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To clarify the effect of various anchor cable failure modes on the dynamic responses of slopes, the FLAC3D software was redeveloped. Constitutive models of cable elements in different anchor cable failure modes were proposed and embedded into the main program of slope dynamic calculation. The axial force, acceleration, and displacement responses in different anchor cable failure modes were compared and analyzed. The effects of seismic parameters on the anchor cable failure modes were also investigated. A matching relationship between the ultimate load-bearing capacities of the anchorage, anchoring interface, and tendon was proposed. The results reveal that the seismic intensity causing anchor cable damage in anchorage failure mode (AFM) and grouting body failure mode is 0.2g–0.3 g lower than that in tendon failure mode. At the moment of failure, the stress released by the anchor cable in AFM is the highest, with the most evident instantaneous slope acceleration fluctuation. In the collaborative seismic design of the anchorage, anchoring section, and anchor tendon, the ultimate load-bearing capacities of the anchorage and anchoring interface should be increased by 1.8 times to match the tensile bearing capacity of the tendon. This study provides a reference for the seismic anchorage design of slopes and offers suggestions for selecting seismic design parameters for anchor cables. • FLAC3D software is redeveloped, and the constitutive model of the cable element is modified. • A dynamic model of the slope considering different anchor cable failure modes is established. • The influence of the failure mode of the anchor cable on the dynamic response of the slope is clarified. • The influence of seismic wave parameters on the failure mode of anchor cable is studied. • A matching relationship of the ultimate bearing capacity of anchor cables under seismic action is proposed. [ABSTRACT FROM AUTHOR]

This paper proposes a self-centering rocking steel frame with column mid-height uplift (SCRSF-CMU) that exhibits high post-yield stiffness and energy dissipation capacity. The hysteretic performance of the SCRSF-CMU was investigated through cyclic loading tests. A numerical model of the SCRSF-CMU was established and validated against experimental results. Subsequently, the seismic performance of the SCRSF-CMU was compared with that of the self-centering rocking steel frame with column base uplift (SCRSF-CBU) using nonlinear time history analysis. Finally, the seismic responses of the SCRSF-CMU and SCRSF-CBU under varying earthquake intensities were analyzed using the endurance time analysis. The results indicate that the designed SCRSF-CMU demonstrates excellent lateral force resistance, energy dissipation, and self-centering capabilities. The rocking effect and the restoring force of the post-tensioned steel strands effectively controlled the residual lateral displacement of the specimens. The multi-scale numerical model of the SCRSF-CMU accurately captured its hysteretic behavior and deformation patterns. Compared to the SCRSF-CBU, the SCRSF-CMU exhibited superior rocking deformation capacity, post-yield stiffness, and hysteretic energy dissipation. Under MCE excitation, both SCRSF-CMU and SCRSF-CBU showed uniform inter-story drift distribution with minimal residual deformation, creating a satisfactory condition for the post-earthquake repair work if necessary. The high post-yield stiffness of the SCRSF-CMU was more effective in reducing both maximum and residual displacements. Endurance time analysis revealed that SCRSF-CMU and SCRSF-CBU exhibited relatively uniform inter-story drift distribution under SLE, DBE, and MCE earthquakes. Under FE excitation, the inter-story drift ratio of both structures were nearly identical; however, under DBE and MCE excitations, the maximum roof drift ratio and inter-story drift ratio of the SCRSF-CBU were larger, indicating that the SCRSF-CBU had higher deformation demands than the SCRSF-CMU. • A self-centering rocking steel frame with column mid-height uplift (SCRSF-CMU) has been proposed, featuring high post-yield stiffness and energy dissipation capacity. • The SCRSF-CMU demonstrates excellent lateral resistance, energy dissipation, and self-centering capabilities, achieving a recovery rate of over 90 % at a 2.5 % roof drift ratio. • SCRSF-CMU demonstrates superior rocking deformation capacity, higher post-yield stiffness, and better hysteretic energy dissipation compared to SCRSF-CBU. • Under MCE excitation, SCRSF-CMU maintains uniform inter-story drift angles and minimal residual deformations, facilitating easier post-earthquake repairs. • Both SCRSF-CMU and SCRSF-CBU show uniform inter-story drift ratios, but SCRSF-CBU has higher deformation demands under DBE and MCE. [ABSTRACT FROM AUTHOR]

It is acknowledged that various sources of uncertainties play a vital role in the seismic vulnerability of slope systems, while many studies ignore these sources in seismic assessments. This is because seismic performance and fragility evaluation of large soil-structure systems is challenging and computationally intensive by conventional nonlinear dynamic analysis methods, especially when the modeling uncertainties are considered. To address this challenge, this paper proposes a new framework for addressing uncertainties in the seismic evaluation of earth slopes using the Endurance Time Analysis (ETA) method. The ETA method is a dynamic pushover procedure in which the slope is subjected to a limited number of artificial intensifying records, and seismic responses are obtained over a continuous range of seismic intensities. For the purpose of this study, probabilistic two-dimensional numerical simulations of earth slopes are created using the FLAC software by considering the soil parameters uncertainty. Latine Hypercube Sampling is employed to generate random simulations. The models are then subjected to the intensifying prefabricated excitations based on the ETA method, and the fragility curves of the slope are obtained in three damage states by considering and not considering uncertainties. The results indicate that as the endurance time, which is a kind of intensity measure, increases, the uncertainties of seismic responses also increase. This shows that the effects of uncertainties become more significant when the slope is subjected to strong ground motions. Additionally, the influence of modeling uncertainty is negligible in the slight damage state, but significant in the extensive damage state. The proposed framework provides an effective and rapid way for performing the fragility and associated risk analysis of earth slopes considering uncertainties. • An efficient framework is proposed for incorporating uncertainties in fragility and vulnerability assessment of earth slopes. • The ETA method is utilized to significantly reduce the required computer run time in nonlinear dynamic analyses. • Ignoring the variability of soil properties can lead to a significant underestimation of the failure probability outcomes. • The OVAT analysis is performed to identify the influence of random variables on annual failure probability of the slope. [ABSTRACT FROM AUTHOR]

In response to the shortcomings of isolation bridge limit devices and friction dampers, a sliding friction bearing exhibiting multi-level working behavior (MSFB) is proposed. Its structure and mechanism are introduced, and a multi-condition quasi-static test is conducted using ABAQUS software. Through comparative analysis of theory and experiment, the theoretical model's accuracy and multi-level sliding friction mechanism of MSFB are verified. The mechanical parameters of MSFB are analyzed, clarifying the influence of various main mechanical parameters on the mechanical performance. The performance parameters of the MSFB are optimized based on a two-degree-of-freedom analysis model for a high-speed railway single-pier bridge equipped with MSFBs. The findings indicate that the seismic responses of MSFB is comprehensively affected by all the parameters, and the variation pattern is complex. By optimizing these performance parameters, MSFB can satisfy the multi-level performance demands of bridges subjected to varying earthquake intensities, and achieve the optimal control effect. The MSFB offers superior isolation efficiency during minor and moderate earthquakes and can substantially decrease the internal forces within the bridge substructure when utilized as a bridge isolation and limit device. During intense and infrequent earthquakes, the MSFB demonstrates remarkable displacement-limiting capacity and good self-centering and energy dissipation abilities. • A sliding friction bearing exhibiting multi-level working behavior is proposed. • The theoretical model's accuracy and multi-level sliding friction mechanism are verified. • The performance parameters are optimized for a high-speed railway bridge equipped with MSFBs. • MSFB can satisfy multi-level performance demands subjected to varying earthquake intensities. [ABSTRACT FROM AUTHOR]

A key component of any probabilistic seismic hazard analysis (PSHA) is the capability of predicting ground motion intensities for future earthquakes with different characteristics and occurrence frequencies. Ground motion models (GMMs) have been the preferred tools to predict, in a probabilistic manner, the size of the ground motion as a function of the earthquake's rupture parameters (i.e., location, depth, orientation of the rupture plane, rupture area, and rupture shape, among others). For this purpose, two different approaches have been used in PSHA practice. The first one, widely used and with hundreds of available models, are semi-empirical derivations of GMMs for response spectral values. The second one, which is less used in professional practice, requires the development of the predicting model for the Fourier amplitude spectrum (FAS) and the duration of the strong motion, to convert them into response spectral values through random vibration theory (RVT). The second approach, although computationally complex, should be preferred when site-effects are considered in the PSHA since these can be incorporated in a more efficient and theoretically correct way. Also, this second approach allows estimating hazard levels for different damping ratios and other hazard intensity measures such as peak ground velocity (PGV) and peak ground displacement (PGD) straightforward. This paper shows the methodology and results of a PSHA for Mexico City, a place with well-known existence and relevance of site-effects, carried out exclusively using Fourier-based GMMs, developed to be representative for the different types of earthquakes that contribute to earthquake hazard in the city (i.e., interface, intraslab, and crustal). The strategy to estimate ground motions in Mexico City consists in obtaining FAS-based ground motion models for a reference firm ground station and multiplying the computed FAS by an empirical transfer function that describes the frequency-dependent amplification factors between the reference station and the soft site of interest. • A PSHA was carried out for Mexico City using Fourier-based ground motion models. • Site-effects in PSHA are more transparent when using Fourier Amplitude Spectra GMMs. • The results of this PSHA are used today to obtain the design spectra in Mexico City. • Fourier-based GMMs allow estimating any damping values and intensity measures. [ABSTRACT FROM AUTHOR]

