Metrics for Bridge Resilience Indicators

The ability to measure resilience critically depends on the underlying conceptual framework that guides the analysis. Yet, in contrast with its popularity in policy-making, resilience is a complex and ambiguous concept addressing multiple dimensions. Definitions and attributes of resilience vary widely between studies. Infrastructure is also a versatile concept and can describe built assets (hard infrastructure) or refers to all the institutions which are required to maintain the economic, health, and cultural and social standards of a country (soft infrastructure). In addition, infrastructure can be considered in terms of physical objects and networks or in terms of services. These different conceptions determine very different perimeters and sectors and ultimately result in divergent approaches to select relevant dimensions and design corresponding indicators. Analysis and modeling are confronted with considerable uncertainties regarding climate system behavior, but also future emissions, development trajectories and urbanization trends, in particular at the regional level. These uncertainties make it difficult, and sometimes impossible, to know exactly what the infrastructure should be adapted to. The past is no longer a reliable guide for the future as both the natural and the social spheres are becoming increasingly dynamic and uncertain. Resilience is increasingly adopted in its broadest and most comprehensive definition which blends persistence and adaptability where Resilience is the ability of X to anticipate, absorb, adapt to and rapidly recover from Y. These different abilities correspond to different temporal phases: A system resists and absorbs during and recovers after a stressful event. All three abilities depend on adaptability efforts to anticipate, prevent and prepare the system which take place before an event. To be used in practice, resilience need to be framed: the nature and focus of methodologies developed to assess and measure resilience depends on the adopted definitions, the type of infrastructure of interest –in particular whether soft infrastructure is included or not, the perimeter, sectors and time horizon considered and last but not least, the purpose of the evaluation. The range of potential evaluation needs and the number of specific challenges precludes the elaboration of a one-size-fits-all set of indicators for infrastructure resilience. If there is no “perfect” operational framework which encompasses all the dimensions of infrastructure resilience, in practical terms, asset owners, local authorities, regulators and insurers face these issues on a daily basis. From an operational point of view, resilient infrastructures should be well designed and well managed. In other words, resilience of infrastructure is the result of: • good design to ensure that the system has the necessary resistance, reliability and redundancy and, • good organization to provide the ability, capacity and capability to respond and recover from disruptive events. Our efforts to identify “indicators” for infrastructure resilience have not revealed many existing indicators of value. Instead, it is clear that best practice guidelines are increasingly perceived as efficient tools to encourage and promote resilience and deliver a level of reassurance not otherwise available through specific indicators. Norms of engineering designs, materials, and retrofit strategies have been developed to enhance the ability of infrastructure elements to withstand natural hazards. Many design and engineering standards already contribute to ensuring resistance and reliability of infrastructure. Risk management and Business Continuity Management standards are generic and comprehensive approaches. They provide frameworks, guidelines and process-based indicators to continually update and improve the abilities of an organization to overcome a disruptive event. Efforts must be pursued to update infrastructure design standards to ensure that future infrastructure capital is more resilient to anticipated climate change and extreme events. Finally, several dynamic fields of investigation are likely to influence conception and methods of infrastructure resilience assessment in the near future, including: • Modeling of infrastructure dependency to account better for the complexity of the systems and ensure that vulnerabilities in one sector do not compromise others. • Ecosystem-based climate change adaptation which cost-efficiency is becoming increasingly recognized • Evaluation of the efficiency of indicators and cost-benefit assessments methods.

Infrastructures, 2022

Urban transport infrastructures (TIs) play a central role in an urban society that faces more and more disasters. TIs, part of critical infrastructures (CIs), are highly correlated with urban disaster management in terms of their resilience when cities are facing a crisis or disaster. According to many studies, indicator assessment has been frequently used for the resilience management of CIs in recent decades. Defining and characterizing indicators can be useful for disaster managers as it could help monitor and improve the capacities and performance of TIs. The purpose of this paper, therefore, is (1) to identify and summarize the existing indicators of TIs resilience from the currently available literature, and (2) to discuss the possible future studies of the resilience indicator of TIs. The first results indicated that there are some barriers to identify indicators following the common search method through keywords. Additionally, the indicators found are mainly related to tech...

