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Subject: search.filters.subject.Análisis estructural (Ingeniería)

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    Metodología numérica automatizada para la evaluación de la respuesta dinámica de construcciones prehispánicas de piedra de junta seca en el Perú
    (Pontificia Universidad Católica del Perú, 2024-05-28) Lipa Cusi, Leonel; Tarque Ruiz, Sabino Nicola
    El estudio y la conservación del patrimonio de estructuras de piedra es una preocupación mundial, sobre todo, si estas construcciones están ubicadas en zonas sísmicas. En el Perú -debido a su gran variedad cultural e histórica- existe un gran número de construcciones de piedra en diferentes sitios arqueológicos, abarcando varias tipologías constructivas. Lamentablemente, gran parte de estas construcciones aún no han sido evaluadas estructuralmente, por lo que se desconoce su comportamiento estructural. También, no se cuenta con una taxonomía de tipologías estructurales y, por ende, diversas características de las construcciones existentes son desconocidas. Una forma de evaluar el comportamiento dinámico no lineal de estas estructuras es usando una rigurosa -pero rápida- metodología numérica que reproduzca adecuadamente los diferentes mecanismos de fallo, basada en la dinámica de cuerpos rígidos bajo el enfoque del método de elementos finitos. Como una primera contribución, en este proyecto se presenta una clasificación taxonómica de construcciones prehispánicas de piedra en el Perú a partir de un estudio de campo. A partir de esta taxonomía, se clasificaron diversos sitios arqueológicos de las regiones de Puno y Cusco, y se identificaron las tipologías más recurrentes de estas regiones. Por otro lado, se elaboraron novedosos códigos en Python, para la obtención del modelo geométrico de estructuras de junta seca, a partir de las imágenes tomadas por un cámara, o de una fotografía existente (incluyendo la identificación de las piedras y las juntas por medio de la segmentación de imágenes). Estas rutinas permiten crear el modelo 3D de cada bloque (piedra), ensamblarlos y exportarlos a un programa de análisis numérico para evaluaciones posteriores. Para el desarrollo de la metodología numérica, se propone la dinámica de los cuerpos rígidos bajo el enfoque del método de los elementos finitos. Cada bloque de piedra se considera como un cuerpo rígido interconectado con otros bloques mediante interfaces no lineales. Esta metodología es validada usando Abaqus, basado en los resultados de ensayos experimentales en esta tesis. En la campaña experimental se construyeron tres muros con bloques de concreto simulando la geometría de estructuras Inca. Los muros fueron construidos sobre una mesa inclinable y fueron ensayados por volteo fuera de su plano. Luego, se elaboraron modelos numéricos de estos ensayos, en los cuales se calibraron las propiedades de contacto con tal que simulen correctamente el comportamiento experimental. Los resultados numéricos del peso, el ángulo de colapso, los desplazamientos relativos en distintos puntos de la estructura y los mecanismos de colapso fueron muy similares a los registrados experimentalmente. Como caso de estudio, se evaluó numéricamente la sección de un muro de contención Inca de Sacsayhuamán, Cusco, frente a diversas acciones sísmicas. El modelo geométrico completo del muro de piedra se obtuvo mediante las rutinas de Python. El terreno contenido detrás del muro se representó por partículas de elementos discretos. Las propiedades del modelo numérico fueron tomadas de la campaña experimental y de calibración, y las frecuencias predominantes de la estructura se obtuvieron por medio del enfoque de vibraciones. Se verificó que la estructura puede soportar adecuadamente estos registros sísmicos escalados hasta una aceleración pico de 0.1 g; sin embargo, la estructura sufre desplazamientos remanentes considerables para registros escalados superiores o iguales a 0.2g. Se concluye que la metodología planteada permite evaluar las estructuras piedra de junta seca de una manera rigurosa, y así conocer si la estructura debe ser intervenida para asegurar su funcionalidad. Se espera que los resultados de esta tesis doctoral puedan contribuir al estudio de las construcciones patrimoniales de piedra, y abrir posibilidades de mejora de la metodología ante diversas configuraciones estructurales.
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    Seismic response of hospitals at different scales
    (Pontificia Universidad Católica del Perú, 2019-03-21) Liguori, Nicola; Tarque, Nicola; Spacone, Enrico
    Nowadays, natural disasters are more frequents and destructives compared to the past, causing many deaths and injuries. Existing hospitals are defined essential structures that have the goal to protect the public health of citizen. They are called to resist not only to the impact of a disaster, but also to be operational in that case. Operational means that all the components of a health facility such as structures, architectural elements, contents, lifelines, key staff and the whole organizational system have to be functional. That objective is a challenge for the existing structures, especially for those built with obsolete seismic codes and in high seismic hazard areas like Lima. Furthermore, in case of an emergency, health facilities are called to response as a network in order to be more efficient and resilient. It implies that hospitals have to be managed not only at small-scale referring to the single hospital, but also at large-scale referring to the whole health system composed by all the health facilities involved in a determined area. Transfer of patients, staffs, water and medicines, can be moved under the coordination of a headquarters in this way. Starting from a developed health sector contingency plan in case of earthquakes for Lima metropolitan area, an assessment of the seismic performance of health facilities at large and small scale was carried out. At large-scale, two exploratory models were developed. The first one adapts to evaluate the basic seismic response capacity of hospitals, while the second one useful to assess the hospital treatment capacity of health facilities in the aftermath of a seismic event. Both models were carried out considering structural and nonstructural building damages using fragility curves provided by international standards, given the lack of Peruvian curves. Both models were proposed for a case study of 41 hospitals in Lima metropolitan. Given the lack of data about Peruvian building fragility curves, for a high rise infilled reinforced concrete hospital building, fragility curves were developed through the capacity spectrum approach including record-to-record variability. The method also allowed to to assess at small-scale the seismic structural performance of the investigate hospital building using the capacity analysis method.
