State fragility and economic vulnerability: what is measured and why?

State fragility is a concept that emerged among the international community of donors in order to adapt aid policies to particularly difficult situations. Fragility has thus been measured to design a special treatment in favour of fragile states, otherwise left behind. In this context, but somewhat paradoxically, fragility has been measured by a low policy and institutional assessment, operated through the “CPIA”, in the multilateral development banks that also used this index as the major indicator to determine their aid allocation. Some other more multidimensional measures have broadened the scope of the indicators used to identify fragility. All these measures appear to be rather subjective, unstable, leading to discordant lists of fragile states and not really representing a risk to fail. For analytical and operational reasons, there may be advantages of turning to the concept of structural economic vulnerability (apparently close, but strongly different). Structural economic vulnerability, the risk to be durably affected by exogenous shocks, depends both on the size of the shocks and on the exposure to the shocks. It can be measured by the Economic Vulnerability Index (EVI), set up at the UN to identify the Least Developed Countries (LDCs). It is a rather objective and stable index, also reflecting a risk of becoming a fragile state, as illustrated by the fact that most of the LDCs have been considered as fragile at least once. Such an index can be used as a positive criterion of aid allocation, besides the CPIA, a low income per capita and a low level of human capital. Its inclusion among aid allocation criteria is supported by equity, effectiveness and transparency reasons. It allows one to treat the case of fragile states in an integrated framework, leaving only the most acute cases of fragility or failure for an exceptional treatment.State Fragility, aid policies

State fragility and economic vulnerability: what is measured and why?

State fragility is a concept that emerged among the international community of donors in order to adapt aid policies to particularly difficult situations. Fragility has thus been measured to design a special treatment in favour of fragile states, otherwise left behind. In this context, but somewhat paradoxically, fragility has been measured by a low policy and institutional assessment, operated through the “CPIA”, in the multilateral development banks that also used this index as the major indicator to determine their aid allocation. Some other more multidimensional measures have broadened the scope of the indicators used to identify fragility. All these measures appear to be rather subjective, unstable, leading to discordant lists of fragile states and not really representing a risk to fail. For analytical and operational reasons, there may be advantages of turning to the concept of structural economic vulnerability (apparently close, but strongly different). Structural economic vulnerability, the risk to be durably affected by exogenous shocks, depends both on the size of the shocks and on the exposure to the shocks. It can be measured by the Economic Vulnerability Index (EVI), set up at the UN to identify the Least Developed Countries (LDCs). It is a rather objective and stable index, also reflecting a risk of becoming a fragile state, as illustrated by the fact that most of the LDCs have been considered as fragile at least once. Such an index can be used as a positive criterion of aid allocation, besides the CPIA, a low income per capita and a low level of human capital. Its inclusion among aid allocation criteria is supported by equity, effectiveness and transparency reasons. It allows one to treat the case of fragile states in an integrated framework, leaving only the most acute cases of fragility or failure for an exceptional treatment.State Fragility;aid policies

Demonstrating adequate safety for a concrete column exposed to fire, using probabilistic methods

Demonstrating adequate safety for exceptional designs and new design applications requires an explicit evaluation of the safety level, considering the uncertainties associated with the design. The recently published PD 7974-7:2019 provides five routes to demonstrating adequate safety through probabilistic methods but does not include worked examples. The case study in this paper presents three state-of-the-art approaches for demonstrating achievement of an absolute safety target (acceptance concept ‘AC3’ in PD 7974-7:2019) for a concrete column in an office building with stringent reliability requirements. The case study shows how fragility curves listed by, for example, industry organizations can support probabilistic approaches and a more comprehensive understanding of design performance

A fragility-oriented approach for seismic retrofit design

This study proposes a practical fragility-oriented approach for the seismic retrofit design of case-study structures. This approach relies on mapping the increase of the global displacement-based ratio of capacity to life-safety demand ( CDRLS) to the building-level fragility reduction. Specifically, the increase of CDRLS due to retrofitting is correlated with the corresponding shift in the fragility median values of multiple structure-specific damage states, observing that a pseudo-linear trend is appropriate under certain conditions. Accordingly, a practical approach is proposed to fit such a (structure-specific) linear trend and then use it by first specifying the desired fragility median and subsequently finding the corresponding target value of CDRLS that must be achieved through retrofit design. The validity of the proposed approach is illustrated for an archetype reinforced concrete (RC) structure not conforming to modern seismic design requirements, which has been retrofitted using various techniques, namely, fiber-reinforced polymers wrapping of columns and joints, RC jacketing, and steel jacketing

Influence of Vertical Ground Motions on the Seismic Fragility Modeling of a Bridge-Soil-Foundation System

This paper explores the effects of vertical ground motions (VGMs) on the component fragility of a coupled bridged-soil-foundation (CBSF) system with liquefaction potential, and highlights the unique considerations on the demand and capacity model required for fragility analysis under VGMs. Optimal intensity measures (IMs) that account for VGMs are identified. Moreover, fragility curves that consider capacity change with fluctuating axial force are derived. Results show that the presence of VGMs has a minor effect on the failure probabilities of piles and expansion bearings, while it has a great influence on fixed bearings. Whether VGMs have an impact on column fragilities depends on the design axial load ratio. Finally, more accurate fragility surfaces are derived, which are compared with results of conventional fragility curves. This study highlights the important role that VGMs play in the selection of optimal IMs, and the capacity and fragility representation of certain components of CBSF systems