating thermal properties (i.e., emissivity, albedo) and Blinn-Phong BRDF values through the integration of thermal imaging and 3D scanning techniques. This approach supports architects and conservators in making informed decisions to protect and maintain cultural heritage structures. The study also highlights gaps in current Indonesian regulations regarding moisture presence and condensation risk detection in heritage buildings.

Legal conditions for renovation works of cultural heritage structures

Preservation, protection, renovation of the historical and cultural heritage items, and furthermore, transmitting them to our later generations in intact is regarded as a priority in the government policies as far as they stand as material monuments of specific characteristics of the nation and its independence. It was not a mere incident that Mongolian government had enacted the Preservation and Protection of Old Items Rules in 1924 right after promulgation of the first Mongolian Constitution as an independent State. Later in 1970, ‘Cultural Monument Protection Law’ was adopted, and then Historical and Cultural Monument Item Renovation Agency was established in 1973 under the Ministry of Culture. Although laws and regulations related with cultural heritage, which are in force today, are comparatively adequate, there are still numerous problems to be solved in their implementations, and particularly in practices of renovation works, preservation and protection of cultural heritage items and constructions. This article deals with some research outcomes on laws and regulations related with renovations of historical and cultural monument structures, and their implementations. Түүх, соёлын дурсгалт барилгыг сэргээн засварлах үйл ажиллагааны эрх зүйн орчин Хураангуй: Түүх соёлын дурсгалт зүйлс нь улс орны үндэсний өвөрмөц онцлогийн илэрхийлэл, тусгаар тогтнолыг батлах хөдөлшгүй нэг баримт болдог тул тэдгээрийг хайрлан хамгаалах, сэргээн завсарлах, хойч үедээ уламжлан өвлүүлэх нь төр засгийн бодлогын чухал зорилт болж ирсэн. Монгол Улс анхны үндсэн хуулиа баталж, тусгаар тогтнолоо тунхагласан 1924 онд соёлын өвийг сэргээн засварлахтай холбоотой харилцааг зохицуулах “Хуучин зүйлийг сахин хамгаалах дүрэм”-ийг баталсан байдаг нь тохиолдлын зүйл биш юм. Энэ үеэс салбарын хууль эрх зүйн орчин бүрдэх үйл авц эхэлсэн бөгөөд 1970 онд “Соёлын дурсгалт зүйлийг хамгаалах хууль” батлагдаж, 1973 онд Соёлын яамны харьяанд Түүх, соёлын дурсгалт зүйлийн засварын газар байгуулагджээ. Өнөөгийн байдлаар салбарын хууль эрх зүйн орчин харьцангуй сайн бүрдээд байгаа боловч соёлын дурсгалт зүйлс, барилга байгууламжийг сэргээн засварлах ажил үйлчилгээний одоогийн практик, хууль тогтоомж, дүрэм журмын хэрэгжилтэд тулгарч буй шийдвэрлэвэл зохих цөөнгүй асуудлууд байсаар байна. Энэхүү өгүүллэгт соёлын дурсгалт барилга байгууламжийг сэргээн засварлах үйл ажиллагааны хууль эрх зүйн зохицуулалт, тэдгээрийн хэрэгжилтийн байдлыг судалсан зарим үр дүнг тусган авч үзсэн болно. Түлхүүр үгс: архитектурын өв, сэргээн засварлалт, хууль эрх зүйн зохицуулалт, эзэмшигч болон өмчлөгчийн эрх, үүрэг

Metagenomic study of the microbiome and key geochemical potentials associated with architectural heritage sites: a case study of the Song Dynasty city wall in Shou County, China

