This article presents the derivation of a fragility model for the Italian masonry school building asset, comprising 265 sets of fragility curves for as many building types, classified on the basis of ...few parameters: construction age, number of stories, plan area, and type of masonry (i.e. with regular or irregular pattern). The fragility assessment was carried out by means of parametric analyses, generating more than 7500 samples which were then analyzed through the mechanics-based procedure Vulnus. Sample fragilities were then linearly combined to obtain fragility curves consistent with the adopted taxonomy based on few parameters. A macroseismic–heuristic model from the literature was used to extend the fragility model to five damage states, according to the European Macroseismic Scale (EMS98). The proposed model was compared to empirical information in terms of observed damage on three existing schools and fragility curves recently derived by processing data of school damaged by the 2009 L’Aquila earthquake, showing a satisfactory agreement. In addition, a comparison with fragility sets for residential buildings was carried out. Both fragility models were developed with the same procedure, so as to point out differences between schools and ordinary buildings. Similar fragilities were observed for schools and residential buildings built before 1945, whereas for later periods, schools showed a higher fragility than the residential asset. Finally, seismic damage maps were developed at national scale showing the distribution of expected damage as a possible application of the derived model.
Vision-based manual inspection technology for identifying and assessing superficial damage of historic buildings is time- and labor-consuming. To overcome these limits, this paper proposed a novel ...automatic damage detection technique using Faster R-CNN model based on ResNet101 framework to detect two categories of damage (efflorescence and spalling) for historic masonry structures. 33 different cases were studied, and the best case shown an average precision (AP) of 0.999 and 0.900 for efflorescence and spalling damage respectively, with a 0.950 mean AP. Moreover, an Internet Protocol (IP) webcam damage detection system combined with workstation was developed to detect the damage in real-time, and an automatic damage detection system based on smartphones was developed, which can realize real-time damage detection of brick masonry buildings. In addition, two on-site experiments were carried out on real masonry buildings to verify the feasibility and effectiveness of the system. Consequently, it was demonstrated that the proposed method was considerably automatic, efficient, and reliable for damage detection of historic masonry buildings and, ultimately, contributing to the management and protection of historic buildings.
•An automatic damage detection strategy based on deep learning is developed.•Deep learning-based damage detection model with 95.0% mean AP is trained.•IP webcam damage detection system combined with workstation is developed.•Mobile damage detection system based on smartphones is developed.
•Mechanical properties of Malatya Taşhoran Church were evaluated.•Destructive and non-destructive techniques were used together.•Differences between restoration stones and original stones were ...compared.
Historical masonry structures are an essential component of cultural heritage. These structures may transfer the lifestyle of previous civilizations to next generations. In order to prevent earthquake damage to these structures, it is important to obtain accurate information on their material properties for reliable computational modelling and strengthening intervention programs. In this context, Destructive Techniques (DT) and Non-Destructive Techniques (NDT) were used together and the results obtained were compared. Taşhoran Church located in Malatya, Turkey was selected as a case study. The aim of this study is to compare the obtained results of Destructive Techniques (DT) and Non-Destructive Techniques (NDT) used to evaluate the original and restoration stones of Taşhoran Church in Malatya, Turkey. The tests conducted include uniaxial compressive strength, flexural strength, water absorption, density, porosity, XRD, SEM-EDX and ageing tests with different solutions (5% H2SO4, 5% HCl and %14 Na2SO4). In addition, NDT methods such as Schmidt hardness, ultrasonic pulse velocity and infrared thermography were used to determine dynamic Poisson's ratio, dynamic modulus of elasticity and UCS. NDT and DT values of the original and restoration stones werepresented.
•Experimental campaign and a critical analysis of structural performance of unreinforced masonry elements.•Large characterization of materials and components used in masonry buildings.•Prisms and ...wallets.•Masonry buildings constructed in Pernambuco and their relationship with several failures.
This paper discusses masonry buildings constructed in Pernambuco and their relationship to several failures that have occurred, some of which included the death of inhabitants. Topics such as the main features of this building technique and its peculiarities that played an important role in its structural behaviour are discussed in detail. Additionally, the paper presents a large characterization of materials and components used constituting the most important current research on this topic in Brazil. Its content analyses in depth, experimentally, the behaviour of single bricks, prisms and wallets that allow the identification and quantification of the influence of several mortar rendering layers on the load capacity of elements tested. A critical analysis concerning the factors that contribute to the performance observed is presented from which it was possible to realize a significant variability of results. A summary with the main results of all experimental tests is presented.
