Search Results (191)

Coseismic landslides are geological events in which slopes, either on the verge of instability or already in a fragile state, experience premature failure due to seismic shaking. On 5 September 2022, an Ms 6.8 earthquake struck Luding County, Sichuan Province, China, triggering numerous landslides that caused severe casualties and property damage. This study systematically interprets 13,717 coseismic landslides in the Luding earthquake’s epicentral area, analyzing their spatial distribution concerning various factors, including elevation, slope gradient, slope aspect, plan curvature, profile curvature, surface cutting degree, topographic relief, elevation coefficient variation, lithology, distance to faults, epicentral distance, peak ground acceleration (PGA), distance to rivers, fractional vegetation cover (FVC), and distance to roads. The analytic hierarchy process (AHP) was improved by incorporating frequency ratio (FR) to address the subjectivity inherent in expert scoring for factor weighting. The improved AHP, combined with the Pearson correlation analysis, was used to identify the dominant controlling factor and assess the landslide susceptibility. The accuracy of the model was verified using the area under the receiver operating characteristic (ROC) curve (AUC). The results reveal that 34% of the study area falls into very-high- and high-susceptibility zones, primarily along the Moxi segment of the Xianshuihe fault and both sides of the Dadu river valley. Tianwan, Caoke, Detuo, and Moxi are at particularly high risk of coseismic landslides. The elevation coefficient variation, slope aspect, and slope gradient are identified as the dominant controlling factors for landslide development. The reliability of the proposed model was evaluated by calculating the AUC, yielding a value of 0.8445, demonstrating high reliability. This study advances coseismic landslide susceptibility assessment and provides scientific support for post-earthquake reconstruction in Luding. Beyond academic insight, the findings offer practical guidance for delineating priority zones for risk mitigation, planning targeted engineering interventions, and establishing early warning and monitoring strategies to reduce the potential impacts of future seismic events. Full article

Multiple uncertainties in traffic demand fluctuations and infrastructure vulnerability during seismic events pose significant challenges for the resilience assessment of highway transportation networks (HTNs). While Monte Carlo simulation remains the dominant approach for uncertainty propagation, its high computational cost limits its scalability, particularly in metropolitan-scale networks. This study proposes an EQResNet framework for accelerated post-earthquake resilience assessment of HTNs. The model integrates network topology, interregional traffic demand, and roadway characteristics into a streamlined deep neural network architecture. A comprehensive surrogate modeling strategy is developed to replace conventional traffic simulation modules, including highway status realization, shortest path computation, and traffic flow assignment. Combined with seismic fragility models and recovery functions for regional bridges, the framework captures the dynamic evolution of HTN functionality following seismic events. A multi-dimensional resilience evaluation system is also established to quantify network performance from emergency response and recovery perspectives. A case study on the Sioux Falls network under probabilistic earthquake scenarios demonstrates the effectiveness of the proposed method, achieving 95% prediction accuracy while reducing computational time by 90% compared to traditional numerical simulations. The results highlight the framework’s potential as a scalable, efficient, and reliable tool for large-scale post-disaster transportation system analysis. Full article

Corrosion can accelerate the deterioration of the mechanical properties of steel structures. However, few studies have systematically evaluated its impact on seismic performance, particularly with respect to seismic economic losses. In this paper, the seismic fragility and loss assessment of a multi-story steel frame with viscous dampers (SFVD) building are investigated through experimental and numerical analysis. Based on corrosion and tensile test results, OpenSees software 3.3.0 was used to model the SFVD, and the effect of corrosion on the seismic fragility was evaluated via incremental dynamic analysis (IDA). Then, the economic losses of the SFVD during different seismic intensities were assessed at various corrosion times based on fragility analysis. The results show that as the corrosion time increases, the mass and cross-section loss rate of steel increase, causing a decrease in mechanical property indices, and theprobability of exceedance of the SFVD in the limit state increases gradually with increasing corrosion time, with an especially significant impact on the collapse prevention (CP) state. Furthermore, the economic loss assessment based on fragility curves indicates that the economic loss increases with corrosion time. Thus, the aim of this paper is to provide guidance for the seismic design and risk management of steel frame buildings in coastal regions throughout their life cycle. Full article

