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EARTH SCIENCES (471 journals)

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Journal Cover Soil Dynamics and Earthquake Engineering
  [SJR: 1.516]   [H-I: 56]   [14 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0267-7261
   Published by Elsevier Homepage  [3175 journals]
  • Seismic response of underwater concrete pipes conveying fluid covered with
           nano-fiber reinforced polymer layer
    • Authors: Mohammad Hadi Hajmohammad; Mostafa Maleki; Reza Kolahchi
      Pages: 18 - 27
      Abstract: Publication date: July 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 110
      Author(s): Mohammad Hadi Hajmohammad, Mostafa Maleki, Reza Kolahchi
      This research deals with seismic response of underwater fluid-conveying concrete pipes during the earthquake in Kobe. The pipe is reinforced with nano-fiber reinforced polymer (NFRP) layer. The displacement filed of the structure is considered based on the sinusoidal shear deformation theory. Navier-Stokes equation is applied to estimate the force due to the inner fluid. Furthermore, the effect of the outer fluid is taken into consideration as an equivalent force. The governing equations are derived on the basis of energy method and using Hamilton's principle. Differential quadrature method (DQM) and Newmark method are applied to obtain the dynamic deflection of the system. The effect of parameters such as NFRP layer, volume percent and agglomeration of nano-fibers, boundary conditions, inner and outer fluids, thickness to radius and length to thickness ratios on the dynamic deflection of the structure is examined. The results show that with increasing the thickness to radius ratio and volume percent of nano fiber and using NFRP layer, the dynamic deflection decreases while considering the inner and outer fluids and agglomeration effect of nano fiber and increasing the length to thickness ratio, the dynamic deflection of the structure increases.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.04.002
      Issue No: Vol. 110 (2018)
       
  • Nonstationary seismic response analysis of long-span structures by
           frequency domain method considering wave passage effect
    • Authors: Yan Zhao; Yuyin Li; Yahui Zhang; David Kennedy
      Pages: 1 - 9
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Yan Zhao, Yuyin Li, Yahui Zhang, David Kennedy
      In this paper, a frequency domain method is proposed for the nonstationary seismic analysis of long-span structures subjected to random ground motions considering the wave passage effect. Based on the correlation analysis theory and fast Fourier transform (FFT), a semi-analytical solution is derived for the evolutionary power spectral density of the random response of long-span structures in the frequency domain. The expression of this solution indicates that the evolutionary property of nonstationary random responses can be determined completely by the modulation function of random ground motions, and hence the solution has clear physical interpretations. For slowly varying modulation functions, the FFT can be implemented with a small sampling frequency, so the present method is very efficient within a given accuracy. In numerical examples, nonstationary random responses of a long-span cable stayed bridge to random ground motions with the wave passage effect are studied by the present method, and comparisons are made with those of the pseudo excitation method (PEM) to verify the present method. Then the accuracy and efficiency of the present method with different sampling frequencies are compared and discussed. Finally, the influences of the apparent velocity of the seismic waves on nonstationary random responses are investigated.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.029
      Issue No: Vol. 109 (2018)
       
  • Sensitivity analysis and calibration of phenomenological models for
           seismic analyses
    • Authors: Corrado Chisari; Gianvittorio Rizzano; Claudio Amadio; Vincenzo Galdi
      Pages: 10 - 22
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Corrado Chisari, Gianvittorio Rizzano, Claudio Amadio, Vincenzo Galdi
      Phenomenological models used in seismic structural analyses are often based on parameters without explicit physical meaning, which must be calibrated by fitting experimental responses. Parameter calibration, as an inverse problem, may suffer from ill-posedness, and thus the results are always to be critically examined before accepting them. In this paper, a comprehensive methodology, comprising repeated optimisation runs, local and global sensitivity analysis and simplified uncertainty analysis is described with the aim of providing some guidelines to assess the calibration results. As exemplary case study, the calibration of a phenomenological model for steel members by means of a series of experimental tests is presented. The experimental response of nominally identical beams tested under monotonic, cyclic and pseudo-dynamic loading were used in the procedure. The main findings of the work indicate that the optimisation process based on Genetic Algorithms is able to find optimal solutions in terms of fidelity to the experimental tests: However, being the problem ill-posed, the same level of fitting may be attained by solutions characterised by different model parameters. Local and global sensitivity analyses may help assess the identifiability of the parameters, while a-posteriori uncertainty analysis provides an estimation of the uncertainty in the prediction. It is shown that increasing the number of calibration tests may reduce the ill-conditioning of the problem, and thus a multi-objective approach is strongly recommended. Finally, a novel procedure recently developed based on tolerance-based Pareto dominance is shown to give similar results to those provided by computationally expensive sensitivity analyses at the computational cost of a single calibration analysis.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.024
      Issue No: Vol. 109 (2018)
       
