Bayesian optimized random forest models for predicting permanent displacement considering fault types and pulse-like ground motion effects

Performance of a shallow-founded building on liquefiable soil at the port of Wellington during the 2013 and 2016 New Zealand earthquakes

Assembly errors in novel self-centering beam-to-column joints: Seismic performance under near-fault and far-field ground motions

Artificial neural network-based non-parametric ground motion models for multiple intensity measures in Türkiye

Ensemble-based uncertainty quantification and decomposition of probabilistic surrogate models using Bayesian neural networks

A probabilistic framework for magnitude-based stochastic ground motion simulation using empirical Green's functions

Study on seismic performance and hysteresis model of RC columns considering the action characteristics of far-field long-period ground motions

ABSTRACT This study investigated the design, seismic performance, and constructability of lead rubber bearing (LRB) systems for two skybridges connecting three high-rise towers. The target structure is a residential complex with three towers approximately 200 m high and two skybridges installed at the 17th floor between adjacent towers. To accommodate relative lateral and torsional displacements caused by differences in tower dynamic characteristics during earthquakes, multidirectional LRBs were installed at the skybridge supports. Linear elastic analyses were conducted to determine design axial forces and displacement demands, followed by nonlinear time-history analyses using seven spectrum-compatible ground motions to evaluate seismic responses. The results showed that maximum horizontal and relative displacements at all isolation interfaces remained within the design allowable limit of 150 mm. Full-scale LRBs manufactured according to the design specifications were tested under pure compression and combined compression – shear cyclic loading following ISO 22762–1. The test results confirmed satisfactory vertical stiffness, effective horizontal stiffness, and energy dissipation capacity. Overall, the proposed LRB system demonstrated reliable seismic performance and practical applicability for skybridges in high-rise building complexes.

A complete and reliable earthquake catalog is the most fundamental dataset for studying regional seismic activity. In this study, a newly compiled catalog of earthquakes with M ≥ 4.7 was constructed to develop a next-generation seismic zonation map of ground motion parameters in China. The dataset was systematically compiled from multiple local, regional, and international sources to ensure comprehensive coverage. To ensure maximal retention of seismicity patterns, the catalog incorporates earthquake clusters, notably foreshock-aftershock sequences. The complete catalog contains the data on 16,403 recorded earthquakes (M ≥ 4.7) spanning 4,324 years from B.C. 2300 to A.D. 2024. The dataset covers China and adjacent areas, with specific longitudinal and latitudinal extents of 65°E-141°E and 3°N-57°N, respectively. As a foundational dataset, it supports two key modeling processes in developing China's next-generation seismic zonation map: (1) seismic activity characterization and (2) potential seismic source zone identification.

ABSTRACT An analytical framework for seismic rocking analysis of nonstructural elements in the monuments of the archaeological site of Bagan, identified as vulnerable in past earthquakes, is presented. While the overarching study focuses on four structural typologies, a nonlinear kinematic analysis incorporating a finite compressive-strength rocking model is adopted specifically for the susceptible rocking elements of three selected representative monuments. Seismic demand is evaluated using three definitions: the recorded 2016 Chauk earthquake ground motion, monument-specific simulated records, and the design spectrum based on Myanmar’s National Building Code of 2020 (MNBC 2020). The floor spectra are computed for each rocking element using the procedure based on Italian norms for construction (CNTC 2019) accounting for height-dependent acceleration amplification. Results show that the main spires of all three monuments are the most vulnerable elements, with amplification factors of 1.65–2.45 relative to ground level. A comparison of the three demand definitions reveals distinct outcomes: The design spectrum definition consistently yields the most conservative demand estimate due to its higher peak ground acceleration, while the spatial variability captured by monument-specific simulated records reveals significant inter-monument differences not apparent from the single record of Chauk earthquake.

