Resilient Cities and Structures最新文献

Complex systems, such as infrastructure networks, industrial plants and jet engines, are of paramount importance to modern societies. However, these systems are subject to a variety of different threats. Novel research focuses not only on monitoring and improving the robustness and reliability of systems, but also on their recoverability from adverse events. The concept of resilience encompasses precisely these aspects. However, efficient resilience analysis for the modern systems of our societies is becoming more and more challenging. Due to their increasing complexity, system components frequently exhibit significant complexity of their own, requiring them to be modeled as systems, i.e., subsystems. Therefore, efficient resilience analysis approaches are needed to address this emerging challenge.

This work presents an efficient resilience decision-making procedure for complex and substructured systems. A novel methodology is derived by bringing together two methods from the fields of reliability analysis and modern resilience assessment. A resilience decision-making framework and the concept of survival signature are extended and merged, providing an efficient approach for quantifying the resilience of complex, large and substructured systems subject to monetary restrictions. The new approach combines both of the advantageous characteristics of its two original components: A direct comparison between various resilience-enhancing options from a multidimensional search space, leading to an optimal trade-off with respect to the system resilience and a significant reduction of the computational effort due to the separation property of the survival signature, once a subsystem structure has been computed, any possible characterization of the probabilistic part can be validated with no need to recompute the structure.

The developed methods are applied to the functional model of a multistage high-speed axial compressor and two substructured systems of increasing complexity, providing accurate results and demonstrating efficiency and general applicability.

Majority of the highly populated regions of the United States are susceptible to multiple natural hazards. In such regions, the design and construction of structures under multiple hazards are critical to achieve the appropriate structural performance and infrastructure resilience. Multi-hazard reliability analysis of structural systems evaluates the system response under multiple random loads, some of which may occur simultaneously, or the effect of one may weaken the structural system before the occurrence of the next event. This paper studies the combined effects of scouring and earthquakes, as two uncorrelated extreme events, on the performance of reinforced concrete highway bridges. In a continuous effort to support future improvement in understanding the impact of multi-hazard loading scenario on bridges and to develop mitigation actions, this paper assesses the seismic vulnerability of a reinforced concrete highway bridge experiencing the effect of erosion due to the increase in frequency of flood events. The analytical fragility approach uses a three-dimensional nonlinear finite element model of the bridge cases with various levels of scouring. Because a bridge is system of components, a component level fragility curve is used to track the response of the components for a given ground motion intensity. The system fragility curves are developed to consider the vulnerability of critical components to assess the probability of bridge damage. The results indicate that under multi-hazard scenarios, the component governing the fragility of the bridge system varies depending on the level of scour sustained by the structure.

This study develops a comprehensive framework to assess the resilience of transportation networks consisting of deteriorating bridges subjected to earthquake events. For this purpose, the structural capacity of highway bridges is estimated during their service life using a set of detailed finite-element models that simulate the progress of deterioration. The developed models take into consideration the main environmental stressors and determine the extent of capacity loss as a function of time. Based on the degraded state of structural components, seismic fragility analyses are performed to obtain a probabilistic evaluation of the extent of damageability of the existing bridges under seismic events. Since each transportation link normally consists of a number of bridges, the state of damage in the individual bridges is mapped to the corresponding links and a scenario-based approach is employed to estimate the resilience of the entire transportation network. To demonstrate how the consequences of structural degradation can be integrated into the developed framework, the large-scale transportation network of Los Angeles and Orange counties is investigated under a series of aging and earthquake scenarios. The outcome of this study indicates how the estimates associated with the functionality measures of a transportation network can be improved if the age factor is properly integrated into the framework used for resilience assessment.

Risk assessment and mitigation programs have been carried out over the last decades in the attempt to reduce transportation infrastructure downtime and post-disaster recovery costs. Recently, the concept of resilience gained increasing importance in design, assessment, maintenance, and rehabilitation structures and infrastructure systems, particularly bridges and transportation networks, exposed to natural and man-made hazards. In the field of disaster mitigation, frameworks have been proposed to provide a basis for development of qualitative and quantitative models quantifying the functionality and resilience at various scales, including components, groups and systems within infrastructure networks and communities. In these frameworks, the effects of aging and environmental aggressiveness must be explicitly considered, affecting the structural performance and functionality of civil infrastructure systems. Significant efforts have been made to incorporate risk and resilience assessment frameworks into informed decision making to decide how to best use resources to minimize the impact of hazards on civil infrastructure systems. This review paper is part of these efforts. It presents an overview of the main principles and concepts, methods and strategies, advances and accomplishments in the field of life-cycle reliability, risk and resilience of structures and infrastructure systems, with emphasis on seismic resilience of bridges and road networks.

After a brief overview of how the dimensionless resilience index has been calculated in the past for buildings, and some of the shortcomings of that approach, the use of a resilience deficit index is advocated to overcome some of these shortcomings. An example is provided and the pros and cons of each approach are discussed, with broad recommendations applicable to the quantification of building resilience.

Internet data center buildings have great importance for maintaining the post-earthquake functionality of telecommunication networks. It is essential to maintain the functionality of internet data center buildings during earthquakes or recover immediately after earthquakes, which is referred to as seismic resilience. In this study, a seismic resilience assessment framework based on the Chinese code GB/T 38591-2020 is introduced first. The seismic damage and post-earthquake repair of both structural components and non-structural components are considered in the resilience assessment framework. A method for post-earthquake functionality loss quantification is proposed based on damage state and functionality loss of component. The subsystem level and system level functionality loss can be obtained by an integration principle. The seismic resilience of a typical internet data center building was evaluated to demonstrate the effectiveness of the proposed method. To enhance the seismic resilience level, different disaster mitigation techniques including the energy dissipation technology using buckling restrained braces and the base-isolation technology using lead-rubber bearings are adopted. The seismic resilience is quantified and the corresponding seismic resilience curves under different earthquake intensities are developed based on evaluation results.