Browsing by Author "Chamorro, Alondra"

Now showing 1 - 12 of 12
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    Asset valuation of low-volume road networks - Application to Chilean unpaved roads
    (NATL ACAD SCIENCES, 2007) de Solminihac, Hernan E.; Hidalgo, Priscila; Chamorro, Alondra
    Asset management is a systematic process of maintenance, modernization, and operation of infrastructure assets in an economically efficient way. For these reasons, asset management has been considered as an emerging concept applied in the area of transport management. Many countries have developed procedures to evaluate pavement infrastructure assets; however, these applications generally have focused on main interurban and urban roads. The objective of this paper is to present a methodology to determine the asset value of low-volume roads and to quantify the impact of maintenance policies on such asset value. As a case study, the proposed methodology was applied to the unpaved road network of Chile, considering different maintenance policies and their impact on the evolution of the road network asset value. A complete analysis that considered the impact of maintenance policies under different budgetary conditions was performed. The analysis was done by using the HDM-4 program, since it performs technical and economic valuations considering a reposition value method. Relationships close to linear were found between final asset value of the unpaved road network under a 20-year valuation. Results showed that medium levels of investment are needed to maintain the network asset value. A small increase of the initial asset value of a network is obtained with high levels of investment. Asset valuation is a good and simple tool that helps agencies during a first-level management process. However, it is not recommended on its own as an optimization tool for the allocation of resources, as social costs and benefits associated with each investment strategy need to be considered.
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    Development and Application of a Sustainable Management System for Unpaved Rural Road Networks
    (2019) Chamorro, Alondra; Tighe, Susan
    For the sustainable management of rural roads, social, institutional, technical, economic and environmental aspects should be considered under a long-term perspective. The current practice in developing countries is that only some of these key sustainable aspects are considered in the management process. In addition, rural roads maintenance management is commonly performed under a short-term basis, not considering the life-cycle costs and benefits in the economic analysis and project prioritization. This paper presents the development of a sustainable management system for rural road networks and its application in developing countries. The approach considers the development of a sustainable framework, application of a network-level condition evaluation methodology, condition performance models for gravel and earth roads, cost-effective maintenance standards, a long-term prioritization procedure that accounts for sustainable aspects, and a computer tool that integrates the system components. The management system has been applied and validated in two unpaved rural road networks in developing countries, located in Chile and Paraguay. Sensitivity analysis was carried out to assess the impacts of input parameters in the performance of developed system. As a result of the research an adaptable and adoptable sustainable management system for rural networks has been developed to assist local road agencies in developing countries.
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    Development and Validation of a Method to Evaluate Unpaved Road Condition with Objective Distress Measures
    (NATL ACAD SCIENCES, 2009) Chamorro, Alondra; de Solminihac, Hernan; Salgado, Mauricio; Barrera, Ernesto
    The condition of unpaved roads is commonly assessed by using qualitative distress measures. Some methods do not consistently consider the relative effect of multiple defects on road condition, or their application is limited to the conditions under which they were developed. In 2007, the Ministerio de Obras Publicas of Chile and a private consultant developed the Modelos de Deterioro de Caminos No Pavimentados study. The scope of the study was to gain experience with and understanding of unpaved road behavior. The main goal of the study was to develop and validate a method for evaluating unpaved road condition by using objective measures of distress, drainage, and profile characteristics. The scope was to design a versatile tool that was applicable to any location, followed a simple procedure, and used cost-effective survey techniques. The proposed approach is to define condition models from a questionnaire administered to a professional panel by applying the Delphi method. As a result of the study, equations representing the unpaved condition index (UPCI) and condition limits were developed for unbound gravel, stabilized gravel, and earth roads subject to three climates: dry, Mediterranean, and humid. UPCI equations and condition limits were validated successfully; the method to assess unpaved road conditions was reliable and versatile.