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    An optimal seismic risk mitigation of public school buildings in Lima through the community resilience concept and the application of MCDM methods and GIS tools
    (Pontificia Universidad Católica del Perú, 2019-02-25) Anelli, Angelo; Santa Cruz, Sandra Cecilia; Laterza, Michelangelo; Tarque, Nicola; Vona, Marco
    Nowadays retrofitting strategies are a typical problem of public administrations. Due to the amount of essential and/or historic buildings that require seismic retrofitting and the restricted economic availability, it is necessary to prioritize interventions on a large territorial scale in order to optimize the allocation of available economic resources, provide transparent guidelines, and identify the best solution with an integrated view of the problem. In this thesis work, a prioritization methodology for seismic risk reduction in public schools is developed. The suggested methodology is based on the community resilience concept, Multi-Criteria Decision-Making (MCDM) methods, and Geographic Information Systems (GIS). It allows to define a proactive and resilient seismic risk mitigation strategy with a geographical, multidisciplinary, and multidimensional perspective. In order to illustrate the proposed methodology, prioritization strategies of retrofit interventions for 1825 public schools in the Lima Metropolitan Area are analyzed. The resilience of the communities has played a key role in the definition of the seismic risk mitigation policies. Three perceptions are identified to use the resilience concept in the present thesis work: seismic risk, emergency management, integration and social cohesion. They represent groups of interwoven technical, organizational, social, and economic dimensions. Based on these aspects, quantitative and qualitative prioritization criteria are selected and analyzed separately using GIS tools in order to model the schools seismic risk components and quantify the spatial and territorial relationships between schools and their surroundings. Through the assignment of criteria weights, numerous political scenarios are defined to perform predictive analysis that consider the possible uncertainties involved in planning and to enrich the decision-making process with more useful information. In order to compare them and identify the most optimal political scenario, a cost-benefit index and an innovative resilience indicator are determined for each one. A new and transparent framework is developed to help decision makers in selecting the political strategies, the relative prioritizations of interventions, and their intervention options in the pre- disaster and post-disaster phases. It provides a simplified methodology with solid technical and scientific bases that aims to optimize community resilience using a multidimensional and xviii spatiotemporal measurement. Decision makers and engineering professionals could use it as a decision support in the prevention and management of various natural and artificial threats.
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    Structural diagnosis for distributed systems
    (Pontificia Universidad Católica del Perú, 2017-09-08) Pérez Zuñiga, Carlos Gustavo; Travé-Massuyès, Louise; Chanthery, Elodie; Sotomayor Moriano, Javier
    The recent development of technological systems implies a high complexity of behaviors for today’s systems. An answer to the increased systems’ complexity is to look at them as a multitude of heterogeneous subsystems and develop distributed techniques to control and manage them. This raises a number of problems. Firstly, as the size and number of components increase, so does the number of fault occurrences that may drive the system to undergo critical failures. Fault detection and isolation (FDI), maintenance and repair are an increasing part of the operational every day’s tasks and they impact drastically the total cost of final products. This thesis focuses on fault detection and isolation. Among the different methods to generate diagnosis tests by taking advantage of analytical redundancy, this thesis adopts the so-called parity space approach based on analytical redundancy relations (ARRs). Given a model of the system in the form of a set of differential equations, ARRs are relations that are obtained from the model by eliminating non measured variables. This can be performed in an analytical framework using elimination theory but another way of doing this is to use structural analysis. Structural analysis is based on a structural abstraction of the model that only retains a representation of which variables are involved in which equations. Despite the rusticity of the abstract model, structural analysis provides a set of powerful tools, relying on graph theory, to analyze and infer information about the system. Interestingly, it applies indifferently to linear or nonlinear systems. The goal of this thesis is to develop effective techniques based on structural analysis for diagnosis of distributed continuous systems. In this framework, the system is decomposed into a set of subsystems according to functional, geographical or privacy constraints. The thesis is organized in two parts, highlighting the redundancies that are built into the global structural model and that can be used to generate diagnosis tests starting from the redundancies existing in the subsystem’s models and formulating and solving the optimization problem linked to the choice of a subset of diagnosis tests at the subsystems level that can lead to a set of diagnosis tests achieving maximum diagnosability for the global system. The first part takes benefit of the concept of Fault-Driven Minimal Structurally Overdetermined Set (FMSO set) that is introduced in the thesis. An FMSO set determines a subset of equations of the model with minimal redundancy from which an ARR sensitive to a set of faults can be obtained. Two solutions for generating FMSOs for the global system are presented, in a decentralized framework with supervisors at each level of a hierarchy and in a totally distributed framework. These are based on the properties of the FMSO sets for the subsystems in relation to those of the global system derived in the thesis. The second part formulates the optimization problem in a heuristic search framework and proposes three solutions based on iterating an A* algorithm combined with a function able to assess whether a global FMSO set can be achieved from the selected local FMSO sets. The concepts introduced in the thesis and the results are applied to the case study of a Reverse Osmosis Desalination Plant and a Spacecraft Attitude Determination and Control System of a Low Earth-Orbit Satellite.