Sima Brum, Jose Fernando
Total activity: 4
Research group
TE - Structural Technology
Department
Department of Construction Engineering
E-mail
jose.fernando.simaupc.edu
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1 to 4 of 4 results
  • Nonlinear response of masonry wall structures subjected to cyclic and dynamic loading

     Sima Brum, Jose Fernando; Roca Fabregat, Pedro; Molins Borrell, Climent
    Engineering structures
    Date of publication: 2011-06
    Journal article

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    The assessment of the dynamic or seismic performance of complex structures often requires the integration in the time domain of the structural equation of motion in the frame of a nonlinear analysis. Although sophisticated methods have been developed for the nonlinear analysis of masonry wall structures, including the macro- and micro-modeling approaches, these require large computational effort still limiting the extent and complexity of the structures analyzed. This paper presents an alternative method based on the Generalized Matrix Formulation for masonry skeletal structures and load bearing wall systems, which has been proved as an efficient formulation for the analysis of the strength capacity of these kinds of structures (Roca et al. (2005) [17]). The basic formulation has been complemented with a uniaxial cyclic constitutive model for masonry and a time integration scheme. The ability of the resulting approach to predict the nonlinear dynamic response of masonry structures is shown through its application to the time domain analysis of an experimental scale masonry building with available experimental results on its dynamic response.

  • Non linear response of masonry wall structures subjected to cyclic and dynamic loading

     Sima Brum, Jose Fernando; Roca Fabregat, Pedro; Molins Borrell, Climent
    Advanced materials research
    Date of publication: 2010-10
    Journal article

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    A method for non-linear dynamic analysis of wall masonry structures is presented. The method takes advantage of a Generalized Matrix Formulation (GMF) for the serviceability and ultimate analysis of structures composed of arches and/or masonry walls, in which open and solid walls are described as equivalent frame systems. This formulation has been complemented with a cyclic constitutive model and an algorithm for the integration of the equation of motion, resulting in a numerically efficient method for non-linear analysis in time domain of complex masonry systems.

  • A model for the non linear dynamic analysis of reinforced concrete and masonry framed structures  Open access

     Sima Brum, Jose Fernando
    Defense's date: 2010-02-05
    Department of Construction Engineering, Universitat Politècnica de Catalunya
    Theses

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    La evaluación de la respuesta dinámica o sísmica de estructuras complejas a menudo requiere de la integración en el dominio del tiempo de la ecuación de equilibro dinámico de la estructura, en el marco de un análisis no lineal. En el caso de estructuras de fábrica y hormigón armado, el uso de este tipo de métodos cobra especial importancia, debido al complejo comportamiento no lineal que presentan, incluso para niveles bajos de carga. Muchas de estas estructuras pueden idealizarse como entramados espaciales de barras. En las últimas dos décadas, se ha desarrollado en la UPC una generalización de los métodos matriciales convencionales para el análisis de entramados espaciales de barras, la llamada Formulación Matricial Generalizada (FMG). La formulación básica para elementos de directriz curva y sección variable fue presentada inicialmente por Carrascón et al. (1987). Posteriormente, Carol y Murcia (1989) aplicaron esta formulación al análisis non lineal de procesos variables en el tiempo. Esta formulación fue extendida luego al análisis no lineal geométrico y del material de estructuras de obra de fábrica (Molins, 1996; Molins y Roca, 1998). Una extensión de la formulación estática básica al análisis dinámico lineal fue presentada por Molins et al. (1998) a través de la propuesta de una matriz de masa consistente. Esta formulación ha probado ser una herramienta eficiente para el análisis no lineal de estructuras de pórticos espaciales, durante más de quince años de aplicación en el Departamento de Ingeniería de la Construcción de la UPC.El objetivo fundamental de este trabajo es extender la FMG al análisis dinámico no lineal de estructuras espaciales de barras de hormigón armado y obra de fábrica. Para ello, la formulación básica ha sido complementada con varias nuevas características: · Se ha desarrollado un modelo constitutivo cíclico uniaxial para el hormigón y la obra de fábrica sometida tanto a cargas cíclicas de compresión como de tracción. Se ha puesto especial énfasis en la descripción de la degradación de la rigidez producida durante los ciclos de carga en tracción y compresión, la forma de las curvas de carga y descarga, y la transición entre abertura y cierre de fisuras. Se consideran dos parámetros independientes de daño, una para tracción y otro para compresión. En el caso de cargas cíclicas de compresión, el modelo se derivó de resultados experimentales obtenidos por otros autores, considerando la dependencia de las diferentes variables con el nivel de daño alcanzado, mientras que en el caso de cargas cíclicas de tracción, se propone un modelo simple basado en observaciones experimentales.· Se adoptó un modelo constitutivo para el acero de refuerzo sometido a cargas cíclicas, el conocido modelo de Menegotto-Pinto.· Finalmente, se adoptó un procedimiento para la integración de la ecuación de equilibrio dinámico de la estructura.Una vez implementado en ordenador, el modelo propuesto a sido aplicado a varios casos de estructuras aporticadas de hormigón armado y obra de fábrica sometidas a cargas de tipo cíclico y dinámico. Los resultados obtenidos demuestran que el modelo propuesto permite predecir adecuadamente la respuesta cíclica/dinámica de este tipo estructuras.