  • Seismic bearing capacity of non-uniform soil slopes using
           discretization-based kinematic analysis considering Rayleigh waves
    • Authors: Changbing Qin; Siau Chen Chian
      Pages: 23 - 32
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Changbing Qin, Siau Chen Chian
      This study aims to present a procedure for predicting the bearing capacity of a soil slope under seismic loading. The emphasis is on the variations of soil strength parameters. In order to account for soil profile with varying friction angles in the generation of a potential collapse mechanism, the discretization technique is introduced. The kinematically admissible failure surface is gradually formed by ‘point-to-point’ method. The modified pseudo-dynamic approach is employed to represent seismic accelerations and forces, with considerations to the Rayleigh wave apart from the primary and shear waves. The upper bound solution of limiting surcharge is formulated from the work rate-based balance equation. The results obtained from the discretization-based kinematic analysis are compared with those computed with the conventional upper bound analysis using the pseudo-static approach. In order to better understand the implication of non-uniform strength parameters on the ultimate bearing capacity and the extent of critical failure surface, a parametric study is carried out to encompass a range of spatial variations of soil strength parameters.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.017
      Issue No: Vol. 109 (2018)
       
  • Site response analysis of an urban area: A multi-dimensional and
           non-linear approach
    • Authors: Gaetano Falcone; Daniela Boldini; Angelo Amorosi
      Pages: 33 - 45
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Gaetano Falcone, Daniela Boldini, Angelo Amorosi
      This paper critically examines the numerical predictions of the seismic site response of both ideal and real cases as obtained by means of mono- and multi-dimensional Finite Element (FE) approaches. Ideal case-studies are first considered, aiming at validating the adopted numerical approach against existing analytical or simple numerical solutions. Then a three dimensional model of the Bovino urban area, located in southern Italy, was generated taking into account the real site conditions. Numerical analyses were thus carried out adopting a non-linear elasto-plastic soil constitutive model implemented in a commercial FE code. The following issues were investigated in detail: geometrical schemes, horizontal direction of the input motion, calibration of the constitutive model and non-linear soil response. Most of the obtained numerical results, presented in terms of amplification factors, indicate that larger amplifications occur when the more realistic multi-dimensional schemes are adopted as compared to the mono-dimensional ones.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.026
      Issue No: Vol. 109 (2018)
       
  • Effect of long-duration earthquakes on the low-cycle fatigue damage in RC
           frame buildings
    • Authors: A. Mantawy; J.C. Anderson
      Pages: 46 - 57
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): A. Mantawy, J.C. Anderson
      Several cases of failure due to rupture of reinforcing bars in RC buildings were reported by inspection teams after the 2010 Muale earthquake in Chile that triggered further research efforts. This paper studies the effect of long-duration earthquakes on the damage potential due to low-cycle fatigue through nonlinear analysis of three existing RC frame buildings. The number of strain cycles and their amplitudes for reinforcing bars at the critical locations within each building were obtained from nonlinear time history analyses. The reduction in the fatigue life has been estimated using S-N curve obtained from the experimental literature and by applying the Palmgren-Miner damage rule. The results showed significant reduction in fatigue life for the low- and medium-rise buildings larger than high-rise buildings. It was found that A706 steel has longer fatigue life than A615 steel. Also, larger diameter steel bars tend to experience less fatigue damage within RC members.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.01.013
      Issue No: Vol. 109 (2018)
       
  • Seismic fragility of arch dams based on damage analysis
    • Authors: Jin-Ting Wang; Ming-Xu Zhang; Ai-Yun Jin; Chu-Han Zhang
      Pages: 58 - 68
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Jin-Ting Wang, Ming-Xu Zhang, Ai-Yun Jin, Chu-Han Zhang
      Seismic fragility provides a measure for evaluating the safety margin of structures above specific hazard levels. This study investigates the seismic fragility of arch dams using the dynamic damage analysis model of dam–reservoir–foundation systems, in which the radiation damping of semi-unbounded foundation rock, opening of contraction joints, and damage cracking of dam concrete are taken into account. The 210m-high Dagangshan Dam in Southwest China is analyzed as a case study. Five hundred nonlinear damage analyses are performed using the Monte Carlo simulation technique considering both epistemic and aleatory uncertainties, which are characterized by random material parameters and ground motions, respectively. Three limit states, i.e., slight damage, moderate damage, and severe damage, are proposed according to the calculated damage distribution and joint opening, and seismic fragility curves are subsequently generated using the incremental dynamic analysis approach. Analysis results show that the Dagangshan Dam may be severely damaged by strong earthquakes when uncertainties in material parameters and ground motions are considered.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.01.018
      Issue No: Vol. 109 (2018)
       
