Search Results (70)

Traditional seismic risk assessments often require specialized expertise and extensive computational time, making probabilistic seismic risk evaluations less accessible to practitioners and decision-makers. To reduce the barriers related to applications of quantitative seismic risk analysis, this paper develops a Quick Loss Estimation Tool (QLET) designed for rapid seismic risk assessment of Canadian buildings. By approximating the upper tail of a seismic hazard curve using an extreme value distribution and by integrating it with building exposure-vulnerability models, the QLET enables efficient computation of seismic loss curves for individual sites. The tool generates seismic loss exceedance probability curves and financial risk metrics based on Monte Carlo simulations, offering customizable risk assessments for various building types. The QLET also incorporates regional site proxy models based on average shear-wave velocity in the uppermost 30 m to enhance site-specific hazard characterization, addressing key limitations of global site proxy models and enabling risk-based seismic microzonation. The QLET streamlines hazard, exposure, and vulnerability assessments into a user-friendly tool, facilitating regional-scale risk evaluations within practical timeframes, making it particularly applicable to emergency preparedness, urban planning, and insurance analysis. 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

The spatial variation characteristics of near-fault velocity pulses lack in-depth understanding, and it is difficult to consider this feature in probabilistic seismic hazard analysis and the ground motion input for structural seismic analysis. Based on ground motion simulation, this study performs spatial characteristic analysis of velocity pulses. The Mw 6.58 strike-slip Imperial Valley and the Mw 6.8 dip-slip Northridge earthquakes are adopted as the cases, and the simulation method is validated by comparing synthetics with observations. The multi-component broadband ground motion fields are simulated, and the pulse parameters and the pulse area are extracted using the multi-component pulse identification method. The spatial characteristics of various pulse parameters are analyzed. The results show that for a single earthquake, the pulse period is a spatial variable related to source-to-site geometry, the pulse amplification factor has great spatial variation, and the orientation of the maximum pulse component is controlled by the radiation pattern. Finally, the influence of slip distribution on pulse is explored based on two earthquakes, in which the uniform slip, the random slip, and the hybrid slip are combined with different rupture directions. This study contributes to a more reasonable consideration of pulse-like ground motion in seismic risk assessment and earthquake response analysis. Full article

A substantial proportion of long-distance oil and gas pipelines in China traverse active faults and high-risk areas characterised by intricate topographic and geological environments. These pipelines are susceptible to a range of safety concerns, exacerbated by the increasing frequency of strong earthquakes in recent years. To address this issue, a comprehensive risk investigation framework has been proposed for long-distance oil and gas pipelines following seismic events. This initiative aims to ensure the safety of pipeline transportation. In this paper, the elements of pipeline safety evaluation under the influence of coseismic hazards are first organized, followed by a construction of post-earthquake pipeline safety rapid assessment theoretical framework based on the seismic geological disaster risk evaluation system. Each method in the system is then introduced one by one. Unlike existing studies that predominantly focus on localized fault activity or static risk assessment, our framework introduces three key innovations: (1) a hierarchical integration of multi-source monitoring data (SCADA, UAV-AI, and numerous monitoring devices) into a unified GIS platform, overcoming the fragmentation of existing systems; (2) a dynamic four-step evaluation process (susceptibility → hazard → risk → safety) that incorporates both pre-earthquake geological conditions and post-earthquake real-time triggers (e.g., PGA, rainfall); (3) a novel risk matrix mechanism for pipeline safety, which dynamically updates risk levels based on field monitoring data rather than relying solely on probabilistic models. This study provides a novel theoretical framework for assessing the safety of pipelines after earthquakes, which can provide a timely basis for pipeline management decisions and reduce the potential damage to pipelines caused by earthquakes. It is important to note that this framework is still in a preliminary stage and needs to be continuously deepened and optimised. Full article

