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- ItemA new method for assessing compatibility of consolodation procedures with conservation principles: Intervention Qualitiy IndexLlera Martin, Juan Carlos de la; Palazzi, Nuria Chiara; Misseri, Giulia; Sandoval, Cristián; Tonietti, Ugo; Rovero, LuisaIn current times, built heritage is being lost at an alarming rate due to natural and human hazards. Policies for its protection and rehabilitation involve, among other things, challenges related to the refinement of suitable structural strengthening approaches. The arduous balance between gaining acceptable safety levels for occupants without deploying intrusive devices, inconsistent with conservation principles such as those of the ICOMOS charters, is not a simple task. The interest and efforts of the scientific community in this regard have been increasing for decades, but still, it is the structural professional´s responsibility and experience which must define this arduous balance on a case-to-case basis. This study addresses the question: How can the quality of structural rehabilitation interventions be assessed in light of conservation principles such as those given by ICOMOS? Here, a preliminary method - called “Intervention Quality Index” (IQI) method is proposed. It assesses the restoration intervention quality in relation to: (i) the level of compliance given by the conservation´s principle score (conservation´s factor, CF); and (ii) the current state of conservation of the monument (safety factor of building considering the seismic intensity, Δs). The IQI method considers the compliance level of the designed reinforcement with conservation principle, formalized through the fulfillment of a category, i.e. respected, partially respected, and not respected. Then, these judgments are translated into scores and statistically evaluated. Scores are attributed in relation to the relevance of the fulfillment of a certain conservation principle (authenticity, minimal intervention and intrusiveness, compatibility, recognizability and reversibility) for the seismic structural safety point of view. Preliminary results show that an effective employment of traditional earthquake-resistant practices together with a wise use of modern retrofit strategies allow for the preservation and reinforcement of built heritage without harming its identity
- ItemA Novel Three-Port NPC Converter for Grid-Tied Photovoltaic Systems with Integrated Battery Energy Storage(IEEE, 2020) Neira, Sebastián; Lizana Gajardo, Alonso Javier; Pereda Torres, Javier EduardoThe variable behaviour of the photovoltaic (PV) generation arises as the main drawback of this technology. Therefore, Battery Energy Storage (BES) units appear as a promising solution to overcome the inherent intermittent generation profile of PV systems. BES can be implemented separated from the PV generation units or integrated within a single power system. The latter option gives a better dynamic response, as the variable generation can be directly complemented with the BES, controlling the power flow between both elements with the grid. Thus, there is a need for power converters with capability of interface both PV and BES with the grid in a reliable and efficient way. This paper proposes a Three-Port NPC converter to connect a PV array and a BES unit with the ac grid using a single power processing stage. The converter is based in the H-NPC inverter and allows the connection of a low voltage battery to act as a power buffer ensuring a firm energy dispatch to the grid. Furthermore, simulation results show that the proposed topology maintains the good performance of the H-NPC in terms of efficiency, voltage harmonic distortion and reduced leakage current
- ItemAccidental and natural torsion in earthquake response and design of buildings(1996) Chopra, A. K.; Llera Martín, Juan Carlos de la
- ItemAir-Pollution Impact of Transmission Line Capacity Expansions in Power Systems(2017) Sauma Santis, Enzo Enrique; González, JulioIn this paper, we study the environmental effects on global and local pollutant emissions derived from the incorporation of new transmission circuits in existing corridors, and the interrelationships with the system economic costs and the system reliability variations. For that purpose, we develop a methodology that allows quantifying the indirect impact on pollutant emissions due to variations in power plants' dispatch when adding a line circuit to a hydrothermal power system. Our methodology also allows the analysis of the effect of N - 1 security criterion over the pollutant emission displacement, as well as the effect of changes in demand, the hydrology scenarios, and the failure cost. We illustrate our methodology using a simplified version of the main Chilean network.
