Conservation Of Historic Buildings Research Articles

Load Bearing Capacity and Failure Analysis of Fibrous Plaster Wads

ABSTRACT Fibrous plaster is a culturally significant material used in high-status buildings from the late nineteenth century. Fibrous plaster ceilings are typically suspended using load-bearing fibrous plaster wads, which are attached to roof structure components. Understanding the behaviour of wads is highly significant, with important safety implications emphasised by the partial collapse of the Apollo Theatre ceiling in 2013. This study demonstrates an original, innovative test method for fibrous plaster wads that enables quantification of load capacities, with manufactured specimens representative of historic in situ wads. The methodology is rigorously evaluated for traditional and alternative wad designs, reinforced with hessian scrim or continuous fibre glass (CFG) mat, with and without steel wires in looped (untwisted) or looped-twisted configurations. Tensile tests generated load-displacement characteristics and determined failure modes including cracking of plaster, deformation and tearing of fibrous reinforcement, and if present, plastic failure of a wire. Results demonstrate that hessian performs better than CFG in axial tension and inclusion of a wire increases tensile load capacity and ductility. An industry standard repair wad with hessian and looped-twisted wire can typically support 3 kN. Looped wire performed better in isolation than looped-twisted wire, with higher peak loads and greater ductility, while looped-twisted wire carried a greater load as part of a fibrous plaster composite wad. The test methodology and findings have revealed new insights into the mechanical behaviour of wads which will inform commercial practice and conservation of historic buildings, preserving important heritage and promoting safe longevity.

Green Building Assessment Model for Historic Buildings of Turkey

Grave structures are architectural works reflecting the cultural accumulation, continuity and political power of societies. In the context of sustainability, while "green building" certification systems are developing in building productions in the world, new guidelines are also being created. Of course, new guidelines are also being developed on the certification as green buildings within the scope of the protection and restoration of historical buildings that should be specially considered. In this study, it is aimed to create a model that will allow the historical buildings in Turkey to be evaluated in the context of “the green building” concept. With this model, it is considered that historical building conservation practices will contribute positively to the works of restorers in making those heritage sites more environmentally friendly and sustainable. For the model designed to evaluate historical buildings within the scope of green buildings, historical buildings were handled under 3 groups: a) 1st Group Historical Buildings, b) 2nd Group Historical Buildings and c) Reconstructed Historical Buildings. As creating the designed model, GBC-Italy system criteria were taken as the basis. The criteria were carried out by conducting a questionnaire with experts in this field. Importance of the relevant evaluation criteria in the scoring system were determined by using the AHP method. As a result of the analyzes and calculations, the accuracy of the scoring was confirmed. As historical buildings are evaluated according to the conditions of their periods, it is obvious that they are sustainable buildings. Naturally, nowadays to be able to preserve historical buildings for the future generations in a proper way is usually ensured by giving them a new function. The requirements of the new functions given to create the necessary equipment to provide today's comfort conditions in historical buildings naturally change the sustainable characteristics of the historical heritage. This evaluation system, designed to preserve the green building characteristics of historical buildings and to ensure their sustainability with their new functions, will be an important guide.

Time demands of traditional hand-hewing techniques for sustainable repair of wooden heritage structures: A comparative study

The hand-hewing of timber has been a fundamental skill for carpenters throughout history. Inevitably though, the majority of wood used in construction at the present time is processed with the use of machines. Repairing heritage objects with machined wood however, as opposed to working replacement timber using similar craft methods and tools as those used in the original, is often in conflict with the principles set forth in the Venice Charter for the Conservation and Restoration of Monuments and Sites. Ultimately, relying on mechanization is a missed opportunity to contribute to the preservation of valued intangible cultural heritage.Whereas the sustainability of traditional woodworking techniques and technologies can be promoted by applying them in the conservation of historical wooden buildings, the labor-intensive and time-consuming nature of manual woodworking makes feasibility questionable. In order to provide valuable insight for planners and monument care workers, the paper presents a study on the time demands associated with processing hand-hewn beams intended for use in the structural repair of wooden heritage objects.A series of experiments was conducted wherein a total of 94 beams 18×22 cm in profile and 2.5 m in length were hewn from spruce logs of various diameters. The relationship between initial log diameter and required processing time is presented as a linear function. The relative proportions of the individual steps to the hewing process as a whole were also documented and showed a clear dependency on the total amount of material removal required. The overall processing time was significantly reduced in the case of timber that was soaked for several months before being hewn into beams, and the low-work hewing technique was shown to be more efficient in comparison to high work on trestles.This paper has been published in memory of Petr Růžička, the great pioneer of forgotten carpentry techniques whose work opened a window to our past for future generations.

