Ground Motion Intensity Research Articles

Seismic fragility analysis of buckling-restrained brace-strengthened reinforced concrete frames using a performance-based plastic design method

An easily-operated performance-based plastic design (PBPD) method for buckling-restrained braced (BRB) reinforced concrete (RC) moment frames is adopted in this research to strengthen existing moment frames by BRBs. The appropriate range of the story base shear ratio p (i.e., the ratio of the base shear resisted by the BRBs to that of the total system) is suggested through a seismic fragility analysis. With an earthquake ground motion set of thirty far-field records, the seismic fragility analysis and risk assessment of an 8-story RC moment frame structure and its strengthened structures with BRBs are reported in this article, in which the fragility curves for different limit states and the corresponding annual exceedance probability are calculated. The applicability of 16 ground motion intensity measures (IMs) in the fragility analysis of the structure before and after strengthening under three damage limit states is further reviewed. As indicated by the fragility analyses, a higher seismic resistance capacity can be obtained for the strengthened structure when the ratio p varies between 0.5 and 0.8. The seismic performance of the structures strengthened using the PBPD method can increase steadily till the advent of the preset target ultimate drift limit, after which the improvement efficiency decreases. The IM Sa,gm(Ti) that considers both effects of softened period and higher mode has a better performance in each limit state of the structure both before and after strengthening.

Identification of optimal ground-motion intensity measures for assessing liquefaction triggering and lateral displacement of liquefiable sloping grounds

This article aims at identifying the optimal scalar- and vector-valued intensity measures (IMs) for predicting liquefaction triggering and the consequence of liquefaction (i.e. permanent deformation of sloping grounds), respectively. A total of 169 ground motions were selected from the NGA-West2 database. Using the selected ground motions as input, one-dimensional dynamic analyses were conducted for generic sloping ground soil profiles consisting of a loose-sand liquefiable layer implemented in OpenSees. The excess pore water pressure ratio and the liquefaction-induced lateral displacement were regarded as the engineering demand parameters (EDPs) of interest. A total of 20 scalar-IMs and 21 vector-IMs representative of various characteristics of seismic loading were evaluated as candidate IMs. The criteria for identifying optimal IMs include consideration for the efficiency, sufficiency, and predictability of the given IMs. An error propagation approach was employed to evalute the overall uncertainty of EDPs under scenario earthquakes using different IMs as predictor variables. Based on the results of extensive comparative analyses, acceleration spectrum intensity (ASI), and the vector of peak ground acceleration and spectral acceleration at 0.3 s (peak ground acceleration (PGA) and Sa(0.3 s), respectively) are identified as the optimal scalar- and vector-IM for liquefaction triggering evaluation, respectively. However, Arias intensity ( Ia) and vectors of [ Ia, cumulative absolute velocity] and [PGA, Ia] are identified as the optimal scalar- and vector-IM for predicting the liquefaction-induced lateral displacements. The optimal IMs identified could be used in performance-based liquefaction hazard evaluations, to assess the liquefaction triggering and consequence of liquefiable sites.

A risk-based evaluation of direct displacement-based design

Recent seismic design approaches developed under the umbrella of performance-based earthquake engineering (PBEE) pursue pre-defined performance objectives in terms of structural response, economic losses, or casualties. The earlier PBEE methods were mainly concerned with the deterministic evaluation of performance at a single ground motion intensity level. This premise, however, provides little insight into the long-term risk-based performance of a structure, and limits the ability to make informed design decisions. Given the inherent sources of uncertainty in all aspects of seismic design, probability theory needs to be employed to enable reliable design solutions. However, applying a risk-oriented design approach is not currently feasible for most practitioners, making it essential to understand how the current deterministic applications of these intensity-based PBEE approaches perform in terms of risk. Specifically, the aim is to investigate the capability of the direct displacement-based design (DDBD) method in producing reliable, risk-consistent designs. A probabilistic PBEE assessment framework is applied as the benchmark to determine the risk of exceeding performance objectives for multiple DDBD-based reinforced-concrete-wall and dual reinforced-concrete-wall/steel-frame buildings located at three different sites. The significant variation in the achieved risk estimates related to the limit states of damage limitation, life safety and global collapse for the buildings considered, questions the ability of DDBD—or any other intensity-based design method that does not account for uncertainty—to offer risk consistency.

