Center Of Quito Research Articles

Modification of the data-driven period/height relationship for buildings located in seismic-prone regions such as Quito (Ecuador)

The fundamental period of structures is a parameter used in structure under design and for evaluating existing structures. Data-driven methods using ambient vibrations have become popular, particularly for the adjustment of empirical relationships applied to building classes. This study presents the results of a survey of ambient vibrations performed in 146 reinforced concrete buildings in the center of Quito (Ecuador). Classical functional forms giving period (T) for height (H) or number of floors (N) are derived and compared with the relationships available in the Ecuadorian seismic design provisions. We highlight variations in the empirical relationships according to soil conditions, but above all according to the date of construction and the historic seismic sequence to which the buildings have been exposed. The cumulative damage effect is finally confirmed by repeating ambient vibration measurements after the 2016 Mw 7.8 Pedernales earthquake located in the subduction zone, about 175 km from Quito. Even with such a long epicentral distance, leading to low macroseismic intensity (IEMS98 = IV), the seismic ground motion of between 0.017 and 0.081 g recorded in Quito reduced the resonant frequency of the buildings tested by between 2 and 13%. This confirms the effect of cumulative damage in reinforced concrete buildings located in seismic zones, even for weak ground motions, and the variability of empirical T/H relationships associated with damage.

Quito’s coronavirus curfew: Escalating tropospheric ozone pollution

The effect of the curfew due to the pandemic of Covid-19 virus on the levels of air pollution in the historic center of Quito was evaluated with a focus on tropospheric ozone (O3). During the curfew period the daily O3 mean concentration increased by 96%, 109% and 95% in comparison to the concentrations for the same period in the years 2017, 2018 and 2019. This increase is mainly explained by considerable reduction in NOx emissions, thus there was little titration of ozone accumulated in the city environment due to its shallow boundary layer by NO, reaching its maximum concentration at midday. Among studied pollutants that influence O3 formation (CO, NO2, PM2.5) during the curfew the contaminant that showed the greatest reduction in the mean concentration compared to three previous years was NO2, followed by CO and PM2.5. The daily O3 8-hour mean concentrations during the curfew both on weekdays and weekends were lower than the limit values. These results are relevant for designing abatement policies of secondary pollutants such as O3 under strict measures of control of primary pollutant emissions.

Large-scale Vulnerability and Fire Risk Assessment of the Historic Centre of Quito, Ecuador

ABSTRACT Risk mitigation is assumed today as a top priority in the international agenda. Recent natural disasters raised the awareness of governments and scientists and have let to the search for more efficient and effective strategies to manage and mitigate risk. Such efforts are especially important in the case of large historic centres, which, by often combining a high heritage value with a high level of physical vulnerability, are particularly sensitive and relevant. Considering the abovementioned, the present work aims at presenting and discussing the fire risk in the Historic Centre of Quito, one of the oldest and most important Spanish colonial settlements in South America. Taking into account the difficulties inherent to the scale of the case study, the evaluation is carried out in a neighbourhood scale, through the application of simplified fire vulnerability and risk assessment methodology. In order to perform the spatial analysis of the outputs, vulnerability and risk indicators are integrated into a Geographical Information System tool and the results are presented in the form of vulnerability maps. In a second-order analysis, these maps are subsequently combined with pre-existing vulnerability data in order to identify targets and priorities in terms of risk mitigation strategies.

Espacios públicos como áreas sensibles en el Centro Histórico de Quito

La ciudad tradicional y dentro de ella los centros históricos se constituyen en áreas muy sensibles de los contextos urbanos. Lugares que han sufrido transformaciones y en la actualidad son protagonistas de los efectos de la degradación de sus edificaciones, la segregación, la excesiva sobreexplotación, además de la agresión del tráfico automotor para lo cual no fueron diseñadas. El diseño de sus espacios públicos de conjunto con el paisaje urbano histórico actúan sin lugar a dudas como criterios fundamentales para estructurar y ordenar el uso y funcionamiento de estos lugares. El presente trabajo centra su atención en el área más central y asociada al período fundacional de la ciudad de Quito, específicamente, el Centro Histórico (CH). El objetivo a alcanzar será mostrar problemáticas existentes a nivel del CHQ en general y en el área de estudio en específico, donde se continúa dando prioridad al tráfico automotor, la inseguridad se incrementa y sus dinámicas de uso continúan regidas por la economía terciaria y la informalidad, existe desarticulación de espacios públicos de alto valor simbólico, patrimonial e identitarios, así como la amenaza de que esta importante zona se convierta en un lugar meramente turístico y escenográfico. Se plantean posibles acciones que contribuyan a consolidar una red de espacios interconectados de lugares donde predominen los intereses del peatón Los centros históricos, su paisaje y la riqueza patrimonial que lo caracteriza se constituyen hoy en día en un valioso recurso, un derecho ciudadano en el cual hemos de apoyarnos para alcanzar la meta de la ciudad sostenible.

Planificación y Diseño Automático Óptimo de Grandes Redes Eléctricas de Distribución: Aplicación al Centro Histórico de Quito

El presente trabajo describe la herramienta computacional desarrollada por CoDyPower (CDP) para la planificación automática óptima de grandes redes eléctricas de distribución. El objetivo principal es el diseño de redes eléctricas que minimicen el coste económico de la instalación y operación. La función de coste a optimizar tiene en cuenta el número y tipo de subestaciones, la longitud y tipo de conductores, la instalación de líneas aéreas o subterráneas y los costes de operación y pérdidas en un horizonte temporal dado. La optimización considera la geometría de las calles, los catálogos de transformadores y cables disponibles para el proyecto, las restricciones de distancias, caídas de tensión, corrientes y potencias máximas. Debido al carácter computacional NP-hard del problema, el software aplica estrategias de inteligencia artificial y de estadística, fraccionando el problema en etapas de macro y micro optimización. Con ello se encuentra un camino viable de cálculo en tiempos de computación accesibles. Además, los algoritmos propuestos son capaces de encontrar soluciones multi-circuito para cada transformador. El presente trabajo muestra también la aplicación del software CDP al diseño y planificación de las redes eléctricas de distribución de baja y media tensión del Centro histórico de Quito, con unos 20.000 usuarios. Los resultados obtenidos cumplen todas las especificaciones y reducen en aproximadamente un 40% el coste inicialmente estimado.

THE CONSERVATION CYCLE IN THE CITIES OF THE DEVELOPING WORLD: IMPLICATIONS FOR AUTHENTICITY AND POLICY

Urban conservation in developing countries takes place despite limited funds, strong forces of deterioration, and the lack of popular and private-sector support. These challenges contribute to the existence of a conservation cycle in which policies evolve from an emphasis on monuments, to largely cosmetic enhancement schemes, to area-improvement projects, and, finally, to more ambitious removal programs. The four stages of the cycle are illustrated with reference to the historic center of Quito, Ecuador. Escape from the cycle to a condition of sustainability is achieved when the private sector is motivated to invest on a scale that generates permanent upgrading. This motivation becomes possible with the area scheme and is a virtual certainty if removal measures come to dominate conservation policy. However, progress through the cycle diminishes the traditional heterogeneity of social groups and ways of life that characterize the historic centers. Reference to the concept of authenticity highlights the ten...