DETECT-AGING blind prediction contest: a benchmark for structural health monitoring of masonry buildings

The installation of monitoring systems on buildings allows analyzing variations in structural parameters over time, creating room for detection of damage. Structural Health Monitoring (SHM) systems have the potential to support pro-active risk management, where structural interventions are planned if specific thresholds related to target performance losses are achieved. DETECT-AGING is a research project of relevant national interest that was funded by the Italian Ministry of University and Research (MUR) through the PRIN 2017 programme. The project started in September 2019 and involves the universities of Bologna, Genova, Napoli Federico II, and Perugia. The main goal of the project is to develop a new analytical-instrumental approach aimed at the quantitative assessment of the effects of aging and material degradation on structural safety of cultural heritage, with special focus on masonry structures. Based on a combined use of structural models and health monitoring systems, indications and operational tools will be provided for the identification and quantification of structural damage, supporting the management of built cultural heritage. To this purpose, a two-storey masonry building, having a single room with a vault at the first floor and a timber roof, was built with the aim of being monitored and progressively and will be damaged during the project. It is equipped with a hybrid SHM system managed by the University of Perugia, which is based on both vibration and strain measurements. The present paper illustrates the main features of the case-study building and presents the results of the experimental program aimed at characterizing the mechanical properties of masonry the materials used. The final part of the paper presents a blind prediction contest based on prediction of modal features of the building in different damaged configurations

Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: Methodology and application at building level

The article proposes a procedure for the derivation of fragility functions for unreinforced masonry buildings considering the in-plane and out-of-plane response. Different approaches are considered for the generation of the corresponding fragility functions and for the evaluation of the propagation of uncertainties. The contributions for the dispersion of the fragility functions account for the variability in the definition of the capacity, the aleatory uncertainty in the definition of the seismic demand and the aleatory uncertainty in the definition of the modified/floor response spectrum, when the local mechanisms are located in the upper level of the building. In the end, the individual fragility curves are properly combined in order to define a single fragility curve for the class of buildings. As a case study, the procedure is applied to the assessment of one of the most vulnerable unreinforced masonry buildings constructed in the early 20th century in Lisbon, considering a typical prototype building with five storeys high. Results for a seismic event, as defined in the earthquake-resistant code for Lisbon, indicate that the typical building has about 50% probability of having heavy damage and about 30% probability of collapse.The first author would like to acknowledge the financial support of Fundação para a Ciência e a Tecnologia (FCT, Ministério da Educação e Ciência, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK- (http://infrarisk.tecnico.ulisboa.pt)

Fragility Functions for Tall URM Buildings around Early 20th Century in Lisbon, Part 2: Application to Different Classes of Buildings

This article describes the application of the procedure for the derivation of fragility functions presented in the companion article entitled Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: methodology and application at building level. The procedure, based on the execution of non-linear analyses, was developed to be applied to unreinforced masonry buildings considering both the in-plane and out-of-plane response. Different sources of uncertainty, both epistemic and aleatory, affecting the behaviour of these unreinforced masonry buildings are discussed and treated with a probabilistic procedure. The fragility curves determined for the different classes of buildings are compared and then combined to define the final fragility curves for these unreinforced masonry buildings. The results put in evidence the high seismic vulnerability of these buildings and the urgent need for the structural intervention and for the design of retrofitting measures in order to reduce potential losses due to future earthquakes

Review article: Current approaches and critical issues in multi-risk recovery planning of urban areas exposed to natural hazards

Post-disaster recovery has been addressed in the literature by different sectoral perspectives and scientific communities. Nevertheless, studies providing holistic approaches to recovery, integrating reconstruction procedures and socio-economic impacts, are still lacking. Additionally, there is a gap in disaster recovery research addressing the additional challenges posed by the effect of complex, multiple, and interacting risks on highly interconnected urban areas. Furthermore, recovery has only been marginally explored from a pre-disaster perspective in terms of planning and actions to increase urban resilience and recoverability. This paper provides a critical review of existing literature and guidelines on multi-risk disaster recovery with the twofold aim of identifying current gaps and providing the layout to address multi-risk recovery planning tools for decision-making. The literature on disaster recovery is investigated in the paper by focusing on the definition of the recovery phase and its separation or overlapping with other disaster risk management phases, the different destinations and goals that an urban system follows through recovery pathways, the requirements to implement a holistic resilience-based recovery roadmap, the challenges for shifting from single-risk to multi-risk recovery approaches, and the available tools for optimal decision-making in the recovery planning. Finally, the current challenges in multi-risk recovery planning are summarized and discussed. This review can be a ground basis for new research directions in the field of multi-risk recovery planning to help stakeholders in decision-making and optimize their pre-disaster investments to improve the urban system's recoverability.</p

Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 2: Application to different classes of buildings

This article describes the application of the procedure for the derivation of fragility functions presented in the companion article entitled Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: methodology and application at building level. The procedure, based on the execution of non-linear analyses, was developed to be applied to unreinforced masonry buildings considering both the in-plane and out-of-plane response. Different sources of uncertainty, both epistemic and aleatory, affecting the behaviour of these unreinforced masonry buildings are discussed and treated with a probabilistic procedure. The fragility curves determined for the different classes of buildings are compared and then combined to define the final fragility curves for these unreinforced masonry buildings. The results put in evidence the high seismic vulnerability of these buildings and the urgent need for the structural intervention and for the design of retrofitting measures in order to reduce potential losses due to future earthquakes.The first author would like to acknowledge the financial support of Fundacao para a Ciencia e a Tecnologia (FCT, Ministerio da Educacao e Ciencia, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK (http://infrarisk.tecnico.ulisboa.pt)