Impact of Ergodic versus Nonergodic Seismic Hazard Estimation on the Risk Assessment of Liquefaction-Induced Ground Damage

ABSTRACT The seismic risk assessment of liquefaction-induced ground damage requires the hazard estimation of ground-motion intensity measures (IMs) through probabilistic seismic hazard analyses (PSHA). Current practice implements PSHA using ground-motion models (GMMs) developed under the ergodic assumption, which considers that the distribution of ground-motion IMs over time at a single site is the same as the distribution of ground-motion IMs over space. With the rapid growth of ground-motion databases, recent efforts have shown that ground-motion recordings are affected by location-specific systematic and repeatable effects favoring the transition to nonergodic approaches. However, the impact of using ergodic versus nonergodic PSHA (accounting for source, path, and site repeatable effects) on the risk assessment of liquefaction-induced damage has not been explored, which is the objective of this study. We consider three sites in California with different availability of ground-motion data to investigate the effects of the amount of available information on constraining repeatable effects and how this affects the final risk estimates within a nonergodic approach. In this context, the nonergodic-based estimates are compared against their ergodic counterparts, and insights are shared. The results from site-specific and regional assessments show important differences between ergodic and nonergodic estimates in terms of the mean risk and its uncertainty; the differences are dependent on the amount of data, and highlight the value of information (i.e., data) in nonergodic approaches.

A generalized ground-motion model for consistent mainshock–aftershock intensity measures using successive recurrent neural networks

Several recent studies have investigated the risk posed to structures by earthquake sequences, proposing state-dependent fragility/vulnerability models for assets in damaged conditions. However, a critical component for such efforts, i.e., ground-motion record selection, has received relatively minor consideration. Specifically, utilization of “consistent” mainshock (MS)–aftershock (AS) ground motions is desirable in practical applications. Such consistency in selecting MS–AS sequences requires proper consideration of the correlations between and within the intensity measures of MS and AS ground motions. Most of the studies in this domain utilize spectral accelerations as the considered ground-motion intensity measures and rely on empirical linear correlation models between the intensity measures of MS and AS ground motions for developing, for instance, record selection approaches. This study proposes a generalized ground-motion model (GGMM) to estimate consistent 30 × 1 vectors of intensity measures for mainshocks (denoted as IMMS) and aftershocks (denoted as IMAS) using a framework of successive long-short-term-memory (LSTM) recurrent neural network (RNN). The vectors of IMMS and IMAS consist of geometric means of significant duration (D_{5 - 95,geom}), Arias intensity (I_{a,geom}), cumulative absolute velocity (CAV_{geom}), peak ground velocity (PGV_{geom}), peak ground acceleration (PGA_{geom}) and RotD50 spectral acceleration (S_{a} left( T right)) at 25 periods for both MS and AS ground motions. The proposed RNN-based GGMM is trained on a carefully selected set of ~ 700 crustal and subduction recorded MS–AS sequences. The inputs to the framework include a 5 × 1 vector of source and site parameters for MS and AS recordings. The residuals of the trained LSTM-based RNN are further used to develop empirical covariance structures for IMMS and IMAS. The proposed framework is finally illustrated to select MS–AS ground motions based on IMMS and IMAS using a multi-criteria objective function. The selected MS–AS ground motion sequences are then used to perform non-linear time-history analyses of a case-study two-spanned symmetric bridge structure. The obtained engineering demand parameters are evaluated and critically discussed.

Impact of loading rate during hybrid simulation on seismic response of steel structures

AbstractThis study investigates the influence of loading rates on the seismic response of steel structures. A series of coupon tests under typical earthquake‐induced loading rates are carried out. In addition to the conventional monotonic tension test, the specimens are also tested under a discontinuous loading protocol that is analogous to the ramp‐and‐hold scheme employed in the pseudo‐dynamic hybrid simulations. The test results are used to develop a uniaxial steel material model to account for the strain rate effect and stress relaxation. The material model facilitates the reuse of existing steel hysteresis models and can be used to model different structural components, such as columns, beams, braces, etc. The material model is then used for a parametric study to evaluate the impact of various loading rates on the global seismic response of a single degree of freedom structural system with different structural periods, and types and intensities of ground motions. It is found that the impact of loading rates is more significant for structures with a period of 0.5 s or less and it thus requires a fast control of the physical specimen in pseudo‐dynamic hybrid testing. In addition, the material model is applied to a five‐storey buckling restrained braced frame (BRBF) building with a structural period of 1.2 s. It is found that the earthquake‐induced loading rates have a minor impact on the global response of the structure.