Conservation, Revitalization and Renewal of Modern Macao's Historic Architectural Heritage: A Case Study in the Site of St. Paul's College

As an essential member of the tangible cultural heritage, historic architectural heritage contains unique historical and social values. This paper describes the current state of conservation of historic buildings and the ways of conservation, revitalization and renewal by the Macao authorities, and draws on the Cathedral of the Merciful Jesus in Goa, India, and Coventry Cathedral in England, to provide suggestions for the conservation and restoration of the site of St. Pauls College in Macao. St. Pauls College is divided into three main parts: St. Pauls Church, the Seminary, and the Fortress, for conservation, revitalization, and renewal. The current conservation and renewal measures of the site are still inadequate. By analyzing the conservation strategies and the current situation, St. Pauls College needs the cooperation of the government and the public to value and improve the reuse value of the site and increase its visibility. At the same time, the use of rich restoration and renewal methods, combined with the current situation of society in the restoration and renewal of the site, can present valuable ideas.

Open HBIM-IoT Monitoring Platform for the Management of Historical Sites and Museums. An Application to the Bourbon Royal Site of Carditello

ABSTRACT This paper describes the implementation of an open-source platform integrating HBIM-IoT monitoring sensors, applied to the Royal Site of Carditello, a Bourbon 18th-century Palace near the city of Capua (Italy). Based on open standards and processes, the platform is accessible on different devices through the Internet and acts as a digital representation of the building and the monitoring system therein, allowing users to navigate a detailed HBIM model and query, visualise and manipulate static and dynamic information attributed to the building and its collections, as well as the data from applied sensors, linked to their virtual objects’ equivalent in the model. Integrating robust data management with a user-friendly 3D interface, this solution aims to enhance the preventive conservation of historical buildings and their collections, which depend on regular monitoring and a systematic diagnostic programme over time.

How to improve the integrity and sustainability of historic architectural complexes and their environments in modern urban planning--an example from the "Wenming Street" historic district renovation project in Kunming

Historic buildings are the bearers of human civilization. Kunming, a famous historical and cultural city in China, has numerous historical and cultural heritages and a diverse and prosperous historical and cultural background. This study takes the renovation project of the historic district of Wenming Street in Kunming as the research object and proposes a holistic, multi-dimensional, and multi-factor planning and renovation method that should focus on the district in the conservation and renovation of historic buildings through the hierarchical analysis method. Through expert scoring and weighting analysis, questionnaires, and index scores, it is found that there is a lack of "spirit of place" and insufficient expression of non-material elements in the renovation of the historic district. This study aims to realize the integration of the historic environment with the needs of modern life using a monistic logic and to provide theoretical reference and practical guidance for the conservation, renovation, and sustainable development of historic buildings and the historic environment.

Preliminary Study on Indoor Air Temperature and Moisture Behaviour in 13th-Century Churches in Latvia

The microclimate plays a crucial role in the conservation of historical cult buildings and their artifacts for future generations. In order to conserve these buildings and their artifacts, it is imperative to ensure that the microclimate is conserved. The norms and standards existing so far in Latvia do not stipulate thresholds for air parameters that would ensure a conserving microclimate for historical cult buildings. In order to identify these thresholds, the air parameters were measured simultaneously at nine measuring points within the Krimulda Church (LV) of the 13th century. The temperatures of the surfaces of the building envelope and potential condensation were calculated using the actual data of indoor and outside air. The indoor and outdoor air humidity ratio was calculated for each measurement. The conservation threshold of indoor microclimate parameters was determined by using intermittent heating on the basis of the air parameter fluctuations and calculations. The moisture vapours from the building structures were quantified in this research. The indoor humidity ratio during the warm season and the upper threshold during the heating season were determined.

