Towards an integrated vulnerability-based approach for evaluating, managing and mitigating earthquake risk in urban areas

Tese de doutoramento em Civil EngineeringSismos de grande intensidade, como aqueles que ocorreram na Turquía-Síria (2023) ou México (2017) deviam chamar a atenção para o projeto e implementação de ações proativas que conduzam à identificação de bens vulneráveis. A presente tese propõe um fluxo de trabalho relativamente simples para efetuar avaliações da vulnerabilidade sísmica à escala urbana mediante ferramentas digitais. Um modelo de vulnerabilidade baseado em parâmetros é adotado devido à afinidade que possui com o Catálogo Nacional de Monumentos Históricos mexicano. Uma primeira implementação do método (a grande escala) foi efetuada na cidade histórica de Atlixco (Puebla, México), demonstrando a sua aplicabilidade e algumas limitações, o que permitiu o desenvolvimento de uma estratégia para quantificar e considerar as incertezas epistémicas encontradas nos processos de aquisição de dados. Devido ao volume de dados tratado, foi preciso desenvolver meios robustos para obter, armazenar e gerir informações. O uso de Sistemas de Informação Geográfica, com programas à medida baseados em linguagem Python e a distribuição de ficheiros na ”nuvem”, facilitou a criação de bases de dados de escala urbana para facilitar a aquisição de dados em campo, os cálculos de vulnerabilidade e dano e, finalmente, a representação dos resultados. Este desenvolvimento foi a base para um segundo conjunto de trabalhos em municípios do estado de Morelos (México). A caracterização da vulnerabilidade sísmica de mais de 160 construções permitiu a avaliação da representatividade do método paramétrico pela comparação entre os níveis de dano teórico e os danos observados depois do terramoto de Puebla-Morelos (2017). Esta comparação foi a base para efetuar processos de calibração e ajuste assistidos por algoritmos de aprendizagem de máquina (Machine Learning), fornecendo bases para o desenvolvimento de modelos de vulnerabilidade à medida (mediante o uso de Inteligência Artificial), apoiados nas evidências de eventos sísmicos prévios.Strong seismic events like the ones of Türkiye-Syria (2023) or Mexico (2017) should guide our attention to the design and implementation of proactive actions aimed to identify vulnerable assets. This work is aimed to propose a suitable and easy-to-implement workflow for performing large-scale seismic vulnerability assessments in historic environments by means of digital tools. A vulnerability-oriented model based on parameters is adopted given its affinity with the Mexican Catalogue of Historical Monuments. A first large-scale implementation of this method in the historical city of Atlixco (Puebla, Mexico) demonstrated its suitability and some limitations, which lead to develop a strategy for quantifying and involving the epistemic uncertainties found during the data acquisition process. Given the volume of data that these analyses involve, it was necessary to develop robust data acquisition, storing and management strategies. The use of Geographical Information System environments together with customised Python-based programs and cloud-based distribution permitted to assemble urban databases for facilitating field data acquisition, performing vulnerability and damage calculations, and representing outcomes. This development was the base for performing a second large-scale assessment in selected municipalities of the state of Morelos (Mexico). The characterisation of the seismic vulnerability of more than 160 buildings permitted to assess the representativeness of the parametric vulnerability approach by comparing the theoretical damage estimations against the damages observed after the Puebla-Morelos 2017 Earthquakes. Such comparison is the base for performing a Machine Learning assisted process of calibration and adjustment, representing a feasible strategy for calibrating these vulnerability models by using Machine-Learning algorithms and the empirical evidence of damage in post-seismic scenarios.This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), reference UIDB/04029/2020. This research had financial support provided by the Portuguese Foundation of Science and Technology (FCT) through the Analysis and Mitigation of Risks in Infrastructures (InfraRisk) program under the PhD grant PD/BD/150385/2019

Seismic Analysis of Historic Masonry Buildings: The Vicarious Palace in Pescia (Italy)