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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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    Fragility curves for road embankments exposed to adjacent debris flow
    (2023) Nieto, Natalia; Chamorro, Alondra; Echaveguren, Tomas; Escauriaza Mesa, Cristian Rodrigo
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    Importance of Noncost Criteria Weighing in Best-Value Design-Build US Highway Projects
    (2021) Calahorra-Jimenez, Maria; Torres-Machi, Cristina; Chamorro, Alondra; Alarcon Cardenas, Luis Fernando; Molenaar, Keith
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    Long-term behaviour model of skid resistance for asphalt roadway surfaces
    (CANADIAN SCIENCE PUBLISHING, 2010) Echaveguren, Tomas; de Solminihac, Hernan; Chamorro, Alondra
    Skid resistance (SR) is relevant to road safety. Several researchers have showed that SR diminishes its value over time depending on the traffic-aggregated interactions, and the presence of heavy vehicles in the traffic stream. The classical SR model shows that its value drops from a starting value to an equilibrium value over time. However, this behaviour in low-volume roads is not entirely true. In this paper, an SR model in a single mathematic specification is proposed, which considers the polishing effect of heavy traffic through the polishing equivalence factor. The model was calibrated by using data measured with a SCRIM device from 1100 test sections in Chile. Considering speed and temperature factors calibrated for Chile, data were processed and corrected. It was concluded that the model for long-term behaviour of SR is satisfactory, but it is necessary to include the seasonal effects for a more realistic model.
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    Natural hazard risk management in the Chilean drinking water industry: Diagnosis and recommendations
    (2023) Molinos-Senante, Maria; Chamorro, Alondra; Contreras, Marta; Echaveguren, Tomas
    Disaster risk management in water infrastructure is still a world challenge. In this study, we present and discuss the results of an extensive survey conducted to Chilean water companies focused on disaster risk management in the production of drinking water. The main conclusions were: i) there is significant heterogeneity in the practices applied by water companies; ii) water companies use a large variety of tools to manage natural disasters; iii) earthquake is the one more relevant hazard for water companies. Based on the main conclusions of the survey, a set of recommendations for the Chilean water industry are proposed.
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    Seismic risk evaluation of highway tunnel groups
    (2021) Cartes, Pablo; Chamorro, Alondra; Echaveguren, Tomas
    Tunnels allow the continuity of rural road and urban transportation networks. Their shutdown provokes a loss in the transport system's level service, which entails higher road user costs. Earthquakes are the hazard that most affect the tunnels' serviceability. Depending on the structural damage's magnitude, the serviceability loss can be at different degrees, from marginal changes in traffic flow, associated with minor damages, to traffic interruption, associated with collapsing. Because of seismic phenomena' randomness nature, its effect on tunnel serviceability is estimated in probabilistic terms. Traffic interruption probability was estimated using fragility curves, representing the probability of achieving a specific damage state regarding the seismic hazard intensity. The calibration of tunnel fragility curves requires large samples of damages, seismic intensities, and geological and constructive data, which are not always available, especially in countries with a small number of tunnels in their road network. This work proposes a simplified procedure for evaluating the tunnels' traffic interruption probability due to earthquakes. The approach proposed uses existent seismic exposures maps, a strategy for selecting from existing fragility curves the more suitable, and a simple method to estimate the traffic interruption probability. The procedure analysed 20 tunnels affected by the Maule earthquake in Chile. These tunnels experimented PGA between 0.12 and 0.36 g. The highest risk values were obtained in tunnels without alternative routes and high repairing costs.
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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.
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    Structured Approach for Best-Value Evaluation Criteria: US Design-Build Highway Procurement (vol 36, 04020086, 2020)
    (2021) Calahorra-Jimenez, Maria; Molenaar, Keith; Torres-Machi, Cristina; Chamorro, Alondra; Alarcon Cardenas, Luis Fernando
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    Traffic interruption risk induced by cut-slope failure: The rainfall effect
    (2023) Jimenez-Ramos, Gustavo; Echaveguren, Tomas; Vargas-Baecheler, Jose; Chamorro, Alondra
    Shallow landslides in road cut-slopes cause traffic disruptions, especially during rainy seasons. Even when the cut slopes are planned for saturation conditions, the variability and uncertainty of the explanatory variables of slope stability combined with pore pressure variation due to rainfall determine the need to probabilistic model the slope stability, considering the effects of rainfall intensity and duration. It is also necessary to know the magnitude of road platform blockage induced by slope failure, which is especially important for rural roads. This paper proposes a method for evaluating the probability of cut-slope landslides and traffic interruption. For this purpose, first-order reliability analysis and a Monte Carlo simulation were used to analyze various slope and rainfall scenarios. The analysis found 24 failure probability curves that were obtained for slope inclination, rainfall intensity, and rainfall duration. Probability values were obtained to achieve "low", "moderate", and "extensive" damage states in terms of roadway blocked due to slope slides and the relationship between roadway blocking width to slope height.