- ItemAnálise Espacial do Transporte de Passageiros por Barcas na Região Metropolitana do Rio de Janeiro/RJ/Brasil(Sociedade Brasileira de Engenharía Naval, 2019) Leite, Aline; Nassi, Carlos DavidÀ medida que as cidades se desenvolvem, aumenta-se a demanda por mobilidade e cresce a necessidade da eficiência da rede de transporte público. A Região Metropolitana do Rio de Janeiro (RMRJ), assim como outras no mundo, convive com problemas crescentes de mobilidade e enfrenta um grande desafio em relação ao transporte público. A rede de transportes da RMRJ é composta por trens, ônibus, BRT (Bus Rapid Transit), metrô, VLT (Veículo Leve sobre Trilhos), teleférico e as Barcas do transporte aquaviário. A literatura informa que o transporte aquaviário, é considerado mais economicamente viável, eficiente, exige menos investimentos nas fases de implantação e manutenção, além de acarretar baixo impacto ambiental relativamente aos demais modos de transporte de passageiros. O interesse por este tema surgiu a partir de trabalhos anteriores que procuraram realizar um diagnóstico do sistema de Bilhete Único (BU) na Região Metropolitana do Rio de Janeiro, considerando os aspectos social, econômico e espacial. Entretanto, sem aprofundar a temática referente ao sistema de bilhetagem aquaviário de implementação posterior, modo importante de deslocamento entre municípios na Baía de Guanabara. Além disso, a inexistência de pesquisas nessa direção, particularmente que envolva estudos sobre o sistema aquaviário integrados a outros modos, é o que motiva e apresenta como contribuição científica, a partir de uma revisão bibliográfica de exemplos internacionais e nacionais. O trabalho teve como objetivo a criação de uma metodologia, tratamento e análise de dados do sistema de bilhetagem eletrônica do Bilhete Único Aquaviário (BUA) que fosse capaz de demonstrar de que forma realizavam-se as viagens por barcas na Região Metropolitana do Rio de Janeiro (RMRJ), bem como produzir mapas da distribuição espacial dos deslocamentos e dos locais de residência dos usuários. Para tanto, foram utilizados dados socioeconômicos das transações do Bilhete Único disponibilizados pela RioCard, sistema de bilhetagem eletrônica de todo do Rio de Janeiro. Como resultados, foi possível averiguar a quantidade de usuários cadastrados no BUA, identificar os fatores que colaboram para o aumento das viagens urbanas por bilhete único aquaviário na RMRJ além de caracterizar os movimentos realizados pelos usuários com mapas de distribuição espacial desses deslocamentos. Conclui-se que, a inclusão do transporte aquaviário no sistema de bilhetagem eletrônica da RMRJ aumentou o número de usuários no sistema, possibilitando maior integração modal, com destaque para os moradores do outro lado da Baía de Guanabara, possibilitando um maior número de viagens e causando impacto significativo no padrão de viagens. Através dos resultados obtidos com este trabalho, foi é possível entender e observar a importância de sistemas de integração tarifária e a mobilidade urbana, para a melhoria dos deslocamentos dentro de um contexto urbano. Isto porque, com a crescente busca de soluções alternativas para o descontentamento da população em relação ao transporte rodoviário urbano de passageiros o transporte hidroviário tem o potencial para ser o ponto de partida para a recuperação da confiança nos sistemas de transporte público.
- ItemAnálisis de envolventes térmicas en el sur de Chile y su influencia en la demanda energética y emisiones de $CO_2$(2018) Carpio Martínez, Manuel; Villanueva, EduardoChile, como la mayoría de los países, presenta un crecimiento continuo en la demanda de energía. Se han fomentado las políticas nacionales relacionadas al ahorro energético en el sector residencial. Una de las soluciones para mejorar el rendimiento energético de las edificaciones es disminuir la perdida de energía a través de la envolvente. En Chile, los requisitos de construcción los reglamenta la Ordenanza General de Urbanismo y Construcción. El objetivo de esta investigación es analizar como diferentes soluciones constructivas tradicionales de la envolvente térmica influyen en la demanda energética y en las emisiones de CO2 en el sur de Chile. Tomando como casos de estudio las capitales regionales de las regiones más australes. La parte analítica de esta investigación consideró una vivienda unifamiliar y 9 tipos de envolventes térmicas tradicionales en que el registro de éstas data de edificaciones construidas desde antes de 1960 hasta la actualidad. Estos modelos fueron simulados en 5 zonas térmicas, obteniendo 45 casos de estudio. La temperatura de confort de las viviendas fue de 20 a 24°C. Los resultados muestran que existe una correlación lineal entre la demanda energética y emisiones de CO2. Se concluye que se puede llegar a reducir la demanda energética un 293% en la zona más cálida y un 248% en la zona más fría construyendo con una solución térmica que cumpla con los requisitos de la reglamentación