Seismic demand analysis using environmental contours of vector-valued ground motion intensity measures

A study is presented on seismic demand analysis using environmental contours of vector-valued ground motion intensity measures. The environmental contours specify combinations of intensity measures for estimating an engineering demand parameter with a given exceedance probability. Copulas are employed to model the joint distribution of vector-valued ground motion intensity measures for developing the environmental contours. A framework is presented for copula estimation of spectral accelerations using ground motion records from stations on stratified sand and silt deposits in Mexico City. The statistical dependence between pairs of spectral accelerations at a range of periods is analyzed in terms of Kendall’s τ and used for estimating parametric copula models. Goodness of fit of the estimated copulas is examined and the Akaike information criteria is applied for selection of copula models. Environmental contours of spectral accelerations are developed adopting the inverse FORM approach and employed to estimate mean exceedance rates of maximum interstory drift of a building model. Both, the cases of deterministic and stochastic response models of interstory drift are examined. The accuracy of the environmental contour estimates is assessed by comparison with Monte Carlo simulations and estimates from long-term analyses. It is found that the approximation of the failure surface in the inverse FORM approach is quite appropriate for a range of return periods for which very precise or reasonably accurate response estimates were obtained from the environmental contours.

Response of reinforced mortar-less interlocking brick wall under seismic loading

Mortar-less construction with interlocking bricks has many advantages, such as improved construction efficiency and relatively low requirements on labour skills. Nevertheless, the seismic performance of interlocking brick structures is not well understood yet. In this paper, laboratory tests and numerical modelling are carried out to investigate the seismic behaviour of interlocking brick walls. Laboratory shaking table tests are performed on a scaled reinforced mortar-less interlocking brick wall. The response and damage modes under in-plane seismic loading are investigated. A detailed numerical model is then generated and validated with the laboratory testing data. Unlike the conventional masonry wall that diagonal shear damage governs the failure, the interlocking brick wall exhibits rocking responses, whose damage is mainly at the two bottom corners of the wall. Full-scale interlocking brick walls are then modelled and compared with conventional concrete masonry unit (CMU) walls bonded by mortar. Comparisons are made between the seismic resistances and damage modes of the two walls. The influences of ground motion intensities, vertical components of seismic excitations and different seismic time histories on the seismic behaviour of the interlocking brick wall are examined. It is found that the interlocking brick wall has a higher seismic resistance capacity than the conventional CMU wall. Inter-brick friction is the main energy dissipation mechanism in the interlocking brick wall. Because of the rocking response, vertical component of the ground motion significantly influences the damage of interlocking brick wall. The interlocking brick wall is insensitive to velocity pulses of ground motions due to its relatively high natural frequency.

Nonlinear Solid–Fluid Coupled Seismic Response Analysis of Layered Liquefiable Deposit

A seismic response analysis of layered, liquefiable sites plays an important role in the seismic design of both aboveground and underground structures. This study presents a detailed dynamic site response analysis procedure with advanced nonlinear soil constitutive models for non-liquefiable and liquefiable soils in the OpenSees computational platform. The stress ratio controlled, bounding surface plasticity constitutive model, PM4Sand, is used to simulate the nonlinear response of the liquefiable soil layers subjected to two seismic ground motions with different characteristics. The nonlinear hysteretic behavior of the non-liquefiable soil under earthquake excitations is captured by the Pressure Independent Multi Yield kinematic plasticity model with a von Mises multi-yield surface. The soil elements are modelled utilizing the solid–fluid fully coupled plane-strain u-p elements. The seismic response of the layered liquefiable site in terms of the development of excess pore water pressure, acceleration, ground surface settlement, and stress–strain and effective stress path time histories under two representative earthquake excitations are investigated in this study. The numerical results indicate that both the characteristics of ground motions and the site profile have a significant influence on the dynamic response of the layered liquefiable site. Under the same intensity of ground motion, the loose sand layer with a 35% relative density is more prone to liquefaction and contractive deformation, which causes irreversible residual deformation and vertical settlement. The saturated soil layer can effectively filter the high-frequency components and amplify the low-frequency components of ground motions. Moreover, the liquified site produces a 40% post-earthquake consolidation settlement after the excess pore pressure dissipation.

