Browsing by Author "Guamán Cabrera, Jaime Wilson"

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    Earthquake‐induced damage assessment of critical medical equipment using experimentally validated rolling and sliding nonlinear models
    (2024) Guamán Cabrera, Jaime Wilson; Llera Martin, Juan Carlos de la
    Hospital functionality relies not only on the building's structural robustness but also on the seismic performance of its Nonstructural elements, Systems, and Contents (NSC). The objective of this study is to characterize the earthquake-induced damage to the medical equipment deployed in the full-scale, five-story concrete building tested at the University of California, San Diego (UCSD) in 2012 when subjected to Design (DE) and Maximum Considered Earthquake (MCE) levels of demand with Fixed-to-the-Base (FB) support condition. The experimental equipment displacement responses are extracted using the Camera Projection Technique (CPT). Then, sophisticated rolling and sliding models, including instantaneous motion tracking and impact detection are developed to reproduce the equipment behavior obtained from CPT. It was found that CPT was capable of extracting the observed responses and identifying impacts despite the severity of the shaking as long as no significant uplift of the equipment occurred. In addition, both numerical models were capable of reproducing the equipment's displacement trajectories, rotations about the vertical axis (yaw), and impacts as long as no interlocking of the equipment's parts occurred. Moreover, a case study of a partially equipped Emergency Room (ER) was set up to demonstrate that even for low-intensity motions, the damage to equipment may be significant. Finally, the impact acceleration ( ) is proposed as a proxy indicator of damage to medical equipment; however, more functionality tests accompanied by detailed pre- and post-inspections are needed to define robust damage limit states and performance objectives for medical equipment.
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    Fragility curves for unanchored medical equipment accounting for building and content interaction
    (2026) Guamán Cabrera, Jaime Wilson; De La Llera Martin, Juan Carlos; Rossetto, Tiziana; Enberg Castro, Luis Fernando; Ioannou, Ioanna
    Currently, construction codes and standards require nonstructural fragility information to define nonstructural performance objectives and expectations for low- and design-intensity earthquake motions. To address this knowledge gap, this study focuses on the development of analytical fragility curves for unanchored medical equipment commonly found in hospital critical rooms, taking into account the building’s performance, damage progression, and content interaction simultaneously. To achieve this goal, a fully equipped emergency room, intensive care unit, and operating room are simulated on the first, fourth, and fifth floors of a mid-rise hospital building, respectively, and subjected to service, design, and maximum considered earthquake levels under fixed-to-the-base (FB) and base-isolated (BI) support conditions. The building’s floor acceleration responses are used as input motions to assess the performance of several pieces of medical equipment using rolling and sliding nonlinear models. This study has included a comprehensive uncertainty analysis to propagate different sources of uncertainty into the fragility curves. Fragility results indicate that, under FB support conditions, equipment malfunctions and failures are expected to occur during low-intensity earthquake motions, even if the hospital building experiences minor structural damage. Furthermore, knowing the damaged condition of medical equipment (malfunction/failure) is crucial for determining its availability and subsequent use to stabilize critical condition patients or save their lives. Finally, these fragility curves can be used to plan post-disaster recovery and make risk-informed decisions in healthcare facilities.
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    Impact on patient waiting and service downtime due to nonstructural earthquake damage of Hospital critical rooms
    (2025) Guamán Cabrera, Jaime Wilson; Llera Martin, Juan Carlos de la; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Proveer cuidado médico continuo y estabilizar a pacientes gravemente heridos son servicios críticos que los hospitales ofrecen durante emergencias causadas por terremotos. Sin embargo, durante las últimas décadas muchos hospitales alrededor del mundo han sufrido daño no estructural significativo que ha impactado severamente la funcionalidad de los servicios médicos, reduciendo drásticamente su capacidad de respuesta hospitalaria. Actualmente, existe escasa investigación acerca de cómo correlacionar adecuadamente el daño de elementos no estructurales, sistemas, y contenidos (NSC) con la funcionalidad de recintos críticos hospitalarios y su posterior recuperación. Para abordar este vacío de conocimiento, esta investigación se enfoca en la estimación del impacto del daño de NSC en la Funcionalidad Residual (RF) y Tiempos de Espera de pacientes (WT) en recintos críticos hospitalarios. Para lograr esto, en primer lugar, la Técnica de Proyección de Cámara (CPT) fue usada para extraer las respuestas experimentales del equipamiento médico instalado en el edificio de cinco pisos, ensayado a escala natural en la Universidad de California San Diego, en 2012. Segundo, tres modelos numéricos no lineales, es decir, rodante, deslizante, y balanceo-vuelco, fueron desarrollados en MATLAB para reproducir las respuestas experimentales obtenidas en CPT. Luego, dos modelos de edificios hospitalarios tridimensionales y completamente equipados fueron desarrollados en OpenSees para simular un Box de Urgencia (ER), una Unidad de Cuidados Intensivos (ICU), y un Recinto Operatorio (OR) en el primer, cuarto, y quinto piso, respectivamente, considerando ambos sistemas de apoyo, Fijo-a-la-Base (FB) y Base-Aislada (BI). Ambos modelos hospitalarios fueron analizados para estimar su desempeño y daño estructural, no estructural, y de contenidos de forma progresiva para los sismos de Servicio (SE), Diseño (DE), y Máximo Sismo Considerado (MCE), y para ambos sistemas de apoyo. Luego, curvas de fragilidad estructural y de contenido médico no anclado fueron específicamente desarrolladas en este estudio usando Análisis Dinámico Incremental (IDA). Posteriormente, se adoptó una metodología probabilística para construir escenarios de daño no estructural usando modelos 3D de Realidad Virtual (3D-VR) mediante el acoplamiento de curvas de fragilidad estructural y no estructural usando 10,000 Simulaciones Monte Carlo (MCS). Luego, estos escenarios 3D-VR fueron usados para llevar a cabo elicitaciones a expertos médicos con la finalidad de obtener opiniones imparciales para RF y WT para cada recinto crítico, nivel de demanda sísmica, y condición de apoyo. Finalmente, los juicios de expertos fueron procesados usando el método Cooke para construir curvas de fragilidad discretas para RF y WT. Esta investigación busca contribuir a un mejor entendimiento del daño NSC, su interacción con el desempeño estructural, y su impacto en la continuidad de servicios médicos.