Historical cultural heritage sites are valuable for all of mankind, as they reflect the material and spiritual wealth of by nations, countries, or specific groups during the development of human civilization. The types and functions of microorganisms that form biofilms on the surfaces of architectural heritage sites influence measures to preserve and protect these sites. These microorganisms contribute to the biocorrosion of architectural heritage structures through the cycling of chemical elements. The ancient city wall of Shou County is a famous architectural and cultural heritage site from China’s Song Dynasty, and the protection and study of this site have substantial historical and cultural significance. In this study, we used metagenomics to study the microbial diversity and taxonomic composition of the Song Dynasty city wall in Shou County, a tangible example of Chinese cultural heritage. The study covered three main topics: (1) examining the distribution of bacteria in the biofilm on the surfaces of the Song Dynasty city wall in Shou County; (2) predicting the influence of bacteria involved in the C, N, and S cycles on the corrosion of the city wall via functional gene analysis; and (3) discussing cultural heritage site protection measures for biocorrosion-related bacteria to investigate the impact of biocorrosion on the Song Dynasty city wall in Shou County, a tangible example of Chinese cultural heritage. The study revealed that (1) the biofilm bacteria mainly belonged to Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, and Firmicutes, which accounted for more than 70% of the total bacteria in the biofilms. The proportion of fungi in the microbial community of the well-preserved city wall was greater than that in the damaged city wall. The proportion of archaea was low—less than 1%. (2) According to the Shannon diversity index, the well-preserved portion of the ancient city wall had the highest diversity of bacteria, fungi, and archaea, and bacterial diversity on the good city wall was greater than that on the corroded city wall. (3) Bray–Curtis distances revealed that the genomes of the two good city walls were similar and that the genomes of the corroded city wall portions were similar. Researchers also detected human intestine-related bacteria in four locations on the city walls, with the proportion of these bacteria in the microbial community being greater on good city walls than on bad city walls. (4) KEGG functional analysis revealed that the energy metabolism and inorganic ion transport activities of the bacterial community on the corroded city wall were greater than those of the good city wall. (5) In the carbon cycle, the absence of active glycolysis, the ED pathway, and the TCA cycle played significant roles in the collapse of the east city wall. (6) The nitrogen cycling processes involved ammonia oxidation and nitrite reduction to nitrate. (7) In the sulfur cycle, researchers discovered a crucial differential functional gene, SoxY, which facilitates the conversion of thiosulfate to sulfate. This study suggests that, in the future, biological approaches can be used to help cultural heritage site protectors achieve targeted and precise protection of cultural relics through the use of microbial growth inhibition technology. The results of this study serve as a guide for the protection of cultural heritage sites in other parts of China and provide a useful supplement to research on the protection of world cultural heritage or architectural heritage sites.

A Comparative Study of Heritage Structures and Modern Construction Practices

A Comparative Study of Heritage Structures and Modern Construction Practices

Implementation of nature-based solutions (NbS) into conservation practices of urban built heritages in Bangladesh: challenges, possibilities, and prospects.

The preservation of rich cultural and architectural heritages in Bangladesh, alongside its diverse natural environment, is increasingly prioritized through conservation efforts. Integration of Nature-based Solutions (NbS) into these practices, leveraging existing green elements and natural landscapes for cost-effective conservation processes. This research explores the potential of Nature-based Solutions (NbS) within the heritage structures of Bangladesh, identifying feasible areas for implementation and examining the benefits beyond regular conservation process. Nature-based Solutions (NbS) not only aids in preserving heritage but also enhances sustainability in water management, promotes health, sequesters carbon, boosts biodiversity, and improves acoustic comfort. By harnessing nature's resilience, these solutions offer sustainable responses to challenges posed by climate change, urbanization, and industrialization, which also threaten heritage sites. Integrating Nature-based Solutions (NbS) requires effective implementation strategies, policy support, and community engagement to ensure success. In this research, specific study- based method was followed and implemented in some heritage sites to generate suggestive conclusions in case of implementation of Nature-based Solutions (NbS). This study aims to analyze the feasibility and suggest practical approaches for implementing Nature-based solutions (NbS) in the conservation of cultural heritages of Bangladesh, emphasizing resilience, socio-economic benefits, and the preservation of natural and built environments.

