Seismic Resilience Assessment Research Articles

A novel urban seismic resilience assessment method considering the weighting of post-earthquake loss and recovery time

Earthquakes impose substantial threats to the built environment of urban communities. To reduce the catastrophic consequences of earthquakes, there is an urgent need to build seismic resilient cites that can better resist seismic damage and enable a rapid post-disaster recovery. This paper gives the definition of urban seismic resilience, and establishes a seismic resilience assessment indicator system for urban built environment that integrates engineering systems, non-engineering systems and secondary disaster risk. A novel urban seismic resilience assessment method based on post-earthquake loss and recovery time is then developed to assess engineering system seismic resilience. Post-earthquake loss is divided into casualties and functionality loss. Adjustment coefficients are applied to account for the effects of non-engineering systems and secondary disaster risks on urban seismic resilience. The analytical hierarchy process is employed to calculate the weights of individual engineering systems. In the end, a city located in southern China is taken as an example to illustrate the proposed method. The assessment results suggest that the urban seismic resilience grade is Ⅱ, which means that the city can effectively resist possible future earthquake disasters.

A belief rule-base approach to the assessment and improvement of seismic resilience of high-speed railway station buildings

As an important part of the railway system and the key node in the railway transportation network, the railway station undertakes the critical task of realizing convenient passenger transfer and efficient mass transportation. Resilience assessment and improvement of complex communal buildings have recently received significant attention, however, the complexity of including components, spatial structure, and engineering facilities made it challenging to find an accepted framework to assess the resilience of high-speed railway (HSR) stations. To overcome this challenge, the included subsystems for various operations of HSR stations are sorted out in detail, and the hierarchical belief rule-base (BRB) is adopted to establish the quantitative relationship between station function and each subsystem at different states after an earthquake through statistical analysis, expert knowledge, and logic analysis. Subsequently, optimization of the initial parameters in BRB is performed as a demonstration in case users need a more accurate BRB based on their experience and statistics. Finally, three subsystems repair sequential solving methods to improve the seismic resilience of HSR stations are proposed and discussed: the traversal algorithm, sensitivity-based method, and simulated annealing (SA) algorithm. The method proposed in this study paves the way for research on the resilience assessment of HSR station buildings.

Seismic fragility and resilience assessment of bridge columns with dual-replaceable composite link beam under near-fault GMs

The beam-column joints of piers with reinforced concrete link beams (RCLB) are easy to be damaged during earthquakes. Post-earthquake maintenance is very inconvenient since the beam-column joints are integrally cast. Therefore, a novel dual-replaceable composite link beam (DRCLB) is proposed to replace the traditional RCLB, which is composed of angle steels, concrete-filled steel tubes (CFST), connection steel plates, and an RC beam. The dual-replaceable mechanism of DRCLB is that the angle steel and CFST of DRCLB are damaged in sequence, and can be quickly replaced separately after the earthquake. The multi-stage damage model of DRCLB is quantified by pushover analysis, which can be applied to seismic fragility and resilience assessment. The seismic fragility and resilience analysis are carried out under near-fault ground motions for double-column piers with DRCLB and RCLB respectively. The results indicate that DRCLB can effectively reduce the peak response of the beam-column joint. Meanwhile, the columns of double-column piers with DRCLB and RCLB respectively present approximately identical performance. Based on seismic resilience analysis, the recovery capacity of the pier is effectively improved due to the well dual-replaceable performance of DRCLB.

Seismic resilience assessment of self-centering prestressed concrete frame with different energy dissipation ratio and second stiffness

This paper presents the effects of two key parameters, energy dissipation ratio and second stiffness, on the seismic performance and resilience of self-centering prestressed concrete (SCPC) frames. The dynamic parametrical analyses under different earthquake intensities and fragility analyses under different performance level have been carried out, the maximum drift (MD) - residual drift (RD) joint probability density method suitable for SCPC structure was proposed, and the damage distribution law of structural members and typical non-structural members was analyzed. The influence of different parameters on the resilience indicators of SCPC framework was studied based on the FEMA P-58 resilience assessment framework. The results indicate that the main structure of the SCPC frame remained intact, while the acceleration-sensitive non-structural components accounted for more than 80% of the total repair cost and repair time. Increasing the second stiffness could reduce the high-order modal effect of the SCPC structure response and the loss in the upper part of the SCPC frame. Increasing energy dissipation ratio could reduce the maximum response of the structure and improve the building resilience. When the energy dissipation ratio was increased from 0.2 to 0.8, the repair cost and repair time were decreased by 13.1% and 17.2%, respectively, under maximum considered earthquake (MCE), and the residual displacement of the structure was still within the re-centering limit of 0.2%.