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    Performance-based damage scenarios of fully-equipped hospital critical rooms taking into account the structural-nonstructural-content interaction
    (2025) Guamán Cabrera, Jaime Wilson; Llera Martin, Juan Carlos de la; Rossetto, Tiziana; Enberg Gaete, Luis Ignacio; Ioannou, Ioanna
    There is still a disconnection between the structural and nonstructural components in the analysis and design stages of healthcare facilities, and consequently, the earthquake-induced nonstructural damage is still causing loss of functionality despite the negligible building’s structural damage. Aiming to bridge this disconnection, the present research focuses on the development of probabilistic damage scenarios of hospital critical rooms taking into account the structural, nonstructural, and content interaction simultaneously. To achieve this goal, an Emergency Room (ER), an Intensive Care Unit (ICU), and an Operating Room (OR) are simulated fully equipped at the first, fourth, and fifth levels of a mid-rise hospital building, developed in OpenSees, and subjected to the Service (SE), Design (DE), and Maximum Considered Earthquake (MCE) levels, considering Fixed-to-the-Base (FB) and Base-Isolated (BI) support conditions. The building’s floor responses are then used as input motions to assess the performance of different Nonstructural elements, Systems, and Contents NSCs arranged at each critical room. Then, fragility analyses, using IDA, are conducted to obtain the structural, nonstructural, and medical content fragility curves. Finally, probabilistic damage scenarios are constructed by coupling structural-nonstructural-content fragilities using the Performance-Based Earthquake Engineering methodology via Monte Carlo Simulations. Results highlight the benefits of base isolation in remarkably reducing structural, nonstructural, and content damage within hospital critical rooms for all earthquake hazard levels. Moreover, it was found that solely preventing structural damage is not enough to ensure the continuity in the provision of medical services. Finally, the urgent need to develop code-based performance objectives for NSC for low-, moderate-, and design-level earthquake motions was quantitatively and qualitatively demonstrated.
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    Seismic performance assessment of medical equipment using experimentally validated rolling and toppling nonlinear models
    (2023) Guamán Cabrera, Jaime Wilson; De La Llera Martín, Juan Carlos; Mery Quiroz, Domingo Arturo
    During the last decades, several hospitals stopped service due to severe seismic damage to nonstructural components and medical equipment. This article investigates the dynamic behavior of medical equipment deployed in a full-scale, five-story building with two different support conditions, base isolated (BI) and fixed to the base (FB). Two nonlinear mathematical models, namely, rolling and toppling, are used to simulate the observed experimental responses using recorded data and the camera projection technique (CPT). CPT generated the possibility of measuring equipment horizontal displacements, slips, rotations, rocking, and toppling responses. The Euler–Lagrange formulation, along with the Stribeck friction model, was used to numerically model the rolling and in-plane rotation behavior of a four-wheel mobile cart (4WMC), which is considered to represent the trajectory of equipment supported on caster wheels. Besides, a simple two-dimensional (2D) rigid block model was used to describe the rocking and toppling behavior of locked and free-standing equipment. It was found that the 4WMC model was sensitive to the platform and wheels’ initial orientation angles, as well as the static and kinetic friction coefficients. As it should be, the toppling model was sensitive to the block dimensions and the intensity of the shaking. It was concluded that both numerical models successfully predicted the equipment rolling, in-plane rotation, rocking, and toppling behavior, as long as neither severe lateral impacts nor significant changes in the equipment mass occur during the motion.