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)

Highway transportation networks play a vital role in today's economic and societal life and affect growth and employment. Hence, their undisrupted functionality and their quick recovery even after extreme natural hazard events are critical. To this end, resilience assessment of transportation networks against natural hazards is needed for decision-making processes in planning maintenance and retrofit actions, as well as for post-event risk management. This study aims to propose a multi-hazard resilience assessment framework for bridges that are the key components of transportation networks. The first step of the framework is the identification of critical hazards (i.e., earthquakes, floods) and the derivation of hazard curves and scenarios based on their probability of occurrence. The second step consists of a fragility assessment process based on computational analysis for single or multi-hazard occurrences given a range of hazard intensities. The third step includes the evaluation of functionality losses based on fragility assessment. In the fourth step, the required restoration time is estimated, and resilience metrics are calculated as dimensionless indicators. The proposed framework is applied to a case study riverine bridge, and comparative results on the single hazard and the multi-hazard resilience metrics are discussed. It has been observed that the effect of the consideration of multi-hazard scenarios is significant on the resilience of bridges.

Sustainable and Resilient Infrastructure

Resilient and sustainable traffic infrastructure systems such as bridges play a crucial role in societal economic growth. During the last decades, substantial research has been undertaken for the optimal management of risks associated with extreme events, and the concept of resilience was introduced. The knowledge on the system characteristics affecting resilience is increasing and so is the capability to model and analyze systems. The first step in systems modelling and analysis is to define the system which has not been addressed methodically in the literature. In this contribution, we provide a framework for systems identification in the context of resilience informed management of historic bridges. The proposed approach rests on the indicator-based systems modelling framework of the Joint Committee on Structural Safety (JCSS). With this basis we identify ten resilience indicators which provide information concerning the resilience performances of historic bridges. Finally, we apply the suggested approach through an example.

As of February 2019, the National Aeronautics and Space Administration (NASA) has reported since 1880 the average global temperature has increased 1°C, with the warmest year on record being 2016. As the years continue to pass, it is becoming more evident that climate change is occurring, which is known to be a catalyst for climatic weather events. Statistically speaking, these events are more prevalent, and catastrophic exemplified as hurricanes, earthquakes, flooding, and fires. In addition to the increase of potentially catastrophic events, society as a whole has become more conscientious in the use and preservation of natural resources, waste generation, and energy consumption. As the overall population continues to grow, the need for safe, secure and sustainable infrastructure increases. Civil infrastructure must be assessed to measure the level at which it will withstand impact from a catastrophic event, as well as how it is utilizing precious resources and energy. In consideration of these previously mentioned issues, several federal agencies, companies, and researchers have put forth an effort to measure and quantify the ability of civil infrastructure to withstand climatic catastrophes. Also, metrics to quantify sustainable construction are increasingly used as a common tool for infrastructure design and development. Most sustainability metrics consider the qualities of a system that revolve around the concept of sustainable development but fail to consider the resiliency of that system. Sustainability assessments are often discrete and will focus on one particular aspect or measure. Resiliency metrics are often overly complex and do not vi fully encapsulate the quality in a way that is pragmatic or useful to practitioners and engineers, or simply neglect sustainable construction methods. Proposed here is a framework that attempts to unify sustainability and resiliency assessment of geotechnical infrastructure, by considering the risk of failure given the probability of a catastrophic event. The framework is developed for use on geotechnical engineered systems, specifically an earthen dam used for flood control. A Bayesian analysis is used to determine the probability of failure given the occurrence of a catastrophic event, in conjunction with both a resiliency assessment, and sustainability assessments. This is to ensure that the sustainability index is jointly dependent upon the changes in resiliency given the occurrence of a catastrophic event. Two separate failure modes that are possible at the location of the earthen dam were modeled to determine the flexibility of the framework. Failure modes include seismic events, and rapid-drawdown and both were modeled with their associated probabilities. Results from the assessment are represented as a single index value that is plotted on a cartesian coordinate system. It is of note that assessment of a particular form of infrastructure mandates analysis of particular failure modes, and changing the system then requires analysis of failure modes to that particular system. In order to fully encapsulate a unified framework for sustainability and resiliency, it was imperative that the thesis provided here focus on one particular infrastructure system, which was chosen to be an earthen dam. vii TABLE OF CONTENTS