The seismic performance assessment of timber structures and topology optimization have been widely researched in recent years. Furthermore, the use of wood as a construction material has increased due to new sustainability challenges. This research assesses the seismic performance of a topologically optimized timber building located in Concepcion, Chile. The structure is a five-story glulam braced frame, designed following current Chilean standards. The structural configuration was obtained through a topology optimization process using a variation of a soft-kill BESO algorithm implemented in MATLAB R2015a, obtaining topologies with low structural redundancy. For the analysis, a full 3D nonlinear model was prepared using OpenSees (Version 3.7.1), and the nonlinear behavior of the structure was only considered at joints using the backbone curves introduced in ASCE 41-13. Six different study cases were analyzed, varying joint strengths and ductility. The fragility curves were determined from a static pushover analysis (SPO) using SPO2FRAG (V1.1), considering the performance levels established in ASCE 41-13. The seismic hazard of the building’s site is estimated through a probabilistic seismic hazard analysis (PSHA), and the seismic performance of each case is determined by computing the probabilities of exceedance of the considered limit states. Analysis results show that wood braced-frame structures with low structural redundancy (and fewer main joints to dissipate energy), such as those obtained from topology optimization algorithms, exhibit a markedly brittle behavior with almost no displacement ductility. This undesirable behavior does not improve by providing more deformation capacity to this structure’s reduced number of main joints. Currently, the Chilean standard for seismic design requires a unique response modification factor R for wood structures. This research suggests that this requirement should be revisited, specifying different R values depending on the wood structure’s redundancy, considering that its displacement ductility comes almost exclusively from the nonlinear deformation capacity of joints. Full article

Post-earthquake fires (PEFs) pose a significant secondary hazard in earthquake-prone regions, compounding the destruction caused by seismic events and threatening structural safety. This review explores the interplay between seismic damage and fire resistance, focusing on ignition sources such as damaged utility systems and overturned appliances, and their cascading effects on structural integrity. Advanced performance-based design approaches are evaluated, emphasizing the integration of probabilistic risk assessments, sequential analysis, and hybrid fire simulations to address multi-hazard scenarios. Key findings of current studies reveal that seismic damage, including spalling, cracking, and loss of fireproofing, substantially reduces the fire resistance of materials like steel and reinforced concrete, exacerbating structural vulnerabilities. Despite advancements, critical gaps persist in experimental data, probabilistic modeling, and comprehensive performance-based design guidelines for PEF scenarios. Addressing these deficiencies requires enhanced data collection, improved modeling techniques, and the integration of PEF considerations into building codes. This study provides a comprehensive review of PEF damage assessment and underscores the need for a holistic, multi-hazard design paradigm to enhance structural resilience and ensure safety in regions subject to seismic and fire risks. These insights provide a foundation for future research and practical applications aimed at mitigating the compounded effects of earthquakes and fires. Full article

This study quantitatively assesses the impact of seismic design strategies on the performance of reinforced concrete (RC) dual wall–frame office buildings by comparing direct and indirect economic losses and downtime in life-cycle terms. A high-rise archetype building located in Santiago, Chile, on stiff soil was evaluated as a benchmark case study. Three design strategies to potentially enhance the seismic performance of a building designed conventionally were explored: (i) incorporating fluid viscous dampers (FVDs) in the lateral load-resisting structure; (ii) replacing conventional non-structural components with enhanced ones (ENCs); and (iii) a combination of the previous two strategies. First, probabilistic structural responses were estimated through incremental dynamic analyses using three-dimensional nonlinear models of the archetypes subjected to a set of hazard-consistent Chilean ground motions. Second, FEMA P-58 time-based assessment was conducted to estimate expected annual losses (EALs) for economic loss estimation. Finally, for downtime assessment, a novel probabilistic framework, built on the FEMA P-58 methodology and the REDi guidelines, was employed to estimate the expected annual downtimes (EADs) to achieve specific target recovery states, such as reoccupancy (RO) and functional recovery (FR). Results revealed that seismically enhancing RC dual wall–frame buildings with FVDs significantly improves resilience by reducing loss and downtime. For example, the enhanced building with FVDs achieved an EAL of 0.093% and EAL of 8.6 days for FR, compared to the archetype base building without design improvements, which exhibited an EAL of 0.125% and an EAD of 9.5 days for FR. In contrast, the impact of ENCs alone was minor, compared to the effect of FVDs, with an EAL of 0.106% and an EAD of 9.1 days for FR. With this detailed recovery modeling, probabilistic methods, and a focus on intermediate recovery states, this framework represents a significant advancement in resilience-based seismic design and recovery planning. Full article