A preliminary general framework for seismic resilience assessment of slope engineering

A preliminary general framework for seismic resilience assessment of slope engineering

Influence of regional background stress fields on the spontaneous rupture of the major faults around Xiluodu dam, China

Simulations of the spontaneous rupture of potential earthquakes in the vicinity of reservoir dams can provide accurate parameters for seismic resilience assessment, which is essential for improving the seismic performance of reservoir dams. In simulations of potential spontaneous ruptures, fault geometry, regional stress fields, constitutive parameters of the fault friction law, and many other factors control the slip rate, morphology, and dislocation of the rupture, thereby affecting the simulated ground motion parameters. The focus of this study was to elucidate the effects of the background stress field on the nucleation and propagation of spontaneous ruptures based on the factors influencing potential M > 7 earthquake events on the Leibo Middle Fault (LBMF) and the Mabian-Yanjing Fault (MB-YJF) in the Xiluodu dam (XLD) region. Our simulation results show that the magnitude of the regional background stress field plays a decisive role in whether a destructive earthquake exceeding the critical magnitude will occur. We found that the direction and magnitude of the regional stress significantly affect the range of rupture propagation on the fault plane, and fault geometry affects the spatial distribution of the rupture range. Under the same regional stress field magnitude and orientation, a more destructive, high-magnitude earthquake is more likely to occur on the LBMF than on the MB-YJF.

Life-cycle seismic fragility and resilience assessment of aging bridges using the endurance time method

This paper presents a framework based on the endurance time (ET) method to evaluate bridge seismic fragility and resilience in the life-cycle context by considering corrosion effects. The ET method has been widely used for seismic analysis of structures in recent years due to its high precision and low computational effort. However, the traditional ET method does not provide any information about the dispersion of seismic responses and can only predict the median of responses. Therefore, a framework for quantifying the record-to-record (RTR) uncertainty through the ET method is proposed. Firstly, a three-dimensional finite element model of a three span bridge in OpenSees was constructed and subjected to the ET intensifying functions. The proposed methodology was then applied to predict the bridge's probabilistic seismic response distribution. The results were compared with those obtained using incremental dynamic analysis (IDA) as a benchmark method. It was demonstrated that the proposed methodology can significantly reduce computational costs while maintaining acceptable seismic response accuracy (both median and dispersion). Next, the life-cycle fragility and resilience of the bridge were evaluated considering the chloride-induced corrosion effects using the proposed framework, which may be challenging to address using the IDA method due to its time-consuming nature. The results show that the seismic resilience decreases, whereas the uncertainty increases with the increasing seismic intensity and age of the bridge. Therefore, it is of great importance to incorporate aging effects into an accurate evaluation of bridge resilience.

Life cycle resilience assessment of RC frame structures considering multiple-hazard

Corrosion can lead to the seismic performance deterioration of RC structures, however, the corrosion effects on the seismic risks and resilience are poorly understood. This paper proposes a framework for assessing the life cycle resilience of RC structures under multi-hazards. The framework integrates the probabilistic corrosion model, seismic hazard model, fragility, seismic risk assessment, resilience assessment, and resilience rating model. The time-variant economic losses that consist of the repair cost and downtime loss are assumed as the functionality indicators. The repair time and idle time associated with impeding factors are considered in the recovery time. To accurately assess the seismic resilience of uncorroded and corroded structures, an innovative recovery model that is validated with recovery data in the previous work is proposed. The resilience rating method that considers economic loss, recovery time, and seismic resilience is suggested to assess the final resilience level. The proposed framework is applied to a four-story reinforced concrete frame office building located in the coastal area where chloride attacks are extreme. The results show that the corrosion increases the seismic risk and decreases the resilience of buildings, which reveals the importance of the life cycle resilience assessment of buildings under multi-hazards. The proposed framework can be modified to incorporate other hazards such as floods and typhoons to assess life cycle disaster resilience.

