A reliability assessment of physical vulnerability of reinforced concrete walls loaded by snow avalanches

Abstract

Abstract. Snow avalanches are a threat to many kinds of elements (human beings, communication axes, structures, etc.) in mountain regions. For risk evaluation, the vulnerability assessment of civil engineering structures such as buildings and dwellings exposed to avalanches still needs to be improved. This paper presents an approach to determine the fragility curves associated with reinforced concrete (RC) structures loaded by typical avalanche pressures and provides quantitative results for different geometrical configurations. First, several mechanical limit states of the RC wall are defined using classical engineering approaches (Eurocode 2), and the pressure of structure collapse is calculated from the usual yield line theory. Next, the fragility curve is evaluated as a function of avalanche loading using a Monte Carlo approach, and sensitivity studies (Sobol indices) are conducted to estimate the respective weight of the RC wall model inputs. Finally, fragility curves and relevant indicators such a their mean and fragility range are proposed for the different structure boundary conditions analyzed. The influence of the input distributions on the fragility curves is investigated. This shows the wider fragility range and/or the slight shift in the median that has to be considered when a possible slight change in mean/standard deviation/inter-variable correlation and/or the non-Gaussian nature of the input distributions is accounted for.

Assessing fragility of a reinforced concrete element to snow avalanches using a non-linear mass-spring model

“…However, to put our results in a broader perspective, the herein obtained fragility curves were plotted against the existing curves. First, the numerical fragility curves proposed by Favier et al (2014) (Fig. 13a) were considered.…”

“…13c) Figure 13. Comparison of the article fragility curve to (a) the numerical fragility curves from Favier et al (2014), (b) the expert judgmental fragility curves of Wilhelm (1998), and (c) the vulnerability curves of Barbolini et al (2004) and Keylock et al (1999). The exact meaning of each curve is provided in text.…”

“…Based on classical engineering approaches, Favier et al (2014) obtained ultimate pressures related to four typical limit states of an RC structure. The limit state "Elast" is related to the reaching of the elastic limit within the RC wall.…”

“…FEA approaches (Berthet-Rambaud, 2004;Bertrand et al, 2010;Ousset et al, 2013) and very simple attempts based of civil engineering abacuses (Favier et al, 2014). The first allows for a better understanding of the detailed interaction between avalanche flows and structures but only under very specific conditions due to the computational burden.…”

A new web-based system to improve the monitoring of snow avalanche hazard in France

“…Specifically, temporal and spatial aspects of snow avalanche activity and risk can now be jointly explored much more efficiently taking into account their main drivers, which represents a crucial improvement both for scientific purposes and for local on-site risk management by technicians and stakeholders. Already available examples having largely beneficiated of these new facilities include detailed investigation of climatic drivers of avalanche activity in the French Alps (Lavigne et al, 2015), long-term forecasting of extreme avalanche events , crosscomparison with tree ring data and connection to afforestation processes (Schläppy et al, 2014), short-term forecasting of major winter storms (Dkengne et al, 2015), socioeconomic assessment of the vulnerability of various types of buildings (Favier et al, 2014) and subsequent risk assessment for inhabited areas (Eckert et al, 2008).…”