This study presents a damage-based comparative assessment of reinforced concrete buildings affected by the 1992 Erzincan earthquake (Mw 6.8) and the 2023 Kahramanmaraş earthquake sequence (Pazarcık, Mw 7.7; Elbistan, Mw 7.6), two destructive earthquake events in Türkiye separated by nearly three decades. A distinctive contribution of the study is the presentation of original color photographs from the 1992 Erzincan earthquake, systematically documented and comparatively evaluated for the first time and directly compared with post-earthquake field observations from Malatya following the 2023 earthquake sequence. To complement the field-based evidence, representative strong ground motion records from both earthquake events were processed and compared using standard seismic intensity and spectral response parameters. The spectral evaluation indicates that the 1992 Erzincan ground motion and the 2023 Elbistan-related motion recorded in Malatya imposed comparable seismic demands relevant to typical reinforced concrete buildings, thereby providing a rational basis for cross-event damage interpretation. Despite substantial advances in Turkish seismic design codes, recurrent damage mechanisms were observed in both building stocks, particularly soft-story formation, short-column effects, inadequate transverse reinforcement, poor beam–column joint performance, and deficiencies in material quality and detailing. The findings demonstrate that seismic safety cannot be improved through code development alone unless design provisions are consistently translated into construction quality, detailing practice, inspection, and field implementation.

Currently, there is an increasing need for low-cost detectors that can measure ground motion with high sensitivity and selectivity. Triboelectric nanogenerators (TENGs) have arisen as low-cost self-powering sensing devices that can be used in multiple applications that involve vibration and motion, such as in earthquake detection. In this work, a TENG-based seismic device (SEISTENG) is designed with the purpose of detecting either 2D or 3D vibrating motion. This device is based on low-cost TENGs and comprises the walls of a 3D-printed polylactic acid box with a sliding metal ball inside and rolling on its horizontal base. The TENG transducer dynamical properties for a high-frequency range (0.5-50 Hz), long duration operation, and robustness were measured. The SEISTENG was validated by simulating the 1995 Kobe earthquake on a biaxial vibration table and the 2011 Lorca earthquake on a triaxial system, demonstrating its ability to detect seismic excitation signals with high accuracy (2D or 3D SEISTENG). The technology produced a response comparable to that of the commercial piezoelectric sensor D220-A4BR-1305YB, and its signals could be monitored remotely in real time using an FPGA-based STEMlab board, a LabVIEW interface, and Internet of things (IoT) platforms.

ABSTRACT How to reasonably consider the effects of vertical ground motion has become a key scientific issue in the current seismic field of engineering structures. In this paper, based on the ground motion records in the Chinese region, several Chinese ground motion models (GMMs) of horizontal and vertical generalized intensity measures (IM) are established. Then the empirical correlations between horizontal-vertical IMs are analyzed, and the nonparametric bootstrap method and Fisher z-transform are used to consider the uncertainty of the correlation coefficients. The empirical correlation coefficients of the horizontal-vertical IMs are modeled to be applicable to the Chinese region. The results show that the GMMs developed in this study for the Chinese region are practical. There is a medium-high correlation mainly shown by the horizontal-vertical homogeneous IMs. The values of the correlation coefficients between horizontal-vertical spectrum-, effective peak-, amplitude-IMs and spectral acceleration (Sa(T)) mainly depend on the defined period. The correlation coefficients of cumulative effect IMs and Sa(T) show a decreasing tendency with the increase of the period. The correlations between duration IMs and Sa(T) show weak negative correlation or no correlation. The correlation coefficients obtained in this study based on the horizontal-vertical Chinese ground motion records are basically consistent with the trends in existing studies. The correlation coefficient prediction models established in this study are well fitted. The results of correlation studies and the GMMs established in this paper can be easily applied to seismic engineering analyses in China.