This study proposes a method for predicting the seismic response of structures using seismic information and structural properties. In the proposed method, the relationship between seismic and structural characteristics and seismic responses was investigated using a convolutional neural network (CNN) to predict the seismic response. Spectral acceleration (Sa) calculated from the seismic wave was selected as seismic information used in CNN-based seismic response prediction techniques. The study introduced seismic information and structural properties, which correspond to the parameters to express the structure's unique characteristics or nonlinear hysteretic behaviors that determine the response characteristics of the structure subjected to seismic waves. Meanwhile, Sa and structural properties were utilized to constitute the input map of CNN and predict the maximum inter-story drift ratio that corresponds to the output of CNN. As data corresponding to the period range of interest rather than a scalar value for a specific period, Sa is rearranged in matrix form to constitute the input map of CNN. Structural properties are also placed in the input map of CNN as scalar values are converted into conditional vectors. To confirm the validity of the proposed method, multiple CNN-based models with changes in the information of the input map are presented, and their prediction performances are compared. Furthermore, CNN-based models that additionally consider seismic intensity measures are presented, and their influences on seismic response prediction performance are analyzed. In addition, a vast number of linear and nonlinear structures were generated, and seismic responses extracted via seismic analysis of multiple earthquakes were used to create datasets for training the presented models. The prediction performance of the presented models trained using the datasets was compared. The validity of the simultaneous use of structural properties with Sa, the introduction of conditional vectors, the additional use of seismic intensity measures, and their contributions to improving prediction performance were also examined. • A CNN-based seismic response prediction method is presented. • Seismic and structural properties are considered in the method. • A conditional vector form for structural properties is proposed and used in the input of the CNN. • Spectral accelerations of ground motions are employed as seismic properties into the CNN. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic response of a model pile-soil-bridge system subjected to seismic loading using a finite element model (FEM) developed in OpenSees. The numerical model is validated against shake table test data from a companion experimental study, which tested a piles-bridge model fabricated from organic glass. The bridge model comprised four piers, each supported by two-by-two pile groups, with edge piers featuring 60 × 60 mm rubber pads between the pier and deck. Two earthquake ground motions, El Centro and Tianjin, were applied at three intensity levels. The calculated and measured responses show good agreement. The validated FEM reveals that the El Centro earthquake typically induces higher acceleration and moment responses in structural elements compared to the Tianjin earthquake, while the Tianjin earthquake results in greater displacement responses. These findings highlight the impact of earthquake wave characteristics, such as predominant period, on the bridge system's response. Furthermore, the bending moments at the pier top for edge piers remain relatively consistent across different earthquake motions and intensity levels, indicating the role of rubber pads in mitigating seismic forces in the piers. • Finite element analyses of Pile-soil-model bridge seismic tests are conducted. • FE models are validated with shake table test data. • Seismic response of pile-soil-bridge elements are elaborated revealing effects of earthquake characteristics. • Kinematic and inertial soil-structure interaction effects are evaluated. [ABSTRACT FROM AUTHOR]

Multi-stage anchoring lattice beam is widely used to support high slope in high earthquake intensity area, while the seismic behavior and interaction are not very clear. The previous studies mainly focused on a single-stage slope, while the analysis of multi-stage effect on the seismic response of anchoring lattice beam is lacking. Subsequently, a shaking table experiment was carried out to investigate the dynamic characteristics and seismic responses of a three-stage slope supported by an anchoring lattice beam. The displacement mode and the residual displacement are observed by Digital Image Correlation (DIC) technology. Kobe and Landers ground motions were input in shaking table test with an increasing order of shaking intensity. The original Kobe motion was applied at the last sequence to investigate the effect of frequency characteristic of ground motion. The results show that the acceleration response increases nonlinearly along the height of three-stage slope, and a reduction of acceleration response is observed at platform. The energy within a frequency band close to natural frequency of three-stage slope is especially amplified. The anchor takes more responsibility to resist the seismic loading, and decreases the earth pressure behind lattice beam. By setting multiple stages, the acceleration amplification and seismic earth pressure are reduced effectively. The intensity and the frequency characteristic of seismic motion affect the axial strain of anchor. The potential local failure and the frequency characteristic of seismic motion are suggested to be considered in seismic design. • The dynamic characteristic and response of a three-stage anchoring lattice beam were studied by shaking table test. • The modal parameter, horizontal and vertical acceleration, displacement, axial anchor strain and earth pressure were studied. • The effect of seismic ground motion and multi-stage effect on seismic response are analyzed. [ABSTRACT FROM AUTHOR]

Seismic fragility of substation equipment is vital in risk analyses, as well as post-earthquake prediction of failure probabilities of multiple equipment for deciding the inspection order. However, the existing fragility curves of equipment are commonly generated without adequately considering intensity measures (IMs) of ground motions. During the post-earthquake use, they are deemed applicable to any earthquake occurring in the region, which is insufficiently precise. Thus, this paper employs a new method to derive more refined fragility curves for substation equipment based on ground motion classifications. It uses principal component analysis to convert IMs into a small number of principal components (PCs). Taking the PCs as indices, the selected ground motions are clearly categorized into distinct classes using the K-means clustering algorithm. Then, a simulation model of equipment is developed and the time-history dynamic analyses are performed to calculate seismic responses under different classes of ground motions. Finally, the refined fragility curves are derived via multiple stripe analysis for each ground motion class. A 500 kV power transformer is used as a case to implement the method. The results show that a small number of PCs can effectively reflect the multiple ground motion characteristics. Different ground motion classes have distinct distributions of IMs and PCs. There are notable discrepancies in the fragility curves of the power transformer when subjected to different ground motion classes. The significant disparities between the refined and original unclassified fragility curves highlight the importance of considering ground motion classifications. • Clustering of ground motions was introduced into seismic fragility analysis of substation equipment. • Principal components analysis on seismic intensity measures was performed. • Principal components were proposed as indices for ground motion classification. • A batch of ground motions was clustered as six classes with distinct characteristics. • Refined seismic fragility curves of a 500 kV power transformer were obtained and compared. [ABSTRACT FROM AUTHOR]

Offshore wind turbines (OWTs) are gaining prominence worldwide, and the hybrid pile-bucket foundation, which combines a monopole and a bucket, has emerged as a noteworthy development. In this study, a 3-D numerical model for the 5-MW OWT was constructed utilizing the OpenSees platform. The dynamic characteristics of the sand was modeled with the PDMY02 constitutive model and the soil was discretized using brick u-p elements. To investigate the dynamic behavior of the OWT in an actual marine environment, the coupled model was subjected to dynamic loadings, encompassing waves, wind, and earthquake. Two seismic motions with different frequency components were considered, respectively. The study focused on exploring the impacts of key influencing factors on the OWT rotation, tower-top acceleration development and spatiotemporal distribution of excess pore water pressure ratio (EPWPR). These factors include dynamic load combinations, earthquake intensity, soil relative density, wind speed, angle between load directions, and pile length. It is revealed that the inclination angle of offshore wind turbines (OWTs) may exceed the allowable threshold under specific conditions of load combinations, seismic motion inputs, and seabed conditions. Thus, it is suggested to appropriately consider the effects of wind and wave actions in the seismic analysis of OWTS. • A 3-D numerical model of 5 MW OWT with hybrid pile-bucket foundation was developed. • Two seismic motion inputs with different frequency components were considered. • The wind and wave loads were generated and imposed at different parts of OWT. • Soil liquefaction, acceleration and rotation angle tower were illustrated. • Load combination, earthquake intensity, soil relative density, wind speed, loading angle and pile length were considered. [ABSTRACT FROM AUTHOR]

Many grain silos in earthquake intensity areas are at significant risk of post-seismic damage, which compromise their functionality and pose an enormous challenge to post-disaster rescue and social stability. However, the current specifications based on fixed-base foundations are not fit for the seismic design of silos in soft soil areas. Therefore, it is of great practical significance to study the seismic disaster prevention of siloes considering soil-structure interaction (SSI) for food security and post-disaster supply. In this research, a column-bearing silo in a soft soil area is taken as the research object. The relative displacement response, elastic-plastic development and storage lateral pressure of the structure under different ground motions are studied in detail when the state of filling storage material is empty, half-filled and fully filled. Compared with the fixed-base model, the mechanism of the ground motion response and the influence of the SSI effects on the dynamic characteristics of the column-bearing silo structure under different storage conditions are revealed. In addition, structural vulnerability analysis is carried out with the incremental dynamic analysis (IDA) method. Finally, the structural damage probability with and without SSI effects under different storage conditions is further discussed. The results demonstrate that the SSI effects have a certain damping effect on the column-bearing silo. The amount of storage material changes the failure probability of the structure. Moreover, full-silo is the most dangerous condition, indicating that the filling state of storage material affects the stiffness degradation. This study provides theoretical insight to the influence of the SSI effect on the seismic resilience of structures. • The influence of SSI on the structural dynamic characteristics and the material lateral pressure are investigated. • The elastic-plastic development coefficient of displacement is proposed to evaluate the safety of the structure. • The vulnerability assessment of the silo with or without SSI effects under different storage conditions is discussed. • The influence of storage material on the failure probability of the structure is evaluated. [ABSTRACT FROM AUTHOR]

Near real-time prediction of earthquake-triggered landslides can rapidly forecast the spatial distribution of coseismic landslides just after a great earthquake, and provide effective support for emergency response. However, the prediction of earthquake-triggered landslides has always been a great challenge because of low accuracy and high false alarms. This work proposes a novel fuzzy deep learning (FuDL) model for near real-time earthquake-triggered landslide spatial prediction. Fuzzy learning theory is for the first time employed in earthquake-triggered landslide prediction. The FuDL has high generalization and robustness, effectively improving the accuracy of earthquake-triggered landslide prediction. Eighteen earthquake-triggered landslide inventories worldwide from 2008 to 2022 are employed to conduct ETL prediction. According to the chronological order, 15 earthquake-triggered landslides from 2008 to 2018 are adopted to train the FuDL model, and 3 earthquake-triggered landslides from 2019 to 2022 are utilized for near real-time earthquake-triggered landslide prediction. Furthermore, this work reveals that ground movement, relatively steep and high topography, and strong seismic intensity are critical factors affecting the spatial distribution of earthquake-triggered landslides. In addition, this work conducted a detailed analysis of the distribution patterns of earthquake-triggered landslides on a global scale. • A novel FuDL model is suggested and achieves high accuracy and good generalization. • FuDL model outperforms the state-of-the-art machine learning or deep learning models. • Topography, ground shake, and seismic intensity dominate the distribution of ETLs. [ABSTRACT FROM AUTHOR]

