Browsing by Author "Alberto, Yolanda"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- ItemComparative qualitative and quantitative analyses of the seismic performance of water networks during the Maule 2010, Christchurch 2010-2011, and Tohoku 2011 earthquakes(ASCE-AMER SOC CIVIL ENGINEERS, 2022) Alberto, Yolanda; Llera Martin, Juan Carlos de la; Aguirre Aparicio, Paula; Monsalve M., Mauricio; Molinos Senante, MaríaRecovery of damaged water supply systems after severe earthquakes is one of the priorities to return to normal conditions. Water supply systems are intrinsically interdependent with other important lifelines such as transportation, energy, health care, and industrial sectors. These interdependencies need to be better understood by means of empirical data and analytical models. This paper is primarily of archival nature and describes empirical impact data of large earthquakes in Chile (Maule 2010), New Zealand (Christchurch 2010-2011), and Japan (Tohoku 2011) on their respective drinking water systems, and summarizes damage observations, emergency actions, and restoration processes within a resilience framework focused on metrics of robustness and rapidity. The archival nature of this article is justified by the paramount importance of systematic data collection to improve network resilience for future analytical models that aim to predict the response and recovery of water networks. Moreover, based on the collected data, the effectiveness of response actions and implemented countermeasures are evaluated relative to the observed earthquake performance of the system components. Important observations are derived to understand the main factors causing water supply system outages, the effectiveness of strategies used, and their capacity to restore the service.
- 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.
- ItemEarthquake response sensitivity of complex infrastructure networks(2020) Llera Martin, Juan Carlos de la; Monsalve, Mauricio; Ferrario, Elisa; Allen, E.; Chamorro, A.; Castro, S.; Alberto, Yolanda; Arróspide, Felipe; Poulos, Alan; Candia, G.; Aguirre, P.Resilience of complex infrastructure networks is critical in achieving earthquake resilience in urban environments. Perhaps due to their modeling complexity, very few research studies have addressed sensitivity of the network response to a severe earthquake hazard field. This research aims to characterize earthquake response sensitivity as a function of different topological parameters of 5 critical complex networks in central Chile, covering the electric, transportation, and drinking water networks. Central Chile was selected because it amounts for almost 50% of the country’s population. What is also particular about this setting, is that the seismic characteristics of the region lead to extended (essentially) N-S strike fault ruptures, which run along the subduction margin defined by the E-W convergence between the South American and Pacific Ocean plates at an unusual rate of about 68 mm/year, thus involving in the strong-motion hazard field geographic scales in the hundreds of kilometers. It is concluded that node and link topological structures differ considerably between these complex systems, which are characterized by several different well-known centrality parameters and other interesting indices and network-class discriminators. Secondly, a component criticality analysis under an earthquake hazard field is also presented just in terms of connectivity/service loss, which enables, at least, a rough identification of the robustness of each network as nodes and links are removed. Results from these topological analyses are useful to identify which components are essential in generating larger earthquake resilience. This is the first time such results are obtained for central Chile using very detailed models of these complex networks
- ItemEvaluating network reduction strategies for consistent risk assessment of critical infrastructures(2020) Llera Martin, Juan Carlos de la; Monsalve M., Mauricio; Ferrario, Elisa; Alberto, Yolanda; Arróspide, Felipe; Castro, Sebastián; Poulos, AlanCritical infrastructure networks are continuously growing, gaining complexity with each urban sprawl, conurbation, technological change, and regulatory update. Consequently, their detailed risk analysis demands large amounts of data, computational resources (required by simulations, optimization, flow equilibria, etc.), and dealing with complex interpretations of the results. This comes with several drawbacks: scarcity of adequately curated data, which instead are usually incomplete and sometimes even incorrect, algorithmic runtime that impairs the full use of Monte Carlo simulations, errors that may propagate extensively, and results that cannot be generalized and extended to other cases. Therefore, researchers have also resorted to analyzing simplified versions of these infrastructure systems. This work evaluates three algorithms for reducing the complexity of infrastructure networks while keeping reasonable accuracy for statistical interpretation. These algorithms transform a detailed graph into a more compact representation, where risk assessments can be performed more easily. The strategies used herein are based on the detection of important edges (backbone detection) and the merging or lumping similar or proximate elements (clustering, contractions). The different complexity reduction algorithms are evaluated on three infrastructure networks, namely: the electric transmission network of Chile, the electric distribution network of the Greater Valparaíso and the drinking water distribution network of the Greater Valparaíso. The experiments show that two of the three graph reduction criteria proposed in this work yield good approximations of the connectivity of the original graphs, when these are reduced to 25% of their size.