- ItemAnálisis y diseño del Hospital Militar(2002) Stagno, Patricio; Frerk, Jaime; Stagno, Daniel; Rendic, Percy; Iturriaga, Waldo; Llera Martín, Juan Carlos de la; Lüders, Carl; Sady, Henry; Guendelman, Tomás; Guendelman, Mario; Lindenberg, Jorge; Astudillo, Misael; Boroschek, RubénEste artículo describe brevemente algunos resultados del análisis y diseño del edificio placa-técnica del nuevo Hospital Militar ubicado en la comuna de la Reina en Santiago. Dicho edificiocuenta con una superficie cercana a los 50 mil metros cuadrados. Por brevedad, se enfatizaúnicamente aquellos aspectos más novedosos de su diseño, entre ellos, el del sistema de aislaciónsísmica basado en el uso de aisladores elastoméricos. A la fecha, este edificio es el más grande quehaya sido proyectado con aislación sísmica en América Latina. Se discuten además aspectosgenerales de la modelación estructural del edificio y los resultados más importantes del análisisdinámico realizado. En particular, se comparan las respuestas para un modelo tridimensional deledificio con el supuesto de comportamiento lineal equivalente y no-lineal del sistema de aislación
- ItemAnalytical and experimental response of asymmetric structures with frictional and viscoelastic dampers(2004) Llera Martin, Juan Carlos de la; Almazán Campillay, José Luis; Vial, Ignacio; Ceballos, Victor; García, MarcosThis article summarizes analytical and experimental results of linear asymmetric structures with frictional and viscoelastic dampers. Such energy dissipation devices may prove useful in controlling the uneven deformation demand occurring in structural members of torsionally unbalanced structures. Torsional balance is defined as a property of an asymmetric structure that leads to similar deformation demand in structural members equidistant from the geometric center of the building plan. It can be defined in a strong or a weak form. The latter, which allows for rotation of the building plan, only implies an equal norm of the displacement demand at resisting planes symmetric with respect to the geometric center. In general, it can be achieved by the use of energy dissipation devices by making the so-called empirical center of balance of the structure to lie on top of the geometric center. Shaking table results conducted on a mass and stiffness asymmetric six-story model with frictional dampers support the analytical results and the concept of weak torsional balance. Similar results may be extended to the use of viscoelastic dampers as well as for inelastic multistory asymmetric structures.
- ItemBarred-beach morphological control on infragravity motion(2012) Almar, R.; Cienfuegos Carrasco, Rodrigo Alberto; Gonzalez, Eduardo; Catalán, P.; Michallet, H.; Bonneton, P.; Castelle, B.; Suarez, L.A conceptual analysis of the coupling between bars and infragravity waves is performed combining laboratory experiments and numerical modeling. Experiments are carried out in a wave flume with a barred profile. The Boussinesq fully-nonlinear model SERR1D is validated with the laboratory data and a sensitivity analysis is performed next to study the influence on the infragravity wave dynamics of bar amplitude and location, and swash zone slope. A novel technique of incident and reflected motions separation that conserves temporal characteristics is applied. We observe that changing bar characteristics induces substantial variations in trapped energy. Interestingly, a modification of swash zone slope has a large influence on the reflected component, controlling amplitude and phase time-lag, and consequently on the resonant pattern. Variations of trapped infragravity energy induced by changes of swash zone slope reach 25 %. These changes in infragravity pattern consequently affect short-wave dynamics by modifying the breakpoint location and the breaking intensity. Our conceptual investigation suggests the existence of a morphological feedback through the action of evolving morphology on infragravity structures which modulates the action of short-waves on the morphology itself.
