Back-analysis of rockfalls for the definition of an empirical vulnerability function for buildings

Author(s):  
Sandra Melzner ◽  
Paolo Frattini ◽  
Federico Agliardi ◽  
Giovanni Battista Crosta

<p>The vulnerability of buildings to the impact of rockfalls is a key component of Quantitative Risk Assessment for rockfall phenomena. Only a few attempts to quantitatively assess vulnerability have been presented in the literature due to the lack of high-quality rockfall and damage data. For processes such as debris flows, snow avalanches or earthquakes, well-established methods for the estimation of physical vulnerability are already available.</p><p>The present work aims to develop an empirical rockfall vulnerability function by coupling rockfall back-analysis modelling of several damaging events occurred in different lithological and geomorphological settings. A sound database of damage to specific categories of structures impacted by rockfalls is build up by archive research of historical events and high-quality field observations of recent events. Damages are classified according to four damage types: superficial (degree of loss: 0.1-0.2) to structural (degree of loss: 1.0). The back-analysis of rockfalls and the interaction with element at risk is performed with the 3D numerical model Hy- STONE. The code uses a hybrid modelling approach and random sampling of input parameters from different probability density distributions (uniform, normal, exponential) to account for the complexity of the rockfall process and influencing factors. The elements at risk are integrated as lines to the model, impact points being able to be displayed and extracted as point vector data. This enables a precise analysis of simulated energies and observed damage for each building impacted in the past to define an empirical vulnerability function. The empirical vulnerability function is established by fitting damage-energy data through a sigmoidal function. This empirical vulnerability function for buildings is fundamental to compute the expected degree of loss for each element of risk, especially in areas where no detailed rockfall or damage data is available.</p>

2009 ◽  
Vol 9 (4) ◽  
pp. 1059-1073 ◽  
Author(s):  
F. Agliardi ◽  
G. B. Crosta ◽  
P. Frattini

Abstract. Rockfall risk analysis for mitigation action design requires evaluating the probability of rockfall events, the spatial probability and intensity of impacts on structures, their vulnerability, and the related expected costs for different scenarios. These tasks were integrated in a quantitative risk assessment procedure supported by 3D rockfall numerical modelling performed by the original code HY-STONE. The case study of Fiumelatte (Varenna, Italy), where a large rockfall in November 2004 resulted in 2 casualties, destruction of several buildings and damage to transportation corridors, is discussed. The numerical model was calibrated by a back analysis of the 2004 event, and then run for the whole area at risk by considering scenarios without protection (S0), with a provisional embankment (S1), and with a series of long-term protection embankments (S2). Computed impact energy and observed damage for each building impacted in 2004 were combined to establish an empirical vulnerability function, according to which the expected degree of loss for each element at risk was computed. Finally, costs and benefits associated to different protection scenarios were estimated, in order to assess both the technical performance and the cost efficiency of different mitigation options.


Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 158
Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests using terms that appear to be the most logic and explicit as possible and describes methods to derive some of the main hazards and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized and diffuse hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed, and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the reach probability, and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (passage frequency) can be derived. This frequency is relevant for risk assessment when the element at risk can be damaged several times. If it is not replaced, the probability that it is impacted by at least one rockfall is more relevant.


2014 ◽  
Vol 11 (2) ◽  
pp. 1411-1460 ◽  
Author(s):  
B. Mazzorana ◽  
S. Simoni ◽  
C. Scherer ◽  
B. Gems ◽  
S. Fuchs ◽  
...  

Abstract. The design of efficient hydrological risk mitigation strategies and their subsequent implementation relies on a careful vulnerability analysis of the elements exposed. Recently, extensive research efforts were undertaken to develop and refine empirical relationships linking the structural vulnerability of buildings to the impact forces of the hazard processes. These empirical vulnerability functions allow estimating the expected direct losses as a result of the hazard scenario based on spatially explicit representation of the process patterns and the elements at risk classified into defined typological categories. However, due to the underlying empiricism of such vulnerability functions, the physics of the damage generating mechanisms for a well-defined element at risk with its peculiar geometry and structural characteristics remain unveiled, and, as such, the applicability of the empirical approach for planning hazard-proof residential buildings is limited. Therefore, we propose a conceptual assessment scheme to close this gap. This assessment scheme encompasses distinct analytical steps: modelling (a) the process intensity, (b) the impact on the element at risk exposed and (c) the physical response of the building envelope. Furthermore, these results provide the input data for the subsequent damage evaluation and economic damage valuation. This dynamic assessment supports all relevant planning activities with respect to a minimisation of losses, and can be implemented in the operational risk assessment procedure.