Seismic intensity measures at different levels significantly impact the seismic damage of building clusters. Reinforced concrete (RC) structures are a type of building widely used in different regions worldwide. A large amount of field seismic damage observation data indicates that within the same seismic intensity zone, the directional effects of varying ground motions lead to significant differences in damage to RC structures on different floors. However, relatively little research has been conducted on estimating the seismic fragility and vulnerability of RC structures considering the directional effects of seismic action. To further study the directional effect of seismic motion on the damage of different floors, this study conducted dynamic time history and spectral analyses on 1472,379 acceleration records in multiple directions obtained from monitoring at nine actual seismic stations during the 2008 Wenchuan earthquake in China. This paper innovatively reports on the actual damage features of RC structures during the Mw6.2 magnitude Jishishan earthquake in Gansu Province, China, on December 18, 2023 (the most severe destructive earthquake in China in 2023) and analyses the influence of earthquake directionality on the damage to different floors of RC structures. A three-dimensional numerical model of a four-story RC frame structure was established using numerical simulation and the finite element method. Different intensity measures were taken to input seismic excitations of different intensities into the RC structure in the 0°, 30°, 60°, and 90° directions, and damage simulation analysis was conducted. The nonlinear dynamic time history curves of structures under multiple directions of seismic excitation in different intensity zones have been developed. Using the interstory stiffness and interstory displacement angle as engineering demand parameters, damage assessment curves and stress clouds for RC structures with 1–4 floors considering different seismic directional effects were generated. The analysis results and major findings indicate that the seismic sequence in the 0° direction has a relatively heavy impact on the first floor of the RC structure in zone IX, which is consistent with the actual field observation results. • The structural failure caused by the most recent earthquake in China was reported. • This paper analyzes the influence of directional effects of ground motion on RC structures. • This paper uses empirical and numerical simulation methods to establish a structural damage model. [ABSTRACT FROM AUTHOR]

This paper presents an application of artificial neural networks (ANN) to ground motion modelling. We focused on developing a generalised ground motion model (GGMM) incorporating several seismic intensity measure (IM) types and their inter-IM correlation. These range from classical IMs, such as peak ground acceleration/velocity/displacement, spectral acceleration, and significant duration, to more advanced IMs recently shown to be better descriptors of structural performa nce, such as average spectral acceleration and filtered incremental velocity. Additionally, three different horizontal component definitions were included for the spectral acceleration-based IMs. A total of nine input ground motion causal parameters are required to use the GGMM developed, based on ground motion records from the NGA-West2 database. ANN was used to perform the regression, which differs from the approaches used in many existing ground motion models (GMMs), and gives the possibility to regress all IMs simultaneously in one model. A mixed-effects regression approach was adopted for the regression and the quantification of the inter- and intra-event variability of the GGMM estimation. The correlations between the IMs were also quantified and briefly presented here, which allows for a more refined prediction of seismic shaking and a unified treatment of prediction and IM correlations. This will allow more advanced record selection for non-linear dynamic analyses to be performed, which can consider several facets of ground shaking currently overlooked in many works. We evaluated the performance of the developed GGMM using several metrics and compared it to various existing GMMs developed with either the classical approach or machine learning methods. The results show that the proposed GGMM exhibits very good predictions, especially considering the wide range of IMs tackled. Lastly, this methodology has the flexibility of being able to add more IMs or horizontal component definitions seamlessly. This manuscript presents a novel generalised ground motion model for traditional and next-generation intensity measures (IMs) used in seismic hazard and risk. Some notable points: • Utilization of artificial neural networks to capture the complex interdependencies among multiple IMs. • The flexibility and accuracy of the model allows for more refined predictions for the next-generation IMs. • All the included IMs are simultaneously regressed using a mixed-effects regression procedure. • The proposed model can be used by the user to provide outputs of several IMs, which accommodates ease of use. • Correlations between the IMs were also quantified to offer a more consistent and unified treatment of IM correlations. • Comparisons of the developed model with existing models from the literature showed good performance and reduced dispersion. [ABSTRACT FROM AUTHOR]

Seismic fragility analysis plays a crucial role in performance-based seismic design (PBSD). The seismic fragility analyses for the concrete gravity retaining walls were performed in this study. Numerical models were developed for two concrete gravity retaining walls using OpenSees, considering two different backfill slope angles (0° and 12°). According to the probabilistic seismic demand models and comprehensive evaluation of intensity measures (IMs), the most suitable IM for concrete gravity retaining walls was determined. An approach for quantifying the limit state performance of concrete gravity retaining walls based on IDA was also proposed, and its reliability was verified based on observed damage during the 2008 Wenchuan earthquake. Seismic fragility curves for concrete gravity retaining walls were established under two backfill slope angles using three IMs. It is demonstrated to what extent a backfill slope angle can influence the damage probability under a specific seismic intensity level. • The finite element models of concrete gravity retaining wall are established. • The optimal IM for the concrete gravity retaining wall is determined. • A method is proposed to quantify limit states of concrete gravity retaining wall. • The accuracy of the method is validated via additional data of earthquake damage. • Seismic fragility curves for concrete gravity retaining wall are established. [ABSTRACT FROM AUTHOR]

High-strength steel-framed-tube structures with low-yield-point shear links (SFT-RLYPSL) exhibit exceptional lateral and torsional stiffness, coupled with significant energy dissipation capacities. This study aims to investigate teh influence of composite floor slabs on the seismic performance of these structures. Expanding on previous research concerning SFT-RLYPSL, this paper presents a simplified numerical model for the SFT-RLYPSL, incorporating the influence of the composite floor slab. The developed model employs the steel4 constitutive relation to accurately depict the behavior of low-yield-point steel. Furthermore, the simplified numerical model utilizes two-node link elements to simulate shear links and integrates composite beams to represent the influence of the composite floor slab. Using this simplified model, elastic-plastic pushover analysis is performed on five distinct SFT-RLYPSL structural cases, and nonlinear time-history analysis is conducted on three structural configurations. The investigation explores various aspects of the seismic performance of SFT-RLYPSL, including modal behavior, pushover curves, progression of overturning failure, time-history roof displacements, inter-story drift angles, base reactions, inter-story shear, failure modes, residual inter-story drift angles, and the manifestation of shear lag phenomena. The findings suggest that incorporating the composite floor slab effect enhances initial stiffness and peak load capacity in pushover analysis, leading to distinct three-stage pushover curves. During nonlinear time-history analysis, the composite floor slab effect increases structural stiffness, decreases roof displacements and inter-story drift angles, while simultaneously increasing base reactions, worsening component damage, and raising collapse risk. Nevertheless, its influence on residual inter-story drift angles remains relatively minor, with a mitigating effect on the shear lag phenomenon. Importantly, the degree of this impact varies with alterations in floor slab thickness and seismic intensity, highlighting the critical importance of considering the composite floor slab effect in structural design deliberations. • A simplified analytical model for analyzing SFT-RLYPSL structures is presented. • Comparison of different methods of considering composite floor slab effect in Pushover analysis. • Utilization of the proposed simplified model to conduct time-history analysis on SFT-RLYPSL structural cases. • Delve into the influence of the composite floor slab effect on the seismic performance of the SFT-RLYPSL structure. [ABSTRACT FROM AUTHOR]

The multiple-probability decision-making method for earthquake hazards considers multiple performance indicators and can be used to effectively estimate the seismic risk of structures. The seismic vulnerability model directly affects the development of the earthquake risk distribution in regional structures. This paper innovatively developed a bivariate intensity measurement method based on macroscopic and instrumental seismic intensities. An optimized instrument intensity calculation model was established considering the actual monitoring data of historical earthquakes in China. A hybrid seismic vulnerability quantification method based on empirical, expert judgement and analysis has been proposed and applied to evaluate the vulnerability levels of three types of building clusters in two typical earthquakes in Qinghai Province, China (the 2008 Dachaidan (DCD) earthquake and the 2009 Haixi (HX) earthquake). A structural hybrid vulnerability matrix and surface for nine zones based on bivariate intensity measures were developed. A synthetic vulnerability membership index considering fuzzy failure criteria and decision theory was proposed, and vulnerability membership curves for different vulnerability levels were established. An improved earthquake economic loss prediction function is proposed, and synthetic economic vulnerability index prediction models for three typical buildings in different regions are established. The estimated and calculated results of the developed multiscale variable parameter synthetic vulnerability model are highly consistent with the actual earthquake loss observations. • This paper proposes a bivariate intensity measure to estimate the seismic fragility of buildings. • An optimized hybrid vulnerability matrix and surface of typical buildings were established. • The 2008 and 2009 Dachaidan and Haixi earthquakes in Qinghai Province, China, were reported. [ABSTRACT FROM AUTHOR]

Seismic fragility assessments that predicts the exceedance probabilities of predefined limit states of a structure subjected to earthquakes are widely used to reduce economic losses and casualties. This paper presents a probabilistic assessment of slopes based on the permanent displacements calculated from a suite of two-dimensional (2D) nonlinear dynamic analyses. The slopes are categorized into four groups based on static factor of safety (FS static). The centrifuge test measurements of a slope composed of granular soil are utilized to validate the 2D finite element numerical model. The Newmark displacements are calculated by integrating the stresses imposed on the sliding surface. The sliding surface is determined from the maximum accumulated strain contours, thereby accounting for the slope and input motion characteristics. The Newmark displacement is correlated with various earthquake intensity measures (IMs). The optimal IMs are selected based on the goodness of fit, efficiency, practicality, and proficiency. The fragility curves are developed using selected optimal IMs for three sliding displacement-based damage levels, which are minor, moderate, and severe. The results show that FS static , which contains information on both the slope geometry and the shear strength of soil, is an effective parameter to estimate the Newmark displacement. In addition, a suite of seismic fragility surfaces are developed using dual IMs. • We develop fragility curves and surfaces for probabilistic estimate of seismic slope performance. • We use the outputs from 2D nonlinear dynamic analyses to determine Newmark displacement (NM). • NM is developed from integration of stress across intensity and slope dependent sliding surface. • NM is highly dependent on the static factor of safety of slopes. • We recommend four intensity measures based on evaluation of 20 parameters. [ABSTRACT FROM AUTHOR]