The seismic design response spectrum is a vital parameter for determining the potential seismic load of the engineering structure. Differential evolution algorithm (DE) with a novel hybrid mutation operator is utilized to calibrate the spectral parameters in order to enhance iteration efficiency. This study calibrates the seismic design response spectrum for China based on the Chinese seismic intensity scale and compares the results with the Code for Seismic Design of Buildings (CSDB2010).The calibration spectra are based on strong ground motion records with destructive power exceeding the Chinese seismic intensity 7 and above. The characteristics of the calibration spectral parameters are analyzed and subsequently compared with the design spectra of the Code for Seismic Design of Buildings (CSDB2010). It is found that: Increasing the number of iterations can enhance the fitting goodness of DE between the calibration spectrum and the record response spectrum. The average site characteristic period (Tg) for rock and hard soil site conditions (Class I and II) is greater than the Tg specified in CSDB2010. The average Tg for intensity 10 + is greater than the average Tg for intensity 7, 8, and 9. Tg increases with the seismic intensity. The average spectra platform value (βmax) from this study gradually approaches the βmax in CSDB2010 as the intensity increases. The average attenuation index (γ) at different intensities of this study is greater than γ in CSDB2010.

ABSTRACT To investigate the dynamic response and failure characteristics of the portal section of a loess tunnel under seismic action under different rainfall intensities, two working conditions – heavy rain (80 mm/24 h) and extreme rainstorm (170 mm/24 h) – were set up for shaking table model tests. Acceleration sensors and strain gauges were used to collect dynamic response data of the tunnel and slope, revealing the deformation patterns and failure mechanisms of the tunnel lining and soil under the coupled effect of rainfall and earthquake. The results show that rainfall intensity significantly affects the dynamic response of the tunnel structure. Under extreme rainstorm conditions, axial cracks appear earlier in the tunnel, and the soil is more prone to liquefaction. The vault and invert are the most sensitive areas for acceleration response, especially under Z-direction loading, showing significant nonlinear amplification effects. The left springing is the strain concentration zone, exhibiting obvious asymmetric pressure characteristics. As seismic intensity increases, the strain response of the lining transitions from linear to nonlinear, with 1.0 g being the threshold for structural degradation. Rainfall exacerbates seismic damage in the portal section of loess tunnels, and under extreme rainstorm conditions, the structure is more likely to enter the plastic stage and fail. It is recommended to strengthen key parts such as the vault, invert, and springing in the seismic design of loess tunnels, and to consider the impact of coupled horizontal and vertical ground motions.

During major earthquakes, fault ruptures frequently lead to significant differences in ground motions across the fault trace. As a result, fault-crossing bridges are subjected to complex seismic demands characterized by the combined effects of transient ground shaking and permanent fault displacement. Accurately representing such coupled effects remains a major challenge due to the limited availability of spatially consistent ground motion records and the complexity of the underlying mechanisms. To address this issue, this study evaluates two practical equivalent seismic input frameworks that explicitly incorporate permanent fault displacement while preserving the essential characteristics of ground motions. The seismic excitation is decomposed into two components: (i) dynamic inertial component induced by ground motion without permanent displacement, and (ii) fault-induced relative displacement component between the two sides of the fault, introduced either as a quasi-static input or as a time-dependent dynamic input. Based on this decomposition, the total structural response is obtained through response-level superposition. Four seismic input modes are systematically investigated, including non-uniform excitation (benchmark), uniform excitation, quasi-static equivalent input, and dynamic equivalent input. A three-dimensional finite element model of a simply supported bridge crossing a strike-slip fault is developed in OpenSees to assess the equivalent input frameworks. Results indicate that uniform seismic input significantly underestimates both peak and residual bridge responses, particularly for structural members located near the fault. In contrast, the two equivalent input approaches effectively reproduce the response characteristics of non-uniform excitation, with deviations within acceptable engineering limits. Thereby, the equivalent input frameworks provide a practical yet reliable seismic input representation for both numerical simulations and experimental studies of fault-crossing bridges.

We report an extraordinary observation of ground motion in Japan after the moment magnitude (MW) 9.0 2011 Tohoku-Oki earthquake attributed to a multiplate-interface slip event triggered by shear wave that traveled to the Earth's core and back. The megathrust earthquake generated a strong ScS phase with a peak-to-peak amplitude exceeding 1 centimeter in Japan. Superposed on this waveform, an eastward steplike displacement of up to 5 to 6 millimeters was recorded in Global Navigation Satellite System (GNSS) data throughout Japan. This likely originated from slip on the megathrust interfaces triggered by the nearly simultaneous arrival of the ScS wave across Japan. Such an ScS triggering is a previously unrecognized source of seismic hazard, which can potentially (re)activate the mainshock area and the broader surrounding megathrust interfaces.