2007 ◽  
Vol 7 (5) ◽  
pp. 495-506 ◽  
Author(s):  
S. Fuchs ◽  
K. Heiss ◽  
J. Hübl

Abstract. In quantitative risk assessment, risk is expressed as a function of the hazard, the elements at risk and the vulnerability. From a natural sciences perspective, vulnerability is defined as the expected degree of loss for an element at risk as a consequence of a certain event. The resulting value is dependent on the impacting process intensity and the susceptibility of the elements at risk, and ranges from 0 (no damage) to 1 (complete destruction). With respect to debris flows, the concept of vulnerability – though widely acknowledged – did not result in any sound quantitative relationship between process intensities and vulnerability values so far, even if considerable loss occurred during recent years. To close this gap and establish this relationship, data from a well-documented debris flow event in the Austrian Alps was used to derive a quantitative vulnerability function applicable to buildings located on the fan of the torrent. The results suggest a second order polynomial function to fit best to the observed damage pattern. Vulnerability is highly dependent on the construction material used for exposed elements at risk. The buildings studied within the test site were constructed by using brick masonry and concrete, a typical design in post-1950s building craft in alpine countries. Consequently, the presented intensity-vulnerability relationship is applicable to this construction type within European mountains. However, a wider application of the presented method to additional test sites would allow for further improvement of the results and would support an enhanced standardisation of the vulnerability function.


2014 ◽  
Vol 18 (9) ◽  
pp. 3817-3836 ◽  
Author(s):  
B. Mazzorana ◽  
S. Simoni ◽  
C. Scherer ◽  
B. Gems ◽  
S. Fuchs ◽  
...  

Abstract. The design of efficient hydrological risk mitigation strategies and their subsequent implementation relies on a careful vulnerability analysis of the elements exposed. Recently, extensive research efforts were undertaken to develop and refine empirical relationships linking the structural vulnerability of buildings to the impact forces of the hazard processes. These empirical vulnerability functions allow estimating the expected direct losses as a result of the hazard scenario based on spatially explicit representation of the process patterns and the elements at risk classified into defined typological categories. However, due to the underlying empiricism of such vulnerability functions, the physics of the damage-generating mechanisms for a well-defined element at risk with its peculiar geometry and structural characteristics remain unveiled, and, as such, the applicability of the empirical approach for planning hazard-proof residential buildings is limited. Therefore, we propose a conceptual assessment scheme to close this gap. This assessment scheme encompasses distinct analytical steps: modelling (a) the process intensity, (b) the impact on the element at risk exposed and (c) the physical response of the building envelope. Furthermore, these results provide the input data for the subsequent damage evaluation and economic damage valuation. This dynamic assessment supports all relevant planning activities with respect to a minimisation of losses, and can be implemented in the operational risk assessment procedure.


Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests to use terms that appear to be the more logic and explicit as possible, and describes methods to derive some of the main hazard and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized hazards and diffused hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the propagation probability and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (reach frequency) can be derived. However, when the element at risk is not replaced or repaired, the probability that it is impacted by at least one rockfall must be considered.


2008 ◽  
Vol 18 (1) ◽  
pp. 24-31
Author(s):  
Martha Wilder Wilson ◽  
Elizabeth Zylla-Jones

Abstract The goal of university training programs is to educate speech-language pathology and audiology students to become competent and independent practitioners, with the ability to provide high quality and professional services to the public. This article describes the behaviors of “at-risk” student clinicians, so they may be identified early in their practica and remediation may be implemented. The importance of establishing a student at-risk protocol is discussed as well as a remediation plan for these students. This article summarized the Auburn University Speech and Hearing Clinic’s Student At-Risk Protocol, which may serve as a model for university training programs. The challenges of implementing such a protocol are also discussed.


EDUKASI ◽  
2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Hendra Karianga

Sources of revenue and expenditure of APBD (regional budget) can be allocated to finance the compulsory affairs and optional affairs in the form of programs and activities related to the improvement of public services, job creation, poverty alleviation, improvement of environmental quality, and regional economic growth. The implications of these policies is the need for funds to finance the implementation of the functions, that have become regional authority, is also increasing. In practice, regional financial management still poses a complicated issue because the regional head are reluctant to release pro-people regional budget policy, even implication of regional autonomy is likely to give birth to little kings in region causing losses to state finance and most end up in legal proceedings. This paper discusses the loss of state finance and forms of liability for losses to the state finance. The result of the study can be concluded firstly,  there are still many differences in giving meaning and definition of the loss of state finace and no standard definition of state losses, can cause difficulties. The difficulty there is in an effort to determine the amount of the state finance losses. The calculation of state/regions losses that occur today is simply assessing the suitability of the size of the budget and expenditure without considering profits earned by the community and the impact of the use of budget to the community. Secondly, the liability for losses to the state finance is the fulfillment of the consequences for a person to give or to do something in the regional financial management by giving birth to three forms of liability, namely the Criminal liability, Civil liability, and Administrative liability.Keywords: state finance losses, liability, regional finance.


2017 ◽  
Vol 3 (2) ◽  
pp. 7
Author(s):  
Saida Parvin

Women’s empowerment has been at the centre of research focus for many decades. Extant literature examined the process, outcome and various challenges. Some claimed substantial success, while others contradicted with evidence of failure. But the success remains a matter of debate due to lack of empirical evidence of actual empowerment of women around the world. The current study aimed to address this gap by taking a case study method. The study critically evaluates 20 cases carefully sampled to include representatives from the entire country of Bangladesh. The study demonstrates popular beliefs about microfinance often misguide even the borrowers and they start living in a fabricated feeling of empowerment, facing real challenges to achieve true empowerment in their lives. The impact of this finding is twofold; firstly there is a theoretical contribution, where the definition of women’s empowerment is proposed to be revisited considering findings from these cases. And lastly, the policy makers at governmental and non-governmental organisations, and multinational donor agencies need to revise their assessment tools for funding.


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