- ItemBoard 119: Pre-engineering Programs and the Instillment of Empowering Abilities for Minorities: the Case of the SaviaLab Program(2019) Miranda Mendoza, Constanza; Goñi, Julian; Fuenzalida Quilodrán, Hellen MassielThis is a Work in Progress. In this article, we will seek to present one of the few exemplars in Chile that can be considered a pre-engineering program. The national program of Savialab. Savialab just recently won the GEDC Diversity Award granted by Airbus and the Engineering Deans Council. We’ll briefly present Savialab’s methodology and describe its participants. Finally, we’ll describe our ongoing research methodology proposed to evaluate the programs impact as a genuine pre-engineering program. STEM study programs have become increasingly relevant in modern societies as they’re considered vehicles for economic and social development. Nonetheless, one of the major concerns in STEM education is the lack of adequate representation of minorities groups in these programs. Examples of this are women, low-income, rural or first-generation students, and ethnic minorities and other social identities typically underrepresented in STEM. To overcome these challenges, many public and private initiatives have been deployed. Among these, engineering schools in the US have developed educational programs to instill engineering abilities in pre-college students. These programs have been called pre-engineering programs. Although there are a significant number of articles showing the positive impact of pre-engineering, there is still concern about the lack of standards in instructional designs. In spite of the fact that ‘pre-engineering’ as a concept is becoming more broadly employed in the US, it hasn’t really reached popularity in Latin America, nor in Chile in particular
- ItemCan Advanced Work Packaging Become a Lean Method?(2023) Sepulveda Solari, Italo Gerald; Alarcón Cárdenas, Luis Fernando; Barkokebas, BedaAdvanced Work Packaging (AWP) is rapidly becoming a popular methodology to improve efficiency in construction projects. It is an innovative approach to project management that focuses on the planning, organization, and control of construction tasks on the job site is based on the idea that by organizing work effectively and reducing lead times, it is possible to maximize efficiency and productivity in construction. Nevertheless, Lean Construction (LC) practitioners identified significant shortcomings in AWP such as the lack of attention to buffers while arguing that this methodology is not effective in a practical setting. In this context, this research presents a literature review identifying the criticism of LC practitioners to AWP while identifying similarities and possible synergies where both approaches can complement each other to render better results during the delivery of construction projects. This research identifies the implementation of the Last Planner System® (LPS®) as means to address significant AWP shortcomings identified by LC practitioners while taking advantage of AWP’s structured approach to better apply LC concepts. Therefore, the identified synergies and combination of both approaches will contribute to more efficient processes and improvement of construction practices.
- ItemClearn: A Cost-conscious Student-led Online Judge for a Large Programming Course(2024) Herskovic Maida, Valeria Paz; Muñoz Gama, Jorge; Balladares Conejeros, Fernando Ignacio; Quiroz Pastor, Nicolas Alberto; Flores, PabloOnline judges in programming courses allow students to improve their coding abilities and instructors to analyze student work and detect challenging topics. Although several online judge platforms are available, most are limited in that they cannot support a large number of students simultaneously working on an assignment during a fixed time period, or can only do so at a significant cost, making the use of such systems in developing countries non-viable. This paper presents Clearn, a new platform that is (1) cost-conscious, as we have focused on lowering costs, (2) student-led, as we have empowered students and teaching assistants to lead its development and maintenance, and (3) highly simultaneous, as it allows over 1,000 students to work simultaneously on a timed assignment. This paper presents the platform, as well as the lessons learned during its development and deployment, and its reception by the students.
- ItemComparison of 3D stress-strain concrete models(2021) Llera Martin, Juan Carlos de la; Chacón, Matías F.; Hube, M. A.; Celentano, Diego J.The inelastic response of reinforced concrete buildings is strongly sensitive to the material stress-strain constitutive model adopted for concrete. This paper is a first step on an ongoing work to do a complete benchmark analysis of available concrete models. Consequently, this article quantifies the differences in the response of three well-known 3D stress-strain continuum concrete models: (i) the Hyperbolic Drucker-Prager (DPH) plastic model; (ii) the UNIlateral (UNI) damage model; and (iii) the Faría-Oliver-Cervera (FOC) plastic-damage model. Consistent algorithms in terms of the updated stresses and the tangent stiffness tensor for all these models were implemented in the ANSYS software using user-material FORTRAN routines adapted to solid-type finite elements. Models results were validated using a set of experimental benchmark tests subjected to uniaxial and biaxial stress states under monotonic and cyclic loading. Moreover, the unilateral (crack opening-and-closure) effect was compared among these models. A set of ten response parameters were compared relative to the experimental tests, e.g., the peak stress, the unloading stiffness at each loading cycle, and the total dissipated energy. Results show that the dissipated energy and the unloading stiffness in the last loading cycle, for all tests, leads to the largest errors.