Comparative analysis between continuous and discontinuous methods for the assessment of a cultural heritage structure

AbstractIn an era marked by the urgent need to ensure the safety of existing buildings according to current standards, evaluating the stability of masonry structures against hazard events has become a significant challenge. Despite the versatility and durability of masonry, structural assessments are hampered by factors such as limited information on material properties, irregular geometries, and ageing. To address this issue, numerous modelling techniques have been developed, supported by extensive scientific literature. However, significant factors related to the case study replication, such as the geometric complexity, the mechanical behaviour of masonry, the loading applications, contribute to the challenges associated with modelling procedures, including computational time, discretization procedures, and step incrementation. This paper critically discusses the most innovative modelling approaches. Specifically, it aims to compare the efficiency of the Distinct Element (discontinuous) Methods and the Finite Element (continuous) Method, both applied to the numerical simulation of a case study structure severely damaged by the 2016 Central Italy earthquake under lateral loading conditions. The continuous method is analysed using Midas FEA NX©, while the discontinuous methods are studied using 3DEC© and LMGC90© software, each with different contact conditions. Finally, the investigation highlights the main advantages and disadvantages of each method. In particular, the discontinuous method demonstrates reliability in accurately replicating failure patterns, whereas the continuous method allows for a faster model setup, making it suitable for preliminary studies on structural dynamics.

From monuments to living heritage. Revisiting the Venice Charter in the conservation of younger industrial heritage

The Venice Charter of 1964 has been the benchmark for tenets governing architectural conservation and set forth pivotal principles that shaped conservation practices for decades. However, conceived during a time when heritage was primarily associated with physical monuments, the landscape of cultural heritage has transformed significantly since then, encompassing immaterial aspects, democratisation of heritage values, and diverse sustainability considerations.This research aims at exploring the strengths, limitations, and adaptability of the Venice Charter in light of evolving perspectives on heritage. The paper delves into the charter's historical context, asking whether it remains a guiding beacon or a potential hindrance. A key focus of the research is the examination of obstacles associated with the conservation of younger heritage in the face of contemporary challenges posed by sustainability imperatives. The inherent complexities of managing heritage structures marked by ongoing developmental histories and changes are explored with an example of industrial heritage dealing with the concept of ‘living heritage’. In the context of a future where resource responsibility and reuse are paramount matters, firm definitions of original substance as defined in the Venice Charter, as well as a static perception of conservation, may pose challenges, particularly for unintentional monuments situated in complex environments or marked by evolving narratives through time. Marking the 60th anniversary of the Venice Charter, this research sheds light on the charter’s legacy and its validity in the contemporary landscape of heritage protection as well as the future role of the monuments in our ever-changing societal context.

Influence of age of fermented Terminalia chebula fruit extract in shell lime: An ancient lime putty production technique adopted in Indian heritage structures

The study examines the influence of fermentation age of 5% w/v extract (K5%) of Terminalia chebula fruit in shell lime, using a 0.75 K5%-to-binder ratio. The carbon dioxide evolution, UV-Spectrometric analysis of K5% followed by Gas chromatography and mass spectroscopy (GC-MS) of the slaked putty variants, identified the predominance of organic acids, fatty acids, and esters. The 90th day physical, mechanical, and durability testing confirmed the lowest water-accessible porosity at 31.07 ±0.11% v/v in K5%-4-90, with capillary porosity trending as K5%-4-90<K5%-7-90<K5%-14-90<R-90<K5%-1-90, affecting compressive strength. Mineralogical and morphological studies confirmed the formation of calcite (CaCO3) polymorphs and calcium oxalates via the oxalate-carbonate pathway. Further, thermogravimetric analysis (TGA) revealed the highest %CaCO3 in K5-4-90 and K5-7-90 samples, linked to carbonation extent. The study specifies that K5% at the 4th and 7th days of fermentation age significantly alters putty characteristics, supporting its widespread application and internal and external finishes in heritage structures.

Digital Construction Preservation Techniques of Endangered Heritage Architecture: A Detailed Reconstruction Process of the Dong Ethnicity Drum Tower (China)

This study suggests a pioneering conservation framework that significantly enhances the preservation, renovation, and restoration of heritage architecture through the integration of contemporary digital technologies. Focusing on the endangered drum towers of the Dong ethnic group in Southwestern China, the research employs a meticulous data collection process that combines manual measurements with precise 2D imaging and oblique unmanned aerial vehicle (UAV) photography, enabling comprehensive documentation of tower interiors and exteriors. Collaboration with local experts in drum tower construction not only enriches the data gathered but also provides profound insights into the architectural nuances of these structures. An accurate building information modeling (BIM) simulation illuminates the internal engineering details, deepening the understanding of their complex design. Furthermore, UAV-obtained point cloud data facilitate a 3D reconstruction of the tower’s exterior. This innovative approach to heritage preservation not only advances the documentation and comprehension of heritage structures but also presents a scalable, replicable model for cultural conservation globally, paving the way for future research in the field.

