The new Austrian standard ÖNORM B4800 for torrent control work

Austria has a wide variety of protection structures at different condition levels due to the long tradition of torrent control works in the Austrian Alps. This has resulted in a large stock of protection structures and load models. In order to standardise the design of technical structures based on the Eurocode, including torrential processes, snow avalanches and rock fall, an interdisciplinary working group (ON-K-256) was established. The standardisation for torrential processes covers the definition and classification, the impact on structures, the design of structures, and the operation, monitoring and maintenance. These parts are based on and interact with EN 1990 (the basis of structural design), EN 1992-1-1 (the design of concrete structures), EN 1997-7 (geotechnical design) and the related documents for the Austrian national specifications. For torrential mass wasting processes with high variability in the concentration of solids, modern protection concepts are scenario-oriented. To optimize the mitigation measures for a multi-stage system, a functional chain must be implemented. This chain should have different structures to perform various functions such as dosing, filtering, and energy dissipation. When designing these torrential mitigation structures, it is necessary to simplify the model parameters, stress model, and load distribution. For debris flows, a standardized stress model combines the static and dynamic loads of debris flow impact on structures. This model was calibrated using available impact measurements of real debris flows and is in good agreement with common engineering design methods in Austria for debris flow impact on torrential barriers. The proposed method enables practitioners to design debris flow countermeasures with limited data availability.