Recent Italian earthquakes have underlined the need for wide monitoring and safety assessment of architectonical heritage. This has emerged also from requirements of the new Italian Technical Recommendations for buildings. Within this subject the paper investigates the seismic vulnerability of a specific monumental masonry building: the Vicarious Palace (Palazzo del Vicario) in Pescia, a small town near Florence. The structural behavior of the Palace was investigated using a finite element model in which the non-linearities of the masonry were considered by proper constitutive assumptions. The seismic behavior was evaluated by the pushover method, according to the Italian Technical Recommendations. The results were compared with the ones obtained by a simplified approach based on the kinematic theorem of limit analysis. Comparisons of the expected seismic demand vs the seismic capacity of the Palace confirm the weakness of this type of building to suffer extensive damage under earthquakes, as frequently observed in similar construction typologies. Additionally, the comprehension of the structural behavior under seismic loading allows the identification of a proper retrofitting strategy

Improving the Structural Performance of Heritage Buildings. A Comprehensive Romanian Experience.

The paper is devoted to historical masonry buildings’ protection against the destructive influence of earthquakes. Experimental and analytical investigations were performed to verify an original methodology that was developed for improving the structural performance of such a building. The seismic retrofitting of the cultural heritage requires compliance with the severe restrictions of the Romanian legislation related to the preservation of the original artistic and structural features. The intervention on the building started with the understanding of the original idea that was in the mind of the first designer. To accomplish this desideratum, two studies have been performed: a historical study and a geotechnical one. These studies have been followed by a technical assessment and a proposal of intervention. As the building has been able to carry severe loads during its lifetime, the possibility of preserving the original idea of its configuration was taken into account. In the paper, the main stages during the technical assessment and the strengthening project are presented. Within the technical assessment, a theory of damage and failure of unreinforced masonry walls was applied. The strengthening solution has been chosen so that the character of historical and architectural monument should not be affected

Digitised engineering knowledge for prefabricated façades

Façade design is a multidisciplinary activity requiring the balancing of many conflicting design requirements. Very often, however, the designed façade does not respond to these requirement, as relevant design and manufacturing knowledge, normally originating downstream in the design process, is not properly used upstream in the process. The inability to respond to this challenge increases the environmental impact of the construction sector, which is currently covering nearly 40% of the global emissions. Also, improving the stagnant sector’s productivity is of paramount importance today, as it is deemed to be nearly as half as that of the manufacturing sector. This research has thus investigated ways to collect, store, represent and digitalise the engineering knowledge that underpins the design of façade products for façades that are better designed. The work has involved a close collaboration with the British general contractor (and façade manufacturer) Laing O’Rourke. The research has explored ways of using design and manufacturing knowledge and it has developed a digital tool and tested its functionalities. In the first part, after a review of the state-of-the-art in knowledge-based approaches in other fields, the digital tool, and relevant methodology, are developed. The tool informs the user about the expected performance and manufacturability of the façade product under analysis. The boundaries of traditional research were also pushed beyond the proof-of-concept by validating the digital tool in both simulated and real-world scenarios. The goal was to understand how people can develop a design solution while being supported by a digital tool. It was found that using such tool increases the user’s awareness about the consequences of the his/her choices in less time. In the last part of the research, the tool was used to develop a novel optimisation algorithm, by including considerations about aesthetics and manufacturability, in parallel with the traditional performance-based approach. The application of the algorithm to a case study has shown that it is possible to improve existing solutions in terms of performance, without affecting aesthetic and manufacturability significantly.EPSRC, Laing O'Rourk

A FLEXIBLE METHODOLOGY FOR OUTDOOR/INDOOR BUILDING RECONSTRUCTION FROM OCCLUDED POINT CLOUDS

Terrestrial Laser Scanning data are increasingly used in building survey not only in cultural heritage domain but also for as-built modelling of large and medium size civil structures. However, raw point clouds derived from laser scanning generally not directly ready for the generation of such models. A time-consuming manual modelling phase has to be taken into account. In addition the large presence of occlusion and clutter may turn out in low-quality building models when state-of-the-art automatic modelling procedures are applied. This paper presents an automated procedure to convert raw point clouds into semantically-enriched building models. The developed method mainly focuses on a geometrical complexity typical of modern buildings with clear prevalence of planar features A characteristic of this methodology is the possibility to work with outdoor and indoor building environments. In order to operate under severe occlusions and clutter a couple of completion algorithms were designed to generate a plausible and reliable model. Finally, some examples of the developed modelling procedure are presented and discussed

