Railway megaprojects: A Semi-probabilistic Approach to Windblown Sand Action

New ultra-long transnational railway megaprojects are currently being planned or under construction. Along their route, they increasingly cross arid and desert regions. In these regions, railways are vulnerable to windblown sand. Several failure cases recently occurred, e.g. along the Linhai-Ceke railway in China, or the Aus-Lüderitz railway in Namibia. We consider windblown sand as an environmental action, analogously to wind or snow actions. We categorize its effects into Sand Ultimate Limit States and Sand Serviceability Limit States. In the design perspective, the quantitative prediction of the windblown sand sedimented along the railway is mandatory. We propose a semi-probabilistic approach to windblown sand action because of the inborn variability of the phenomenon. The proposed method allows evaluating the design value of the windblown sand action for a given site.