Modeling the cyclic shakedown and ratcheting of sand remains a great challenge. An isotropic-kinematic hardening model is presented within the bounding-surface framework. By incorporating new features, a combined isotropic-kinematic hardening rule is extended to the deviatoric stress-ratio space. The hardening rule treats cyclic loading as a sequence of monotonic loading events. The kinematic mechanism

Long-period pulse-like ground motions in the near-field are likely to induce severe damage to large structures due to resonance at the natural frequencies of engineered construction. To investigate the origin and characteristics of large velocity pulses from the seismic source, this study identifies 14 stations with velocity pulses from 32 strong-motion seismographs located in the near-field of the

As one of the prefabricated structures, precast segmented bridges can be used to shorten construction time, reduce traffic delays, improve quality control, and minimize environmental impact. Despite the numerous advantages of segmented pre-fabricated rapid assembly technology, it is not widely used in high seismic hazard zones nor applied to complex water-abundant situations because of the lack of

Any design of standard structures in keeping with seismic safety norms is usually founded on an approach characterised by force-based design. Research has proven, over the course of several decades, that such an approach has a solid basis and can easily be applied by the engineers in charge of the design project. Furthermore, when taken in conjunction with principles of capacity design, the force-based

Soil-structure interaction (SSI) phenomena subjected to seismic loadings are investigated in this study. Firstly, shaking table tests on dynamic soil‐structure interaction subjected to seismic loadings are carried out, and SSI effects are analyzed through a comparative study between the soil-structure system and the rigid foundation condition. Then, a corresponding numerical model on the SSI tests

Observations from previous strong earthquakes reported severe damage of piles installed in different soils, particularly liquefiable saturated sand deposits. This paper examines the seismic performance of pile group-structure system in liquefiable and non-liquefiable sand deposits using large-scale shaking table tests, and discusses the possible failure modes of pile foundation in liquefied site and

The paper studies the response of a 3-storey building subjected to reverse faulting. 1 g physical model tests are conducted using a 3m long split-box, modelling the nonlinear response of structural members with artificial plastic hinges. The experimental results are used to validate the numerical modelling technique, which is subsequently employed to conduct a parametric study on sand density, foundation

Particle breakage of carbonate sand under cyclic loading might be of interest in some circumstances, while few research results were reported. Drained and undrained cyclic triaxial tests terminated at different loading cycles were conducted on a carbonate sand to investigate the evolution characteristics of particle breakage during cyclic shearing. Considerable breakage was observed after successive

The stress-strain-strength response of soils is of significant interest to development and calibration of realistic constitutive models that can be used in numerical simulation of geotechnical engineering problems. An extensive characterization of Ottawa F65 sand along with various monotonic and cyclic tests conducted during the course of the Liquefaction Experiments and Analysis Projects (LEAP) are

Risk assessment of the propagation of stress waves induced by blast loading is an important aspect engineering design and practice. Pre-existing geological structures affect the propagation of stress waves in the rock masses/strata. For homogenous materials, the wave energy scatters in the forms of wave reflection, refraction, diffraction, and mode conversion. The coefficient of absorption and scattering

This paper examines downhole measurement inaccuracy with respect to the sampling interval by utilizing theoretical simulation and experimental data collected during the Seismic Microzonation study in Central Italy. Numerical simulation concerning the expected experimental data shows that the percent uncertainty relative to measured P-wave velocity (Vp) values increases with increasing sampling intervals

Multi-pulse characteristics of near-fault ground motions, such as the number of inherent pulses, pulse periods, and amplitudes, have notable influences on the response of structures. To investigate these important parameters, an automatic detection procedure, which is conducted on the rough pulse signal that is extracted by the HHT method, is proposed in this work. This procedure can localize all inherent

This study aims to investigate the undrained shear strength of sand with added materials at different mean diameter ratios D50/d50 (D50 and d50 respectively represent the mean diameter of host sand and added materials) in loose state by performing a series of undrained triaxial tests. For this purpose, a very low density index of sand matrix IDmat equaling to 0.00 was employed and the fines of C500

This paper investigates the static and cyclic characteristics of a fouled sub-ballast material using static and cyclic triaxial tests. Static triaxial tests were conducted first to determine the peak strength, which was used as the applied stress in the cyclic tests. Moreover, the results of the displacement-controlled static triaxial test were used to assess the shear stiffness and strength during

Vulnerability of subsea high pressure/high temperature (HP/HT) pipelines to seismic actions is studied numerically. Unlike most of the existing researches on buried or trenched pipelines, this study is focused on the response of an unburied pipeline with D/t = 20, laid on the seabed and resting on a sleeper. Two different scenarios: (1) earthquake imposed on a laterally buckled pipeline, and (2) earthquake