The seismic damage assessment for structures is an essential investigation to guarantee the seismic performance-based design. However, the seismic responses and damage development process of underground structures are now unclear due to the complicated soil-structure interaction, which results in a lack of the seismic damage assessment for underground structures. In this paper, the seismic damage mechanism and seismic failure path of the underground large-scale frame structure (ULSFS) are investigated, and a novel seismic damage assessment is proposed for the ULSFS based on the structural characteristics and seismic action distributions. During earthquakes with different seismic intensities, the seismic responses of the ULSFS are investigated. The vulnerable structural components are clarified and the seismic damage mechanisms are revealed. Focusing on the representative times, the seismic failure path of the ULSFS is studied throughout the whole seismic history. Based on the damage distribution characteristics and seismic failure mechanism, the entire ULSFS is divided to be outside damage region and inside damage region, respectively. According to the modal frequency response analysis, the seismic damage coefficients of columns and beams in different damage regions are determined. Based on the stiffness variations of damage components, an analysis method is proposed to achieve the seismic damage weights of columns and beams on different stories. Associating the seismic damage coefficients with seismic damage weights, the seismic damage assessment for the ULSFS is developed. The results show that: the outside damage region of ULSFS where the soil-structure interaction is considerable undergoes more considerable seismic damage than that of the inside damage region (roughly 30 % on average), and the seismic failure path would develop from outside to inside and from bottom to top in the ULSFS; the proposed seismic damage assessment is credible with the consideration of damage distribution characteristics and seismic failure paths of the ULSFS; during small earthquakes, middle earthquakes and great earthquakes, the seismic damage of the ULSFS is quantified to be approximately 0.05, 0.40 and 0.75, which indicates the ULSFS suffers the rare damage, medium damage and severe damage respectively. This paper can provide the necessary supplements and theoretical references for the seismic performance evaluation of large underground structures. • The seismic failure path of the underground large-scale frame structure (ULSFS) is revealed. • ULSFS is divided into outside and inside damage regions based on damage distribution characteristics and failure mechanism. • Seismic damage coefficients of components on the same story are developed by modal frequency responses. • Seismic damage weights of components on different stories are proposed corresponding to the stiffness variation. • A seismic damage assessment for the ULSFS based on damage distribution characteristics and seismic failure path. [ABSTRACT FROM AUTHOR]

For evaluating the post-earthquake failure probability of the immersed tunnel of Hong Kong-Zhuhai-Macao Bridge subjected transverse earthquake loading. A two-dimensional (2-D) finite element model considering the water-soil-tunnel interaction has been built based on the Abaqus software platform, and a more refined three-dimensional(3-D) model was built to examine the preciseness of the 2-D model in calculating the displacement response of immersed tunnel. The seismic damage evaluation of immersed tunnel was presented based the numerical analysis results of 3-D model, and it indicated the IDR is significant related to the damage level of tunnel. The inter-story drift ratio limits of immersed tunnel were defined based on the seismic performance curve obtained from the Pushover analysis. The non-linear dynamic analysis was performed for the 2-D model subjected different amplitude-modulated earthquake records according to the incremental dynamical analysis (IDA) procedure. The IDA curve cluster and corresponding 16 %, 50 %, 84 % percentile lines were plotted by defining the damage measure as the inter-story drift ratio, and employing the PGA to describe the intensity measures. The probability of the immersed tunnel exceeding different seismic performance level subjected different earthquake intensity have been given, and the finding shown the immersed tunnel perform enjoying good seismic performance. • The seismic damage evaluation of immersed tunnel were presented. • The displacement response of tunnel based on 2-D and 3-D model has been compared. • The IDA curves and its percentiles were plotted for the immersed tunnel. • The seismic fragility curves of immersed tunnel have been established. [ABSTRACT FROM AUTHOR]

Seismic structural reliability is typically quantified in terms of the mean annual number of earthquakes causing the structure of interest to exceed, in a single shock, a performance threshold (conventionally referred to as failure). This requires the definition of a hazard curve, which probabilistically characterizes the ground motion intensity at the site of interest, and a fragility curve that provides the failure probability given the ground shaking intensity. Recently, research attempted to account for the possible failure due to subsequent earthquakes, that is, damage accumulation, an issue neglected in the mentioned (classical) approach. To this aim, the so-called state-dependent fragility functions are often used. They provide the probability of getting any intermediate damage condition as a function of the intensity of the earthquake and the damage state of the structure. Fragility functions can also be developed for structural typologies (i.e., matching a given taxonomy), rather than individual structures, for large-scale seismic risk assessment. The presented study developed, in a reproducible manner, state-dependent fragility functions for Italian building typologies derived via back-to-back incremental dynamic analyses of equivalent-single-degree-of-freedom systems. The latter are taken from the outcomes of the SERA project (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe) and refer to existing reinforced concrete and masonry residential buildings. • Methodology for large-scale risk assessment accounting for seismic damage accumulation. • Parametric state-dependent fragility functions for Italian residential building typologies. • Shown results are one of the outputs of the RISE (Real-time Earthquake Risk Reduction for a Resilient Europe) project. • Influence of damage accumulation on the structural reliability assessment over time for some cases. [ABSTRACT FROM AUTHOR]

In this study, the seismic resilience of granular column-supported road embankments on liquefiable soils is examined to enhance the understanding and seismic design of resilient transportation infrastructure. A nonlinear dynamic analysis of embankments on liquefiable soils is performed, and the results are validated against centrifuge test data. In the assessment, a functional analysis framework encompassing fragility, vulnerability, and restoration functions is employed to evaluate the robustness and recovery of embankments. The resilience of embankments is quantified by the comprehensive life-cycle resilience index (R), which considers various factors, such as the embankment height, the liquefiable soil thickness, and the area replacement ratio (A R) of granular columns. A simplified design method is proposed that involves a model for rapidly assessing the resilience state of embankments under varying seismic intensities. The analysis highlights the essential role of granular columns in mitigating liquefaction-induced damage during seismic events, improving robustness, and recovering post-earthquake functionality, and a practical and reliable tool is developed for assessing embankment resilience across diverse seismic scenarios. • The seismic resilience curves for granular column-supported embankments on liquefiable sites are established. • The effect of embankment height, liquefiable soil thickness, and A R on the resilience of embankments are evaluated. • A simplified design method is proposed for rapidly analysing the resilience state of embankments. [ABSTRACT FROM AUTHOR]

In order to investigate the seismic behavior of pile-cap system installed in inclined soft clayey ground, a series of 1-g shaking table model tests were conducted on a 2 × 2 pile-cap system installed in an inclined kaolin clay bed. The test results suggested that the inclined clayey ground could considerably amplify the seismic ground motions, especially at pile cap and slope top; the frontal piles nearer to the slope top were found to experience evidently larger bending moments than the rear piles, suggesting that much larger amounts of downward thrust during seismic shakings were shared by the frontal piles, exhibiting a shadowing effect in the pile group. Additionally, a suite of three-dimensional (3D) finite element (FE) analyses were performed to systematically study the factors of inclination angle, horizontal seismic intensity, pile flexural rigidity and incorporation of vertical shaking on the seismic response of pile. It was found that, with the increasing horizontal seismic intensity or decreasing pile flexural rigidity, the piles could experience severe structural damages, which tended to be more significant with the increasing inclination angle; the influence of incorporating vertical shaking had a similar effect but in a much minor manner, suggesting that the horizontal shaking is more critical influencing the stability of the whole system. The findings obtained from this study can provide valuable reference for the seismic design and relevant risk assessment of piles constructed in inclined clayey ground. • Both 1-g shaking table tests and extended numerical parametric analyses are performed. • Increasing slope angle of clay ground can significantly increase seismic pile response. • Horizontal seismic intensity is more influential than the vertical seismic intensity. • Increasing seismic intensity or reducing pile flexural rigidity can cause pile damages. [ABSTRACT FROM AUTHOR]

Three-dimensional physics-based numerical simulations (3D-PBS) of the seismic response of the Santiago Basin, Chile, were performed considering a large-scale velocity model and shallow crustal earthquake scenarios, associated with the west-verging thrust San Ramón Fault. Numerical results show that competent gravelly soils in the center of the basin respond with low seismic amplification and shorter durations of strong ground motions, unlike less competent fine-grained soils in the northern area. A significant increase in the seismic intensities is observed in the vicinity of rock outcrops, attributable to the generation of surface waves. Seismic amplification factors were calculated with respect to a reference site on gravel and their values show high levels of amplification in the vicinity of the seismic source, and on soils with low shear wave velocities (V s) and long fundamental vibration periods. On the other hand, empirical ground motion models (GMM) were used to estimate amplification factors for peak ground accelerations and spectral accelerations at various periods. Results from GMMs and 3D-PBS were compared, showing similarities in the attenuation pattern on stiff soils, but differences in soils with low V s. Moreover, 3D-PBS captured site effects associated with the local geomorphology, unlike GMMs. • Two scenarios of Mw 6.0 earthquakes generated at the San Ramon Fault were evaluated. • 3D physics-based numerical simulations (3D-PBS) consider a large-scale Vs model. • Amplification patterns from 3D-PBS tend to agree with results from ground motion models. • Differences in predictions are detected in sites prone to develop surface waves. • Fine-grained soils away from the fault scarp amplify and extend the ground motion. [ABSTRACT FROM AUTHOR]

