Browsing by Author "Bustos, M"

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    Assessment of horizontal curves of an existing road using reliability concepts
    (CANADIAN SCIENCE PUBLISHING, 2005) Echaveguren, T; Bustos, M; de Solminihac, H
    Horizontal curves on road are commonly analyzed under design speed point of view, where it is assumed that the maximum speed of a vehicle in a curve is the design speed. The empirical evidence has demonstrated that when the design speed is low, the operating speed tends to be higher. This happens because of an available remaining lateral (or transverse) friction for speeds over design speed. This condition is determined by a speed limit, obtained from the demand and supply equilibrium of friction of a pavement. The difference between operating and design speeds is usually considered as the margin of safety of a horizontal curve on a road. In this study, a methodology to determine the margin of safety of an existing curve is proposed. The methodology is based on the reliability theory by which reliability of operational conditions can be analyzed by using a reliability index as a margin of safety. A case study for light vehicles is evaluated to determine high impact variables over reliability, such as, macrotexture, skid resistance, curve radius, and superelevation. The results obtained in this study demonstrated that curve radius, skid resistance, and macrotexture are variables with high impact over failure probability. In constrast, superelevation has little effect on the failure probability.
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    Development of correlation equations between different measurements of skid resistance in pavements
    (NATL INST SCIENCE COMMUNICATION-NISCAIR, 2006) Bustos, M; Echaveguren, T; de Solminihac, H; Caroca, A
    Friction is an indicator of the safety level supplied by a pavement. It is obtained by skid resistance and texture measures performed with static and high performance devices. Because the physical principle applied by each equipment differs from one another, it is necessary to harmonize measures in order to compare them. From literature review different harmonization procedures are identified: equipment direct correlations, high scale harmonization experiments an statistical analysis of skid resistance measures. Harmonization based on direct correlations and statistical analysis has the disadvantage that they do not consider texture as a variable, making them applicable only under certain conditions. In this paper, a harmonization methodology is proposed based on the PIARC (the World Road Association) harmonization procedure. The proposed methodology has the advantage that a reduced amount of data is needed and also texture measures are considered. From the application of the methodology under data simulation it is concluded that under a certain texture range the correlation is almost linear. This range depends on the texture measurement device: as, when using accurate equipments non-linear distortions are deduced under low texture levels.