This present paper proposes a spectral-acceleration-based earthquake intensity measure, which considers the higher modes effect and period elongation effect. A comprehensive study has been carried out to investigate the correlation between structural damages of high-rise chimneys and the proposed intensity measure as well as a number of widely used ground motion parameters under far-field ground motion

Seismic site classification plays a significant role in the estimation of site response and is carried out using average shear wave velocity through the top 30 m (VS30) soil layers. Meanwhile, at some sites with a number of boreholes, identification of the VS30 acquired from different boreholes does not lead to the classification of the site into one single category, and this makes the seismic classification

One of the influential components in the probabilistic seismic-hazard analysis (PSHA) is selecting appropriate ground motion prediction equations (GMPEs). To handle the source of epistemic uncertainty, the most common approach is considering several GMPEs in a logic tree framework. In such an approach, the selected GMPEs and the weights assigned for each one are usually determined by experts, mostly

The irregular particle shape is the significant feature of calcareous sands. It is known that calcareous sands generally show a higher liquefaction resistance than that of quartz sands, but the contribution of particle shape to the liquefaction resistance has not been well understood. In this paper, the particle shapes of calcareous sand, quartz sand and steel ball were quantitively assessed. Then

In the recent years, the construction of urban infrastructure projects has developed rapidly. When the structure systems of these major infrastructures are subjected to various horizontal loads during operation, it may cause permanent lateral deformation of the pile and instability and damage of the foundation soil. Therefore, it is important to study the interaction of pile-soil system under horizontal

Previous studies developed several types of weak and soft walls to deviate reverse fault ruptures and to absorb the compressional soil deformation. However, different strategies are required to address the extensional soil deformation caused by normal faulting. This study proposes a rigid diaphragm wall with a relief shelf (RDWRS) to mitigate soil and shallow foundation deformations in normal fault

The Liquefaction Experiments and Analysis Projects (LEAP) provides an international collaboration platform to assess key aspects related to seismic induced soil liquefaction. Within this scope, the current study investigates the influence of dilatancy and post-liquefaction shear strain on the seismic response of mildly sloping liquefiable ground, based on simulations of LEAP 2017–2019 centrifuge tests

Passively controlled structural systems may be exhibiting scarce capability in resisting dynamic solicitations under adverse special or unexpected conditions. Improvements of the overall performance of the passive system may be obtained when introducing supplemental corrective control actions, possibly coupling different technologic solutions and moving to mixed systems. In the paper the performance

The present research deals with the study of soil electrical conductivity as an earthquake precursor along the Margalla fault line and its correlation with the increase in temperature due to global warming. Moreover, comparative study to analyze correlation of EC with physico chemical properties of soil like moisture content, pH, temperature and texture has been conducted. This correlation can help

The unequal-height pier configurations commonly exist in bridge engineering for the adaptation of the varying topography. However, this makes the stiffness of unequal-height piers fluctuating due to the pier's height difference. As piers are the main seismic-resisting components under earthquakes, the irregular stiffness distribution induced by unequal-height pier configurations are unfavorable to

The Daguangbao landslide, with a volume of 1.16 × 109 m3 and an area of 7.2 km2, is the largest landslide triggered by the 2008 Wenchuan earthquake in China. To examine the initiation mechanism of this landslide, a detailed field investigation and a series of saturated triaxial tests were carried out. The field investigation revealed that the Daguangbao landslide initiated along a mylonite zone, the

In this paper, the effect of different thicknesses of Deconstructed Tires Under Sleeper Pads (DT-USP) and different Unconfined Compressive Strength (UCS) values of mother rocks of ballast aggregates were studied in the degradation of railway ballast. For this purpose, in the first step, both static and dynamic bedding modulus of DT-USP's were extracted in the laboratory according to DIN standard requirements

Ensuring adequate seismic reliability levels for existing infrastructure components is a key issue for owners in earthquake-prone countries. In particular, bridges may suffer relevant damage in case of a seismic event, and this issue can be magnified due to deterioration phenomena induced by environmental agents, like CO2 emissions or chlorides. Among the available techniques, seismic retrofitting

In this paper an estimation of seismic losses for various seismic scenarios of the Cephalonia and Ithaca islands, Greece, is proposed. The area under consideration is located in one of the most seismically active regions with the most damage and human casualties in recent history. Seismic losses were estimated at buildings, economic and human level. The estimation method is based on the assumption

