Browsing by Author "Fredes Siervo, José Ignacio"

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    Análisis numérico de muros de albañilería de ladrillo con aberturas reforzadas mediante estrategia de placa metálica mas anclajes embebidos
    (2024) Fredes Siervo, José Ignacio; Sandoval Mandujano, Cristián; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    La albanilería de ladrillo no reforzada es un sistema estructural ampliamente presente en edificios de alto valor historico y cultural, los cuales debido principalmente a la amenaza sísmica requieren trabajos de restauracion y refuerzo estructural de manera de mantener su integridad estructural y arquitectonica en el tiempo. Una de las tecnicas de mas reciente uso es el refuerzo de aberturas (ventanas o puertas) con elemento metalicos. Sin embargo, la escasa investigacion relacionada a este tema se ha enfocado en labores y tecnicas constructivas distintas a las utilizadas en este tipo de trabajos, que corresponde al uso de placas metalicas con conectores de acero de baja longitud. En Chile se ha aplicado recientemente esta técnica, pero aumentando el largo de los conectores esperando un mejor desempeño de la estructura. Por lo anterior, esta tesis propone dar un primer paso en la comprension general de la tecnica de refuerzo de aberturas mediante placa metalicas con anclajes embebidos. Los primeros analisis ejecutados pudieron demostrar la relevancia de utilizar conectores de mayor longitud. En seguida, un analisis parametrico para diversas variables fundamentales permitio concluir que el potencial de aumento del corte maximo es amplio y permite controlar defectos de la albañileria a no reforzada, pero que las perdidas o ganancias en ductilidad son dependientes del metodo de calculo utilizado. La tecnica permite ademas homogeneizar el patron de da no en el muro y que las mayores ventajas en terminos de diseño sismico se dan para placas de menor ancho y albañileria de baja calidad. Los resultados permitieron estimar de manera precisa la respuesta numerica de una fachada de gran dimension reforzada con esta tecnica. Finalmente, futuras campanas experimentales seran necesarias para validar los resultados y sugerencias propuestas.
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    Influence of Joint Reinforcement on the Shear Behavior of Masonry Panels: Experimental and Numerical Assessment
    (Springer Nature, 2025) Calderón, Sebastián; Fredes Siervo, José Ignacio; Sandoval Mandujano, Cristián
    In seismic-prone regions, providing shear reinforcement is crucial for controlling the damage to masonry structural elements. In this context, shearresistant behavior has been the focus of several investigations due to its complexity and importance to withstand seismic demands. Different studies have intended to understand more in-depth how shear reinforcement improves the performance of reinforced masonry; despite these efforts, many questions remain open. For instance, it has been observed that shear reinforcement starts interacting with masonry only after cracks are developed. However, the pre-cracking behavior of reinforced and unreinforced masonry walls somewhat differ. Furthermore, it has been proven that the behavior of masonry built with different unit types (i.e., multi-perforated clay bricks, hollow concrete blocks, and solid clay bricks) may exhibit significant variations, implying that masonry built with all unit types must be evaluated. Motivated by this knowledge gap, this study assesses the behavior of masonry panels about 0.8 × 0.8 m made of multi-perforated clay brick, with and without shear reinforcement, and subjected to diagonal compression. Ladder-type steel reinforcement was placed at the mortar bed-joints. The experimental results are complemented with numerical simulations (detailed micro-models) to extend the achieved understanding. The study concluded that the horizontal reinforcement ratio did not significantly influence the behavior of the panels based on the findings that shear strength, shear strain, and shear modulus did not exhibit significant differences. Also, the reinforcement started collaborating with masonry only after the shear strength was achieved when specimens were too damaged to gain higher stresses.
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    Masonry panels with different bed-joint reinforcement ratios under diagonal compression: An experimental and numerical study
    (Elsevier B.V., 2025) Calderón, Sebastián; Fredes Siervo, José Ignacio; Sandoval Mandujano, Cristián
    Masonry made of Multi-Perforated Clay Bricks (MPCLB) has a complex mechanical behavior due to the geometry of the units, especially under shear forces. The behavior becomes even more complex when masonry contains steel bars embedded in bed joints, as occurs in reinforced masonry and, to a lesser extent, confined masonry. Despite the devoted research effort, the interaction between masonry and joint reinforcement remains incompletely understood and characterized. Therefore, further research is required to evaluate the shear behavior of masonry with reinforcement embedded in mortar joints. This work presents new evidence on the shear behavior of masonry panels with varying joint reinforcement ratios and anchorage conditions, which were tested under diagonal compression. The experimental research was complemented by numerical modeling, utilizing both micro- and macro-modeling approaches. The shear strength of the panels ranged from 0.71 to 1.14 MPa, and the shear modulus between 1262.6 and 4110.2 MPa. It was found that changing the reinforcement ratio in panels did not significantly influence the shear strength, shear strength strain, shear modulus, failure mode, and pre-peak shear stress-strain of the experimentally tested panels. Additionally, both modelling approaches are suitable for reproducing the initial stiffness, shear strength, and failure mode of unreinforced and reinforced panels. However, detailed micro-modelling overpredicts the shear modulus of unreinforced panels. The models also corroborate experimental observations, noting that increments in shear reinforcement produced variations in load capacity of less than 5 %, but improved the post-peak integrity of the panels.