Browsing by Author "de Solminihac, Hernan"

Now showing 1 - 5 of 5
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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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    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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    Proposal of an Integrated Index for Prioritization of Bridge Maintenance
    (ASCE-AMER SOC CIVIL ENGINEERS, 2010) Valenzuela, Sergio; de Solminihac, Hernan; Echaveguren, Tomas
    The bridge rating used in bridge management systems commonly uses only a structural condition. Factors such as seismic risk, hydraulic vulnerability, and strategic importance are commonly used in an isolated fashion. However, these factors are relevant when there is no possibility to calibrate deterioration models. This research uses the needs-based framework for developing an integrated bridge index (IBI) as an aid for prioritization and decisions made on maintenance and rehabilitation of bridges. The index weighs the structure distresses, hydraulic vulnerability, seismic risk, and strategic importance of the bridge. The index was calibrated using visual inspection, survey to experts, and regression analysis. After, the index was applied on six bridges placed on a primary road of Chile. To organize visual inspection, bridge inventory, and compute IBI and rank bridges, a software was developed. The calibration of the IBI index shows a correlation of 98% and all the parameters obtained were significant. Further research is needed to integrate cost with the proposed index and allocate maintenance activities.
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    Roughness of Unpaved Roads Estimation and Use as an Intervention Threshold
    (NATL ACAD SCIENCES, 2009) Namur, Emil; de Solminihac, Hernan
    One of the main tasks of the Chilean Direccion Nacional de Vialidad and its regional and provincial secretariats is to determine the maintenance requirements of its roads. In developing countries, most roads managed under this process are unpaved. The traditional way of determining maintenance requirements relies on the criteria applied by whoever inspects the roads. To improve this process, the present work proposes an easy, objective method for determining the conservation requirements of unpaved roads. Roughness thresholds are proposed because they adequately summarize the functional characteristic of this kind of road. Roughness thresholds were determined for different road types after consulting public-, private-, and academic-sector experts who proposed international roughness index (IRI) values based on the characteristics of each road. To measure the roughness of unpaved roads, the use of a response-type roughmeter is recommended. When this type of equipment is not available, it is proposed that IRI be estimated with data obtained from visual inspection. The main distresses of unpaved roads and IRIs were correlated by using data collected from 61 test sections.
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    Seasonal variability of skid resistance in paved roadways
    (ICE PUBLISHING, 2011) Echaveguren, Tomas; de Solminihac, Hernan
    Skid resistance is relevant for road safety. Past research studies have shown that in the long term, skid resistance oscillates around a trend value. Weather conditions, traffic, microtexture, macrotexture and polishing aggregate susceptibility are factors that contribute to this behaviour. Present models simulate this oscillatory pattern by considering a fixed wavelength adjusted to a calendar year, for a limited number of test sections and considering only heavy traffic. In the present study, an analysis of the long-term fluctuations of skid resistance was performed. Seventeen models were calibrated with different macrotexture levels, traffic and types of pavement surface. The investigation applied the concept of a polishing equivalence factor for traffic modelling in order to evaluate a truck as an equivalent car in terms of polishing. Models were based on a survey of skid resistance and macrotexture developed in the Chilean paved road network. It was concluded that asphalt surfaces were highly sensitive to factors that followed the seasonal pattern. The fluctuation obtained ranged between 0.08 and 0.25. In contrast, fluctuation was valued between 0.04 and 0.11 in cement concrete surfaces. Therefore, skid resistance values should be adjusted considering the season of the year in which they were measured and the type of pavement surface to obtain a value that can be compared with thresholds.