VULNERABILITY OF HERITAGE SITES TO CLIMATIC EXTREME EVENTS: KHALIFATABAAD ANCIENT MOSQUE

Built heritage is the pride of human civilisation and the built environment. But nowadays, they are gradually threatened by various natural decay, deterioration, and effects of extreme climate events. Khalifatabaad (present Bagerhat) in the southwestern part of Bangladesh has a rich heritage value and was also enlisted as one of the world heritage sites by UNESCO in 1985. The Department of Archaeology Bangladesh and UNESCO are working together to conserve Khalifatabaad's heritage sites. But due to climate change and the increased number of tropical climate extreme events like sea-level rise, tropical cyclones, super cyclones, storms, tidal surges, waterlogging, salinity, dampness, etc., significant problems are arising to preserve and conserve the heritage structures of tropical regions. This paper aims to investigate and analyse the vulnerabilities of these heritage structures due to extreme climate events by following building pathology principles. The DPSIR (Driver-Pressure-State-Impact-Response) method is used as the research framework. The research data are collected and documented through a literature review, site survey, detailed observation, documentation, oral statement records, and qualitative analysis. The research outcome is focused on investigating the most responsible climate extreme events, their short-term and long-term impacts on heritage buildings, and presenting conservation strategies for the historical sites in Khalifatabaad.

Seismic Upgrading of the Heritage-Protected Reinforced Concrete Warehouse in Rijeka, Croatia

Despite Croatia experiencing two strong earthquakes in 2020, Rijeka was not directly affected, underscoring the importance of proactive seismic assessment and strengthening in all seismic regions. This paper presents a comprehensive case study on the seismic strengthening of a 20th-century concrete building located in Rijeka, Croatia, originally designed according to Austro-Hungarian construction norms and practices. As a heritage-protected structure, the building’s architectural features and construction practices were examined and contextualized within its historical background. The assessment and renovation phases of this project are discussed in detail, demonstrating the practical application of modern seismic strengthening techniques while preserving the building’s historical integrity. This case study aims to highlight the need for such measures to protect heritage structures and to show the implementation of rapid and new (ad hoc) norms for earthquake-damaged buildings in Croatia. This study serves as a reference for engineers, architects, and conservationists involved in the preservation of heritage buildings, demonstrating that it is possible to enhance their structural safety without compromising their architectural authenticity.

Re-designing demolished Cultural Heritage. A study of a thin shell design for earthquake-destroyed churches in Finiq municipality

This scientific study involves the methods for the design of thin shells on top of cultural heritage buildings that have already collapsed in the municipality of Finiq. The studied object is an orthodox church in Finiq municipality, in Leshnica e Sipërme village. Its roof has already collapsed because of an earthquake and the degradation of the mate- rial. However, the dominant part of the structure, such as walls and columns, is still standing, even though need reinforcement. The maximum span of the roof is long enough to justify the use of a thin shell structure. This study tries to find an elegant solution to this problem, which combines structural beauty with the efficiency of the design and building process, defined as important aspects of a good structural design. The methods proposed for the reconstruction of the existing part of the church are the restoration methods used for monuments in Albania. The propositions take into consideration the state of degradation of each structural element. The primary goal for the reconstruction of the reinforcing elements is that they will not affect the primary function of the building and to restore and keep the cultural heritage values of the object. The pre-design of the roof is made using non-linear analyses. The shape of the new roof and its thickness are chosen to use the Hanging Model Analysis, the Sanders-Koiter equations, the Membrane Theory and a buckling analysis using the software Karamba. The designing of rigid joints, which connect the roof with the other part of the structure, is made so that the entire structure could work and behave as one, while it is loaded during its lifespan. The shell is designed as a pre-fabricated one using UHPC material and divided into panels with rigid joints between them. The analysis and validation of the design of the structure is made with the Load Capacity Analysis in the Ultimate Limit State of it using the software Karamba. The paper concludes by highlighting the importance of recovering the already degraded cultural heritage structures and the role that technology can play in ensuring the integration of the old part of the structure with the new one.