Proceedings of the Institution of Civil Engineers - Bridge Engineering, 2021

Bridges and critical transport infrastructure are primary assets and systems that underpin human mobility and activities. Loss of bridge functionality has consequences on entire transport networks, which are also interconnected with other networks. Cascading events then unfold in the entire system of systems, leading to significant economic losses and societal disruption to business and society. Recent natural disasters have revealed the vulnerabilities of bridges and critical assets to diverse hazards (e.g. floods, blasts, earthquakes), some of which are exacerbated due to climate change. The assessment of bridge and network vulnerabilities by quantifying their capacity and functionality loss and adaptation to new requirements and stressors is thus of paramount importance. The aim of this work was try to understand the main compound hazards, stressors and threats that have short- and long-term impacts on the structural capacity and functionality of bridges and the impact of bridge ...

2015

Within a life-cycle context, infrastructure systems may be subjected to abnormal events, which can hamper functionality of these systems. Maintaining functionality of highway bridges under hazard effects is gaining increased attention. In this paper, a framework for performance assessment of highway bridges under seismic hazard considering risk and resilience is presented. The time effects and uncertainties are integrated within the proposed seismic risk and resilience assessment procedure. Overall, the risk and resilience assessment of a bridge under seismic activity is based on a set of damage states, which are mutually exclusive and collectively exhaustive. Additionally, the probabilistic direct loss, indirect loss, and resilience of a bridge under seismic hazard are investigated. Sustainability assessment of highway bridges is also investigated. The assessment of probabilistic risk, resilience, and sustainability of highway bridges under seismic hazard can aid in implementing ri...

The capacity of critical infrastructure is one of the main components for infrastructure resilience. By improving the capacity increased resilience, and reduce the risks and impacts. There are several dimensions of resilience that need to be taken into consideration when trying to achieve a holistic approach for infrastructure resilience. One of this components anyway are the resilience parameters: anticipation, absorption, coping, restoration and adaptation. These parameters correspond to the critical infrastructure capacities and are a possible way to quantifying these capacities, with appropriate measurable resilience indicators. This paper presenting a list and description of possible generic resilience indicators, that are the same for all type of hazard and all type of critical infrastructure. This work is the result of scientific research in the EU-CIRCLE project, that is financed through the Horizon 2020 program of the European Union.

Engineering Structures, 2010

The concepts of disaster resilience and its quantitative evaluation are presented and a unified terminology for a common reference framework is proposed and implemented for evaluation of health care facilities subjected to earthquakes. The evaluation of disaster resilience is based on dimensionless analytical functions related to the variation of functionality during a period of interest, including the losses in the disaster and the recovery path. This evolution in time including recovery differentiates the resilience approach from the other approaches addressing the loss estimation and their momentary effects. The recovery process usually depends on available technical and human resources, societal preparedness, public policies and may take different forms, which can be estimated using simplified recovery functions or using more complex organizational and socio-political models. Losses are described as functions of fragility of systems that are determined using multidimensional performance limit thresholds. The proposed framework is formulated and exemplified for a typical Californian Hospital building using a simplified recovery model, considering direct and indirect losses in its physical system and in the population served by the system. A hospital network is also analyzed to exemplify the resilience framework. Resilience function captures the effect of the disaster, but also the results of response and recovery, the effects of restoration and preparedness. Therefore, such a function becomes an important tool in the decision process for both the policy makers and the engineering professionals.

Sustainability, 2020

Infrastructure resilience ascribes into the United Nations’ agenda for sustainable development. The more information supporting infrastructure resilience enhancement, the higher chance that it will be done objectively and effectively, and especially in a sustainable way. In spite of many different approaches and data sources, there is a lack of information that respects the emergency service point of view. The main research objective is to investigate factors determining sustainable infrastructure resilience enhancement that reflects direct protection of the most important values (human life and health) by connecting multiple variants of infrastructural resilience corresponding with the voice of emergency service and based on real data risk assessment. The methodology consists in formulation of a reference model for informing sustainable infrastructure resilience enhancement, risk assessment for infrastructure safety in terms of emergency service perspective and risk-based rationali...