This paper presents an advanced seismic performance evaluation of reinforced concrete (RC) seismically isolated frame structures under the conditions of rare earthquakes. By employing an elastic–plastic analysis in conjunction with a nonlinear multi-degree-of-freedom model, this study innovatively assesses the incremental dynamic vulnerability of isolated structures. A novel equivalent linearization method is introduced for both single- and two-degree-of-freedom isolation structures, providing a simplified yet accurate means of predicting seismic responses. The reliability of the modified Takeda hysteretic model is verified through comparative analysis with experimental data, providing a solid foundation for the research. Furthermore, a multi-degree-of-freedom shear model is employed for rapid elastic–plastic analysis, validated against finite element software, resulting in an impressive 85% reduction in computation time while maintaining high accuracy. The fragility analysis reveals the staggered upward trend in the vulnerability of the upper structure and isolation layer, highlighting the importance of comprehensive damage control to enhance overall seismic performance. Full article

This paper evaluates the time-dependent fragility and post-earthquake residual seismic performance of existing steel frame columns in offshore atmospheric environments. Based on experimental research, the seismic failure mechanism and deterioration laws of the seismic behavior of corroded steel frame columns were revealed. A finite element analysis (FEA) method for steel frame columns, which considers corrosion damage and ductile metal damage criteria, is developed and validated. A parametric analysis in terms of service age and design parameters is conducted. Considering the impact of environmental erosion and aging, a classification criterion for damage states for existing steel frame columns is proposed, and the theoretical characterization of each damage state is provided based on the moment-rotation skeleton curves. Based on the test and numerical analysis results, probability distributions of the fragility function parameters (median and logarithmic standard deviation) are constructed. The evolution laws of the fragility parameters with increasing service age under each damage state are determined, and a time-dependent fragility model for existing steel frame columns in offshore atmospheric environments is presented through regression analysis. At a drift ratio of 4%, the probability of complete damage to columns with 40, 50, 60, and 70-year service ages increased by 18.1%, 45.3%, 79.2%, and 124.5%, respectively, compared with columns within a 30-year service age. Based on the developed FEA models and the damage class of existing columns, the influence of characteristic variables (service age, design parameters, and damage level) on the residual seismic capacity of earthquake-damaged columns, namely the seismic resistance that can be maintained even after suffering earthquake damage, is revealed. Using the particle swarm optimization back-propagation neural network (PSO-BPNN) model, nonlinear mapping relationships between the characteristic variables and residual seismic capacity are constructed, thereby proposing a residual seismic performance evaluation model for existing multi-aged steel frame columns in an offshore atmospheric environment. Combined with the damage probability matrix of the time-dependent fragility, the expected values of the residual seismic capacity of existing multi-aged steel frame columns at a given drift ratio are obtained directly in a probabilistic sense. The results of this study lay the foundation for resistance to sequential earthquakes and post-earthquake functional recovery and reconstruction, and provide theoretical support for the full life-cycle seismic resilience assessment of existing steel structures in earthquake-prone areas. Full article

Shear walls, integrated into conventional reinforced concrete (RC) moment-resisting frame systems (RC frame–shear wall building), have proven to be effective in improving the structural performance and reliability of buildings; however, the seismic behavior of the building depends directly on the location of these elements. For this reason, this paper evaluates the structural reliability of ten medium-rise RC buildings designed based on the Mexico City Building Code, considering different shear wall configurations. With the aim to estimate and compare the seismic reliability, the buildings are modeled as complex 3D structures via the OpenSees 3.5 software, which are subjected to different ground motion records representative of the soft soil of Mexico City scaled at different intensity values in order to compute incremental dynamic analysis (IDA). Furthermore, the parameter used to estimate the reliability is the maximum interstory drift (MID), which is obtained from the incremental dynamic analysis in order to assess the structural fragility curves. Finally, the structural reliability estimation is computed via probabilistic models by combining the fragility and seismic hazard curves. It is concluded from the results that the structural reliability is maximized when shear walls are symmetrically distributed. On the other hand, the configuration with walls concentrated in the center of the building tends to oversize the frames to reach a reliability level comparable to that of symmetrical arrangements. Full article