In this study, the effect of dynamic soil-structure modelling assumptions on the calculated seismic response of railway bridges with single column piers resting on shallow foundations is investigated. For this purpose, 10 structural models of a typical railway bridge are built in decreasing levels of complexity, starting from the most complicated model with nonlinear elements to accurately simulate dynamic soil-structure interaction. Then, the structural model is gradually simplified to a level where the effects of foundation-soil and abutment-backfill interactions are totally eliminated. Nonlinear time history analyses of the structural models are conducted with a set of ground motions with various intensities representing small, medium and large intensity earthquakes. Analyses results revealed that removing the abutments from the structural model results in significant discrepancies in the longitudinal direction response of the bridge but has negligible effect in the transverse direction. Furthermore, analyses results show good correlation between the complex and simplified models in deck displacement and bearing displacement but notable differences are observed in substructure responses when the soil-structure interaction is neglected. Therefore, at least linear soil-structure interaction modeling should be considered in the analyses for correct estimation of the substructure responses. • Effect of soil-structure modelling assumptions on the seismic response of bridges resting on shallow foundations is outlined. • Effect of including and excluding the abutments from the structural model on the seismic response of bridges is outlined. • The effect of radiation damping and equivalent hysteretic damping on the seismic response ofbridges is presented. • Information on structural modeling of bridges for seismic analyses is provided. [ABSTRACT FROM AUTHOR]

Earthquake waveforms are necessary for simulation, verification, and validation during the development of structural and earthquake engineering. However, due to the fact that the processes of earthquake preparation and generation are extremely complex and the human observations cover a relatively short period compared to large earthquake cycles, recorded earthquake waveforms are often limited and quite imbalanced. Consequently, the generation of artificial earthquake waveforms is meaningful and can produce useful earthquake data. In this study, a new method based on a generative approach is proposed by leveraging machine learning (ML) techniques. The generative models based on generative adversarial network (GAN) and conditional GAN (cGAN) are introduced, and the adversarial training between the generator and the discriminator is utilized to learn how to generate artificial earthquake waveforms. In addition, several criteria are exploited to terminate the adversarial training early in order to prevent modal collapse. Besides, different earthquake datasets and several earthquake features are used to verify the proposed method. The preliminary generation is carried out using the dataset recorded during the Chi-chi earthquake, and the generated samples show similar earthquake features to those extracted from the earthquake dataset. Subsequently, conditional generation is conducted using several sub-datasets recorded in different areas around Taiwan. The results demonstrate that the well-trained model can efficiently generate waveforms according to a pre-specified seismic intensity, with an overall accuracy of up to 90%. Although the model is reliable for Taiwan and in general to restricted subdomain of the probability distribution support, the proposed method shows its ability to produce new samples for a given class, even when the number of generated samples exceeds the number of training samples. • A large number of artificial earthquake waveforms are generated by using generative adversarial networks (GAN). • Several criteria based on the generated samples are used to terminate the adversarial training early to avoid modal collapse. • The conditional generation enables GANs to generate artificial earthquake waveforms according to various labels. [ABSTRACT FROM AUTHOR]

Tunnels, as critical underground infrastructures, often intersect with faults. Field investigations have underscored the susceptibility of fault-crossing tunnels to extensive damages during earthquakes. Hence, large-scale shaking table tests are conducted to investigate the deformation pattern and failure mechanism of fault-crossing tunnels under transverse excitation, particularly in non-rupture scenarios. The dynamic behavior of the tunnel, as expected, is dominated by the surrounding strata. Acceleration responses vary notably across different regions of the fault site. The disparity increases with the increments of seismic intensity and input frequency. The tunnel section at the interface between the fault and the hanging wall manifest the strongest acceleration, where the largest strains of the tunnel and most of the lining cracks also occur, highlighting its vulnerability to seismic vibrations. The damage-induced non-linearity of the tunnel is then identified by the decreasing dominant frequency thereof. The fault-crossing tunnel exhibits unique three-dimensional shearing-torsional deformations, elucidated through the test data and an analytical model. This deformation pattern provides a better understanding of the seismic responses of fault-crossing tunnels under seismic vibrations. • Dynamic responses of fault-crossing tunnels under seismic vibrations are studied by large-scale shaking table tests. • Faults have significant influence on tunnels under seismic vibrations even without rupture. • Vulnerable region of the tunnel, which is most intensely affected by the fault, is identified. • Deformation pattern and failure mechanism of fault-crossing tunnels under seismic vibrations are revealed. [ABSTRACT FROM AUTHOR]

The gravity-type wharf is generally more vulnerable during earthquakes due to its massive gravity quay wall, especially when located in a liquefiable area. Therefore, this study aims to develop numerical analysis procedure for its seismic performance assessment and fragility analysis considering the influence of soil liquefaction. Firstly, the quantitative damage criteria for gravity-type wharves were introduced and verified by case histories. Then, the finite element (FE) modeling of a gravity quay wall founded on liquefiable ground for seismic response analysis using PLAXIS 2D was suggested. Utilizing this modeling, the earthquake-induced damage cases of two gravity-type wharves in two ports in Taiwan were simulated for validation. The seismic performance of both wharves was further assessed by comparing the analyzed response under design earthquake with the damage criteria. Finally, the procedure of seismic fragility analysis based on massive numerical analysis was proposed. Actual earthquake records were scaled to various seismic intensity levels to serve as input motions. Thus, the relationships between the seismic intensity and the damage probability of a gravity-type wharf corresponding to different damage levels, namely, the fragility curves, can be accordingly obtained. These results benefit the seismic performance design and rapid estimation of possible seismic damage of port facilities. • Existing seismic damage criteria of gravity-type wharf justified by case histories. • FE modeling for seismic performance assessment of gravity-type wharf suggested. • Fragility curves of gravity-type wharf derived using massive numerical analysis. • Case studies performed for demonstration and results compared with real situation. • Procedure of performance assessment and fragility analysis verified satisfactory. [ABSTRACT FROM AUTHOR]

To investigate the seismic reinforcement performance of compression and self-recovery (C&S–R) anchor cables, a series of shaking table comparison tests were conducted on rock slopes reinforced by two types of anchor cables: C&S–R anchor cables and conventional anchor cables, under different seismic intensities. During the tests, multiple accelerometers, displacement meters and strain gauges were synchronously arranged to monitor the strain of anchor cables and the dynamic response of the anchored slopes. The test results reveal that C&S–R anchor cables had better seismic performance. Compared to conventional anchor cables, C&S–R anchor cables had a peak axial strain reduction of approximately 23.0% and an increase in seismic intensity of 0.1g–0.2g. The final natural frequencies of the slope reinforced by C&S–R anchor cables and that of the slope reinforced by conventional anchor cables were 31.25 Hz and 26.1 Hz, respectively, confirming that C&S–R anchor cables reduce the internal damage of the anchored slopes during earthquakes. The results provide guidance and basis for the seismic optimization design of anchored slopes. • A new type of compression and self-recovery (C&S–R) anchor cable was developed. • The shaking table comparison tests on C&S–R anchor cable reinforced slopes were carried out. • The seismic frequency range in which the seismic devices of C&S–R anchor cables function was studied. • Dynamic response of anchored slopes was compared and analyzed considering anchor cables failure process. • The effect of C&S–R anchor cables on slope stability during or after earthquakes is clarified. [ABSTRACT FROM AUTHOR]

South Korea has implemented borehole-type seismometers for reliable earthquake observations and earthquake early-warning systems, with approximately 85% of seismometers being replaced by borehole-type seismometers after the Gyeongju earthquake. Although these seismometers are more effective at detecting earthquakes owing to the reduced artificial ambient noise, they do not record surface-level shaking. Therefore, it is necessary to estimate ground surface shaking directly associated with potential damage when using borehole-type seismometers without surface sensors. This study investigated and compared various methods, including the stochastic point-source ground-motion model, transfer function based on ambient noise, and one-dimensional site response, to estimate horizontal seismograms of the ground surface. We assessed the accuracy of these methods by comparing the waveforms generated in event cases (magnitude from 2.5 to 5.8, with epicentral distances spanning 22 km–209 km) in terms of Fourier spectra, intensity, and spectral acceleration. Among the methods assessed, the transfer function approach, which does not account for the geophysical characteristics such as V S 30 , proved to be the most appropriate for correcting ground-surface effects. • Estimating seismic intensity measurements (IMs) at ground surface from borehole seismometers. • Approach for estimating IMs without ground surface seismometers. • Comparing methods: ambient noise transfer, point-source models, and 1D site response. [ABSTRACT FROM AUTHOR]

Understanding the seismic characteristics of submarine sites and conducting seismic response analysis for such locations are crucial for the safety of marine engineering. However, due to a shortage of strong motion records, the ground motion of offshore earthquakes has not yet been fully characterized. The actual seabed conditions are highly intricate, necessitating consideration of factors such as the dynamic coupling effect between seawater and seabed, the strong nonlinearity of seafloor soft sediments, and the diverse nature of natural submarine terrain. In this study, the modified Davidenkov dynamic constitutive model is used to simulate the nonlinear behavior of the soil. The Coupled Acoustic-Structure method is utilized to simulate the interaction between seawater and seabed. Three typical and simplified terrains, namely flat terrain, valley terrain, and hilly terrain, are individually modeled. The measured seafloor ground motions with different frequency components are used as bidirectional seismic excitations input from the bedrock. The amplification factor in terms of CAV is introduced to evaluate the amplification of seismic ground motion characteristics at seabed surface with respect to those at the bedrock surface. The acceleration response spectra in both horizontal and vertical directions, as well as the corresponding vertical-to-horizontal response spectral ratios, at the representative points are obtained, respectively. Several key findings are consistent with the features of the observed offshore and onshore earthquake ground motions. Numerical examples are presented to illustrate the different influence rules of terrain condition, overlying water depth, and seismic intensity on the nonlinear seismic response characteristics. • Both the nonlinearity of soil and the seawater-seabed dynamic interaction are considered. • Three typical terrains, namely flat, valley, and hilly terrains, are individually modeled. • Bidirectional seismic input from the bedrock with different frequency components are adopted. • Amplification factors in terms of CAV in horizontal and vertical directions are adopted. • The acceleration response spectra as well as the vertical-to-horizontal response spectral ratios are respectively obtained. [ABSTRACT FROM AUTHOR]