- ItemConstruction and risk evaluation of a water distribution network under seismic hazard in central Chile(2021) Llera Martin, Juan Carlos de la; Castro, S.; Arróspide, F.; Poulos, A.; Alberto, YolandaWater distribution is of critical importance under regular conditions, and more so in times of an emergency induced by a large natural event, which also stresses the performance of other lifelines and critical infrastructure. Being able to compare the network operation in normal conditions with, that during an extreme event, is useful for decision makers in defining investment priorities for mitigation plans. This work aims to perform risk analysis under seismic hazard on the water network of a large conurbation in central Chile formed by the cities of Valparaíso and Viña del Mar. A hydraulic network model of the water network was developed first considering the physical properties of network elements and their estimated head losses. Herein, the methodology for the network construction is described, which combines datasets available in official repositories. As a first attempt, damage scenarios are generated using peak ground acceleration maps constructed using a ground motion prediction model. Pipeline failure is evaluated using fragility functions available in the literature; hydraulic analyses are then carried out on the damaged network. The performance of the network is measured in terms of connectivity (loss) and percentage of unsupplied demand. Finally, a seismic risk analysis on these two indices is presented to enable identification of the relevant characteristics of the constructed network.
- ItemControl of tuned masses using MR dampers and a new real time feedback signal and physical controller(2012) Zemp, René; Llera Martin, Juan Carlos de la; Weber, F.A scaled prototype of an MR damper was active in passive mode on a 160 ton tuned mass in a 21-story building in Santiago, Chile, during the February 27, 2010 earthquake. More recently, a full scale ±100 cm stroke MR damper was designed, manufactured, and is being tested for the same building. The implementation considers a new real time structural measurement system developed to acquire building displacements as feedback for the physical controller of the TM-MR damper assembly. The new measurement system was successfully tested on a shaking table model at Empa. Moreover, results from a number of nonlinear simulations on the building with the full scale semi-active damper shows that the mean displacement reduction for the setup considered is 22% more effective than the building with the bare tuned masses. Finally, the solution was identified to be fairly cost-effective as compared with a passive solution or the bare case
- ItemCriterio unificado para distribución en planta de disipadores de energía en estructuras asimétricas lineales sometidas a sismo(2008) Almazán Campillay, José Luis; López-García, Diego; Llera Martin, Juan Carlos de laLa asimetría en planta es considerada por las normas de diseño sísmico y por la profesión en general como una propiedad no deseada de una estructura. De hecho, algunas normas limitan y castigan severamente la construcción de edificios fuertemente asimétricos. Sin embargo, y debido principalmente a razones arquitectónicas, estas estructuras se construyen muy frecuentemente en la práctica, haciendo indispensable el desarrollo de procedimientos para controlar su respuesta torsional. El uso de disipadores pasivos de energía es, en muchos casos, la solución práctica más aconsejable en la actualidad. Para atenuar los efectos torsionales y hacer un uso eficiente de estos disipadores, se requiere estudiar cuidadosamente tanto su distribución en altura como en planta. En los últimos 15 años se han propuesto numerosos métodos para optimizar la distribución en altura. Algunos de ellos proponen minimizar un cierto funcional definido en forma más o menos heurística, mientras que otros son aplicaciones de la teoría de control. En base a estudios sobre modelos planos de múltiples pisos, los resultados indican claramente que la reducción de la respuesta es muy sensible a la distribución en altura. Un poco más recientemente, se han propuesto también criterios para la distribución en planta de los disipadores, aunque la mayoría de ellos sólo son aplicables a modelos de un piso. Por lo tanto, no existe claridad respecto a cómo este conocimiento puede aplicarse a estructuras reales. Para ayudar a resolver este problema, se presenta en este trabajo un método que permite encontrar la distribución en planta y en altura en forma simultánea. El método consiste en minimizar un funcional calculado a partir de las deformaciones de entrepiso en los bordes del edificio, y en cada una de las dos direcciones principales. Los resultados encontrados indican que este procedimiento logra uniformar las deformaciones de entrepiso tanto en planta como en altura. Aunque en este caso se han usado modelos lineales sometidos a excitación sísmica probabilística, es posible aplicar el concepto a modelos no-lineales sometidos a cualquier tipo excitación.