Knowledge-rich optimisation of prefabricated façades to support conceptual design

One of the principal challenges in façade design is to support the architectural intent by devising technically viable (i.e. standard-compliant and manufacturable) solutions from as early as possible in the design stage. This is increasingly relevant as prefabricated façades increase in complexity and bespokedness in response to current societal, financial and environmental challenges. In this paper a process that addresses this challenge is presented. The process consists of two sub-processes 1) to build product-oriented knowledge bases and digital tools for supporting design on a project-by-project basis and 2) to help designers identify a set of optimal solutions that consider the façade-specific trade-off between architectural intent and performance requirements, while meeting the largest number of production-related constraints. This process was applied to a case study and the results were compared with those obtained from a recently-developed façade. It was found that, although the proposed process produces optimal solutions that are approximated, designers can benefit from more control over the product’s manufacturability, performance and architectural intent in less time.Laing O'Rourke pl

Documentation of a historical house with close range digital photogrammetry

Thesis (Master)--Izmir Institute of Technology, Architectural Restoration, Izmir, 2008Includes bibliographical references (leaves: 121-128)Text in English; Abstract: Turkish and Englishxii, 128 leavesThis study aims to document the original architectural characteristics, alterations and damages of a historical house by combining the digital photogrammetric techniques with the mapping concepts of architectural conservation so that an architectural conservation project can be guided. The proposed documentation is carried on the entrance façade of a 19th century house located in the urban conservation site of Alaçatı, ..zmir, Turkey. The Demiral House has conservation priority among the other listed houses because of its vacant state and damages.Analytic recording of the façades of the historical houses in Alaçatı can be made fast with the rectification option of close range monoscopic softwares. A calibrated digital camera and a total station are the other tools used in this process. The colored thematic maps prepared are accurate enough for 1/50 scale analysis and they possess the qualitative information on the photographs. After it is checked that the threedimensional measurements defining the general geometry overlap with the 1/50 scaled rectified image mosaic, the details concerning the deteriorations are decided to be drawn to the scaled elevation drawing from this mosaic.This study has proposed a contemporary documentation technique so that architect-conservators can easily adapt in their conservation projects. When compared to the frequently applied documentation techniques like hatching on scaled twodimensional elevation drawings, it takes shorter time to prepare the proposed mapping method on rectified image mosaic. The architect-restorer has also the chance to examine many constructional details on the scaled rectified image mosaic. The end results are more realistic. Keywords: Architectural conservation, Close range, Rectification, Mapping, Alaçatı

Studenica Marble: Significance, Use, Conservation

Studenica marble is the stone used in creating the mediaeval Serbian cultural heritage. This is a historical overview of the importance and use of stone from prehistoric times to the Middle Ages, when the most imposing religious architectural structures were built. The significance of Studenica marble is particularly manifested in the Virgin’s Church at the Studenica Monastery. For its marble façades and artistic architectural elements, among other things, the church was inscribed in the UNESCO World Cultural and Natural Heritage List in 1986. Through centuries, the Virgin’s Church suffered multiple destructions. In order to restore the marble façades properly and its architectural elements, the marble deposits where the stone was once quarried had to be located anew. When the stone material characterisation had been performed, the right stone was selected for the complex conservation works on the churches in Studenica and Sopocani. A practical implementation of the research results raised the awareness of the marble deposits in the Studenica vicinity, being also part of the national heritage. The Studenica Monastery Cultural Landscape Management Plan envisions preservation of the deposits and their sustainable use for restoration purposes in the future