We present a sensitivity analysis on the impact of input parameters and methods used on the results of a probabilistic seismic hazard assessment (PSHA). The accurate estimation of the parameters in recurrence models (declustering and fitting methods), along with the selection of scaling relationships for determining maximum magnitude and the selection of ground motion models (GMMs), enhance control over epistemic uncertainties when constructing the logic tree, minimizing final calculation errors and producing credible results for the study region. This study focuses on Central America, utilizing recent data from seismic, geological, and geophysical studies to improve uncertainty analyses through classic statistical methods. The results demonstrate that proper fitting of the recurrence model can stabilize acceleration variations regardless of the declustering method or b-value fitting method used. Regarding scaling relationships, their low impact on the final results is noted, provided the models are tailored to the tectonic regime under study. Finally, it is shown that the GMM contributes the most variability to seismic hazard results; therefore, their selection should be conditioned on calibration with observed data through residual analysis where region-specific models are not available. Full article

The increasing demand in structural engineering now extends beyond collapse prevention to encompass business continuity planning (BCP). In response, energy dissipation devices have garnered significant attention for building response control. Among these, buckling-restrained braces (BRBs) are particularly favored due to their stable hysteretic behavior and well-established design provisions. However, BCP also necessitates the prevention of furniture overturning—an area that remains quantitatively underexplored in the context of buckling-restrained braced frames (BRBFs). Addressing this gap, this research designs BRBFs using various design criteria and performs incremental dynamic analysis (IDA) with artificially generated seismic waves. The results are compared with previously developed fragility curves for furniture overturning under different BRB design conditions. The findings demonstrate that the fragility of furniture overturning can be mitigated by a natural frequency shift, which alters the threshold of critical peak floor acceleration. These results, combined with hazard curves obtained from various locations across Japan, quantify the mean annual frequency of furniture overturning. The study reveals that increased floor acceleration in stiffer BRBFs can lead to a 3.8-fold higher risk of furniture overturning compared to frames without BRBs. This heightened risk also arises from the greater hazards at shorter natural periods due to stricter response reduction demands. The probabilistic risk analysis, which integrates fragility and hazard assessments, provides deeper insights into the evaluation of BCP. Full article

The 1755 Lisbon earthquake holds significant historical importance in Portuguese history. The subsequent tsunami resulted in extensive destruction and damage, affecting not only Lisbon but also other regions of Portugal, Spain, and North Africa. This significant and hazardous event led to an increase in awareness about earthquake and tsunami risks, not only within Portugal but throughout Europe. This heightened awareness facilitated advancements in scientific developments, including design codes, standards, and earthquake engineering. However, recent studies focusing on hazard assessment for Lisbon are limited. For this reason, this paper aims to present a comprehensive probabilistic seismic hazard analysis (PSHA) for the Lisbon metropolitan area. The first stage of PSHA involves defining applicable and active seismic source models (area and line sources) within the study area. Subsequently, historical and instrumental earthquake records are collected to build a homogenized earthquake catalog, utilizing both global and local earthquake databases. Following this, the completeness level of the earthquake catalog is tested. By incorporating suitable ground motion models to the region and local soil characteristics, seismic hazard maps for various return periods and hazard curves in terms of peak ground acceleration (PGA) are developed. The findings based on the area source model agree with existing literature, indicating PGA values ranging from 0.3 g to 0.9 g, 0.2 g to 0.7 g, 0.2 g to 0.5 g, and 0.1 g to 0.3 g for return periods of 2475, 975, 475, and 50 years, respectively. Full article