Discussion of “Seismic Rehabilitation Optimization of Water Pipe Networks Considering Spatial Variabilities of Demand Criticalities and Seismic Ground Motion Intensities” by Binaya Pudasaini and Mohsen Shahandashti

Discussion of “Seismic Rehabilitation Optimization of Water Pipe Networks Considering Spatial Variabilities of Demand Criticalities and Seismic Ground Motion Intensities” by Binaya Pudasaini and Mohsen Shahandashti

Ground-Motion Observations and Probabilistic Seismic Hazard: Frequently Asked Questions

Abstract Observed exceedances of ground-motion intensity from probabilistic seismic hazard analysis (PSHA), in countries where it is used for structural design, spark significant public attention, rekindle scientific debates, and are sometimes discussed in trials about the accountability for structural failures and other earthquake-related losses. This short article addresses, in a question-reply format, some recurring issues and related research findings that should be carefully taken into account by those who author or face these reasonings. It considers Italy as a reference, yet the discussed issues are common to several other countries worldwide and thus may be interesting at an international level. The arguments provided, mainly stemming from the fact that observed cases of exceedance should not necessarily be considered a failure of PSHA, can possibly help in gaining a more informed perception of seismic hazard assessment and structural design as implemented in building codes.

Strong Motion Models for Duration and Arias Intensity for Strong Motion Records in Chile

Chile presents a high seismicity and very particular characteristics due to its subductive environment and high convergence rate of the interacting plates. In this paper, ground motion models (GMM) for Arias Intensity and strong ground motion duration are developed based on recently compiled Chilean earthquakes records. The Chilean derived GMM are later compared with global and subduction models. For the duration case, two definitions are considered: significant duration and bracketed duration. Care is taken to consider newly define rupture areas for the major earthquake in the catalog, which allows to redefine the distances to be used in the analysis. The strong motion records are processed using robust techniques and standardized procedures. The model parameters are selected using a Bayesian updating method. This allows to estimate the parameters as well as their corresponding uncertainties recognizing the variability of the coefficients and of the selected model. The derived ground motion predictive model associated is validated through a residual analysis and probability distributions, obtained from the adjustment method. Additionally, for the bracketed duration analysis, a classification method based on Support Vector Machine (SVM) is used, with the aim to incorporate the records with duration of zero seconds. The comparison of the resultant model with the existing ones allows to confirm the differences that the tectonic Chilean environment produces, characterized mainly by a high relative convergence rate between plates and interplate thrust earthquakes with high magnitudes.

Seismic Ground Motion Amplification in a 3D Sedimentary Basin: Source Mechanism and Intensity Measures

Ground motion amplification has been observed in most earthquakes triggered near the sediment-filled basins such as 2015 Nepal and 1999 Chi–Chi events. Many numerical studies pointed out the effect of various parameters such as material properties and geometric features of the basin on ground motion amplification but the effect of the complete range of source mechanism parameters needs to be addressed. This paper presents the effect of source mechanism parameters, such as strike, dip, rake angle of fault and moment magnitude ([Formula: see text] on amplification of ground motion intensity measures (IMs) due to sediment-filled basins. It is found out that the maximum spectral amplification, when subjected to the source of lateral strike mechanism, is 45, whereas for thrust fault mechanism, it is 30. Within the lateral strike mechanism, if the dip angle is increased from 0∘to 90∘, the spectral amplification increases from 10 to 30 times. The results also suggested that it is important to consider detailed focal parameters to study basin amplification. The amplification of IMs in the basin is more sensitive to variation of dip angle than the other source parameters and the magnitude of earthquake has an insignificant role in basin amplification.

Machine learning-based models for estimating seismically-induced slope displacements in subduction earthquake zones

The assessment of the seismic performance of slope systems often relies on estimating the amount of seismically-induced slope displacements (D) using semi-empirical D models. These models take as inputs the slope properties and ground motion intensity measures (IMs) to provide D estimates that are used in engineering design. However, most of the available D models have been developed for regions affected by shallow crustal seismicity. Comparatively, the available D models for subduction tectonic settings are scarce. Moreover, most existing models have been developed using traditional statistical methods that do not take advantage of modern data-driven approaches. In this study, we develop new machine learning (ML) based D models applicable to subduction earthquake zones (considering both interface and intraslab mechanisms) using the NGA-Sub ground motion database. A systematic feature selection is performed using three ML procedures, finding that the yield coefficient (ky), the initial fundamental period of the slope system (Ts), the earthquake magnitude (M), the peak ground velocity (PGV), and the pseudo-spectral acceleration at 1.3Ts(Sa(1.3Ts)) are efficient features for estimating D in subduction earthquake zones. Based on the selected features, we develop five ML-based D models by using modern ML procedures (i.e., ridge regression, random forest, gradient boosting decision tree (GBDT), support vector regression (SVR), and residual neural network (ResNet)). The developed ML-based D models do not need to be restricted to predefined fixed functional forms, as has often been the case for previously developed D models. The ridge regression model is used to represent generic traditional D models as it has a polynomial-based functional form. Compared to the ridge regression model, the other developed ML-based models are able to better capture the complex relationship between D and the slope properties and IMs, showing a better predictive performance on test tests; hence, they outperform traditional models. In addition, we compare the performance of the developed ML-based models in terms of predictive performance, model trends, and computational cost for training. Lastly, the developed ML-based models also enhance the treatment of epistemic uncertainty in the estimation of D, given the scarcity of available robust D models for subduction zone tectonic settings.