Digital Surveying for Revitalization of Finiq Municipality in Albania: Utilizing 3D Technologies for Heritage Preservation and Development

The Finiq Municipality in Albania is a rural region that is faced with a number of pressing challenges, including a declining population, isolation, and a lack of identity. These is- sues are prevalent in many rural areas of Albania and other countries and can have a substantial impact on the preservation of heritage structures and the overall development of the municipality. However, the territory possesses several potential advantages, such as its proximity to Saranda and the Albanian Riviera, the archaeological site of old Phoeniciae, and the 13th-century Orthodox monastery dedicated to St. Nicholas of Myra, as well as the qual- ity agribusiness production. Proper implementation of policies at the national, regional, and local levels could lead to a tourism-based revitalization of the area. In this framework, data plays a crucial role in project development as it forms the basis for informed decision-making and efficient planning. One of the key benefits of data is its ability to reveal patterns and trends, which can be leveraged for decision-making and improvement opportunities. In addition to demographic and sociological data, information describing the territory and human artifacts in their physical form is also essential. GIS tools are already in use and provide useful cartographic data, which effectively represents the complexity of the territory and the relationships between its various components. This data forms the founda- tion for creating advanced information systems, such as territorial digital twins, to deepen the knowledge of the territory. Integrated digital surveys, utilizing three-dimensional acquisi- tion technologies such as lase scanning and photogrammetry, can serve as a reliable source of input data for creating these knowledge tools. Point clouds offer valuable morphometric databases that are often critical for documenting not only architectural and cultural heritage but also infrastructure, modern artifacts, and larger portions of the territory. Different multis- calar approaches can be adopted to cater to the specific needs and requirements, for instance providing a detailed understanding of archaeological and monumental heritage, or the contextualization of settlements in the surrounding area. By integrating these data with GIS platforms and BIM models to create a comprehensive understanding of the municipality's territory, they can be utilized for preservation and conservation efforts, urban planning and development, and identifying potential structural issues. Additionally, the data collected through 3D survey technologies can be utilized to monitor the condition of the buildings and infrastructure, promoting better maintenance and planning, even considering the risks posed by the area, such as seismic risk. The digital data can also be used to create virtual tours and interactive models, promoting the municipality's cultural heritage and economic development. While the use of these procedures in a marginal area may initially seem disproportionate, it is not so much in relation to the subject of the survey, given the universally recognized historical and artistic value of some areas. The financial effort required to undertake such campaigns may seem substantial, but the project can be implemented in phases, integrated, and completed over time.

Analysis of the form, construction, and structural conception of Silberkuhl shells through construction history and advanced HBIM

In the 20th century, the development of industrial buildings featured a strong relationship between form, conception, needs of production processes, and advanced structural solutions. The knowledge, safeguard, and valorization of the industrial heritage structures, of the 20th century, requires a multidisciplinary approach, including construction history, structural analysis, and advanced 3D modeling. In particular, the study of shape-resistant structures in reinforced concrete – such as thin shells – needs to consider the deeply intertwined aspects of form, construction, and structural conception. The main aim of the present paper is to set a methodological workflow based on the combination of archival research, Historic/Heritage Building Information Modeling (HBIM), and numerical structural analysis to support the knowledge, safeguard, and valorization of the thin shells in reinforced concrete. The effectiveness of the proposed methodology, scalable for the analysis of historical shell structures in reinforced concrete, is tested on the noteworthy case study of the so-called Silberkuhl shells. According to their convenience in terms of structural efficiency and economy of construction, this system stood out worldwide for industrial roofing in the second half of the 20th century, exploiting the possibility of both industrial production and on-site precast, adapting to different economic and technological backgrounds.

Importance of Heritage Structures as Bat Roosts in the Sahara Desert

ABSTRACTIn addition to the availability of water and invertebrate prey, roost sites are considered the main factors enabling bats to survive in desert areas. Because suitable roost sites are often limiting resources, human constructions are also important for these animals. Conversely, in the context of built heritage conservation, bats are often discussed as a cause of damages. However, if historic structures deteriorate, they may lose their suitability as roosting sites for bats. This study examines how the condition of domed tombs in Sudan affects their use by bats. Inspections of 19 tombs revealed that bats occupied only undamaged structures, with 1652 individuals of four species found. Slightly and partially damaged tombs were not used by bats. These findings highlight the importance of preserving man‐made structures as critical roosting sites in arid environments to support local bat populations.