Assessment of Seismic Resilience in Urban Water Distribution Network Considering Hydraulic Indices

Assessment of Seismic Resilience in Urban Water Distribution Network Considering Hydraulic Indices

Seismic resilience assessment of reinforced concrete structures under salt erosion

In recent years, researchers have been concerned with the seismic resilience of structures under salt-erosion environments. As an important part of the resilience assessment, loss estimation, particularly considering the structural loss caused by salt erosion, become a research hotspot. This study presents a methodology to develop loss estimation for deteriorating reinforced concrete (RC) structures by combining it with a quantitative analysis method. The replacement cost of a deteriorated structure was defined to establish a deteriorating reinforcement model based on the loss of a corroded section. The deteriorating reinforcement model was further utilized to establish a post-earthquake loss estimation function of the structure owing to chloride-induced corrosion by considering the cumulative effect of chloride erosion and earthquakes on deteriorating RC structures. Sigmoidal functions were used to simulate post-earthquake recovery paths depending on the extent of damage after an earthquake. Then, the structural resilience was estimated by combining it with a time-varying function. Finally, the resilience assessment calculation of a three-story RC structure example model was considered, and the applicability of the research method established in this study was verified. The calculation results show that the structural loss increased with an increase in the chloride erosion time at any specific PGA and led to a gradual decrease in the structural resilience. Reinforcement corrosion has a significant effect on structural resilience under earthquakes, and ignoring the effect of chloride salts on a structure can lead to an overestimation of resilience.

Rapid seismic response prediction of RC frames based on deep learning and limited building information

Building portfolio is the important urban engineering system, and the seismic resilience assessment of a city needs the quick and accurate prediction of the seismic responses of existed buildings. However, many existed buildings generally possess the problem that the design information materials are incomplete or completely lost. The major challenge in the seismic resilience assessment of building portfolio is how to predict the seismic responses of buildings quickly and accurately just using limited building information. This manuscript aims to develop a method for the seismic response prediction of the existed reinforced concrete (RC) frame buildings just using limited building information. A total of 162 typical RC frame buildings of low to medium rise are designed, and the inter-story drift (IDR) as well as peak floor acceleration (PFA) of each floor in each building are computed for 200 ground motions with nonlinear time history analysis (NLTHA) method. A convolutional neural network (CNN) is developed with ground motion records and five easy-getting building parameters as inputs. The outputs are IDR and PFA of each floor for the given building. Considering the physical means of an input parameter—number of stories, the modified loss function and modified evaluation function are proposed. The developed network is trained with the computed dataset and the modified loss function, and the trained model (referred to StruNet) can take the characteristics of ground motions and structures into consideration together comparing to previous studies. The proposed model is verified through four cases (i.e., 4 actual buildings with different construction time, occupancy types, and plane layouts), which are independent of the deep learning dataset. The results confirm that the proposed method offers prediction results with sufficient accuracy and shows high computational efficiency.

Restored quality of life-based approach (REQUALIFE) for urban seismic resilience assessment: Quantitative method

With rapid urbanization, today's cities are increasingly vulnerable to unpredictable and catastrophic environmental hazards such as earthquakes. A quantitative approach for seismic resilience assessment at the urban scale is still a challenging task because of the extreme complexity of urban systems. This study proposes a Restored Quality of Life-based Approach to evaluate urban seismic resilience. First, extensive literature is reviewed and analyzed to determine the mathematical definition of urban seismic resilience. Performance-based methods are selected, and urban seismic resilience is calculated by comparing desired city performance with actual city performance after an earthquake. Second, the concept of post-disaster quality of life is applied to indicate the city performance. A set of indicators is constructed preliminarily based on literature to measure the quality of life and is then validated by a Delphi survey. Finally, a framework is recommended to apply the proposed approach. The Restored Quality of Life-based Approach offers an effective tool for evaluating and improving the urban seismic resilience of a city and lays a theoretical and methodological foundation for better insights into and analysis of the urban seismic resilience in the future.