Monopile has been the most widespread foundation type for Offshore Wind Turbines (OWTs) in shallow waters. Caisson (skirted) foundations have also been evaluated in some projects as an economical alternative. While the main concern in design of offshore foundations has been the environmental loads, the recent growth in construction of OWTs in seismic regions with the possibility of soil liquefaction

Monopile offshore wind turbines (MOWT) are inserted into sea water and sea bed soil. As the piles are usually embedded into the soil as deep as about 40 m, dynamic pile-water and pile-soil interactions, as well as seismic excitation non-uniformity, often occur under earthquake. In this paper, the response spectrum method (RSM) is developed to calculate the maximum response of MOWT considering the pile-water

An extradosed bridge is a hybrid structure that combines the main elements of the classic cable-stayed bridge and continuous girder bridge. Almost all extradosed bridges have the main girder transversely restrained at the pier locations, which may cause extremely large transverse shear force and bending moment on bridge substructures during strong earthquakes. This study thoroughly investigates the

Surface ruptures caused by strong earthquakes are one of the most concerning issues for construction projects. In this paper, geotechnical centrifuge model tests is performed to successfully simulate the reverse faulting process. Using a linear laser displacement sensor (LLDS) and the particle image velocimetry (PIV) technique, the surface deformation process and faulting behaviours are studied in

To facilitate the rapid, though, reliable assessment of mainshock-damaged structures against the succeeding aftershock excitations, the γ-index is introduced, defined as the ratio of the residual displacement of a structure under the mainshock excitation over the aftershock-induced maximum inelastic displacement of the damaged structure. Over 200 mainshock-aftershock sequences from very dense and stiff

In the paper, the effect of modeling strategies regarding the dynamic behavior of a railway slab track on a layered half-space is studied. The track is modeled with various degrees of accuracy through the use of either beam theory, shell finite elements or solid finite elements. The underlying soil response is included through a dynamic stiffness, obtained via the Green’s function for a horizontally

The ground motion pulse-like effect depends on its orientation, it is thus necessary to identify the direction of the ground motion with the strongest pulse. A simple yet efficient method to identify the strongest pulse over all orientations in multicomponent ground motions is presented in this study, through rotating the ground motions to the orientation associated with the maximum peak ground velocity

In this paper, the possible application of the hybrid sliding rocking column as a supporting system of an elevated reservoir is investigated. In order to evaluate the efficiency of the proposed system, a comparative analysis is conducted on an elevated reservoir with other common supporting systems. To this purpose, a benchmark tank model with a normal circular column is considered and modelled in

This paper presents an integrated, customized routine that uses object-oriented programming and a “super element class” to apply an integrated approach to simulate soil-structure interaction (SSI) problems. The scaled boundary finite element method (SBFEM) and finite element method (FEM) are applied together with the quad tree technique to implement cross-scale modeling for solid elements. Meanwhile

This paper presents a finite element scheme for analyzing the dynamic response of the saturated poroelastic media. The proposed scheme employs the standard finite element method for space domain discretization of the dynamic u-p equation system. We introduce the precise time step integration method as an explicit, direct integration algorithm for handling the time derivatives. The spectral radius analysis

Ordinary stone columns and Geosynthetic Encased Stone columns are used in remediation of soft soils with low bearing capacities. Primary objective of granular columns is to provide structural support to the overlying foundation layers. Given that the granular columns implemented in soft soil conditions support a large portion of the surcharge pressure, developing an understanding of settlement response

The present paper proposes the simultaneous optimization of the placement and parameters of rotational friction dampers (RFDs) for the seismic protection of a nonlinear steel moment-resisting frame (SMRF). In that respect, the placement and parameters of RFDs in the framework of an optimization problem is simultaneously optimized for a ten-story SMRF subjected to an artificial earthquake. In the optimization

A consistent procedure is required to deal with uncertainties in seismic hazard studies. In particular, uncertainties in shear wave velocity (VS) profiles are important for 1D numerical simulations of site response conducted within a probabilistic framework. This work proposes a new geostatistical model for shear wave velocity profiles. The main characteristic of the model is the separation of the

Far-field long-period ground motions (long-period ground motions) are likely to excite significant responses from high-rise buildings. A method for performing stochastic long-period simulations that incorporate envelope delays and basin-induced amplifications is developed, improving upon the conventional point-source model, which generates ground motions without considering nonstationary properties

Underground structures are more vulnerable to faulting than earthquake shaking. However, there are no effective mitigation measures for the damages of underground structures subjected to normal faulting. This study proposes a novel structure for new subway stations to mitigate the normal fault induced damages. The novel subway station consists of a rectangular cross-section and two rigid diaphragm

Presented is a time domain intrusive framework for probabilistic seismic risk analysis. Seismic source characterization is mathematically formulated. Methodology for simulating non-stationary seismic motions for given source, path and site is proposed. Both uncertain motions and uncertain structural parameters are characterized as random process/field and represented with Hermite polynomial chaos.