The First Year of Sars-Cov-2: Which Mutations Spread Rapidly Around the Word?-Minireview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide crisis with profound effects on both public health and the economy. In order to combat the Sars-Cov-2 pandemic, research groups have shared viral genome sequence data through the Global Initiative on Sharing All Influenza Data (GISAID). SARS-CoV-2 is an RNA virus, which is a family with significant adaptive evolution). Worldwide research groups are generating and sharing SARS-CoV-2 proteome sequence data in a rapid fashion as a global effort to combat the COVID-19 pandemic. The rapid spread of an alternative variant of coronavirus has been blamed for the introduction of strict tier four mixing rules for many people, strict restrictions on mixing at Christmas in England, Scotland and Wales, and other countries placing the United Kingdom on a travel ban. So how has it gone from being non-existent to the foremost common sort of the virus in parts of England during a matter of months? Now that vaccines have been developed and are being deployed to address the COVID-19 pandemic, a major concern is the emergence of mutations in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that confer immune escape or enhanced fitness. As such, it is important to assess how rapidly SARS-CoV-2 proteins are mutating . While it is currently unclear if these mutations benefit the virus, their continued surveillance and the detection of new proteome variants are likely to illuminate key aspects of viral function. The government's advisers on new infections now say they need "high" confidence that it's more ready to transmit than other variants

INVESTIGATING THE SEISMIC RESPONSE OF URM WALLS WITH IRREGULAR OPENING LAYOUT THROUGH DIFFERENT MODELING APPROACHES

The façade and internal walls of unreinforced masonry (URM) buildings often present an irregular opening layout, due to architectural reasons or modifications to the structure, which make the expected seismic damage pattern less predictable a priori. Therefore, the discretization of the walls in structural components is not standardized, conversely to cases with a regular opening layout for which the available modeling methods are corroborated by seismic damage surveys reporting recurrent failure patterns. The structural component discretization is a relevant step for the code-conforming seismic assessment, typically based on comparing the internal forces and drifts of each component to strength criteria and drift thresholds. Therefore, the lack of well-established approaches can significantly influence the assessment. The issue is even more evident when the structural components must be identified a priori in the modeling stage, namely for equivalent frame models. The applicability of available methods for discretization of URM walls with irregular opening layout has been already investigated in literature, but a conclusive judgment requires further studies. In this context, this paper presents an overview of the preliminary results addressing the numerical modeling of this type of walls within the framework of the DPC-ReLUIS 2022-2024 project (Subtask 10.3), funded by the Italian Department of Civil Protection. The Subtask aims to propose consensus-based recommendations for researchers and practitioners which can contribute to harmonize the use of different modeling approaches. Seven research groups are involved in the research, adopting different modeling approaches and computer codes, but similar assumptions and the same analysis method (pushover) are used. The benchmark URM structure illustrated in the paper is a two-story wall from which four configurations with increasing irregularity of opening layout were derived. The results of four modeling approached are presented. Three of them reproduce the mechanical response of masonry at the material scale by means of FE models implemented in OpenSees, DIANA and Abaqus software, while the remaining approach describes the mechanical response of masonry at the macro-element scale in 3DMacro software. Results were compared in terms of capacity curves, predicted failure mechanisms and evolution of internal forces in piers. The adoption of consistent assumptions among the different approaches led to an overall agreement of predictions at both wall and pier scales, particularly in terms of damage pattern with higher concentration of damage at the ground story. Despite that, differences on the pushover curves have been highlighted. They are mainly due to some deviations of the internal forces in squat piers deriving from a complex load flow in these elements

Investigating the seismic response of URM walls with irregular opening layout through different modeling approaches

TThe façade and internal walls of unreinforced masonry (URM) buildings often present an irregular opening layout, due to architectural reasons or modifications to the structure, which make the expected seismic damage pattern less predictable a priori. Therefore, the discretization of the walls in structural components is not standardized, conversely to cases with a regular opening layout for which the available modeling methods are corroborated by seismic damage surveys reporting recurrent failure patterns. The structural component discretization is a relevant step for the code-conforming seismic assessment, typically based on comparing the internal forces and drifts of each component to strength criteria and drift thresholds. Therefore, the lack of well-established approaches can significantly influence the assessment. The issue is even more evident when the structural components must be identified a priori in the modeling stage, namely for equivalent frame models. The applicability of available methods for discretization of URM walls with irregular opening layout has been already investigated in literature, but a conclusive judgment requires further studies. In this context, this paper presents an overview of the preliminary results addressing the numerical modeling of this type of walls within the framework of the DPC-ReLUIS 2022-2024 project (Subtask 10.3), funded by the Italian Department of Civil Protection. The Subtask aims to propose consensus-based recommendations for researchers and practitioners which can contribute to harmonize the use of different modeling approaches. Seven research groups are involved in the research, adopting different modeling approaches and computer codes, but similar assumptions and the same analysis method (pushover) are used. The benchmark URM structure illustrated in the paper is a two-story wall from which four configurations with increasing irregularity of opening layout were derived. The results of four modeling approached are presented. Three of them reproduce the mechanical response of masonry at the material scale by means of FE models implemented in OpenSees, DIANA and Abaqus software, while the remaining approach describes the mechanical response of masonry at the macro-element scale in 3DMacro software. Results were compared in terms of capacity curves, predicted failure mechanisms and evolution of internal forces in piers. The adoption of consistent assumptions among the different approaches led to an overall agreement of predictions at both wall and pier scales, particularly in terms of damage pattern with higher concentration of damage at the ground story. Despite that, differences on the pushover curves have been highlighted. They are mainly due to some deviations of the internal forces in squat piers deriving from a complex load flow in these elements.DPC - Dipartimento della Protezione Civile, Presidenza del Consiglio dei Ministri(LA/P/0112/2020