•Nonlinear static analyses for the seismic assessment of masonry buildings.•Seismic assessment of existing complex masonry buildings with flexible floors.•Vulnerability assessment of mixed ...masonry–reinforced concrete buildings.•Reliable models and strength criteria for masonry pier and spandrel elements.•An advanced modelling tool useful both at research level and engineering practice.
The seismic analysis of masonry buildings requires reliable nonlinear models as effective tools for both design of new buildings and assessment and retrofitting of existing ones. Performance based assessment is now mainly oriented to the use of nonlinear analysis methods, thus their capability to simulate the nonlinear response is crucial, in particular in case of masonry buildings. Among the different modelling strategies proposed in literature, the equivalent frame approach seems particularly attractive since it allows the analysis of complete 3D buildings with a reasonable computational effort, suitable also for practice engineering aims. Moreover, it is also expressly recommended in several national and international codes. Within this context, the paper presents the solutions adopted for the implementation of the equivalent frame model in the TREMURI program for the nonlinear seismic analysis of masonry buildings.
Although Portugal has not been hit by high‐magnitude earthquakes in recent years, its history is marked by tragic seismic events and it remains susceptible due to its geographical location. The ...Portuguese building stock is constituted approximately by 45% masonry residential buildings and most were built before the enforcement of the first seismic code in 1958. For several years, structural interventions in these buildings were allowed without the need to assess their seismic vulnerability. In 2019, a new law was approved to regulate the rehabilitation interventions to provide safety and comfort of existing buildings. The seismic assessment of existing buildings became mandatory and based on the procedures and requirements included in NP EN 1998–3: 2017 (Portuguese version of Eurocode 8 – part 3), which establishes the performance requirements and compliance criteria for existing buildings subjected to a certain level of seismic action. According to this normative requirements, analytical seismic vulnerability assessment and reliability‐based analyses were carried out on a large set of masonry buildings representative of the Portuguese housing stock, leading to the development of surrogate and expeditious method for seismic assessment in compliance with the reference method defined in the European standard. The method allows the seismic assessment of masonry buildings with rigid and flexible floors, without explicit numerical analyses, using only geometric parameters and the material properties. Compliance of results assessed by the proposed method and the corresponding values obtained by the code were carried out by confidence tests.
In this study typological fragility curves are proposed with a macro-seismic approach. To this scope, a stock of 56.338 residential masonry buildings struck by L’Aquila 2009 seismic sequence is ...analyzed, whose AeDES forms are archived within Da.D.O. platform, that is a web-gis database collecting the observed seismic damage data related to buildings surveyed after several Italian earthquakes.
Moreover, issues significantly influencing the fragility curves derivation are in depth discussed. In particular, a criterion for the buildings stock completion adding undamaged and not surveyed buildings is proposed, based on the distributions known of the residential building typologies. Comparisons highlight that the database completion affects the resulting fragility curves, and in particular for low damage levels. Furthermore, it is shown how the fundamental parameters estimation, by using the Maximum Likelihood Estimation (MLE) method, is conspicuously influenced by the PGA intervals number (nint), that is an issue often ignored when fragility curves are derived. The numerical investigations show that, although a non-monotonic trend is observed, the fundamental parameters tend to converge to the asymptotic values as the nint of PGA increases, and that they are markedly dispersed when nint is low.
•Employing digital documentation techniques, numerical analysis, and on-site wind speed estimations to evaluate the behavior of historic masonry buildings impacted by tornadoes.•Highlighting the ...urgent need for comprehensive reevaluation of how historic masonry buildings are assessed in tornado-prone regions.•Advocating for the development of more nuanced, preservation-compatible guidelines integrating structural analysis techniques while respecting architectural integrity and historical significance.•Emphasizing the necessity of a multidisciplinary approach integrating insights from structural engineering, material science, historic preservation, and computational modeling to enhance the resilience of historic masonry structures against extreme wind forces.
During the Midwest Tornado outbreak in December 2021, the historic downtown of Mayfield, Kentucky was heavily impacted. Employing digital documentation, numerical analysis, and on-site wind speed estimations, this study evaluates the behavior of the impacted historic masonry buildings. It explores the structural damages and stress distributions observed in historic masonry buildings impacted by tornadoes, comparing them to predictions made by the ASCE 7–22 standard for tornado loads. Through this investigation, it becomes evident that the stress distribution and damages produced by the on-site tornado wind speeds were significantly different than those derived from the ASCE 7–22 standard. The current standard does not account for most historic structures, typically classified as Risk Category.