  • Seismic uplift capacity of shallow strip anchors: A new pseudo-dynamic
           upper bound limit analysis
    • Authors: R. Ganesh; Sunil Khuntia; Jagdish Prasad Sahoo
      Pages: 69 - 75
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): R. Ganesh, Sunil Khuntia, Jagdish Prasad Sahoo
      Using a new pseudo-dynamic approach for the inclusion of seismic body forces, the seismic vertical uplift capacity of horizontally placed strip plate anchors in sand at shallow depths has been computed with the application of upper bound theorem of limit analysis. Unlike the earlier pseudo-dynamic approaches, in this study, the nonlinear variation of both horizontal and vertical acceleration along the depth of soil layer, and in the values of amplitude and phase of accelerations has been considered with the satisfaction of stress boundary condition at the ground surface. The seismic uplift factor F γs due to the unit weight of soil for different combinations of seismic acceleration coefficients, internal friction angle of soil, and the embedment ratio of anchors has been obtained. The solutions indicate that the magnitude of F γs decreases substantially with an increase in seismic acceleration coefficients; whereas as expected, increases with an increase in embedment ratio of anchors and soil friction angle. This study produces the least upper bound solutions in comparison to the earlier reported results in the literature.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.004
      Issue No: Vol. 109 (2018)
       
  • Experimental study on relative displacement responses of bridge frames
           subjected to spatially varying ground motion and its mitigation using
           superelastic SMA restrainers
    • Authors: Bipin Shrestha; Li-Xiang He; Hong Hao; Kaiming Bi; Wei-Xin Ren
      Pages: 76 - 88
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Bipin Shrestha, Li-Xiang He, Hong Hao, Kaiming Bi, Wei-Xin Ren
      Contemporary bridge codes recommend adjusting the fundamental frequencies of adjacent segments close to each other to mitigate relative displacement induced damages arising during the strong seismic events. Previous studies revealed that such recommendation leads to effective mitigation of damages on the bridge structures subjected to uniform ground motions. However, in an elongated bridge structure spatial variations of earthquake ground motions at different supports are inevitable which can result in larger relative displacements. This study presents experimental results from a large-scale (1/6) shake table testing of bridge models with two bridge frames having a total length of 16.67 m, subjected to spatially varying ground motions. Experiments were also carried out with bridge model with superelastic Shape Memory Alloy (SMA) restrainers to evaluate its effectiveness on mitigating bridge responses. It is revealed that even the adjacent bridge frames with fundamental frequencies close to each other are susceptible to the localized damages at the joints due to poundings, which could lead to delayed access to the affected sites after an earthquake. Superelastic SMA restrainers could effectively reduce the opening relative displacement and pounding intensity. Moreover, owing to its superelastic behaviour the restrainers would not require replacement even after strong seismic events. Finally, numerical models of the bridge were developed and parametric studies were performed to comprehend the results of the experiment.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.005
      Issue No: Vol. 109 (2018)
       
  • Seismic response of buried reservoir structures: a comparison of numerical
           simulations with centrifuge experiments
    • Authors: E. Esmaeilzadeh Seylabi; C. Jeong; S. Dashti; A. Hushmand; E. Taciroglu
      Pages: 89 - 101
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): E. Esmaeilzadeh Seylabi, C. Jeong, S. Dashti, A. Hushmand, E. Taciroglu
      Centrifuge experiments on seismic performance of relatively stiff underground reservoir structures in dry sand are modeled numerically. The capabilities of numerical simulations with calibrated equivalent linear soil properties in capturing the main features of experimentally measured responses are explored for both low and high amplitude earthquake motions. The scattering effects of the centrifuge container boundaries are also investigated by modeling the same soil deposit resting on an elastic bedrock and extending infinitely laterally, using the domain reduction method. It is observed that the calibrated equivalent linear soil models perform well in predicting accelerations, racking, and bending strains on the buried structure, even for high amplitude motions for which significant soil nonlinearity is expected. While not as accurate, the seismic lateral earth pressures predicted with these models are in fair agreement with direct measurements made with tactile sensors. The mismatches in earth pressures are likely due to local nonlinearities of soil and frictional contact, which were absent from the numerical models. It is also observed that the scattering effects of the container boundaries become more significant closer to the soil surface, and their characteristics are seen to depend on both the side boundaries and the embedded structure's stiffness.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.003
      Issue No: Vol. 109 (2018)
       