A significant challenge in probabilistic seismic demand analysis lies in selecting appropriate intensity measures and investigating their relationships with demand parameters to ensure accurate seismic fragility predictions. A single ground motion intensity measure is insufficient to capture the complex characteristics of ground motion, leading researchers to focus on compound intensity measures. It is essential to investigate the selection of ground motion features and the number of features included in the construction of compound intensity measures, as these measures cannot comprise an unlimited set of ground motion features. This study focused on machine learning feature selection methods to select ground motion features for compound intensity measures, utilizing mutual information for feature selection. Considering the symmetry and asymmetry requirements of this process, optimized features were selected. Based on the selected features, the compound ground motion intensity measure was constructed to evaluate structural seismic fragility. The compound ground motion intensity measure was evaluated against scalar intensity measure in terms of correlation, efficiency, practicality, proficiency, and sufficiency. A comprehensive comparative analysis demonstrates the applicability of the compound intensity measure. The study’s findings support fragility analysis and performance evaluation using compound intensity measures. The corresponding results can be applied in the risk analysis aspect of performance-based earthquake engineering. Full article

The 2012 Emilia earthquake highlighted the vulnerability of fortified architecture. Based on the observed seismic behaviors, this research proposes a GIS geodatabase, designed with a proactive approach, for the prediction and prevention—at a territorial scale—of the most frequent damage mechanisms of the investigated typology. The designed geo-database allows for the identification of possible correlations between constructive features and the occurrence of damage, through statistical and geo-referenced analysis. Moreover, the designed geodatabase, by enabling the comparison of the damage level data with the seismic action of the site, through INGV (National Institute of Geophysics and Volcanology) shakemaps, allowed the definition of experimental fragility curves, for three of the most common damage mechanisms. By applying these functions to castles in the province of Parma, it was possible to define future seismic risk scenarios for the mechanisms considered, thanks to the use of the seismic hazard map. Therefore, the described methodology could be functional to identify the most urgent and high-priority interventions in order to optimize the management of economic resources. The final aim is to promote the application of the concept of minimum intervention, and more in general to preserve the architectural heritage, avoiding emergency interventions and aiming instead to apply planned conservation strategies. Full article

This paper presents a framework for evaluating the impact of seismic retrofitting alternatives on seismic risk, specifically focusing on economic losses, social losses, environmental losses, resilience, and vulnerability of reinforced concrete (RC) structures. From a cost-effectiveness perspective, this study concentrates on the retrofitting of ground story columns, which has proven to be highly effective in enhancing the performance of the structure, particularly when its behavior is mainly governed by column capacities and story response. The methodology is divided into three main parts. The first part involves a global damage evaluation, which is estimated using a seismic vulnerability assessment based on the collapse fragility function. This function is derived from capacity curves obtained through nonlinear pushover analysis. The second part focuses on assessing seismic risk for various earthquake intensities, where fragility functions and consequence functions are derived and evaluated for structural components. This allows for the calculation of losses in terms of social, economic, and environmental impacts. The third part addresses the functionality and recovery of the structure, along with its resilience, by considering repair times and associated delays. Indices are developed for all direct and indirect losses, and weightage factors are assigned to each category to optimize the selection of the most suitable retrofitting alternative for specific scenarios. To illustrate this framework, a five-story hospital building is used as an example, as hospitals are critical structures that need to remain operational after earthquakes. Four retrofitting alternatives are proposed to identify the optimal choice that effectively meets all desired functions. Full article

