Browsing by Author "Lopez-García González, Diego"

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    Including problem-knowledge based modification into a Differential Evolution Algorithm for optimizing planar moment-resisting steel frames
    (2025) Contreras Bejarano, Óscar; Villalba-Morales, Jesús Daniel; Lopez-García González, Diego
    The Differential Evolution Algorithm (DEA) has been demonstrated to be capable of effectively addressing engineering challenges, although its performance varies considerably when applied to different problems. Customizing the algorithm to the specific characteristics of a given problem has been identified as a valid strategy to enhance its effectiveness and reliability. In this study, a tailored version of the DEA is proposed for the optimization of planar Moment-Resisting Steel Frames (MRSFs) subjected to static loads. A diverse set of heuristics and techniques were incorporated, including advanced strategies for parameter control, initialization, mutation operators, crossover operators, diversity conservation, constraints handling, and dynamic population management. To evaluate the performance of the proposed heuristics and techniques, 7800 DEA configurations were applied to the optimization of seven representative MRSFs. Results indicate that through problem-specific modifications the DEA is highly likely to identify the optimal solutions. By emphasizing both computational efficiency and solution quality, this research provides valuable insights into enhanced applicability of the DEA to structural optimization problems. It is shown that a customized algorithm is a reliable, effective, and robust tool to optimize MRSFs.
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    Optimized reduction of the seismic floor acceleration response in multistory buildings with supplemental viscous dampers
    (2025) Ortega Peláez, Marío Andrés; Lopez-García González, Diego
    Height-wise distributions of viscous dampers for the optimal reduction of peak floor accelerations in multi-story buildings subjected to earthquakes are obtained. The effects of the fundamental period, the frequency content of the seismic excitation, the number of stories, and the velocity exponent of the dampers are also investigated. The seismic excitation is modeled as a non-stationary stochastic process and the stochastic structural response is obtained by the Explicit Time Domain method. Optimal damper distributions are found using zero-order optimization algorithms. Sub-optimal solutions that minimize the amount of added damping to produce a response reduction constrained to a fraction of the optimal reduction are also explored. The effects of the optimized damper distributions on other response quantities are also assessed. The optimized solutions are validated by a case study that considers a realistic structure subjected to actual seismic ground motions. It is found that the optimal reduction of peak floor accelerations depends mainly on the relationship between the fundamental period of the structure and the frequency content of the seismic excitation. It is also found that sub-optimal solutions are more convenient than optimal solutions in the sense that they require smaller (much smaller in many cases) amounts of supplemental damping to achieve response reductions that are just slightly smaller than the optimal reductions. Finally, it is observed that damper distributions optimized solely for the reduction of the peak floor acceleration response also lead to significant reductions in other relevant response quantities such as inter-story drift and base shear.
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    Optimized reduction of the seismic floor acceleration response in multistory buildings with supplemental viscous dampers
    (2025) Ortega Peláez, Marío Andrés; Lopez-García González, Diego
    Height-wise distributions of viscous dampers for the optimal reduction of peak floor accelerations in multi-story buildings subjected to earthquakes are obtained. The effects of the fundamental period, the frequency content of the seismic excitation, the number of stories, and the velocity exponent of the dampers are also investigated. The seismic excitation is modeled as a non-stationary stochastic process and the stochastic structural response is obtained by the Explicit Time Domain method. Optimal damper distributions are found using zero-order optimization algorithms. Sub-optimal solutions that minimize the amount of added damping to produce a response reduction constrained to a fraction of the optimal reduction are also explored. The effects of the optimized damper distributions on other response quantities are also assessed. The optimized solutions are validated by a case study that considers a realistic structure subjected to actual seismic ground motions. It is found that the optimal reduction of peak floor accelerations depends mainly on the relationship between the fundamental period of the structure and the frequency content of the seismic excitation. It is also found that sub-optimal solutions are more convenient than optimal solutions in the sense that they require smaller (much smaller in many cases) amounts of supplemental damping to achieve response reductions that are just slightly smaller than the optimal reductions. Finally, it is observed that damper distributions optimized solely for the reduction of the peak floor acceleration response also lead to significant reductions in other relevant response quantities such as inter-story drift and base shear.
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    Testing the influence of system effects on the lateral response in t-shaped wood frame shear walls
    (2025) Valdivieso Cascante, Diego Nicolás; Almazan Campillay, José Luis; Lopez-García González, Diego; Montaño Castañeda, Jairo Alonso; Liel A.B.; Guindos Bretones, Pablo
    This paper examines the impact of transverse shear walls (TSW), out-of-plane bending stiffness of diaphragms (FDIA), and axial (gravity) loading (AXL) on the lateral response of strong wood-frame shear walls (SWs) in multistory light frame timber buildings (LFTBs). Experimental tests assessed the lateral cyclic response of T-shaped SW assemblies with and without diaphragms and gravity load. Tests showed that the TSW effect enhances the lateral stiffness and strength but reduces the deformation capacity. The FDIA and AXL effects further influence the stiffness and strength and compensate in part for the reduction of the deformation capacity due to the TSW effect. Diaphragms also made the T-shaped SW response more symmetrical and improved the evolution of secant stiffness, cumulative dissipated energy, and equivalent viscous damping as the lateral drift increases. Numerical analyses of a theoretical building model with T-shaped SWs showed significant reductions in lateral drift and uplift compared to those of Planar SWs alone, highlighting the importance of considering system effects in the seismic design of LFTBs.