The selection of an appropriate intensity measure to assess the seismic performance in steel buildings is an important step to reduce uncertainty in the structural response. Hence, in this study, a scalar ground motion intensity measure able to increase the efficiency in the prediction of nonlinear behavior effects of steel structures subjected to earthquake ground motions named the generalized intensity measure I Npg is analyzed. The intensity measure is based on a proxy of the spectral shape N pg , where it can be defined by using different types of spectral shapes, such as those obtained with pseudo-acceleration, velocity, displacement, input energy, inelastic parameters and so on. This work shows the efficiency of the generalized intensity measure named I Npg when the spectral parameters of pseudo-acceleration and velocity are used. Therefore, to improve the performance of the analyzed intensity measure, two engineering demand parameters, maximum inter-story drift and horizontal peak floor acceleration, of steel frames with 5, 10, 15 and 20 stories subjected to several narrow-band ground motions are estimated as a function of the spectral acceleration at first mode of vibration of the structure Sa(T 1) , which is commonly used in earthquake engineering and seismology, and with the two particular cases under study of the recently developed parameter related to the structural response known as I Npg. In general, the intensity measure here studied is able to efficiently predict nonlinear structural demands on steel buildings under earthquake ground motions. Further, the analyzed intensity measure must be considered to estimate maximum inter-story drift and horizontal peak floor acceleration demand of multi-story buildings. • The study demonstrates the efficiency of I Npg in predicting structural response compared to Sa(T 1). • The I Npg intensity measure significantly reduces the uncertainty in the structural response. • The I Npg intensity measure is based on the spectral shape to predict nonlinear structural behavior. • The I Npg intensity measure incorporates a wide range of spectral parameters derived from various types of spectra. [ABSTRACT FROM AUTHOR]

During previous medium intensity earthquakes, several cantilevered retaining structures shoring waterfront areas experienced large deformations or even collapsed. This was in contrary to the caisson type quay walls which performed better even during the very strong 1995 Kobe earthquake. Within this realm, recent studies have highlighted that saturated backfill adjacent to retaining structures may not fully liquefy and has a strong potential for shear-induced dilation mechanics owing to the presence of substantial static shear. However, despite these negative excess pore pressures and absence of a full liquefaction state in the backfill, cantilevered retaining walls may still experience large deformations. In this paper, a deformation mechanism is proposed for an embedded cantilever retaining wall supporting a submerged backfill made of Ottawa F-65 sand using a geotechnical centrifuge experiment. The dynamic response of the soil–structure system was measured, and the intra-cyclic mechanics were investigated. The entire earthquake duration of 20 s was divided into three different phases. In phase I (comprising of initial 6 s), the retaining wall experienced "sliding" deformations owing to its inertia with negligible soil straining at the backfill. Under the application of subsequent seismic pulses in phase II, large suction drops in excess pore pressures were observed during the translation of the retaining wall toward the backfill, which caused the negative excess pore pressure to exceed the hydrostatic value. However, the temporary release of the suction drops during the deformation of the wall toward the seaside resulted in significant softening as soil crosses the phase-transformation line. This ultimately resulted in significant plasticization of the backfill, and the wall initiated a "rotation" type deformation mechanism with a pivot point located near its base. Intra-cyclic observations revealed an increase in the magnitude of the phase transition in excess pore pressures, which contributed to the increased accumulated soil straining along the backfill. Owing to this, the wall experienced increasing rotations with the application of subsequent cycles in phase II (until 14 s) until the passive resistance in front of the wall was fully mobilized. However, a sudden catastrophic collapse of the wall could be avoided owing to the re-dilation mechanism, during which the soil again underwent a phase transformation and generated negative excess pore pressures on the completion of the wall translation toward the seaside. With the reduction in the amplitude of the applied cycles toward the end of shaking (phase III), the effective stress path in front of the wall moved away from the origin, and the mobilized passive stress reduced, which eventually resulted in the retaining wall achieving a stable state with no additional deformations. The proposed deformation mechanism highlights that a state of full liquefaction is not a necessary prerequisite for an embedded cantilever retaining wall to experience significant deformations, and an understanding of suction mechanics during excess pore pressure generation is critical. • Deformation mechanism for the embedded cantilever structure retaining a submerged backfill is proposed. • The reasons for the cantilever retaining wall to experience significant deformations are explored. • During the initial cycles, the wall undergoes a "sliding" type deformation mechanism owing mostly to inertia forces. • Under the application of subsequent strong seismic pulses, the retaining wall experiences a "rotation" type deformation mechanism. • The intra-cyclic shear-induced dilation mechanics and intra-cyclic soil shearing at the backfill plays an important role. [ABSTRACT FROM AUTHOR]

Ground motion duration has been demonstrated to exert a significant impact on structural responses for self-centering systems in the companion paper (part 1), yet it has not been explicitly considered in the evaluation of structural collapse capacity. This paper investigates the influence of seismic duration on assessments of structural collapse capacity for self-centering systems with varying structural features. Nonlinear incremental dynamic analyses are conducted using two record sets with different durations, while spectrally equivalent process is employed to isolate duration effects from seismic intensity and frequency. The procedure outlined in FEMA P695 is adopted to assess structural collapse risk, while the recommended duration-blind earthquake records are examined for their reasonability. Meanwhile, the discrepancy in duration effects between conventional and self-centering systems is investigated. Results show that earthquakes with longer duration elevate the collapse risk significantly compared to shorter duration earthquakes. Self-centering systems with varying structural features consistently meet the performance objectives stipulated in FEMA P695. Notably, enhancing the self-centering parameter proves effective in mitigating structural damage. Furthermore, conventional systems exhibit heightened sensitivity to seismic durations compared to self-centering systems. While the structural collapse capacity evaluated using the FEMA record set aligns with that from the short duration set, it underestimates collapse risk for systems under earthquakes with longer duration. The results highlight the imperative of explicitly considering earthquake duration in structural collapse capacity assessments. • The influence of ground motion duration on structural collapse assessments in self-centering systems is investigated. • The reasonability of the earthquake records recommended by FEMA P695 in evaluation of structural collapse is examined. • The discrepancy in duration effects on structural collapse between conventional and self-centering systems is analyzed. [ABSTRACT FROM AUTHOR]

The influence of earthquake duration is increasingly recognized for its significant impact on structural responses and performance. However, existing studies have predominantly focused on analyzing the duration effects on structural responses of conventional structures. This paper aims to investigate the impact of earthquake duration on nonlinear behaviors and damage development for self-centering single degree of freedom (SDOF) systems considering various structural features, including ductility, post-yield stiffness and energy-dissipating capacity. Two sets of earthquake records with long and short durations are selected to perform nonlinear time history analyses, while spectrally equivalent procedure is employed to isolate the duration effect from seismic intensity and frequency. Hypothesis tests are utilized to further examine the correlation between structural responses and duration effects. The study also compares the duration effects between conventional and self-centering systems. Results show that earthquake duration only has slight impacts on maximum deformations in self-centering systems with high ductility levels in the long-period range. Long-duration earthquakes would impose higher input energy and hysteretic energy demands in self-centering systems, regardless of structural features. Furthermore, the study reveals strong correlations between earthquake duration and damage development, as long-duration earthquakes tend to cause more damage in systems. Compared to self-centering systems, maximum deformations of conventional structures show less sensitivity to earthquake duration, as well as the ratio of hysteretic energy demands to input energy demands. Nevertheless, both self-centering systems and conventional structures experience increased damage under long-duration earthquakes. • The influence of seismic duration on structural behaviors and damage development in self-centering systems is investigated. • Hypothesis tests are utilized to quantitatively analyze the correlation between structural responses and duration effects. • The discrepancy in duration effects between conventional systems and self-centering systems is examined. [ABSTRACT FROM AUTHOR]

The seismic resilience of underground structures is generally based on the results of the seismic fragility analysis and the damage of all the structural components comprehensively. Whereas, the seismic behavior of underground structures is greatly influenced by the vertical ground motions. Therefore, this paper proposed a new method to study the seismic fragility of underground structures subjected to both horizontal and vertical ground motions, and by considering the damage weight coefficients of the structural components to the overall structure. Pushover/pseudo-gravity analyses were conducted to determine the demand measures and seismic performance levels of all the structural components. Then the intensity measures of earthquakes were determined and the seismic fragility curves of structural components were built by combining the seismic performance levels of structural components and the 3D incremental dynamic analyses on the underground structures. Meanwhile, according to the damage probability of each structural component, the damage weight coefficients of components to the damage of the overall structures were calculated. After that, the seismic fragility surfaces of the underground structures were built and the seismic fragility of the structures was discussed. The method developed in this study could not only be used to evaluate the damage probability of underground structures caused by the vertical ground motions, but also to evaluate the damage probability and post-earthquake repairability of the components. • Seismic fragility of underground structures based on 3D IDA analyses. • Damage probability of each structural component. • Damage weight coefficients of the structural components. • Fragility surfaces of the underground structure suffered bi-direction ground motions. [ABSTRACT FROM AUTHOR]

Dynamic soil-structure interaction is typically decomposed in kinematic and inertial effects. Inertial interaction generally results in an increase in the fundamental period and damping of the system, which, for slender structures, corresponds to a decrease of the inertial forces transmitted to the superstructure. Relations to estimate the period increase are mainly available in the literature for shallow foundations. In this paper, the fundamental period of bridge piers on compliant caisson foundations was obtained from dynamic centrifuge tests. A rigid and a flexible bridge pier were subjected to trains of sinusoidal waves and real ground motions. The interpretation of the experimental results permitted to (i) evaluate the increase of period with respect to fixed-base conditions; (ii) assess the dependency of the compliant-base period on the motion intensity. The second aspect sheds light on the role played by non-linearity of soil behaviour and emphasises the importance of performing preliminary soil response analyses. • Inertial interaction results in an increase of the system fundamental period. • Dynamic centrifuge tests of bridge piers on caisson foundations were performed. • The increase of the fundamental period with respect to the fixed-base was evaluated. • The dependency of the fundamental period on the earthquake intensity was assessed. • The results emphasises the need of performing preliminary soil response analyses. [ABSTRACT FROM AUTHOR]

