Browsing by Author "Fernandez, C."

Now showing 1 - 4 of 4
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    Absence of point spectrum for unitary operators
    (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2008) Astaburuaga, M. A.; Bourget, O.; Cortes, V. H.; Fernandez, C.
    Let us consider the time-dependent Schrodinger equation,
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    Floquet operators without singular continuous spectrum
    (2006) Astaburuaga, M. A.; Bourget, O.; Cortes, V. H.; Fernandez, C.
    Let U be a unitary operator defined on a infinite-dimensional separable complex Hilbert space R. Assume there exists a self-adjoint operator A on R such that
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    Performance of an RC building under seismic and tsunami actions in sequence via nonlinear dynamic analysis including soil-structure interaction
    (2022) Cortez, C.; Junemann, R.; Fernandez, C.; Urrutia, A.; Crempien, J. G. F.; Cienfuegos, R.
    This research presents a methodology to study the behavior of buildings subjected to seismic and tsunami loading in sequence, considering soil structure interaction effects through a complete dynamic analysis. The case-study building is an RC frame, which is assumed to be located in a coastal city in Chile, and built on sandy soil. A 3D Soil-Structure Interaction (SSI) model, including the non-linear behavior of both the structure and the soil using finite element method (FEM) was presented. Synthetic seismic ground motion records and tsunami inundation time histories were generated, consistent with the same earthquake source. Building performance was first assessed considering the SSI model for each hazard separately and compared to a Fixed Base (FB) model. Then, the SSI model was subjected to seismic and tsunami loading in sequence. Engineering Demand Parameters (EDPs) of roof displacement, interstory drift ratio (IDR) and reinforcement strain in beams and columns were analyzed. These EDPs presented a larger response to the tsunami when the response to the previous earthquake was larger. Finally, two vertical evacuation building scenarios were studied: the location of the refugees and the effect of an aftershock occurring simultaneously with the tsunami inundation. Results showed that the location of the ref-ugees did not generate significant differences in the building response, and the aftershock increased the response only when it coincided with the maximum tsunami force.
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    Singular rank one perturbations
    (2022) Astaburuaga, M. A.; Cortes, V. H.; Fernandez, C.; Del Rio, R.
    In this paper, A = B + V represents a self-adjoint operator acting on a Hilbert space H. We set a general theoretical framework and obtain several results for singular perturbations of A of the type A(beta) = A + beta tau*tau for tau being a functional defined in a subspace of H. In particular, we apply these results to H-beta = -Delta + V + beta|delta >