Problems of Supplementing the Formed Historic Development with new Objects

In the article, the authors discussed the course in the subject of heritage protection, including the conservation of historic buildings and placing new objects within historically formed development, at the Faculty of Architecture of the Poznan University of Technology. The authors emphasise the importance of analysing the composition of historical buildings' elevations existing in the vicinity of the designed object. Capturing the main compositional structures and guidelines of the facades of historical objects is difficult, and hence the authors show different ways to achieve this, emphasising different ways of observing the object and graphically recording the layout of the composition and later using these effects in the design stage. The aim is to acquire and improve the ability to fit the designed object into its historic context.

Research on the Investigation and Value Evaluation of Historic Building Resources in Xi’an City

In China, as statutory non-cultural relic buildings, the conservation and reuse of historic buildings have received increasing attention in recent years. Among them, the investigation and value evaluation of historic buildings are the basis and core of the conservation work, and many cities have explored related technologies and methods according to local conditions. This paper takes the historic building resources in Xi’an as the research object, with the core of historic building registration and the principles of scientificity and operability. It proposes the methods and basic processes for investigating historic building resources and constructs a step-by-step evaluation system for the historic buildings in Xi’an. This research first formulates a registration standard for the identification and evaluation of historic buildings, then applies the analytic hierarchy process, Delphi method, and fuzzy comprehensive evaluation method to assess the comprehensive value of historic buildings. Finally, it was recognized that the historic building resources are primarily modern and contemporary buildings, playing a significant role in the cultural continuity of the ancient capital, Xi’an. In its value evaluation, emphasis should be placed on the environmental landscape value and socio-cultural value. At the same time, it is necessary to consider the comprehensive value and sub-indicators of historic buildings so that they can guide conservation and adaptation practices in a targeted manner.

HBIM: A Tool for Enhancing the Diagnosis of Historical Buildings: The Case of St. George’s Memorial Anglican Church, Oshawa

The primary objective of this research is to address the research gap in the conservation of heritage buildings in Canada by integrating Historical Building Information Modeling (HBIM) as a tool. The proposed study aims to develop an enhanced framework for the preservation of historical buildings through the utilization of HBIM and 3D-scanning technology. As a result, the research aims to generate a comprehensive database comprising various families of models while also incorporating strategies for point-cloud clustering data. The significance of this research lies in its potential to contribute to the conservation and restoration process of historical buildings. Currently, there are a lack of standardized approaches and comprehensive databases for accurately documenting and reproducing historical buildings. By integrating HBIM and 3D-scanning technology, this research will enable the creation of highly accurate three-dimensional virtual models, consisting of millions of points, which will serve as a comprehensive dataset for the restoration of heritage buildings. The findings of this research will benefit multiple stakeholders. Preservation architects, conservationists, and heritage professionals will gain a valuable tool for documenting and analyzing historical buildings with a high level of precision. The comprehensive database and framework proposed in this study will facilitate decision-making processes during the restoration and preservation phases, ensuring that the original architectural elements and materials are faithfully reproduced. Additionally, policymakers and governmental organizations involved in heritage conservation can use the outcomes of this research to establish standardized guidelines and regulations for the preservation of historical buildings in Canada. Ultimately, the broader community will benefit from the enhanced preservation efforts, as it will contribute to the cultural and historical identity of the nation, fostering a sense of pride and connection to the past.