Restored Quality of Life-based approach (REQUALIFE) for urban seismic resilience assessment: Case study

Management of urban seismic resilience relies on effective assessment approaches. However, developing an approach for the quantitative assessment at the urban scale remains to be a challenging task due to the complexity and heterogeneity of urban systems. Accordingly, Part I proposed a Restored Quality of Life-based approach to bridge this gap. As an extension of Part I, this study conducted a case study on a test city in China that experienced the devastating Wenchuan earthquake in 2008 to demonstrate the applicability of the proposed approach. The desired and actual performance curves of the city were delineated according to the collected data and materials of the field survey. The overall urban seismic resilience of the city was then assessed, and details from the temporal and spatial dimensions were investigated. The case study demonstrated that the need satisfactions of residents in different phases varied. Moreover, the resilience differences within the city were demonstrated. The causes for these differences were further analyzed. This case study calibrates the proposed approach and serves as a valuable reference for the effective assessment and improvement of urban seismic resilience.

Seismic Resilience Assessment Strategy for Social and Sustainability Impact Evaluation on Transportation Road Network: A Seismic Liquefaction-Induced Damage Application

Transport networks play a critical role for living communities, as they facilitate the exchange of people and goods and foster economic growth. Improving their resilience against seismic hazards, among which liquefaction is by far one of the most significant and complex, is consistent with most of the Sustainable Development Goals pinpointed by the United Nations’ Agenda. In this paper, an original methodological framework, combining innovative Geo-statistical approaches to analyze soil properties, prediction models for soil liquefaction, and calibrated transport demand models providing the social and economic cost associated with seismic-induced road damages and closures within a renewed Geographical Information Systems (GIS) workspace, is proposed. In particular, based on traditional risk assessment evaluation, an innovative approach to evaluate the exposure in terms of economic loss due to lack of accessibility is presented. The methodology is applied to a district area in northern Italy that underwent a recent seismic event that caused several soil liquefaction phenomena. Results provided by a sensitivity analysis on a stochastic (return period) basis are derived: as the seismic intensity increases, the total social costs increase, but the trend of the rates due to traffic delays and the loss of accessibility are irregular. Although further simulation scenarios need to be undertaken, the proposed methodology seems to provide an effective planning tool to evaluate preventive strategies aimed at improving the resilience of transport networks against liquefaction risk.

A new method for function-loss based seismic resilience assessment of buildings

Seismic resilience assessment of buildings is an important aspect in developing resilient buildings. To evaluate seismic resilience of general buildings directly and quickly using a comprehensive index, a new framework of seismic resilience assessment for buildings by assembly-based function loss quantification is developed. Considering the fuzziness uncertainty in evaluation, a new method quantifying function loss of buildings is firstly proposed by consequence analysis of components, logic trees connected with fuzzy operators, and logic system of buildings including relevance between stories. Then the repair scheme of buildings is proposed to compute the time-varying function loss of buildings during the whole recovery process. The proposed method is embedded in probabilistic performance-based earthquake engineering (PBEE), in which uncertainty factors during the whole life cycle of buildings can be considered. Case study on a ten-story RC moment-resisting frame building is provided to demonstrate the applicability of the proposed method. Results show that the case building’s resilience index can be easily and reasonably computed by the proposed framework at different earthquake intensity levels. Compared with the existing assembly-based function methods and resilience assessment methods, the proposed method avoids subjectivity during evaluation greatly. The proposed resilience assessment method can help to develop resilient buildings.

Seismic Resilience Assessment in Optimally Integrated Retrofitting of Existing School Buildings in Italy

Modern society requires that structures exhibit greater levels of resilience, especially under earthquakes. The seismic resilience of buildings is thus gaining increased attention as a particular, beyond-code approach. Seismically retrofitted buildings behave satisfactorily under expected earthquake scenarios; however, this does not guarantee operativity after a seismic event. This study critically reviews several methods currently available in the literature that quantify the seismic resilience level of buildings from different perspectives. An existing reinforced concrete school building, retrofitted according to four distinct strategies, is first evaluated in terms of seismic resilience levels. The overview and critical analysis of available resilience assessment frameworks determine the most suitable parameters to measure the seismic resilience for buildings. Subsequently, this metric is incorporated as an additional decision variable into an integrated seismic and energy retrofitting set of strategies. A multicriteria decision-making analysis is performed to select the optimally combined seismic and energy retrofitting alternative under social, technical, environmental evaluation, and seismic resilience aspects. We show how resilience impacts the preference for integrated seismic and energy retrofitting strategies, especially when this metric is considered as an annualized expected value.