The goal of this study is to determine the scope of the impact of pile driving construction vibration on surrounding residential houses and buildings during engineering construction. Firstly, introducing the gradient factor of unsaturated soil, proposed a model for non-uniform variation of pores with depth. Secondly, Consider the coupling between the model and soil skeleton density, relative fluid density, relative gas density, pore fluid, pore gas, and shear modulus. Finally, coupling the pile with the driving depth and propose a pile driving vibration model for non-uniform unsaturated soil. Proposed a new method for solving coupled equations using Hankel transform. Moreover, the analytical solution of this study was validated through on-site experiments. Results show that, deeper the pile is inserted into the soil, the greater the peak vertical velocity at different measuring points. The vibration of the pile is strongest at the last 1 m into the soil. When close to the vibration source, the amplitude values in the three directions are: maximum in vertical direction, followed by horizontal and radial direction, and minimum in horizontal and tangential direction. When pile driving construction is carried out outside the range of vibration influence, the seismic damage generated is equivalent to the seismic intensity below V (excluding V). The rate amplitude calculated by the model established in this study is closer to the measured value. Therefore, using the model established in this work can more accurately evaluate the impact of pile driving vibration during the construction process of highways and high-speed railways. • A pile driving vibration model for non-uniform unsaturated soil is established. • Gradient factor is introduced for uneven changes in porosity with depth. • The analytical solution of this study is validated through on-site experiments. • Variation pattern of vibration distance attenuation is analysed. • Results show significant improvement compared to uniform model. [ABSTRACT FROM AUTHOR]

Current design and assessment guidelines define several seismic performance levels, aiming to ensure that structures exhibit adequate behaviour at different seismic intensity levels. Typically, the acceptance criteria at different performance levels are met by ensuring that local deformation demands are lower than pre-defined capacities. Despite the proven effectiveness of such an approach, it provides an ambiguous measure of the performance of the building, which, in most cases, is neither meaningful nor appropriate for building owners, stakeholders or decision-makers. The main objective of the research presented in this paper is to evaluate the expected direct economic seismic losses of steel moment-resisting frame structures designed according to Eurocode 8 (EC8). A set of 120 archetype buildings, representative of the current building stock in Portugal, were designed according to Part 1 of EC8 using three different behaviour factors, q : a) code-prescribed upper bound limits for medium and high ductility classes; b) behaviour factor defined according to an Improved Force-Based Design (IFBD) procedure. The PEER-PBEE methodology with the improvements proposed by Ramirez and Miranda [1] was employed for the estimation of expected seismic losses evaluated for the seismic intensity levels considered in Part 3 of EC8. The results obtained indicate that the buildings designed in accordance with EC8 comply with the non-collapse criteria. However, the level of damage could imply significant repair costs. Importantly, the results also highlight that a rational selection of the behaviour factor can result in a reduction of steel weight but still ensuring acceptable levels of expected annual losses. • A study concerning the evaluation of seismic losses of steel moment frames designed in accordance EC8 is presented. • The PEER-PBEE methodology procedure with the improvements proposed by Ramirez and Miranda was used to evaluate a set of 360 steel MRF archetypes. • All the studied archetypes comply with the non-collapse criteria defined in EC8 for the design intensity level. • However, the level of damage could imply repair costs of around 30% of the building replacement value. [ABSTRACT FROM AUTHOR]

Proposed in the late 1980s, cumulative absolute velocity (CAV) is a new intensity measure for earthquake ground motion characterizations, followed by studies and applications such as CAV ground motion prediction equations (GMPEs). In this study, two new CAV GMPEs were developed with 24,667 strong-motion records from Taiwan, and the first CAV seismic hazard assessment for Taipei (the most important city in Taiwan) was then conducted using the local CAV models. It shows that the annual rate for the study area to encounter a ground motion with CAV >0.97 g-sec is 0.002 per year, corresponding to a 10% occurrence probability in 50 years. By contrast, the deterministic scenario-based analysis shows that the CAV seismic hazard is about 0.60 g-sec for the study area. Future studies are worth conducting to develop more sophisticated, local CAV GPMEs and to explore more applications of such CAV prediction models, such as the developments of PGA-CAV joint probability distributions for conducting PGA-CAV joint seismic hazard assessments. • First CAV GMPE for Taiwan areas. • More than 4,000 strong motion records used. • CAV-based seismic hazard analysis for Taipei. [ABSTRACT FROM AUTHOR]

Seismic damage and its correlation with the earthquake intensity measures (IMs) are important for both record selection and probabilistic seismic risk assessment studies. A lot of studies considering the various structural properties were performed to investigate the correlations of mainly PGA and PGV under different strength reduction (R) and ductility factors (μ). In this study, correlation of many scalar IMs named as PGA , PGV , a rms , v rms , d rms , I a , CAV , ASI , SI are studied. Building represented by single degree of freedom (SDOF) models were classified according to lateral strength ratios (V t /W), ratio of strength capacity at yield (V t) to seismic weight (W), varying from 10% to 50%. Effects of post yield stiffness capacities, hysteretic behavior type and the soil properties on deformation demand of SDOF models are also taken into account. Post yield stiffness ratios of 0%, 5% and 10% considered and assigned to building models. Elastic-perfectly plastic and modified Clough hysteretic models were used in the non-linear dynamic analyses. Strong motion records obtained from firm and soft soil sites were classified according to V s30 and inelastic deformation demands obtained from both soil conditions are calculated and compared. Variation of correlation coefficients of different IMs indicates that SI is the best earthquake parameter especially along the period range of 0.5–2 s which can be thought to represent building type structures. Furthermore, it was observed that sensitivity of SI parameter to post yield stiffness, hysteretic behavior type and the soil properties is very limited with respect to considered IMs. Correlation coefficients obtained from SDOF models are compared to that of multi-story buildings and the compatibility of both SDOF and MDOF models are presented. • Effects of post yield stiffness, hysteretic behavior and soil properties considered. • Correlations are calculated for V t /W ratios instead of R and μ coefficients. • Correlation of IMs evaluated and compared for SDOF and MDOF systems. • SI found best IM along period range of 0.5–2 s that represent building type structures. • SI is less sensitive to post yield stiffness, hysteretic behavior and soil properties. [ABSTRACT FROM AUTHOR]

This technical note aims to investigate the accuracy of the so-called Coefficient Method included in the ASCE/SEI 41-17 standard for estimating the maximum (target) roof displacement demands in reinforced concrete frames subjected to pulse-like near-fault earthquake ground motions. Additionally, enhanced coefficients C 1 and C 2 introduced in the literature to be used in the Coefficient Method were also included in this investigation. Results obtained from this study reveal that the current coefficient C 1 included in the ASCE/SEI 41-17 standard leads to a standard error larger than that when enhanced coefficients are employed. Particularly, this observation is attributed to the limitation of current coefficient C 1 to capture the empirical spectral trend when structures are subjected to pulse-like near-fault earthquake ground motions. • Review of the Coefficient Method in ASCE 41-17 and suggested improvements. • Evaluating of the accuracy of the Displacement Coefficient Method included in ASCE/SEI 41-17 standard for estimating the maximum inelastic roof displacement under near-fault ground motion records. • Investigating if the enhanced equations introduced in the literature for coefficients C 1 and C 2 improve its accuracy. [ABSTRACT FROM AUTHOR]

Offshore wind turbines (OWTs) are more and more widely used to produce electrical energy nowadays. Besides the constant wind and wave loads, earthquake excitation can be another important vibration source to the OWTs since many OWTs have been/will be constructed in the seismic prone areas. Extensive research works have been carried out to understand the dynamic behaviours of OWTs when they are subjected to multi-hazards (e.g. the simultaneous wind, wave and/or earthquake loadings). However, when seismic excitations are considered, the onshore earthquake records are normally used as inputs in the analyses due to the lack of offshore data and the difficulty in synthesizing the offshore seismic motions. This practice may lead to inaccurate structural response estimations since it is well known that the seawater can significantly suppress the seafloor vertical motions near the P wave resonant frequencies of the seawater layer, which in turn results in the different characteristics of onshore and offshore earthquake recordings. Moreover, the earthquake motions along the pile of OWTs are different from those at the ground surface, i.e. the earthquake motions vary with the soil depth. Recently, a method to stochastically simulate the earthquake ground motions on the offshore site was proposed, in which the influence of seawater layer was considered and the earthquake motions at any soil depth could be obtained. This paper carries out numerical simulations on the dynamic behaviours of OWTs subjected to the combined wind, wave and earthquake loadings, and the depth-varying offshore seismic motions are used as inputs in the analyses. The seismic responses of OWTs obtained from the onshore and offshore earthquake motions are calculated and compared. The influence of depth-varying ground motions on the dynamic responses of OWTs is discussed. • The influence of onshore and offshore ground motions on the dynamic responses of OWT is investigated. • The influence of depth-varying ground motions on the dynamic responses of OWT is studied. • The influence of different operational conditions (i.e. parked and operating) is examined. [ABSTRACT FROM AUTHOR]