With the rapid development of nuclear industry in China, an increasing number of nuclear power plants (NPPs) are unavoidable to be constructed upon non-lithological foundations. Therefore, it is essential to optimize the current evaluation methods for non-lithological foundation reinforcement plans. By using the Octree discretization method combining with the scaled boundary polyhedron finite element

Damping modification factor (DMF) plays an important role in seismic design and hazard analysis. Many studies have dedicated to the DMF, but the existing formulations still show a quite large scatter. This study proposes a new theoretical approach for analyzing the DMF. The proposed approach models the seismic ground motion with a source-based Fourier amplitude spectrum (FAS) and estimates the DMF

Site period maps at various strain levels were developed for the combined cities of Ottawa and Gatineau in eastern Ontario and western Quebec. These maps were developed to support earthquake response studies in areas containing post-glacial, soft, silty-clayey sediments, which comprise 60% of the urban areas. Approximately 21,700 boreholes and over 1000 surface and downhole geophysical measurements

The principal stresses that occur in soil below ground level often change direction due to engineering activities. A typical example would be the cyclic loading applied by waves and currents onto the foundation of offshore structures. Even though the principal stress rotations (PSR) are recognized as some kind of “loading” that is exerted onto seabed soil, it is ignored in most investigations into

We estimated the spectral decay parameter, kappa (κ) for the Northwest (NW) Himalaya and the Northeast (NE) Himalaya, particularly NE India, using the strong motion records obtained from accelerographs installed in these regions. We estimated κ from the horizontal as well as vertical records from 294 accelerograms (three components). It has been observed that in the NW Himalaya and NE India, the value

The energy-based method is a promising tool for evaluating soil liquefaction potential. In this study, the effects of initial deviatoric stress (qs) and cyclic stress amplitude (qcyc) on soil liquefaction potential in undrained cyclic triaxial tests were evaluated using the energy-based method. The testing results indicate that the required dissipated energy for the onset of liquefaction is influenced

The impact of freeze-thaw cycling on freshly exposed loess is a major concern in design and construction of embankments or earth dams in the Loess Plateau in China. Due to complex nature of loess as compared with the conventional soils such as sand or clay, characterizing the strength of loess to account for this impact is challenging, in particular in the field conditions. In previous research a systematic

To the end of investigating the potential nonlinear soil behavior at 44 strong motion stations during the 2016 Mw7.8 Kaikōura, New Zealand earthquake, we analyzed the modifications of the site response under the strong mainshock recording based on the horizontal-to-vertical spectra ratio, including the shift of the predominant frequency, and three nonlinearity indicators, DNL, ADNL, and PNL. Significant

This paper presents an approach for assessing the failure probability of a road system due to its interaction with landslides induced by the earthquake. The landslide occurrence and failure probability of the road system is estimated by considering the spatial variation of earthquake ground motion. Since significant incoherence in earthquake ground motions is usually observed within the spatial dimensions

Shaking table model tests were carried out to study the seismic behaviors of double box utility tunnel with joint connections and the surrounding soil. The seismic wave obtained from 1952 Taft earthquake was employed as the input in this study, and its PGA has been adjusted to 0.2 g, 0.4 g, 0.8 g, and 1.2 g, respectively. In addition, a series of sine waves with PGA of 0.2 g and frequencies of 5 Hz

Seismic bearing capacity of strip footings placed near c-φ soil slopes is investigated in this work using finite element limit analysis combined with an adaptive remeshing procedure. In the analysis, the so-called pseudo-static approach is employed to quantitatively describe the seismic effects. Based on the method, the upper and lower bounds of the normalized seismic bearing capacity factor p/γB are

Detailed information of soil/rock variability and properties for the entire volume of supporting materials is crucial for the successful design and construction of deep foundations. Traditional invasive testing methods such as the standard penetration test (SPT) and the cone penetrometer test (CPT) only sample a small volume of soil/rock properties near the device's tip. Surface-based seismic methods

The seismic responses of precast concrete structure are studied under the earthquake excitations, by applying the shaking table test on the 12-storey, two-bay, 1/5 scale monolithic prefabricate concrete shear wall structure (MPCSWS), which is designed with the Chinese codes and assembled by the precast elements and cast-in-place boundary elements in the laboratory. The model MPCSWS is subjected to