Priscila Hidalgo

Calibration of Performance Models for Surface Treatment to Chilean Conditions The HDM-4 Case

The HDM-4 (Highway Development Management) model used for pavement management activities must be adjusted to the specific conditions of a country or region where they are to be used by adjusting certain calibration factors. The results obtained from calibrating the cracking, raveling, potholing, rut depth, and roughness models contemplated in HDM-4 version 1.1 for surface treatments are presented and compared with the results obtained from equivalent models of HDM-III. In this task, the “windows” methodology was used, which consists of reconstructing the distress performance curve of a specific road category starting with observation of the condition of different roads with similar characteristics (such as traffic, pavement structural capacity, and climatic conditions) but of different ages. On the basis of the results obtained, recommendations for calibrating the performance models are proposed, and calibration factors more adequate for characteristics specific to Chilean surface treatments are established. On comparing the results of the calibrated models of HDM-III and HDM-4, it is concluded that both cases furnish similar values, and use of HDM-4 models is recommended because of their operating advantages and because they afford a greater flexibility, which allows them to more aptly adapt to a broader number of cases and situations.

Asset Valuation of Low-Volume Road Networks: Application to Chilean Unpaved Roads

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.