Evaluation of the Load Carrying Capacity of a Rockfall Protection Gallery

Abstract:

Mountainous areas of Switzerland are exposed to complex natural conditions, which combined with climate changes cause a variety of natural hazards. Rockfall is one of these hazards, and the risk associated with it tends to increase in recent years. The roads below the Lopper cliff at the shore of Lake Lucerne lead through one of these endangered areas. The roads are closed for traffic, following a rockfall incident in October 2009. Some rockfall protection galleries at the Lopper, which were built during 1979-1981, are subjected to a structural evaluation to allow for decisions on their further use. The current work covers estimation of the impact load carrying capacity of one of these galleries. The gallery analyzed is a cantilever pre-stressed concrete slab with variable thickness, covered by a cushion layer of soil. The behavior of the gallery is examined using finite element analyses as well as an analytical model based on a System of Multiple Degrees of Freedom (SMDF) method. The evaluation has shown that for the chosen loading case based on trajectory analyses with return periods of 30 years, the load carrying capacity of the gallery is satisfactory. However, for extreme rockfalls with return periods of 100 years, a local (punching) failure as well as a global (bending) failure can happen given that a critical section is hit

• Periodical: Applied Mechanics and Materials (Volume 82)
• Pages: 235-240
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.82.235
• Online since: July 2011
• Authors: Sara Ghadimi Khasraghy, Christina Röthlin, Thomas Vogel
• Keywords: Finite Element Analysis (FEA), Impact Loading, Pre-Stressed Concrete Slabs, Rockfall Protection Gallery

References

[1] Slongo, R.: Steinschlagschutzbauten am Lopper. Schweizer Ingenieur und Architekt, Vol. 100, pp.873-876, (1982).

[2] Dr. von Moos AG. Aktennotiz: Beurteilung der Stein- und Blockschlagrisiken bei der Galerie 1. Nr. 8693_AN_09-09-08, Zürich (2009).

[3] CUBUS: Finite-Element-Programm CEDRUS-5, CUBUS AG, Zürich.

[4] ASTRA, SBB: Einwirkungen infolge Steinschlags auf Schutzgalerien, Richtlinie (2008).

[5] LS-DYNA: Keyword User's Manual, Version 971, Livermore Software Technology Corporation (2007).

[6] DiMaggio, F., L., and Sandler, I. S.: Material models for granular soils: Journal of Engineering of the Mechanics Division, 97(3), pp.935-950 (1971).

DOI: 10.1061/jmcea3.0001427

[7] Ghadimi Khasraghy, S., Kishi, N., and Vogel, T.: Numerical Simulation of Consecutive Impacts on Reinforced Concrete Slabs, Sustainable Infrastructure, 33rd IABSE Symposium, 9-11 September, Bangkok, Thailand. (2009).

DOI: 10.2749/222137809796078289

[8] Schellenberg, K.: On the Design of Rockfall Protection Galleries, Dissertation, Diss. Nr. 17924, ETH Zürich. (2008).

[9] Röthlin, C.: Überprüfung der Steinschlagschutzgalerie 1 am Lopper, Master Thesis, ETH Zürich. (2010).

[10] SIA 262. Concrete Structures. Swiss Society of Engineers and Architects (2003).