Proposal of New Natural Hydraulic Lime-Based Mortars for the Conservation of Historical Buildings

NHL mortars are known to be compatible materials for the conservation of architectural heritage. To improve their properties with regard to salt resistance and lower their carbon footprint, NHL-based mortars with salt inhibitor agents were studied and different formulations were produced: NHL-based mortars (MSs), composed of natural hydraulic lime; and sand and cocciopesto mortars (MSCs), in which NHL, sand and brick powder were admixed with two different products, diethylenetriaminapenta and chitosan, in different concentrations. The mortar performance was tested against freeze–thaw and salt crystallization through immersion–drying cycles in a 14% sodium sulfate solution. The results highlighted that the addition of cocciopesto was effective in increasing the salt resistance, but increased the water intake during the freeze–thaw tests. The use of DTPMP produced less thixotropic mortars and decreased the water uptake, but worsened the salt resistance of hardened mortars. Chitosan allowed a good workability of fresh mortar; its water uptake was similar to the reference mortar and slightly increased the salt resistance. In the cocciopesto samples, both additives reduced the weight variation during freeze–thaw tests; meanwhile, for the lime samples, the additives increased the weight variation during the final cycles.

Renewing the old, creating the new: examining the strategies and results of urban conservation in Singapore and Shanghai

This paper explores the concept of authenticity in the conservation and renewal efforts in Singapore and Shanghai. Despite the past belief that demolishing or modifying historical buildings was acceptable for rapid urban development, the cities have recognized the value of preserving these buildings to maintain a sense of cultural heritage and authenticity. Through the analysis of typical conservation cases in both cities, the study examines the relevant strategies, methods, and results, and compares the changes and progress of conservation over time. The study finds that the conservation of historical buildings and districts can contribute to the authenticity and cultural identity of a city, fostering a sense of community and pride among residents. However, the concept of authenticity can be complex, and there may be debates over the appropriate level of restoration or modification required. Overall, the dissertation highlights the importance of balancing urban development and conservation and the evolving strategies towards people-based and coordinated development in both cities.

Integration of photogrammetry and laser scanning for enhancing scan-to-HBIM modeling of Al Ula heritage site

The study highlights the significance of combining imaging and laser scanning techniques to enrich point clouds used for reliable documentation and Heritage Building Information Modeling (HBIM). The fusion-based approach was used to document Al Ula Heritage site in Saudi Arabia, a UNESCO World Heritage Site with well-preserved tombs from the first century BC. The HBIM parametric modeling process requires a detailed survey to collect all geometric data. Although terrestrial laser scanners (TLS) are an efficient tool for 3D recording of heritage scenes in a short period of time, the data resolution is insufficient for identifying and evaluating the spatial distribution of surface weathering forms. Furthermore, combining scans collected at different times may pose difficulties in recording the texture. These issues have an impact on the subsequent 3D modeling phase as well as the efficiency of interpreting and tracing surface features in the Scan-to-BIM process. The proposed workflow using imagery data to enhance both the geometry and coloring of laser point clouds. In addition to texture mapping, the high-resolution imagery is used to densify the laser data using dense image matching, allowing for a clear reading of the surface features, and serving as a useful tool to identify the type, extent, and severity of façade damage. TLS and imagery data were collected separately, with images taken at the best time and location for realistically recording of surface details. Finally, the captured images are orthorectified by TLS geometric information and used for HBIM texturing to provide realistic decay mapping. The results showed that the combination of TLS and photogrammetry allowed for the efficient collection of 3D data, which improved tracing and digitizing HBIM with complete mapping information. The research findings will be greatly useful in the management and planning of historic building conservation and restoration projects.

Sustainable Hybrid Lime Mortars for Historic Building Conservation: Incorporating Wood Biomass Ash as a Low-Carbon Secondary Binder