  • Advanced scalar intensity measures for collapse capacity prediction of
           steel moment resisting frames with fluid viscous dampers
    • Authors: H.R. Jamshidiha; M. Yakhchalian; B. Mohebi
      Pages: 102 - 118
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): H.R. Jamshidiha, M. Yakhchalian, B. Mohebi
      Nowadays, passive energy dissipation systems are used in the seismic design of new structures and the retrofit of existing structures. Fluid Viscous Dampers (FVDs) are one of the important types of passive energy dissipation systems. Using FVDs can considerably decrease the seismic demands on structures. In this study, seismic collapse behavior of steel Special Moment Resisting Frames (SMRFs) equipped with FVDs is investigated using different scalar Intensity Measures (IMs). Incremental Dynamic Analysis (IDA) method is applied to determine the collapse capacity, IM col , values for low- to mid-rise steel SMRFs equipped with FVDs. After determining the collapse capacity, IM col , values by using each of the IMs, the efficiency and sufficiency of the IMs for predicting the seismic collapse capacity of the structures are investigated. Then, advanced scalar IMs, including the effects of spectral shape and ground motion duration, are proposed to reliably predict the collapse capacity of steel SMRFs equipped with FVDs. The results indicate that the proposed IMs possess high efficiency and sufficiency for collapse capacity prediction of steel SMRFs equipped with FVDs.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.01.009
      Issue No: Vol. 109 (2018)
       
  • Excess pore pressure generation in sand under non-uniform cyclic strain
           triaxial testing
    • Authors: Saizhao Du; Siau Chen Chian
      Pages: 119 - 131
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Saizhao Du, Siau Chen Chian
      Two sets of strain-controlled cyclic triaxial tests were conducted to investigate soil liquefaction of clean sands. The first set involved conventional uniform strain amplitude cyclic tests, while the second set examined non-uniform strain amplitude cyclic tests. Comparisons were made between the two sets of results with respect to the generation of excess pore pressure and relationship between strain amplitude and stress path. In the case of uniform strain-controlled cyclic tests, larger strain amplitude produced more rapid generation of excess pore pressure. Conversely, for non-uniform strain-controlled tests, larger strain amplitudes may generate lower excess pore pressure instead. Such counter-intuitive phenomenon has design implications if irregular earthquake loadings in the field are incorrectly represented as equivalent uniform loading in the laboratory. Details are described in this paper.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.016
      Issue No: Vol. 109 (2018)
       
  • An efficient PDE-constrained stochastic inverse algorithm for
           probabilistic geotechnical site characterization using geophysical
           measurements
    • Authors: Siddharth S. Parida; Kallol Sett; Puneet Singla
      Pages: 132 - 149
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Siddharth S. Parida, Kallol Sett, Puneet Singla
      This paper develops an efficient, PDE-constrained stochastic inverse analysis methodology to probabilistically estimate site-specific elastic parameters of soil from sparse geophysical test measurements by accounting for the uncertain spatial variability of soil deposits and any measurement uncertainty associated with the geophysical experiment. Hypothesizing the soil parameters at any site to be three-dimensional, heterogeneous, anisotropic random fields, the methodology first probabilistically simulates the geophysical experiment using the finite element method in conjunction with a stochastic collocation approach to compute statistical measures of a quantity of interest such as the soil displacement or acceleration throughout the soil domain. To this end, the random fields are discretized into finite number of random variables by utilizing a Gaussian mixture model that allows for mimicking the soil formation process. The parameters of the random fields are initially assumed based on the generic data available in the literature for the geological soil type. The stochastic collocation approach utilizes a recently developed non-product quadrature method, conjugate unscented transformation, to accurately estimate the statistical moments corresponding to the model response variables in a computationally efficient manner. The methodology, then, employs a minimum variance framework to fuse the finite element model output with sparse real measurements to update the initially assumed soil statistical parameters. The methodology is illustrated through numerical geophysical experiments at a fictitious geotechnical site and is verified with three very different true profiles of the soil modulus. Moreover, a probabilistic sensitivity analysis is carried out by varying the number and locations of sensors. It is observed that by judiciously selecting the sensor locations, following a set of information maps, obtained by exploiting the equations of the minimum variance scheme, more information may be extracted from any geophysical experiments, leading to less uncertain estimates of the soil parameters.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.01.030
      Issue No: Vol. 109 (2018)
       
