Issue 47

M. Marchelli et alii, Frattura ed Integrità Strutturale, 47 (2019) 437-450; DOI: 10.3221/IGF-ESIS.47.34 437 A quick-assessment procedure to evaluate the degree of conservation of rockfall drapery meshes M. Marchelli, V. De Biagi, D. Peila Politecnico di Torino, Turin, Italy maddalena.marchelli@polito.it, https://orcid.org/0000-0002-9919-2916 valerio.debiagi@polito.it, http://orcid.org/0000-0003-1866-9362 daniele.peila@polito.it, https://orcid.org/0000-0002-1771-8874 A BSTRACT . Drapery meshes are protection devices installed on a cliff for mitigating rockfall hazard. They can prevent the detachment of rock fragments and control the dynamics of the falling blocks. During their design working life, drapery meshes are subjected to ageing phenomena, corrosion and impact, which can invalidate the purposes of the protection devices. A novel procedure based on a multi-hierarchical assessment of the damages is proposed. The approach is tailored for two technologies well diffused in the Alps. The main components of the system are identified and the effects of each potential damage on the overall behaviour are taken into account through risk analysis approached. A site campaign serving to test the procedure is described. The proposed approach can be modified to consider other drapery mesh installation types. K EYWORDS . Rockfall; Drapery mesh; Quick assessment; Ageing effects Citation: Marchelli, M., De Biagi, V., Peila, D., A quick-assessment procedure to evaluate the degree of conservation of rockfall drapery meshes, Frattura ed Integrità Strutturale, 47 (2019) 437-450. Received: 24.09.2018 Accepted: 11.12.2018 Published: 01.01.2019 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ockfall represents one of the most hazardous landslide phenomena that can cause fatalities to people and damages to structures and infrastructures [1-3]. Protection structures are installed for reducing rockfall risk in inhabited areas. These can be classified into active (if rock block instability is prevented) and passive (if the blocks are intercepted and stopped before reaching the targets). Drapery meshes are protection structures that can be classified either passive or both active and passive simultaneously [4]. They generally consist of steel wire mesh panels, suspended from upslope anchors [5], capable to control the movement of rock fragments (acting as an active protection), to withstand the punching force of falling rocks, driving the detached blocks at the foot of the slope in a controlled manner (acting as a passive protection). To achieve such goals, the mesh should be kept as close as possible to the slope and be secured both at the top and the bottom of the slope. This is one of the most adopted solutions in case of cliffs close to transportation route or to inhabited areas [6]. Other types of passive protection systems comprise embankment and ditches, rockfall protection galleries and flexible protections systems, such as rockfall barriers [3]. Various technical solutions exist [4]. They generally consist of a suspended mesh, with additional horizontal and vertical ropes. In addition, the drapes can be combined also with face bolts or other kind of anchors, which directly act on the stability of the block, connected each other and to the nets through diagonal ropes. This system prevents rockfall and R