In relation to its rapid infrastructure expansion, exemplified by projects like the Najran Valley Dam or the rehabilitation of agricultural terraces, Saudi Arabia stands out among the Arabian Gulf nations. To mitigate the earthquake-related risks effectively, it is imperative to conduct an exhaustive analysis of its natural hazards. The southwesternmost region of Saudi Arabia is the main subject area of this study for the probabilistic seismic hazard assessment (PSHA), which aims to identify the peak ground acceleration (PGA) and spectral acceleration (SA) values. The investigation encompasses a 10% and 5% probability of occurrence over a 50-year exposure time for both B/C and C NEHRP soils. In order to take into account the earthquake activity that takes place in the vicinity of the Red Sea Rift, which in fact may have an impact on the seismic hazard in this active tectonic region, different seismic source zones were especially designed for this evaluation. Various characteristics such as the uncertainties related to the b-value, the expected maximum magnitude, and different ground motion prediction equations (GMPEs) were integrated using a logic tree scheme. Additionally, regression relationships between the computed ground motion values were established, and a novel design response spectrum was developed and recommended for several cities. Regarding the key findings, it is significant to highlight that the seismic hazard decreases towards the northeast, when moving away from the Red Sea Rift, confirming anticipated trends where proximity to the rift corresponds to increased seismic hazard. Notably, cities such as Farasan Island, Jazan, Al Qunfundhah, Al Lith and Al Birk present the highest observed hazard values among all the cities analyzed. For these cities, the obtained maximum SA values for both 475 and 975 years under B/C site conditions are as follows: 0.268 g and 0.412 g, 0.121 g and 0.167 g, 0.099 g and 0.150 g, 0.083 g and 0.135 g, and 0.066 g and 0.118 g, respectively. These results emphasize the crucial necessity of adequately evaluating and thoroughly updating the seismic hazard inherent to these particular areas to enhance the risk reduction and disaster readiness initiatives. Full article

Slope stability analysis plays a crucial role in geotechnical engineering, particularly in regions susceptible to seismic activity. The inherent non-homogeneity and uncertainty of soil properties pose significant challenges in assessing slope stability under seismic conditions. To address these complexities, a novel and efficient methodology named DUBLA-PDM-PCK is proposed. In this methodology, the effects of soil non-homogeneity and uncertainty, along with the time and spatial variations of seismic loading, are systematically considered. The deterministic framework integrates discretized upper bound limit analysis (DUBLA) to accommodate soil non-homogeneous characteristics, and the pseudo-dynamic method (PDM) to model seismic loading variability. Then, a robust and efficient probabilistic analysis method, PCK-MA, is implemented utilizing adaptive Polynomial Chaos Kriging metamodeling, Monte Carlo Simulation, and Analysis of Covariance to investigate the uncertainty of the parameters. This approach treats nine key parameters, including soil cohesion, friction angle, non-homogeneous coefficients, horizontal and vertical seismic coefficients, period, and amplification factor, as random variables to assess their uncertainty effects on failure probability (stability level) and sensitivity indices. The DUBLA-PDM-PCK methodology offers a streamlined and reliable tool tailored for assessing slope stability in seismic environments, demonstrating notable efficiency in addressing soil variability and seismic loading uncertainties. Its application holds promise for guiding engineering practices and enhancing understanding of slope behavior in regions prone to seismic hazards. Full article