II. Based on the results of this research, even when these structures are treated as Risk Category III, the stresses estimated by the standard are much lower than the ones experienced on-site. This disparity raises critical questions for preservationists evaluating similar masonry structures in tornado-prone regions. Historic preservation emphasizes minimal intervention, so understanding and addressing the specific vulnerabilities of historic masonry structures to tornadoes is crucial. The analysis in this study identified uplift forces on the roof and high stresses on windward walls as primary causes of damage in these structures, which aligned with the observed collapse mechanisms. Preservationists can use these insights to develop targeted retrofitting strategies that address these vulnerabilities while minimizing impact on the historic fabric. Recognizing these nuances and their impact on structural behavior is crucial for safeguarding the resilience and significance of historic civil structures. Thus, this study lays the groundwork for developing evidence-based, preservation-sensitive guidelines for mitigating tornado damage to irreplaceable historic masonry structures.
•Seismic analysis considering the soil-foundation-structure-iteration.•Seismic analysis on a soft soil with massive gravitational loads.•Comparison of results obtained with fixed and SFSI ...conditions.•Seismic failure and damage expected for different return periods.•Moderate time calculation for a very large FE model (1,104,735 solid elements).
The seismic safety of heritage buildings may be affected by the interaction between the soil, the foundation and the structure, which is usually neglected in conventional seismic assessments. These factors are particularly important in the case of slender constructions, such as masonry towers, over soft strata. Hence, this work deals with the influence of the soil-foundation-structure interaction in the seismic behaviour of complex heritage masonry towers. The investigations have been carried out considering the case study of the Giralda tower in Seville, Spain. The region is an earthquake-prone area, characterised by far away very large earthquakes with long-return periods. The Giralda tower is a slender brick unreinforced masonry tower, 95 m high and about 13 m wide. It features a high artistic value and popularity as it has been the historical symbol of the city. It was declared a UNESCO Word Heritage Site of Outstanding Universal Value in 1987. Apart from its slenderness, the tower presents some other seismic vulnerabilities: openings irregularities, material heterogeneity and the position of a belfry on the top. Furthermore, the building is placed on soft alluvial strata and has a shallow foundation. Likewise, the tower has a considerable weight, which has caused large settlements. A thorough evaluation of the soil, the foundation and the structure has been carried out to develop a complex and detailed finite element model. Macro mechanical elements and the direct method have been used to develop the numerical model of the tower in the OpenSees framework. Free ambient vibration tests and non-destructive experiments have been used to calibrate the model. Its dynamic behaviour has been evaluated considering the seismic action suggested by the Spanish Code and those determined through a seismic response analysis, bearing in mind different return periods and considering real ground motions. Finally, the numerical results showed that the effect of the soil and the foundation have a significant impact on the seismic behaviour of the bell tower, amplifying the acceleration and its damage at the top.
We present a method for segmenting cracks in images of masonry buildings damaged by earthquakes. Existing methods of crack detection fail to preserve the continuity of cracks, and their performance ...deteriorates with imprecise training labels. We address these problems by adapting an approach previously proposed for reconstructing roads in aerial images, in which a Convolutional Neural Network is trained with a loss function specifically designed to encourage the continuity of thin structures and to accommodate imprecise annotations. We evaluate combinations of three loss functions (the Mean Squared Error, the Dice loss and the new connectivity-oriented loss) on two datasets using TernausNet, a deep network shown to attain state-of-the-art accuracy in crack detection. We herein show that combining these three losses significantly improves the topology of the predictions quantitatively and qualitatively. We also propose a new continuity metric, named Cracks Per Patch (CPP), and share a new dataset of images of earthquake-affected urban scenes accompanied by crack annotations. The dataset and implementations are publicly available for future studies and benchmarking (https://github.com/eesd-epfl/topo_crack_detection and https://doi.org/10.5281/zenodo.6769028).
•Evaluation of a loss function for crack detection using deep learning that emphasize the correct representation of crack topology.•A solution for continuity crack detection problems using deep learning that does not require pixel-precise labels.•New metric to assess continuity preservation in crack prediction.•New training dataset of real-world post-earthquake building images containing labeled cracks.