- ItemDeep Neural Networks on Mobile Healthcare Applications: Practical Recommendations(2018) Benedetto, Jose I.; Sanabria, Pablo; Neyem, Andres; Navon, Jaime; Poellabauer, Christian; Xia, Bryan (Ning)Deep learning has for a long time been recognized as a powerful tool in the field of medicine for making predictions or detecting abnormalities in a patient’s data. However, up until recently, hosting of these neural networks has been relegated to the domain of servers and powerful workstations due to the vast amount of resources they require. This trend has been steadily shifting in the recent years, and we are now beginning to see more and more mobile applications with similar capabilities. Deep neural networks hosted completely on mobile platforms are extremely valuable for providing healthcare services to remote areas without network connectivity. Yet despite this, there is very little information regarding the migration process of an existing server-based neural network to a mobile environment. In this work, we describe the various techniques and considerations that should be taken into account when developing a deep-learning enabled mobile application with offline support. We illustrate the above by providing a concrete example through our experience in migrating to mobile an in-house developed medical application for detecting early signs of traumatic brain injuries.
- ItemDesign, testing and implementation of TADAS devices in three RC buildings with shear walls and coupling beams(2017) Zemp, René; Urrutia, R.C.; Rendel, Michael; Cavalla, G.; Llera Martin, Juan Carlos de laA Triangular Added Damping and Stiffness (TADAS) device is an economic energy dissipation solution to improve the earthquake performance of flexible buildings. TADAS devices have a very stable force displacement constitutive relationship and a high capability of energy dissipation. This research proposes the use of TADAS dampers in coupling beams or lintels between reinforced concrete (RC) shear walls. Coupling beams are typical of RC shear wall buildings with flat slabs and staircase and elevator shear wall cores. The proposed solution integrates into the structure without a relevant impact on the architecture, a significant advantage over other energy dissipation solutions. In this article, three different building applications with TADAS devices are presented. Numerical simulations for these buildings show that drift, displacement, and base shear reductions typically range between 10% and 30%. An effective TADAS design balances stiffness, energy dissipation, and fatigue life of the device under cyclic plastic deformations. Fatigue life for mild steel was determined experimentally and the TADAS devices were designed with a simple model validated by testing of single triangular plates. As expected for rate independent plasticity, tests at different frequencies showed negligible performance variations with deformation velocity. Several TADAS prototypes were cyclically tested and their results are reported in this article. In an effort to analyze the performance and stiffness of the connection between the damper and RC beam, the prototype tests include a section of the capacity-designed concrete beam with the device under simulated as-built conditions. The final design also allows replacing the damper, if needed, after a strong earthquake, and considers an installation procedure that minimizes slip in the connection to the concrete beam.
- ItemDeveloping a More Comprehensive Instrument to Assess the Entrepreneurial Mindset of Engineering Students(ASEE's Virtual conference, 2020) Miranda Mendoza, Constanza; Goñi, Julian; Berhane, Bruk T.; Sotomayor, TrinidadThis is a Work in Progress: Goals of becoming more entrepreneurial have placed considerable pressure on institutions of higher education to generate educational programs that are consistent with the entrepreneurial mindset. Surpassing business programs, engineering education has had an exponential growth in entrepreneurship instruction in curricula and publications related to the topic. However, there are still many conceptual and methodological challenges described in recent literature left unresolved by current assessment methods. As an international and interdisciplinary research team, we seek to develop a new survey instrument to assess the entrepreneurial mindset in engineering students. In the next two years, a preliminary quantitative version of the instrument will be applied to an incrementally larger body of Chilean and United States students in order to evaluate its utility across a much larger sample size. Through this research effort and a critical review of the literature, we aim to produce a more comprehensive and situated method for defining and articulating the entrepreneurial mindset for stakeholders in engineering education. Long-term implications for this project include alignment of the entrepreneurial mindset with objectives articulated by the Accreditation Board for Engineering and Technology (ABET)
- ItemDevelopment of seismic fragility functions of partially grouted reinforced masonry shear walls(2019) Sanhueza, Matías.; Araya Letelier, Gerardo Andrés; Calderón Díaz, Sebastián Andrés; Sandoval Mandujano, Cristián; Murcia Delso, Juan.