    The assessment of the dynamic or seismic performance of complex structures often requires the integration in the time domain of the structural equation of motion in the frame of a non-linear analysis. In the case of masonry and reinforced concrete structures, the use of these methods for the assessment of the structure become of great importance, due to its complex non linear behavior, even for low levels of loading. A great number of these structures may be idealized as spatial frames. A generalization of the conventional matrix methods for the analysis of spatial framed structures has been developed in the UPC during the last two decades, the so-called Generalized Matrix Formulation (GMF). The basic formulation for curved elements with variable cross section was presented by Carrascón et al. (1987). Carol and Murcia (1989) extended this flexibility based formulation to the non linear time dependant analysis. This formulation was later extended to the geometrical and material non linear analysis of masonry framed structures (Molins, 1996; Molins and Roca, 1998). An extension of the basic formulation to the linear dynamic analysis was later proposed by Molins et al. (1998) through the introduction of a consistent mass matrix. The formulation has proved for more than fifteen years of extensive use, to be an efficient tool for the analysis of 3D framed structures.The aim of this research is to extend the GMF to the non linear dynamic analysis of reinforced concrete and masonry framed structures. Following this main goal, the basic formulation has been complemented with a series of new features:· A uniaxial constitutive model for concrete and masonry subjected to cyclic loadings in both compression and tension has been proposed. Particular emphasis has been paid to the description of the strength and stiffness degradation produced by the load cycling in both, tension and compression, the shape of unloading and reloading curves and the transition between opening and closing of cracks. Two independent damage parameters in compression and in tension have been introduced to model the concrete degradation due to increasing loads. In the case of cyclic compressive loading, the model has been derived from experimental results obtained by other authors by considering the dependency of the cyclic variables with the damage level attained by the concrete. In the case of cyclic tension a simple model is adopted based on experimental observations.· A constitutive model for the cyclic behavior of reinforcing steel, the well known Menegotto-Pinto model, has been adopted. · Finally, a time step procedure for the integration of the dynamic equilibrium equation of the structure has been adopted.In order to show the capabilities of the proposed formulation, once implemented in a computer program, it has been applied in three examples of structures subjected to cyclic and dynamic loadings. The obtained results show that the model may adequately predict the cyclic/dynamic response of this type of structures.

  • Non linear response of masonry wall structures subjected to cyclic and dynamic loading

     Sima Brum, Jose Fernando; Roca Fabregat, Pedro; Molins Borrell, Climent
    International Conference on Structural analysis of Historic Constructions
    Presentation's date: 2010
    Presentation of work at congresses

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    A method for non-linear dynamic analysis of wall masonry structures is presented. The method takes advantage of a Generalized Matrix Formulation (GMF) for the serviceability and ultimate analysis of structures composed of arches and/or masonry walls, in which open and solid walls are described as equivalent frame systems. This formulation has been complemented with a cyclic constitutive model and an algorithm for the integration of the equation of motion, resulting in a numerically efficient method for non-linear analysis in time domain of complex masonry systems.