The assemblage of a building inventory is necessary for the evaluation of seismic impact scenarios at the territorial scale. Building inventory, representing the distribution of building vulnerability classes at the territorial scale, could be performed at different levels of detail, depending on the size of the building stock, the territorial unit of analysis and on the adopted vulnerability model. Census-based data are usually employed as primary source for building inventory. A recent advancement towards compilation of regional scale inventories is provided by the interview-based Cartis approach, implemented in Italy within "Territorial themes" Reluis project, financed by the Italian Civil Protection Department. This paper proposes a first comparison of the results in terms of building inventory and the subsequent impact assessment that are obtained using Census (CE) and Cartis-based (CA) data for a town in southern Italy; a probabilistic framework for inventory is applied. Different vulnerability models are adopted and results compared. Moreover, a simple procedure that combines the informative levels present in the two approaches is proposed, allowing a mixed-type inventory from Census and Cartis data (CC) to be used for seismic impact assessment. Results of the application show that the inventory and related damage distribution changes as a function of the method adopted and in relation to the parameters considered for building classification in the vulnerability model. Comparing the impact in terms of a mean value of damage over the entire municipality, d m , calculated for various seismic intensities and starting from CE, CA and CC inventory, it is seen that the CC inventory is generally more conservative with respect to CA and CE for all the vulnerability methods, and a maximum scatter of approximately 45% in terms of d m is obtained for the considered application with one of the vulnerability methods. • The paper presents simplified methods to assemble building inventory. • Initial considered databases for building inventory are census returns and a newly developed interview-based database. • First comparison of the results on building inventory and damage assessment obtained using three types of building inventory. • Different vulnerability methods are considered for building classification and expected damage calculation. • The method is applied for a case study town in southern Italy. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a probability-based method, based on the design required separation length, to evaluate the likelihood beyond the required separation length of pounding of bridge structures under seismic excitations. Firstly, based on the stochastic vibration theory, the probabilistic pounding model was developed to model the influence of different seismic intensity levels and local soil condition on determination of the required separation gap between bridge segments. Then, the varying relationship between exceedance probability of pounding and seismic intensity measure (PGA) was derived. The proposed probability-based pounding evaluation approach was applied to a real bridge for predicting the pounding occurrence under various seismic intensity levels, along with the finite element model of the bridge pounding system built in ANSYS. Finally the pounding risk assessment beyond the required separation length of the bridge structure was conducted and presented based on the required separation distance. The results of this study delivered explicit and direct specifications and guidelines for seismic pounding design of bridges with different separation gap. Highlights • A probability-based method is proposed to evaluate the likelihood of  pounding of bridge structures under seismic excitations. • The probabilistic method can predict whether the pounding occur at different seismic intensity levels in newly built and existing bridges. • The relationship between conditional exceeding probability of pounding beyond the design required separation distance and seismic intensity measure (PGA) is derived. • Recommendations for actual seismic pounding design of bridges with different separation gap are drawn. [ABSTRACT FROM AUTHOR]

Abstract In performance-based earthquake engineering, probabilistic seismic demand models of structures are essential components that provide probabilistic estimates of earthquake-induced demands as a function of a variable(s) called the ground motion intensity measure (IM). Uncertainties in these models are often dependent on the IM used. Extending from traditional integer order IMs, this study assesses the performance of fractional order (FO, order of α) IMs on the probabilistic seismic demand modeling of extended pile-shaft supported bridges sited in liquefiable and laterally spreading ground. Uncertainties in structural and geotechnical material properties as well as geometric parameters of the bridges are considered in finite element models to achieve comprehensive scenarios. The FO IMs considered include peak ground response (PGR α), cumulative absolute response (CAR α) and its modified version (CAR 5 α), spectral acceleration at 2.0 s for a fractionally damped single degree of freedom (SDF) system (S ad- 20 α) and for a conventional SDF system with fractional response (S ar- 20 α), spectrum intensity for a fractionally damped SDF system (SI dα), as well as for a conventional SDF system with fractional response (SI rα). Metrics such as efficiency, practicality, proficiency and sufficiency are measured to assess the optimal α with respect to different demand parameters. Results show the advantages of FO IMs as they increase confidence in demand models compared to traditional integer order IMs. In particular, the proposed fractional spectrum intensities (SI dα and SI rα) with their optimal α values produce significant improvements in practicality, efficiency and proficiency, while maintaining sufficiency. Therefore, FO IMs can provide more reliable demand models for probabilistic seismic demand analysis of extended pile-shaft supported bridges in liquefiable and laterally spreading ground. Highlights • Novel fractional order (FO) seismic intensity measures (IMs) are proposed. • A coupled bridge-soil-foundation model considering lateral spreading is developed. • The proposed FO IMs show significant advantages compared to traditional IMs. • Optimal fractional orders for the FO IMs are stable for various modeling scenarios. [ABSTRACT FROM AUTHOR]

Abstract This work conducts a seismic stability of a three-dimensional (3D) geosynthetic-reinforced slope in soils following the linear and nonlinear Mohr-Coulomb failure criterion. Three categories of reinforcement distribution patterns and four kinds of clays are considered. Within the framework of limit analysis and the generalized tangent technique, expressions of required reinforcement strength and the stability factor under different distribution patterns are derived from the energy balance equations. Comparisons are conducted to verify the validity of new expressions. Parametric analysis is conducted to explore the impacts of seismic force, soil strength nonlinearity, 3D character of slope and reinforcement strength on slope stability. It is found from the results that the downwardly-strong triangular (DTD) distribution pattern is the most effective choice for slope reinforcement, while the upwardly-strong triangular (UTD) pattern is the worst. One should intensify the density of reinforcement layers at the bottom of the slope to achieve a better slope stability condition. Besides, soil strength nonlinearity and seismic forces both have non-negligible negative effects on slope stability. Highlights • A 3D failure mechanism of a reinforced slope is adopted with three kinds of soil reinforcement distribution patterns. • The generalized tangent technique is employed to capture the shear strength of soil. • Numerical solutions are presented in form of tables for practice use. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the role of soil plasticity on the seismic performance of bridge piers founded on cylindrical caissons through a numerical study where the geometrical and mechanical properties of the caisson and the pier, as well as the weight of the deck, are varied. Numerical models of the soil-caisson-pier-deck systems are subjected to six real acceleration time histories differing in frequency content, strong-motion duration and intensity. Three-dimensional coupled dynamic analyses are carried out in the time domain in terms of effective stresses, assuming an undrained response for the foundation soils. The studied systems are designed to be characterised by the same safety factors under static vertical loads, to evaluate the seismic performance of different systems endowed with similar mobilised shear strength, and by a low pseudo-static factor of safety to promote the activation of plastic mechanisms during seismic shaking. To reproduce the initial state of stress around the caissons, the effects induced by the construction stages are also simulated in the analyses through a simplified procedure. Seismic performance of the systems is evaluated comparing the maximum and the permanent deck drift ratios with corresponding threshold values related to ultimate limit states. It is shown that seismic performance is strongly related to the ratio between the fundamental periods of the flexible-base system and the soil, as well as to the strong motion duration. The range of systems and input properties for which soil plasticity is significant is identified, thus avoiding excessive overestimates of earthquake-induced displacements and inertial forces on the superstructure. Highlights • Soil plasticity can reduce substantially inertial forces acting on superstructure. • Influence of earthquake strong-motion duration is crucial for seismic performance. • Even accounting for soil plasticity seismic performance worsens at resonance. • Linear viscous-elastic models provide reliable results for flexible structures. [ABSTRACT FROM AUTHOR]

Abstract Amplitude, duration and frequency content are the three key characteristics of a ground motion time history. Few ground motion parameters quantifies two and rarely three of these features. There are even fewer ground motion prediction equations (GMPEs) available for these ground motion parameters. In this study, new GMPEs are derived for a total of 21 parameters representing peak amplitude, energy, intensity, frequency, duration and evolutionary characteristics of a ground motion acceleration time history. An extensive dataset of Japan, comprising 96880 ground motions with magnitudes ranging from M w 5.0 to M w 9.0 is used to calibrate the model. The model includes the effects of magnitude saturation, tectonic source mechanism, focal mechanism, geometric and anelastic attenuation, volcanic arc and site effects. Median results of estimates are compared against recorded data of the twin Kumamoto earthquakes of M w 7.3 and 6.5. These results are also compared against previously developed GMPEs of the region. Further, towards the verification of the functional form, behavior of inter and intra event residuals is verified against magnitude (M w), distance and shear wave velocity (V s30) respectively. Highlights • Literature review indicates the need for development of ground motion prediction equations for many higher order parameters. • Model analysis confirms lower magnitude saturation at near fault distances for major and great earthquakes. • Comparison of estimates with other regionally established models verifies the effectiveness of the current model. [ABSTRACT FROM AUTHOR]

Seismic histories induced by minor earthquakes could improve the sand liquefaction resistance, whereas those induced by strong earthquakes could decrease the sand liquefaction resistance. The action of upward pore fluid seepage on shallow sand deposits during the post-liquefaction process was determined to be one of the mechanisms of these natural phenomena. Based on this background, a series of 1 g shaking table tests were carried out to analyze the effects of pore fluid seepage on the sand reliquefaction resistance in subsequent earthquakes. Experimental results showed that the decreasing effects of the seepage history on the sand liquefaction resistance were limited by the input seismic intensities and applied hydraulic gradient (i). Weaker or more extensive seismic motions (c yclic s tress r atio, CSR <0.32 or >0.67, respectively) and i values less than 0.5 would not noticeably decrease liquefaction resistance. In the case of inputting successive motions with a medium CSR and i =3.0, the liquefaction resistance of the sand deposits with seepage histories decreased in the first two shakes in comparison with the deposit models without seepage histories. A longer seepage duration correlated to a much lower liquefaction resistance. These results demonstrated that the interaction of the soil layers during reconsolidation should be considered in evaluating the liquefaction risk of the ground. • Effects of pore water seepage on liquefaction resistance under sequential earthquake were studied by 1 g shaking table tests. • Weaker or more extensive earthquake and hydraulic gradient less than 0.5 slightly influence reliquefaction resistance. • Under medium earthquake and higher hydraulic gradient, reliquefaction resistance decreased in the first two motions. [ABSTRACT FROM AUTHOR]