Browsing by Author "Contreras-Jara, Manuel"

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    Estimation of Exceedance Probability of Scour on Bridges Using Reliability Principles
    (2021) Contreras-Jara, Manuel; Echaveguren, Tomas; Chamorro, Alondra; Vargas-Baecheler, Jose
    Scour is one of the most relevant causes of bridge collapse. Most existing scour models have been focused on estimating scour depth as input for bridge design. This estimation is mainly deterministic. Parameter uncertainty has been considered to estimate expected scour as well. This framework is suitable for bridge design but has limitations for risk analysis of bridge networks, in which exceedance probabilities are needed. In this paper we use the first-order reliability method to estimate the probability that the actual scour will exceed the design scour, considering the uncertainty in hydraulic and hydrological parameters. The procedure was applied to a case study in Chile using the flood-flow history between 30 and 60 years of eight fluviometric stations. The local, contraction, and general scour were estimated for return periods between 2 and 500 years. The exceedance probability obtained was highly dependent on the uncertainty in annual maximum flow, Froude's number, top width, and riverbed longitudinal slope.
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    SIGeR-RV: A Web-Geographic Information System-Based System for Risk Management of Road Networks Exposed to Natural Hazards
    (2023) Chamorro, Alondra; Echaveguren, Tomas; Pattillo, Carlos; Contreras-Jara, Manuel; Contreras, Marta; Allen, Eduardo; Nieto, Natalia; de Solminihac, Hernan
    The consequences of natural hazards are frequently estimated by the direct cost of recovering damaged infrastructure and the indirect costs to road users, economic activities, and impacts on society. Road networks are crucial in economic systems, logistic chain continuity, accessibility, mobility, and the evacuation of population during and after extreme events. Risk management systems (RMS) are used to estimate the potential consequences of natural events and to assess strategies for risk reduction. These commonly assess hazards, assets exposure, economic losses, and risk mitigation actions, among others. The general framework of RMS can be adapted to different scenarios. Still, local characteristics, such as the types of hazards and physical assets, cannot always be directly adopted from these systems. This study discusses the development of SIGeR-RV, an RMS developed in Chile for road networks exposed to multiple natural hazards. The RMS was implemented in a web-based geographic information system platform able to display hazard maps, quantify risk levels, prioritize mitigation strategies, and estimate direct and indirect costs and social vulnerability. The content and various capacities of the system are detailed, following the steps marked in its framework. This first version of SIGeR-RV considers seismic hazard, volcanic lahars, and hydro-meteorological hazards that affect road platforms, bridges, tunnels, and cut slopes. The system currently serves as a tool for the Ministry of Public Works of Chile and other decision makers to estimate budget requirements for increasing resilience of the road network, identifying vulnerable road segments, and assessing the socioeconomical impacts of risk reduction.