Experimental measurements of flood-induced impact forces on exposed elements

¹ Unit of Hydraulic Engineering, University of Innsbruck, 6020 Innsbruck, Austria
² Ingenieurbüro Thomas Haug, 6600 Lechaschau, Austria
³ Institute of Earth Sciences, Universidad Austral de Chile, 5090000 Valdivia, Chile
⁴ Millennium Nucleus CYCLO - The Seismic Cycle Along Subduction Zones, Valdivia, Chile
⁵ Research Centre for Assessment and Mitigation of Natural and Anthropogenic Risks (RiNA), Universidad Austral de Chile, 5090000 Valdivia, Chile
⁶ Institute of Mountain Risk Engineering, University of Natural Resources and Life Sciences, 1180 Vienna, Austria

^* Corresponding author: michael.sturm@uibk.ac.at

Abstract

Torrential flood hazards are a major threat for inhabited alluvial fans. They have the potential to relocate large amounts of sediment from the upper catchments to settlement areas on the alluvial fans where typically distributary processes take place. The approaching water-sediment-mixture impacting on building walls are part of a set of damage-generating mechanisms and may cause severe damages to buildings and infrastructure. It is difficult to predict the magnitude and temporal forces on buildings due to the complex flow patterns and sediment deposition processes around obstacles on the floodplain. Our work focuses on experimental measurements of impact forces of flood events on buildings at a 1:30 scale model. It covers the alluvial fan of the Schnannerbach torrent (Austria) with a set of building structures which are equipped with force measurement devices. The measured impact forces are correlated to the approaching flow heights. Influencing factors on the impacts forces such as surrounding buildings on the floodplain and the presence of openings in the building envelope are also analysed. The influence of different hydraulic flow patterns on the impact forces and regression analyses for an estimation of impact forces are presented.