Dynamic structural capacity of reinforced concrete slabs due to rockfall

Rockfall is a relevant hazard in the Alpine regions of Switzerland, the risk of which tends to increase in time. Rockfalls are hard to predict, release large energies, have short warn-ing times and may lead to severe consequences. The research on rockfall involves different disciplines to identify potential detachment zones, to determine frequency and size of released blocks, to pursue the trajectories, to quantify damages as well as to formulate and implement protection levels. Measures may be taken in the initiation zone, along the transit path and in the deposit zone. Galleries are suitable to protect roads and railway lines in the range of impact en-ergy from 200 to 10'000 kJ, if the threatened zones are short and well defined and if the risk requires measures to be taken. Alternatives are retained flexible nets in the same range of energy absorption capacity and embankments as well as reinforced dams for higher impact energies. According to an enquiry with operators of road and rail networks Switzerland holds more than 350 galleries and tunnel entrances that provide a certain degree of rockfall protec-tion. Many of these structures protect also from snow and avalanches or have been erected for other purposes. A cushion layer covers most of the classical galleries and half of them abut on a tunnel. About a third has been built in the 1960s, 1970s and 1980s, re-spectively. The most common type consists of concrete slabs subjected to bending, cast in place, and reinforced with mild steel [Schellenberg 2008]. Starting point for the research project were three rockfall events in 2003. They all con-cerned structures that had not been designed for such impact energies, led to heavy local damage but did not injure persons. A further event with two fatalities in 2006 and the general decrease of risk acceptance on the transit routes resulted in rockfall becoming a research topic again. Already in the 1990s falling test were executed at EPFL that served as basis for the ASTRA/SBB guidelines of 1998/2003. The present research project aimed at investigating the impact of blocks on reinforced concrete slabs to assess that approaches and to extend them for larger falling heights and smaller thicknesses of the cushion layer. On the methodical level, analytical approaches were developed and nu-merical simulations with finite elements were applied and compared with test results in different scales.

  • Corporate Authors:

    BUNDESAMT FUER STRASSENBAU (ASTRA) / OFFICE FEDERAL DES ROUTES (OFROU)

    MUEHLESTRASSE 2, ITTIGEN
    BERN,   Switzerland  CH-3003
  • Authors:
    • VOGEL, T H
    • SCHELLENBERG, K
    • GHADIMI KHASRAGHY, S
  • Publication Date: 2015-11

Language

  • English

Media Info

  • Pagination: 249P
  • Serial:
    • Issue Number: 673

Subject/Index Terms

Filing Info

  • Accession Number: 01595896
  • Record Type: Publication
  • Source Agency: Ecole Polytechnique Fédérale de Lausanne (EPFL)
  • Files: ITRD
  • Created Date: Apr 11 2016 4:54PM