ABSTRACT A sodium-cooled fast reactor plant uses liquid metal sodium as a coolant. Sodium has a high boiling point and excellent heat transfer capabilities. These properties allow the reactor to operate at low pressure. However, thermal fatigue occurs due to repeated thermal expansion and contraction within the creep temperature range. Accordingly, the fast reactor’s components and piping are designed with thin walls. Seismic isolation systems are used to reduce the seismic loads acting on components. Seismic isolation systems are used to reduce the seismic loads acting on components. Research and development of seismic design methods is progressing. Applying seismic isolation to nuclear power plants requires clarifying the design margin approach for equipment in fast reactor plants and seismic isolation devices. Here, the design margin refers to the margin relative to the design criteria for components or seismic isolation systems, i.e. the ratio of seismic response to the design criteria for the design basis ground motion, The design margin should be set to a value equal to or greater than the safety margin. Here, the safety margin is defined as the minimum margin specified in regulatory requirements and standards. This report proposes an approach for determining design margins for fast reactor plants with the horizontal seismic isolation system. We conducted the seismic response analysis of the reactor building and created the fragility curve with buckling evaluation of the reactor vessel. Based on these results, an approach for determining design margins of the components and the horizontal seismic isolation system was investigated.

The assessment of seismic hazard and risk requires a catalogue of earthquakes (both historical and recorded during the instrumental era), where the location and magnitude of events affecting the study area are reported. Mw is commonly used for this aim, but it is a static measure of earthquake size and it cannot capture the full extent of earthquake source complexity. Other magnitude scales connected to the rupture kinematics and dynamics should complement Mw in hazard studies, but this required efforts in re-analyzing catalogs of intensity data. To this aim, we developed a high-frequency magnitude (m3Hz) estimated using a random or log-averaged horizontal component of ground motion from frequencies above the highest corner frequency of the earthquake source spectrum. Here, we apply the novel procedure to the intensity data from the Parametric Catalogue of Italian Earthquakes (CPTI15). We derive m3Hz for 1,951 earthquakes (from 1117 to 2020). The new earthquake catalog is defined by the acronym ICEM. For all earthquakes a quality index based on the variance-to-mean ratio (VMR) has been assigned.

Inelastic responses are used in seismic design to estimate inelastic seismic demand from known elastic demand, yet current provisions remain limited, especially when damping and displacement ductility are considered. This study investigated the inelastic displacement ratio and inelastic velocity ratio for single degree of freedom (SDOF) systems subjected to near-fault ground motions, with particular focus on the effects of fling-step and forward-directivity motions. For numerical modeling and analysis, an extensive nonlinear response history analysis (NLRHA) was conducted on SDOF systems incorporating parametric variations in dynamic characteristics of structural systems such as elastic period, displacement ductility, and viscous damping under different ground motion conditions. From numerical modeling, empirical equations are proposed to express the inelastic displacement ratio ( I R D ) and inelastic velocity ratio ( I R V ) using elastic period, viscous damping ratio, displacement ductility, and the type of ground motion. In parallel, neural networks are trained on a dataset of 36,456 samples using additional variables, including the predominant period of the ground motion, moment magnitude, and closest rupture distance. Neural network models achieved R 2 = 0 . 944 (for I R D ) and R 2 = 0 . 916 (for I R V ) for unseen data, indicating the highest accuracy. Model explanations indicated that the predictions adhere to the domain knowledge. Comparative assessments reveal that while empirical equations capture general trends for design purposes, neural network models accurately predict even minor variations in inelastic responses. These data-driven methods provide a complementary approach in predicting the inelastic response compared to empirical equations. • Numerically simulated the inelastic responses of SDOF systems with damping under near-fault motions. • Influence of the ductility and viscous damping on inelastic responses was evaluated. • Empirical equations are proposed to estimate the inelastic displacement and velocity ratios. • Transformer-based models are developed to predict the inelastic responses.