Fragility-based framework for optimal damper placement in low-rise moment-frame buildings using machine learning and genetic algorithm

Commonly, seismic fragility is used as an assessment tool rather than a design constraint for existing building structures. In addition, the degree of seismic fragility safety margin after retrofitting existing structures is usually unknown during the early retrofit design stage. The current study proposes a framework that allows the designer to assign the preferred seismic fragility margin as a design variable before retrofit of a structure using soft computing techniques. In addition, it provides the design damping ratio to achieve the optimal damper capacity distribution required for retrofit. To this end, a machine learning model (MLM) is used to construct safety margin curve (SMC) graphs for the structural system considering different limit states to obtain the design damping ratio. This MLM is trained with a wide range of structural systems subjected to various levels of ground motion intensities for predicting seismic responses of the system. The main role of the MLM and SMC is to provide a reasonable approximate range for damper capacity in each story to reduce the computational time required for the optimization process. After that, a genetic algorithm (GA) optimization process is implemented to obtain the optimum capacities of the energy dissipation devices (EDDs) required for retrofitting the structure using the design damping ratio obtained from the SMC. Displacement-dependent EDDs are used in the current study because of their effectiveness in dissipating seismic energy. The EDDs are arranged such that the seismic demands are controlled to achieve the required basic seismic safety objective maintaining the optimal EDD capacity for each story. The reliability and robustness of the framework are investigated using various case-study examples and validated by comparing the results with those obtained from nonlinear time history (NLTH) and nonlinear static methods. The proposed framework is validated for low-rise moment-resisting frame buildings that can be represented using a single degree of freedom (SDOF) system. The framework is expected to enable researchers and engineers to effectively implement the required level of seismic safety in retrofitted structures with less computational cost and allows the designer to select the most suitable retrofit scheme considering multiple limit state criteria checks.

Influence of ground motion duration on seismic performance of RC frame isolated by high damping rubber bearings

The high damping rubber bearing (HDRB) is an advanced seismic isolation component currently used in building structures with sound energy dissipation capacity. This study examines the effects of ground motion duration on the seismic performance of reinforced concrete frame isolated by HDRBs. The effect of ground motion duration is isolated from other effects due to ground motion amplitude and acceleration spectral shape by using 44 pairs of short-duration and long-duration spectrally equivalent ground motions. Nonlinear time-history analyses are conducted on a base-isolated building using HDRBs. The numerical analyses considered the calibrated parameters of the HDRB model based on experimental data. The stiffness degradation of the HDRBs due to Mullins’ effect under cyclic loading is accounted into the numerical model. The influence of ground motion duration is evaluated by comparing the seismic responses of the isolator components and the superstructure. The results indicate that the ground motion duration generates a significant influence on seismic responses. The influence varies as the ground motion intensity changes. The stiffness degradation of the HDRB becomes evident with the increase of the earthquake intensity, and the effect of such degradation on the structural responses is more significant when under long-duration ground motions.

Time-dependent Seismic Fragility for Aging RC Frame Structures in the Inland Atmosphere Environment

ABSTRACT For inland cities with high concentration of carbon dioxide in the air, the seismic performance of RC structures deteriorates over time. In this study, a previously developed concrete carbonation and corrosion model was introduced to the framework of seismic fragility analysis to investigate the effects of environmental factors on the seismic performance of RC structures, considering carbon dioxide, humidity, and temperature. An approach to quantify the effects of these environmental effects on the time-dependent fragility of deteriorated RC buildings in the inland atmosphere environment was proposed. A four-story three-bay RC structure was analysed as a case study. Pushover analysis was performed to identify the damage limits of the structure as a function of the exposure time (0, 25, 50, 75 and 100 years). Fragility curves of the structure at different exposure times were developed based on the time-dependent seismic demands and predefined limit states. The results show that the structure deteriorates when exceeding the design life of durability. In general, the damage to the deteriorated structure increases with time and intensity of ground motions. In particular, the margin between severe damage and collapse decreases significantly over time. This means that aging structures are likely to collapse suddenly after severe damage occurs. Therefore, the time-dependent seismic performance of the aging structures in the inland cities should be carefully considered.