Renewables-based power grid expansion has increased the use of wood biomass as a low-carbon fuel, resulting in the generation of predominantly inorganic wood biomass ash (WBA) as waste during biomass combustion. The conservation of historically valuable, damaged, and energy-inefficient buildings can help downsize carbon emissions and energy consumption, while promoting the use of alternative repair materials, including unavailing materials such as WBA, and implementing zero-waste measures. This study aims to underscore the importance of a proactive approach in managing WBA and its application in artificial hydraulic lime (AHL) mortars. Hybrid lime mortars were prepared by combining natural hydraulic lime (NHL) as the primary binder with fly wood biomass ash (WBA) as the secondary substitute, using different mass ratios of NHL to WBA (100:0, 80:20, and 70:30). The experimental framework encompassed interconnected analytical steps, ranging from binder analysis to paste and mortar preparation. The chemical and mineralogical composition, physical properties, and reactivity of WBA were evaluated to determine the appropriate proportion of WBA for low-carbon AHL binder formulation. Prior to mortar mixing, the water demand, setting time, and soundness of the AHL pastes were assessed. The effects of each AHL binder blend on the mechanical properties of the AHL mortars were analyzed based on compressive and flexural strength measurements after 28 days of curing under different CO2 and moisture conditions (CO2~400 ppm at 70% RH and 95% RH; CO2~30,000 ppm at 60% RH). Additionally, changes in the porous structure were studied. Notwithstanding the greatly prolonged setting time, the results indicate that the mechanical properties of AHL mortars can be enhanced by the addition of WBA in a moderate ratio, empowering the development of environmentally friendly lime mortars suitable for conservation purposes.

Investigating the historical building materials with spectroscopic and geophysical methods: A case study of Mardin Castle

Today, the building materials form the historical buildings are being exposed to various deteriorations increasingly due to different causes. Many historical masonry constructions in the world are on the edge of extinction due to the increasing frequency and changing models of material deterioration. The materials as close as possible to the original materials in terms of their chemical compositions and physical properties are required in the reconstruction and maintenance of the buildings that have historical importance. In addition, the properties of the materials used in the historical buildings are generally not known with a sufficient accuracy. This causes misapplications in case of emergencies, and also may lead to future potential greater damages on the building. The lack of data regarding the engineering properties of these buildings causes long-term damages on the buildings due to inappropriate conservation methods and materials. Therefore, it is necessary to investigate the properties of certain materials for application in the renewal of the historical buildings. Within this context, in this study the construction materials of Mardin Castle, which is located in Mardin Province, Turkey and existing for centuries as the symbol of the city, are investigated and its properties are reached. Experimental research methods were used in the study. Primarily, the castle structure was examined on-site by field study and sampling was carried out from the areas determined. The samples were analyzed via various spectroscopic and geophysical methods, and various findings were achieved. Relatively variable and high levels of salinization were determined in the findings regarding the average values in stone samples of Mardin Castle’s Fortification Walls. Results of the research document the conservation status regarding Mardin Castle and provide an experimental base and also a theoretical support for the conservation of historical buildings in Turkey; and present indicative suggestions to establish conservation schemes of the historical buildings.

Creating Historical Building Models by Deep Fusion of Multi-Source Heterogeneous Data Using Residual 3D Convolutional Neural Network

ABSTRACT There are a large number of historical buildings in the world, but many of them are seriously damaged. A fundamental task to revitalize them is to record their details and redraw them, but it is a highly inefficient task. This paper aimed to create three-dimensional (3D) models automatically for those damaged historical buildings while respecting the 1964 Venice Charter, the ICOMOS recommendations, and local ordinances. After reviewing the advantages and disadvantages of various measurement tools, we implemented a machine learning algorithm, the residual 3D convolutional neural network (CNN) method, to combine heterogeneous data from multiple sources including a 3D laser scanner, an unmanned aerial vehicle, a total station, and a camera, in a historical building information model (HBIM) to increase its accuracy. Those data, preprocessed by four steps including data registration, reducing noises, filtering data, and data integration, were trained and fused in a 3D CNN model, which consisted of one input layer, five 3D convolutional and pooling layers, and two connected layers. A Shanghai historical building conservation project was taken as a pilot case to verify its productivity and accuracy in developing the HBIM, on which the architectural features were thoroughly recorded, and the damaged details were recovered.

