Browsing by Author "de Solminihac, Hernan E."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Friction reliability criteria applied to horizontal curve design of low-volume roads
    (SAGE PUBLICATIONS INC, 2007) de Solminihac, Hernan E.; Echaveguren, Tomas; Vargas, Sergio
    Design of road horizontal curves usually considers geometric characteristics and surface pavement condition by means of friction, superelevation, and speed equations in a deterministic point of view: a unique radius and superelevation are selected, considering a uniform behavior of drivers and pavement surface condition. However, empirical evidence shows that operating speed usually exceeds design speed when design speed is lower than 100 km/h. This means that the aggregated friction demand exceeds the design friction. The friction threshold and variability are not considered in design at the present time. Therefore, the designer does not know the remaining friction available and cannot estimate the margin of safety provided by the design. This problem is important in low-volume roads (LVRs) because the design speed usually considered is lower than 100 km/h. In this paper a methodology to design horizontal curves for LVRs is proposed, considering the variability of skid resistance, pavement texture, driver behavior, and geometric design elements. Critical speed is obtained for two conditions: consistency between design and operational conditions and consistency between friction thresholds considered for the pavement surface and operational condition. For this purpose, a reliability index is estimated by using the Hasofer-Lind method. Results show that a more realistic design is obtained when an aggregated friction demand based on driver behavior is considered. A good design is obtained when design speed ranges around 60 km/h and the standard deviation of curve radius is lower than 20% of the mean radius.