  • Dynamic response of an infinite beam resting on a Winkler foundation to a
           load moving on its surface with variable speed
    • Authors: Edmond V. Muho; Niki D. Beskou
      Pages: 150 - 153
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Edmond V. Muho, Niki D. Beskou
      The problem of the dynamic response of an infinite beam resting on a Winkler foundation to a load moving on its surface with variable speed is solved here analytically/numerically under conditions of plane strain. The beam is linearly elastic with viscous damping and obeys the theory of Bernoulli-Euler. The elastic foundation is characterized by its spring constant and hysteretic damping coefficient. The moving point load has an amplitude harmonically varying with time and moves with constant acceleration or deceleration along the top beam surface. The problem is solved by first applying the Fourier transform with respect to the horizontal coordinate x and the Laplace transform with respect to time t to reduce the governing equation of motion of the beam to an algebraic one, which is solved analytically. The transformed beam deflection solution is inverted numerically after some simplifying analytical manipulations to produce the time domain beam response. Parametric studies are conducted in order to assess the effects of the various parameters on the response of the beam, especially those of acceleration and deceleration. Comparisons with the case of a finite beam are also done in order to assess the effect of the beam length.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.034
      Issue No: Vol. 109 (2018)
       
  • Seismic performance assessment of monopile-supported offshore wind
           turbines using unscaled natural earthquake records
    • Authors: Raffaele De Risi; Subhamoy Bhattacharya; Katsuichiro Goda
      Pages: 154 - 172
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Raffaele De Risi, Subhamoy Bhattacharya, Katsuichiro Goda
      The number of offshore wind turbine farms in seismic regions has been increasing globally. The seismic performance of steel monopile-supported wind turbines, which are the most popular among viable structural systems, has not been investigated thoroughly and more studies are needed to understand the potential vulnerability of these structures during extreme seismic events and to develop more reliable design and assessment procedures. This study investigates the structural performance assessment of a typical offshore wind turbine subjected to strong ground motions. Finite element models of an offshore wind turbine are developed and subjected to unscaled natural seismic records. For the first time, the sensitivity to earthquake types (i.e. crustal, inslab, and interface) and the influence of soil deformability and modeling details are investigated through cloud-based seismic fragility analysis. It is observed that monopile-supported offshore wind turbines are particularly vulnerable to extreme crustal and interface earthquakes, and the vulnerability increases when the structure is supported by soft soils. Moreover, a refined structural modeling is generally necessary to avoid overestimation of the seismic capacity of offshore wind turbines.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.015
      Issue No: Vol. 109 (2018)
       
  • Dynamic centrifuge tests on effects of isolation layer and cross-section
           dimensions on shield tunnels
    • Authors: Zhiyi Chen; Sunbin Liang; Hao Shen; Chuan He
      Pages: 173 - 187
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Zhiyi Chen, Sunbin Liang, Hao Shen, Chuan He
      An isolation layer, consisting of a rubber layer wrapped around the outside of a tunnel lining, acts as a countermeasure to enhance the safety of a tunnel during an earthquake. The main objective of the present paper is to verify the seismic efficiency of isolation layers in shield tunnels, and to study the influence of cross-section dimensions on seismic isolation effectiveness. Two sizes of shield tunnel model (with and without isolation layers) are prepared, and six groups of dynamic centrifuge tests are conducted. The test results show that the isolation layer effectively decreases dynamic bending moments in both large and small cross-section tunnels. The smaller cross-section tunnel with smaller ratio of tunnel diameter to isolation layer thickness has a greater reduction of structural response, because more soil deformation is absorbed.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.002
      Issue No: Vol. 109 (2018)
       
