Author(s): Fabrizio Cabas

Linked Author(s): Fabrizio Cabas

Keywords: Road drainage systems; Rational Method; Linear Reservoir Approach; Bell’s relationship; Viaduct on Polcevera River;

Abstract: Road and railway drainage systems must be adequately designed to avoid the occurrence of aquaplaning/hydroplaning phenomena or frost heave, thaw softening, attrition of ballast and weakening of the load bearing capacity of the track. Several methods to estimate the peak flow discharge are available in technical literature. In the paper, the well-know “Rational Method” and the “Linear Reservoir Approach”, based on the variable “water storage volume”, are analysed. Rainfall records with duration shorter than 1 hour are generally considered to estimate the designed peak flow discharge values, but these data are not always available. However, rainfall data with duration longer than 1 hour can be considered through Bell’s relationship. The procedure applied to the design of the drainage system of the new road viaduct over the Polcevera River in Genoa is described and analysed. Referring to the rainfall data available for Genoa, comparisons between the two considered methods to evaluate the peak discharge and the Rainfall-Duration-Frequency curves derived from the statistical analysis of rainfall records with duration shorter than 1 hour and Bell’s relationship (based on rainfall data with duration longer than 1 hour), for different values of the average recurrence interval (ARI), are carried out. In addition, evaluations/considerations about aquaplaning phenomena are also reported.

DOI: https://doi.org/10.3850/38WC092019-1620

Year: 2019