A new method for earthquake-induced damage identification in historic masonry towers combining OMA and IDA

AbstractThis paper presents a novel method for rapidly addressing the earthquake-induced damage identification task in historic masonry towers. The proposed method, termed DORI, combines operational modal analysis (OMA), FE modeling, rapid surrogate modeling (SM) and non-linear Incremental dynamic analysis (IDA). While OMA-based Structural Health Monitoring methods using statistical pattern recognition are known to allow the detection of small structural damages due to earthquakes, even far-field ones of moderate intensity, the combination of SM and IDA-based methods for damage localization and quantification is here proposed. The monumental bell tower of the Basilica of San Pietro located in Perugia, Italy, is considered for the validation of the method. While being continuously monitored since 2014, the bell tower experienced the main shocks of the 2016 Central Italy seismic sequence and the on-site vibration-based monitoring system detected changes in global dynamic behavior after the earthquakes. In the paper, experimental vibration data (continuous and seismic records), FE models and surrogate models of the structure are used for post-earthquake damage localization and quantification exploiting an ideal subdivision of the structure into meaningful macroelements. Results of linear and non-linear numerical modeling (SM and IDA, respectively) are successfully combined to this aim and the continuous exchange of information between the physical reality (monitoring data) and the virtual models (FE models and surrogate models) effectively enforces the Digital Twin paradigm. The earthquake-induced damage identified by both data-driven and model-based strategies is finally confirmed by in-situ visual inspections

An innovative SHM solution for earthquake- induced damage identification in historic masonry structures

Tese de Doutoramento Engenharia CivilO principal objetivo deste trabalho de investigação dizia respeito ao desenvolvimento e validação de uma metodologia inovadora para a deteção, localização e quantificação de danos causados por sismos em estruturas históricas de alvenaria. A metodologia proposta, designado por DORI, baseia-se na combinação de métodos baseados em dados e métodos inovadores baseados em modelos, abordando a identificação de dano com base na análise modal operacional (OMA), modelação rápida de substitutos e análise dinamica incremental (IDA) para edifícios de alvenaria do Património Cultural (CH) sujeitos a sismos. Mais detalhadamente, a metodologia DORI propõe a fusão de dados estáticos e dinamicos no método de deteção de dano baseado em OMA e estende a OMA através da introdução e implementação de dois métodos inovadores independentes e complementares baseados em modelos, para localização e quantificação de danos induzidos por sismos em construções históricas de alvenaria com monitorização permanente: o primeiro método é baseado num modelo substituto, uma ferramenta rápida que combina dados de monitorização de vibração a longo prazo (ou seja, OMA) e a modelação numérica, enquanto o segundo método é baseado em IDA não linear sísmica. A Tese está focada na validação de diferentes aspetos da metodologia DORI, através da aplicação a quatro estruturas que servem de casos de estudo: uma estrutura de alvenaria ensaiada em laboratório e reconhecida internacionalmente, designada por Brick House, e tres edifícios de alvenaria de CH equipados com sistemas permanentes de monitorização de saúde estrutural, nomeadamente o Palácio de Consoli, a Torre Sciri e a Torre sineira de San Pietro. Em conclusão, a metodologia DORI proposta nesta Tese para deteção, localização e quantificação de danos induzidos por sismos é uma nova abordagem metodológica, aplicada e validada com sucesso em estruturas históricas de alvenaria, constituindo uma ferramenta promissora para a rápida avaliação de danos pós-sismo das estruturas de CH sob monitorização SHM a longo prazo.The main objective of this research work concerned the development and validation of an innovative methodology aimed at the detection, localization and quantification of earthquake-induced damages in historic masonry structures. The high cultural, economic and political value set upon historic buildings spread out all over the world has made the earthquake-induced damage identification, as well as preservation and conservation of architectural heritage, a subject of outstanding importance. The proposed methodology, called DORI, is based on the combination of data-driven, as well as innovative model-based methods, addressing the Damage identification based on Operational modal analysis (OMA), Rapid surrogate modeling and Incremental dynamic analysis (IDA) for Cultural Heritage (CH) masonry buildings subjected to earthquakes. More in detail, the DORI methodology proposes the static-and-dynamic data fusion in the OMA-based damage detection method, and extends it through the introduction and implementation of two independent and complementary innovative model-based methods, for localization and quantification of earthquake-induced damage in permanently monitored historic masonry buildings: the former is a surrogate model-based method, a rapid tool which combines long-term vibration monitoring data (i.e. OMA) and numerical modeling, while the latter is based on non-linear seismic IDA. The Thesis focuses on the validation of different aspects of the DORI methodology, through application to four case study structures: an internationally well-known laboratory masonry structure, called the Brick House, and three CH masonry buildings equipped with permanent Structural Health Monitoring systems, namely the Consoli Palace, the Sciri Tower and the San Pietro Bell Tower. In conclusion, the DORI methodology proposed for earthquake-induced damage detection, localization and quantification is a novel methodological approach, successfully applied and validated in historic masonry structures, constituting a promising tool for rapid post-earthquake damage assessment of CH structures under long-term SHM monitoring

Four years of structural health monitoring of the San Pietro bell tower in Perugia, Italy: two years before the earthquake versus two years after

This paper addresses the structural health monitoring (SHM) of the bell tower of the Basilica of San Pietro in Perugia, Italy, which is located in a seismic area. Known as one of the landmarks of the Umbrian capital, the tower belongs to a monumental complex of exceptional historical and cultural value. Therefore, its protection with respect to earthquakes is an important issue. To this purpose, a vibration-based SHM system able to detect anomalies in the structural behaviour by means of statistical process control tools has been installed in the tower and is under continuous operation since December 2014. The effects of the 2016-2017 Central Italy seismic sequence were clearly detected by this system, even if earthquakes took place at relatively large distance from the bell tower. The large amount of SHM data collected over four years allowed to assess the modifications in the structural behaviour of the bell tower in post-earthquake conditions

Rapid post-earthquake damage localization and quantification in masonry structures through multidimensional non-linear seismic IDA

This paper presents a methodology aimed at addressing the rapid post-earthquake damage localization and quantification tasks in heritage masonry structures, based on non-linear Incremental Dynamic Analysis (IDA). The proposed methodology relies on pre-run multidimensional non-linear IDA simulations carried out using a numerical Finite Element model together with vibration data recorded during an earthquake. The IDA curves are built with reference to different portions of the structure, relating meaningful local damage parameters to relevant seismic intensity measures. The selection of appropriate intensity parameters is crucial and a study on this aspect is carried out. The methodology is validated through application to a numerical model of a reduced-scale masonry structure, called Brick House, which is a well-known international benchmark tested on the LNEC-3D shaking table. The obtained results demonstrate that, if the set of IDA curves has been previously constructed using a suitable model, the proposed methodology yields an immediate and accurate estimation of damage conditions after an earthquake is recorded.This work was supported by the Italian Ministry of Education, University and Research (MIUR) through the funded Project of Relevant National Interest "DETECT-AGING -Degradation effects on structural safety of cultural heritage constructions through simulation and health monitoring" (protocol no. 201747Y73L)