Seismic Fragility Assessment for Steel Buildings with Different Performance Levels

The probability of failure associated with drift criterion exceeding certain performance levels for the intensity of earthquake record ground motions has been necessitated for the development of fragility curves in the recent past as a better performance check tool. In the recent past, the reappraisal of fragility curves formation due to incremental dynamic analysis has been possible because of modeling and simulation of structures under varying earthquake ground motions. The content of this paper is the formation of fragility curves using drift as the output of steel building frames under varying earthquake ground motions. The fragility curves were developed through nonlinear time-history analysis assessments of selected ground vibrations with varying magnitudes, distances from the source, and site circumstances. The entire process given in this paper can be utilized to develop probabilistic fragility curves for structural buildings of various layouts. As an illustration, fragility curves for two steel building structures for various performance levels: Collapse prevention (CP), Life Safety (LS), Immediate occupancy IO), & operational performance (OP), were developed using Ram Perform 3D, using a set of 20 earthquake ground motions. The fragility curves formed using drift for different performance levels reveal a robust damage index for evaluating building structures under the high level of seismic hazards.

Comparison of Various Types of Seismic Hazard Assessment and their Influence on Structural Vulnerability

This work sought at enhancing techniques for the assessment of seismic risk in order to understand displacement effects and impacts of different seismic hazard estimation techniques on structural vulnerability. The analysis is useful because the number of earthquakes around the world is on the rise, and there is a necessity to eliminate the potential threat. Weighted Average of Ground Motion intensities was used to determine hazard parameters, along with PSHA and DSHA. The information regarding seismicity was collected from the regional networks and catalogs with the help of geotechnical investigation for site characteristics. An assessment of structural resilience was accomplished with building inventories and retrofit projects data with the help of FEA for computational modeling. The degree of earthquake was recorded to be from 4. 5 to 7. 5 Mw, with PGA ranging from 0 to 0. 2 to 0. 3g. During preliminary screening, Sites were ranked into high PSA and low PSA divides as well as Low Seismic Hazard and Medium to High Seismic Hazard. These retrofitting measures such as base isolation and strengthening further improved performance of buildings, in that they reduced peak drift ratios by up to 50% and, base shear force capacity by 30% of average value. The Effectiveness Index of retrofitting work varied from 0. 732 to 0. 912, from which one can draw the conclusion concerning appreciable enhancements of earthquake resistance. The study thereby laid a foundation to prove that it is possible to reduce the seismic risk by using the advanced hazard analysis methods and based on these analyses, some systematic retrofit interventions are effective enough in achieving the objective of sustainable urban development. The conclusions derived in this paper present quantitative information relevant for understanding actions toward earthquake prevention in vulnerable territories.

Nonlinear seismic response and amplification effect of 3D sedimentary basin based on bounding surface constitutive model

Sedimentary basins can have significant amplification effects on seismic ground motion. It is very necessary to use appropriate nonlinear soil constitutive model to quantitatively analyze the seismic response of three-dimensional (3D) sedimentary basins subjected to strong ground motion. This paper employs a bounding surface constitutive model to simulate the soil nonlinearity, which is successfully incorporated into ABAQUS software. A finite element model is then established to investigate the nonlinear seismic response of 3D sedimentary employing the constitutive model along with viscoelastic artificial boundary and equivalent nodal force method. The nonlinear amplification effect of a typical 3D layered sedimentary basin is extensively evaluated. The influence of a soft interlayer in the sedimentary basin on the seismic amplification is further analyzed. The results demonstrate that the maximum surface peak acceleration usually occurs in specific areas; as the input ground motion intensity increases, the focusing and amplification effects become more significant in deeper soil layers. A soft interlayer will significantly increase the short period component of the surface response spectrum, and shorten the predominant period of sedimentary basin. These results can provide a reference basis for seismic risk analysis and determination of ground motion parameters in a sedimentary basin.