A Bibliometric Analysis of Research on Historical Buildings and Digitization

The wealth of published data are valuable because, in addition to contributing to the advancement of scientific, technical, and policy knowledge, they can also provide critical information and guidance regarding published content, subject changes, and trends that demand greater attention. In the 21st century, digital technologies play an increasingly important role in “data capture”, “building management”, “virtual reconstruction”, and “building restoration”. The indispensable role of digital technology in addressing “data capture”, “building management”, “virtual reconstruction”, and “building restoration” has resulted in the publication of several high-quality publications. In this study, we retrieve textual data from Web of Science and mine the content of the documentary data using COOC, VOSviewer, CiteNetwork, and academic influence evaluation (AIE) software to gain insights into the prospects and opportunities for historic architecture and digitization research. The results indicate that greater progress has been made in research on the use of digital technologies for the conservation of historic buildings from 2019 to 2023, but cross-disciplinary, cross-institutional, and cross-border collaboration should be enhanced. The research frontiers identified indicate that photogrammetry, 3D modeling, point cloud, and deep learning will require sustained attention in the near future. Additionally, computational analyses of academic influence reveal that Italian institutions and authors have dominated research in this field in recent years. A new strategy and framework for data-driven bibliometric analysis involving historical architecture and digitization techniques are presented in this study. Based on general bibliometric methods, this study innovatively explores the scientific knowledge base and knowledge flow of highly cited articles, provides comprehensive evaluation indicators such as H-index, G-index, P-index, and Z-index for high-impact journals, institutions, and authors, and proposes a COOC-based idea to address the consistency of data sources among multiple software.

Freeze-thaw resistance of pozzolanic hydrated lime mortars

Degradation of hydrated lime mortars subjected to freezing and thawing is common in historic building conservation. The pozzolanic additions, Argical M1000, diatomite (diatomaceous earth) and brick dust, were evaluated for their ability to improve performance for up to 720 days. Pozzolanic reactions influenced the pore structure evolution, mechanical performance, and chemical reactivity of the mortar matrix. Argical-lime mortars exhibited a sudden failure, while a gradual reduction in mechanical strength was observed for mortars containing brick dust. A slower rate of failure in diatomite mortars was attributed to pore refinement, which was associated with superior freeze thaw performance. This study has advanced the current state of the art regarding how pore structure affects lime mortars' freeze and thaw resistance. Therefore it provides spesifications on how to optimise mortars for historic masonry. A key impact is the more effective use of lime mortars for conservation, thereby protecting heritage structures from degredation.

A new proposed semi-quantitative method for the organic additives analysis in traditional lime mortar

To improve the performance of lime mortar, ancient craftsmen often added various additives to mortars, including inorganic and organic materials. The analysis of mortar additives plays an important role in the conservation and restoration of historical buildings. However, it is quite difficult to accurately identify the species of additives. This paper proposed a series of semi-quantitative analytical procedures to identify the organic additives in ancient lime mortars. By using reagents such as phenolphthalein, periodic acid, acetylacetone, anthrone, bicinchoninic acid (BCA), iodine-potassium iodide, chloramine T, etc., organic additives such as triglyceride, soluble sugar, starch, and protein (including blood, gelatine, and other unknown proteins) remaining in ancient lime mortar were accurately detected, respectively. The linear relationship of the standard curve was significant, and the detection limits for the target additives were below 7 µg/mL. The process is easy to operate within 6 h, and it is suitable for rapid in-situ testing.

Sustainable Competitive Advantage of Cultural Heritage Sites: Three Destinations in East Asia

Cultural heritage plays an important role in the creation of creative cities, giving them a new lease of life and generating employment opportunities and local economies in the process. The revitalisation and development of cultural heritage and intangible cultural heritage have become a major part of national development policies worldwide. This study adopts a multiple case analysis approach. Four cultural heritages of three destinations in East Asia (Hong Kong, Macau and Taiwan) were selected as case studies because they have all adopted a public–private partnership approach to the conservation and reuse of historic buildings. In this study, semi-structured interviews were conducted and secondary data collected from a variety of sources to bring the findings of this study closer to the practical development of cultural heritage. Base on Five Forces analysis, we propose an “Extended Five Forces” model of cultural heritage. The new component, i.e., historical landscapes and cultural sustainability, is proposed to expand the theoretical foundations of the sustainable management of cultural heritage. The findings show how they can collaborate with communities to create value and gain a sustainable competitive advantage on a global scale and contribute to the sustainable management of cultural heritage in Asia.