This study develops empirical fragility curves for concrete and masonry buildings in Haiti, utilizing data from the 2021 earthquake. A dataset of 3527 buildings from the StEER database, encompassing a diverse range of building types, is used. These buildings types include reinforced concrete structures with masonry infills, confined masonry buildings, reinforced masonry bearing walls, and unreinforced masonry bearing walls. Shakemaps from the USGS are utilized to assess the earthquake’s intensity at each building, with the peak ground acceleration (PGA) as the intensity measure. Damage is classified into five distinct states: no damage, minor, moderate, severe, and partial or total collapse. For each of these states, the corresponding probabilities of exceedance are calculated, and log-normal cumulative distribution functions were fitted to those data to produce empirical fragility curves. The results show a notable similarity in performance among the four types, each having high probability of failure even under low-intensity earthquakes. Total fragility curves (including all four building types) are developed subsequently and they are convolved to the probabilistic seismic hazard map of Haiti to assess the seismic risk. This includes estimating the annual probability of partial/total collapse and the probability of partial/total collapse in the event of 475-year and 2475-year earthquakes. The results indicate a significant risk, with up to 64% probability of collapse in certain areas for the 2475-year earthquake and a probability of collapse of 15% for a 475-year earthquake. These findings underscore the critical vulnerability of Haiti’s buildings to seismic events and the urgent need for their retrofit. Full article

Earthquake-triggered landslides have been widely recognized as a catastrophic hazard in mountainous regions. They may lead to direct consequences, such as property losses and casualties, as well as indirect consequences, such as disruption of the operation of lifeline infrastructures and delays in emergency response actions after earthquakes. Regional landslide hazard assessment is a useful tool to identify areas that are vulnerable to earthquake-induced slope instabilities and design prioritization schemes towards more detailed site-specific slope stability analyses. A widely used method to assess the seismic performance of slopes is by calculating the permanent downslope sliding displacement that is expected during ground shaking. Nathan M. Newmark was the first to propose a method to estimate the permanent displacement of a rigid body sliding on an inclined plane in 1965. The expected permanent displacement for a slope using the sliding block method is implemented by either selecting a suite of representative earthquake ground motions and computing the mean and standard deviation of the displacement or by using analytical equations that correlate the permanent displacement with ground motion intensity measures, the slope’s yield acceleration and seismological characteristics. Increased interest has been observed in the development of such empirical models using strong motion databases over the last decades. It has been almost a decade since the development of the latest empirical model for the prediction of permanent ground displacement for Greece. Since then, a significant amount of strong motion data have been collected. In the present study, several nonlinear regression-based empirical models are developed for the prediction of the permanent seismic displacements of slopes, including various ground motion intensity measures. Moreover, single-hidden layer Artificial Neural Network (ANN) models are developed to demonstrate their capability of simplifying the construction of empirical models. Finally, implementation of the produced modes based on Probabilistic Landslide Hazard Assessment is undertaken, and their effect on the resulting hazard curves is demonstrated and discussed. Full article

The utilization of the Monte Carlo method in conjunction with probabilistic seismic hazard analysis (PSHA) constitutes a compelling avenue for exploration. This approach presents itself as an efficient and adaptable alternative to conventional PSHA, particularly when confronted with intricate factors such as parameter uncertainties and diverse earthquake source models. Leveraging the Monte Carlo method and drawing from the widely adopted Cornell-type seismicity model in engineering seismology and disaster mitigation, as well as a seismicity model capturing temporal, spatial, and magnitude inhomogeneity, we have derived a formula for the probability of earthquake intensity occurrence and the mean rate of intensity occurrence over a specified time period. This effort has culminated in the development of a MATLAB-based program named MCPSHA. To assess the model’s efficacy, we selected Baoji City, Shaanxi Province, China, as our research site. Our investigation delves into the disparity between occurrence probability and extreme probability (a surrogate commonly employed for occurrence probability) in the Baoji region over the next 50 years. The findings reveal that the Western region of Baoji exhibits a heightened hazard level, as depicted in the maps, which illustrate a 10% probability of exceedance within a 50-year timeframe. The probability of earthquake occurrence under various intensities (VI, VII, and VIII) over 50 years follows a declining trend from west to east. Furthermore, the likelihood of seismic intensity exceeding VI, VII, and VIII indicates the lowest exceeding probability in the northeast and the highest in the northwest. Notably, for intensities VI-VII, the difference between occurrence probability and extreme probability approaches twice, gradually diminishing with increasing intensity. This study underscores the MCPSHA model’s efficacy in providing robust technical support for mitigating earthquake risk and enhancing the precision of earthquake insurance premium rate calculations. Full article