Reconstructing the local structures of Chinese ancient architecture using unsupervised depth estimation

Digitalization of ancient architectures is one of the effective means for the preservation of heritage structures, with 3D reconstruction based on computer vision being a key component of such digitalization techniques. However, Chinese ancient architectures are located in mountainous areas, and existing 3D reconstruction methods fall short in restoring the local structures of these architectures. This paper proposes a self-attention-guided unsupervised single image-based depth estimation method, providing innovative technical support for the reconstruction of local structures in Chinese ancient architectures. First, an attention module is constructed based on features extracted from architectural images learned by the encoder, and then embedded into the encoder-decoder to capture the interdependencies across local features. Second, a disparity map is generated using the loss constraint network, including reconstruction matching, smoothness of the disparity, and left-right disparity consistency. Third, an unsupervised architecture based on binocular image pairs is constructed to remove any potential adverse effects due to unknown scale or estimated pose errors. Finally, with the known baseline distance and camera focal length, the disparity map is converted into the depth map to perform the end-to-end depth estimation from a single image. Experiments on the our architecture dataset validates our method, and it performs well also well on KITTI.

Evaluating building stones: Physical-mechanical changes from high-temperature fire and water cooling

Heritage sites built with natural stone are at risk from fires, which can alter stone properties and compromise its structural integrity. Over 60 studies in the past three decades have examined fire impact on natural stone, providing insights for their prevention and restoration. The primary objectives are to develop effective strategies to mitigate fire risks, protect heritage structures, and ensure the preservation of our cultural legacy. Two noteworthy Portuguese limestones used as heritage building materials: Lioz (LL) and grey Ançã stone (GAS), were studied regarding the effect of high-temperature exposure for simulating fire at 200 °C, 400 °C and 600 °C, followed by cooling in water to reproduce fire extinguish in natural stone buildings. The findings provided insights into how the different temperatures impact the stone morphological, physical and mechanical properties. Color measurements (CIE L*a*b*) showed a color difference from 3 to 32 %; SEM-EDS confirmed microstructure modifications after fire exposure with cracks formation and intragranular porosity development. Among the diverse physical and mechanical properties of the stones, uniaxial compressive strength decreased from 1 to 33 %, Leeb D hardness decreased up to 12.2 %, lowering in open porosity was detected in the range 70–289 % and ultrasound speed propagation were significantly affected after thermal cycle at 600 °C with a negative variation reaching 49 %. Results from TGA show a loss of mass due to retained water (∼40 °C) and loss of hydration water at ∼ 120 °C in both limestones. The total mass loss (∼42–∼44 %) is associated with the loss of H2O, CO2. In conclusion, stones with higher toughness and compression strength exhibited reduced damage at high temperatures due to their enhanced resistance to fracturing under stress. As limestone's mechanical strength decreases under high temperatures, it's advisable to increase its thickness to ensure sufficient support for loads and intended conditions of use. The deficiency of analysis on limestone's mechanical decay from fire reveals a significant knowledge gap regarding the complete extent of damage and deterioration in stone heritage structures.

Rocking block simulation based on numerical dissipation.

In this paper, a computational approach based on numerical dissipation is proposed to simulate rocking blocks. A rocking block is idealized as a solid body interacting with its foundation through a contact-based formulation. An implicit time integration scheme with numerical dissipation, set to optimally treat dissipation in contact problems, is employed. The numerical dissipation is ruled by the time step and the rocking dissipative phenomenon at impacts is accurately predicted without any damping model. A broad numerical campaign is conducted to define a regression law in analytic form for the setting of the time step, depending on the block size and aspect ratio, the contact stiffness, as well as the coefficient of restitution selected. The so-obtained regression law appears accurate and an a posteriori validation with cases not in the training dataset confirms the effectiveness of the approach. Finally, the comparison with available experimental tests highlights the approach efficacy for free rocking and harmonic loading cases (in a deterministic sense), and for earthquake-like loading cases (in a statistical sense). It is found that rocking blocks with sizes of interest for structural engineering (e.g., cultural heritage structures) can be simulated with time steps within 10-3 ÷ 10-1s, so allowing very fast computations.