Tesis doctoral de José Fernando Sima Brum
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.
Datos académicos de la tesis doctoral «A model for the non linear dynamic analysis of reinforced concrete and masonry framed structures«
- Título de la tesis: A model for the non linear dynamic analysis of reinforced concrete and masonry framed structures
- Autor: José Fernando Sima Brum
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 05/02/2010
Dirección y tribunal
- Director de la tesis
- Pere Roca Fabregat
- Tribunal
- Presidente del tribunal: Antonio ricardo Marí bernat
- daniel vitorino Castro oliveira (vocal)
- salvador Ivorra chorro (vocal)
- carmelo Javier León gonzález (vocal)