Traditional buildings constructed in Yemen during the 20th century often lacked adequate seismic protection. Today, most reinforced concrete (RC) residential buildings in the country are designed with beam–column systems that primarily carry gravity loads without considering lateral seismic forces. As a result, these structures are potentially vulnerable to earthquakes and require further investigation. This study aims to develop analytical seismic fragility curves for residential RC buildings in Yemen with varied heights. Three building heights were considered, namely three, five, and seven stories. While in most studies, the infill walls are regarded as non-structural elements, and their contributions to resisting earthquake actions are ignored, in this study, the contribution of the infill wall was taken into account by utilizing a compression strut modeling of the infill wall. In addition, an investigation was conducted to study the effect of soft stories on the seismic vulnerability of residential RC buildings. Finite element models were developed, and 900 Incremental Dynamic Analyses (IDAs) were conducted. Three damage limit states were defined: Immediate Occupancy (IO), Life Safety (LS), and Collapse Prevention (CP). Based on these results, cumulative distribution functions (CDFs) were calculated to derive the seismic fragility curves. The findings indicate that taller buildings are more likely to reach or exceed the defined damage states, making them more vulnerable to earthquakes. Infilled frame structures demonstrate better seismic performance due to the contribution of infill walls to lateral resistance. In contrast, buildings with soft stories are more vulnerable due to abrupt changes in stiffness, resulting in greater deformation concentration in the soft story. The developed fragility curves provide a quantitative basis for assessing seismic damage in Yemeni RC residential buildings and offer a foundation for future seismic risk evaluations. Full article

Seismic risk assessment is pivotal for ensuring the reliability of prefabricated subway stations, where selecting optimal intensity measures (IMs) critically enhances probabilistic seismic demand models and fragility analysis. While peak ground acceleration (PGA) is widely adopted for above-ground structures, its suitability for underground systems remains debated due to distinct dynamic behaviors. This study identifies the most appropriate IMs for soft soil-embedded prefabricated subway stations at varying depths through nonlinear finite element modeling and develops corresponding fragility curves. A soil–structure interaction model was developed to systematically compare seismic responses of shallow-buried, medium-buried, and deep-buried stations under diverse intensities. Incremental dynamic analysis was employed to construct probabilistic demand models, while candidate IMs (PGA, PGV, and v_rms) were evaluated using a multi-criteria framework assessing correlation, efficiency, practicality, and proficiency. The results demonstrate that burial depth significantly influences IM selection: PGA performs optimally for shallow depths, peak ground velocity (PGV) excels for medium depths, and root mean square velocity (v_rms) proves most effective for deep-buried stations. Based on these optimized IMs, seismic fragility curves were generated, quantifying damage probability characteristics across burial conditions. The study provides a transferable IM selection methodology, advancing seismic risk assessment accuracy for prefabricated underground infrastructure. Through a systematic investigation of the correlation between IM applicability and burial depth, coupled with the development of fragility relationships, this study establishes a robust technical framework for enhancing the seismic performance of subway stations, and provides valuable insights for seismic risk assessment methodologies in underground infrastructure systems. Full article

In developing countries with high seismic activity, a need exists to construct resilient infrastructure and reduce the housing deficit. Industrialized timber construction and the implementation of seismic isolation interfaces may represent a good alternative to respond to these demands. This paper studies the feasibility of constructing cross-laminated timber (CLT) buildings equipped with frictional pendulum bearings in Chile or similar highly seismic regions. The first part of this study shows a first-order approach for modeling the highly nonlinear behavior of CLT walls using a Smooth Hysteretic Model (SHM). An equivalent model of a base-isolated building was developed using the SHM as well as a physical model of the Friction Pendulum System in order to assess the seismic performance of CLT buildings with frictional isolators. The second part of this research presents and discusses the results of a broad parametric analysis concerning the seismic performance of base-isolated CLT buildings. The seismic assessment was carried out by deriving fragility curves and including the uncertainty linked to the seismic input and the friction coefficient of the isolation system. Constructing lateral resistant systems based on CLT walls presents a feasible alternative for buildings in high seismic hazard areas. Excellent seismic performance is achieved if the superstructure’s is designed with a reduction factor of 1, or if the superstructure’s fundamental period ranges from 0.6 to 0.9 s and is designed with a reduction factor of 2 and ductility capacity of 6 or more. An excellent seismic performance can be obtained for larger reduction factor values if the superstructure has middle to high maximum ductility capacity. Full article

