A Factor Strength Approach for the Design of Rock Fall and Debris Flow Barriers

This paper discusses the applicability and the limitations of an approach to the limit states design of flexible barrier in which the soil/rock strength are factored as required in the European construction code. It shows as this approach has different implications if it is applied to the same kind of structure when loaded by different phenomena rockfall and debris flow in particular). Flexible barriers are common countermeasures to protect from rockfall hazard and to restrain debris flow events. Even if an intense scientific production has demonstrated the difference between the two phenomena, the protection systems are still often designed in the same way. Additionally, the Eurocode 7 (EC7), which is the European Standard concerning geotechnical design, has not been conformed to these kinds of structures and consequently a relationship between the reliability of the system and the partial factors does not exist. Since most of the parameters that rule these systems are not even considered in the code, the Authors propose the study of two cases, in which rockfall and debris flow occur, respectively, to analyse the applicability and the limitations of EC7 principles to design the suitable kind of structure.