Seismic resilience of internet data center building with different disaster mitigation techniques

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.

Seismic performance and resilience assessment of friction damped self-centering prestressed concrete frames

This study evaluated the hysteretic behavior, seismic performance, and resilience of friction based (FD) self-centering prestressed concrete (SCPC) frames. First, an experimental study on a one-story one-bay FD-SCPC frame was conducted. Second, dynamic analyses and fragility analyses of multi-story FD-SCPC frames with different design parameters under fortification and rare earthquakes were conducted. Finally, considering the repair cost and repair time as criteria, the resilience assessment of structures employing FD-SCPC frames was performed. The analyses results indicated that the FD-SCPC frames achieved the expected hysteretic behavior in terms of recentering capacity and mitigated damages in the structural components. Under fortification earthquakes, the FD-SCPC frames showed seismic behavior and resilience similar to those of cast-in-place reinforced concrete frames. Under rare earthquakes, owing to the unique rocking mechanism and frictional energy dissipating mechanism, the damage of the structural components of the FD-SCPC frames was much less than that of the traditional cast-in place concrete frames. Considering the repair cost and time for the structural and nonstructural components, the seismic behavior and resilience of the FD-SCPC frame were found to be significantly superior to those of the cast-in-place reinforced concrete frames.

Post-earthquake assessment model for highway bridge networks considering traffic congestion due to earthquake-induced bridge damage

Reliable post-earthquake modeling of a highway bridge network (HBN) is essential for seismic reliability, risk, and resilience assessment. This requires the accurate modeling of the effects of earthquake-induced bridge damage on traffic congestion. Accordingly, a novel post-earthquake HBN simulation method, wherein each bridge is defined as a link instead of as a part of a highway link, was proposed herein. In addition, the feasibility of implementing machine learning methods for fragility modeling of regular highway bridges was explored as well. The developed artificial neural network (ANN) fragility model can accurately capture the seismic damage of highway bridges at trivial computation costs compared to time-history analysis methods. Finally, the proposed methods were combined with probabilistic seismic hazard analysis, traffic demand assessment and distribution, etc., and applied to an HBN that connects several cities in Arizona and New Mexico to validate their efficacy and scalability. The results revealed that compared to the proposed HBN simulation method, conventional HBN modeling methods may underestimate the seismic resilience of HBNs.

Seismic resilience assessment of buildings: A simplified methodological approach through conventional seismic risk assessment

A simplified methodology to evaluate seismic resilience of buildings through a probabilistic risk assessment is proposed. The methodology uses the results from the conventional seismic risk assessment with the inclusion of social and economic aspects. The seismic resilience assessment process considers the workforce population, repair time, direct and indirect losses. They can be applied within the damage definition stage with the aim of the vulnerability functions for a specific building typology, and loss estimation stage of the probabilistic risk assessment. For the case of the definition of vulnerability functions a previous methodological approach is used with fewer modifications. In addition, a new risk figure called average annual repair time is introduced in the probabilistic risk assessment allowing to obtain the resilience index. Aspects such as expected repair time, quantities of crew members, business interruption losses, workforce population capacity and risk figures: average annual loss, probable maximum loss and average annual repair time are considered. Then, all those aspects are integrated within the exposure, damage, and loss estimation models with additional considerations to perform the calculation of the resilience. Finally, the results are represented by means of a unitless simplified resilience index allowing to be compared among different scenarios. The methodology is illustrated using two study cases. The first one represented its application at damage definition stage and is comprised by 3-, 6- and 9-story reinforced concrete moment resisting frame school buildings designed for special seismic code level. The second one covered the application at loss estimation stage and considers a fictitious portfolio of approximately 190,000 buildings composed by the previous three building typologies located along the whole country of Peru. The results show a highly sensitivity associated to workforce population, repair time, and indirect losses. Conclusions and possible applications related to Disaster Risk Reduction are summarized.