Liquid-storage tanks are critical components in industrial plants, especially during seismic events. Tank failures can cause significant economic losses, operational disruptions, and environmental damage. Therefore, accurate design and performance evaluation are essential to minimize these risks. However, past earthquakes have highlighted the need for a better understanding of tanks’ seismic behavior. This requires selecting the appropriate seismic input and ground motion records to properly simulate tank responses. This study examines the seismic behavior of various tank types using different earthquake record sets, including both far-field and near-field events. The tanks were modelled with varying geometries, such as diameter–height ratios, wall thickness, liquid height, and radius. Time-history analyses were conducted to generate fragility curves and evaluate the seismic performance of the tanks based on specific limit states. The findings show that the choice between far- and near-field records significantly influences seismic response, particularly in terms of fragility curve variation. The fragility curves derived from this analysis can serve as valuable tools for risk assessments by governments and stakeholders, helping to improve the safety and resilience of industrial plants. Full article

Power transmission tower-line systems are exposed to various dynamic hazards, including wind and earthquakes, among others. Despite the multitude of dampers proposed to mitigate vibrations, the dual control effect on both seismic and wind-induced vibrations has rarely been addressed. This paper introduces a comprehensive methodology for evaluating the reliability of power transmission towers under a range of dynamic disasters, encompassing both earthquakes and wind loads. Subsequently, a lifelong reliability approach was employed to assess the efficacy of a pounding tuned mass damper (PTMD). The proposed algorithm leverages the incremental dynamic analysis (IDA) method to compute structural fragility with regard to each type of disaster and integrates these findings with hazard functions to determine the probability of overall failure. The results conclusively demonstrate that the PTMD substantially diminished the towers’ dynamic response to both earthquakes and wind loads, thereby enhancing their overall reliability. Specifically, the PTMD reduced the vibration reduction ratio by 10% to 30% under wind loads and by 20% to 80% under seismic actions, with more pronounced effects at higher wind speeds and peak ground accelerations (PGAs). Furthermore, the reliability index (β) of the transmission tower increased from 2.1849 to 2.4295 when the PTMD was implemented, highlighting its effectiveness in dual-hazard scenarios. This study underscores the potential for reliability to be considered as a key metric for optimizing damping devices in power transmission structures, particularly in the context of multi-hazard scenarios. Full article

This paper validates the effectiveness of the modeling approach based on the finite element analysis of shaking table tests, establishing finite element models for both a base-isolated structure and a hybrid base-isolated structure designed to address overturning issues in the diesel engine building of a nuclear power plant. By using the Incremental Dynamic Analysis (IDA) method, a fragility analysis of the overturning resistance was conducted for both isolation systems. This study demonstrates that the hybrid base isolation scheme, which incorporates additional dampers, effectively enhances the structure’s overturning resistance and reduces the probability of failure. When evaluating the seismic fragility of the structure by using the TP value, which is related to the tensile stress of the isolation bearings, as a damage index, the results are more conservative compared with those obtained by using shear strain ($\gamma$). This highlights the importance of improving the tensile capacity of the isolation bearings in structural design. Furthermore, fragility assessment using $\gamma$ as a damage index can provide design references for the collision limit of the isolation moat in the base-isolated structure of the diesel engine building in nuclear power plants. Full article