Browsing by Author "Pinto, Hernan"

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    Development of the Historical Analysis of the Seismic Parameters for Retroffiting Measures in Chilean Bridges
    (2023) Calderon, Enrique; Valenzuela, Matias; Minatogawa, Vinicius; Pinto, Hernan
    Chile is exposed to the occurrence of medium- and large-magnitude earthquakes. As a result, national and international design codes have been developed, whose objectives are to grant an ideal behavior to the structures. However, in Chile, many of these structures do not comply with the design and construction standards of current regulations. Therefore, we propose to carry out a historical compilation that allows establishing the components that present the seismic vulnerability in bridges built from 1920 to 2010. We explored information gathered from the Government of Chile. We analyzed 553 bridges out of a total of 6835, considering superstructure and infrastructure components and seismic design evolution. The analysis emphasizes the elements that help improve the seismic performance of a bridge when natural or induced dynamic forces act on it, such as the length support, elastomeric bearing, seismic hold-down bars, transverse girders, seismic stoppers, bracing, and expansion joints. We identified that the most significant problems in bridges are the lack of seismic stoppers, both interior and exterior; lack of development length in the support tables; use of deficient expansion joints; and the inefficient construction of cross girders and baring support; in addition to the presence of differential settlements in elements of the infrastructure.
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    Exterior Wood-Concrete Slabs, Experimentation and Modeling of Mechanical Behavior. Part 1
    (2015) Pena, Alvaro; Fuentes, Sebastian; Fournely, Eric; Navarrete, Benjamn; Pinto, Hernan
    Structural elements of composite materials are widely used as them allow conceiving stronger as well as economic structures. In the case of wood-concrete composite slabs, the high compressive strength of concrete, together with the great performance and behavior of wood under traction, allows to obtain a resistance, weight and stiffness effective structure; features widely proven in indoor environments. The objective of this research is to analyze wood-concrete slabs behavior under outdoor environmental conditions in order to study its usage in walkways. Experimental tests were performed in two composite slabs, which were subjected to diverse loading configurations for 1250 days in outdoor environment. According to the results, was determined that the real moisture is greater than the theoretical one, which promotes the decay of wood, nevertheless, this variation did not produce a significant change in the overall mechanical characteristics of composite slabs
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    Exterior wood-concrete slabs, experimentation and modeling of mechanical behavior. Part 2.
    (2015) Pena, Alvaro; Fuentes, Sebastian; Fournely, Eric; Navarrete, Benjamin; Pinto, Hernan
    Structural elements of composite materials are widely used as them allow conceiving stronger as well as economic structures. In the case of wood-concrete composite slabs, the high compressive strength of concrete, together with the great performance and behavior of wood under traction, allows to obtain a resistance, weight and stiffness effective structure; features widely proven in indoor environments. The objective of this research is to model the behavior of wood-concrete slabs at an outdoor environment conditions in order to study its usage in walkways. To achieve this goal, the behavior of the wood-concrete slabs will be conducted through the use of finite element models that are going to be validated with the experimental data previously obtained from tests performed in two composite slabs, which were subjected to diverse loading configurations for 1250 days in outdoor environment (Pena, Fuentes, Fournely, Navarrete, & Pinto, 2015). According to the results, it was possible to conclude that real moisture is greater than the theoretical one, which promotes the decay of wood, nevertheless, this variation did not produce a significant change in the overall mechanical characteristics of composite slabs; in the other hand, numerical modeling demonstrated the importance of the connection transverse stiffness, besides enabling the incorporation of wood moisture effect over its mechanical properties, allowing to quantify the effect of the connection stiffness.
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    Mesostructural Model for the Fatigue Analysis of Open-Cell Metal Foams
    (2024) Pinto, Hernan; Sepulveda, Alexander; Moraga, Paola; Galvez, Hector A.; Pena, Alvaro; Gornall, Jose; Garcia, Jose
    Metallic foams exhibit unique properties that make them suitable for diverse engineering applications. Accurate mechanical characterization is essential for assessing their performance under both monotonic and cyclic loading conditions. However, despite the advancements, the understanding of cyclic load responses in metallic foams has been limited. This study aims to propose a mesostructural model to assess the fatigue behavior of open-cell metal foams subjected to cyclic loading conditions. The proposed model considers the previous load history and is based on the analogy of progressive collapse, integrating a finite element model, a fatigue analysis model, an equivalent number of cycles model, and a failure criterion model. Validation against experimental data shows that the proposed model can reliably predict the fatigue life of the metallic foams for specific strain amplitudes.