  • Deeper Vs profile constraining the dispersion curve with the ellipticity
           curve: A case study in Lower Tagus Valley, Portugal
    • Authors: Fátima Gouveia; António Viana da Fonseca; Rui Carrilho Gomes; Paula Teves-Costa
      Pages: 188 - 198
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Fátima Gouveia, António Viana da Fonseca, Rui Carrilho Gomes, Paula Teves-Costa
      Shear wave velocity profile and bedrock depth are key parameters for seismic site response estimation and a reliable tool to evaluate liquefaction potential in soil deposits. They can be determined using in-situ geotechnical tests such as the seismic Cross-Hole (CH), seismic Cone Penetration Test (SCPT), seismic Dilatometer Test (SDMT), or through geophysical surface wave methods. The main advantages of surface wave methods are their non-invasive nature and the ability to characterize the shear wave velocity of the soil at a larger scale. However, the investigation depth in general is less than 20 m. Using the Rayleigh ellipticity curve to constrain the dispersion curve from active and/or passive measurements, deeper Vs-profile is obtained. In this study, the Vs profile of the soil at a site located over Lower Tagus alluvial Valley was obtained using different surface wave methods. For this purpose, ambient vibration measurements using a single three-component seismic station were made, to complement active and passive linear measurements. The Rayleigh wave ellipticity curve was computed from the single station recordings using the RayDec method and dispersion curves were estimated with the array recordings processed using f-k based methods: MASW, ReMi and conventional f-k method for non-linear array data. A joint inversion procedure was applied to the data and the results were compared with Vs profiles obtained from direct measurements with Cross-Hole and SDMT tests. The results show that considering the passive ellipticity curve in the joint inversion process with the dispersion curve, it is possible to obtain deeper and less scattered Vs profiles.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.010
      Issue No: Vol. 109 (2018)
       
  • Reduction factors to evaluate acceleration demand of
           soil-foundation-structure systems
    • Authors: Anna Karatzetzou; Dimitris Pitilakis
      Pages: 199 - 208
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Anna Karatzetzou, Dimitris Pitilakis
      The seismic acceleration loading of structures founded on compliant soil is investigated through numerical elastic time history analyses of coupled soil-foundation-structure (SFS) systems and appropriate reduction factors of acceleration demand for free-field to evaluate acceleration demand for the SFS systems are proposed. The proposed reduction factors are the division of the acceleration demand for the coupled SFS system over the acceleration demand for the free-field, and propose an alternative method to calculate the actual acceleration loading considering interaction effects. The advantages of the proposed methodology are i) its accuracy, as the reduction factors result from coupled SFS numerical finite element analyses and consider both inertial and kinematic interaction effects and ii) its practicality, as it can be applied by the user performing no finite element numerical analysis. Additionally, the presented methodology can be applied to systems with important mass (e.g. bridge structures). The proposed acceleration reduction factors are presented in terms of dimensionless engineering parameters such as soil to structure stiffness ratio and the structure's aspect ratio. The accuracy, efficiency, and practicality of the proposed methodology are highlighted through an application to a typical bridge structure. Because structures with surface foundations are examined, inertial interaction mainly affects the acceleration demand. Therefore, the proposed reduction factors clearly demonstrate and quantify the beneficial effect of damping on buildings and bridges, as the maximum average acceleration at the top of the actual SFS system can reduce to about 55–85% of the acceleration demand for the free-field motion.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.017
      Issue No: Vol. 109 (2018)
       
  • Base-isolation systems for the seismic retrofitting of r.c. framed
           buildings with soft-storey subjected to near-fault earthquakes
    • Authors: Fabio Mazza; Mirko Mazza; Alfonso Vulcano
      Pages: 209 - 221
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Fabio Mazza, Mirko Mazza, Alfonso Vulcano
      More studies are needed to evaluate the effectiveness of the base-isolation in seismic retrofitting of reinforced concrete (r.c.) framed structures in the case of masonry infills (MIs) not uniformly distributed in elevation. Moreover, amplification of the inelastic demand is generally expected for base-isolated structures located in a near-fault area, in the event of long-duration velocity pulses. In order to understand the nonlinear seismic behaviour of masonry-infilled base-isolated r.c. framed structures, first a six-storey r.c. framed building is primarily designed (as fixed-base) in compliance with a former Italian seismic code, for a medium-risk zone. Then it is retrofitted by the insertion of a base-isolation system with elastomeric and sliding bearings to meet the requirements of the current Italian code, in a high-risk seismic zone. Failure mechanisms of totally and partly infilled structures are compared by considering three structural models: (i) bare structure with nonstructural MIs; (ii) infilled structure with in-elevation uniform distribution of structural MIs; (iii) infilled structure with in-elevation uneven distribution of structural MIs. Nonlinear dynamic analysis of the original (fixed-base) and retrofitted (base-isolated) structures is carried out by a lumped plasticity model describing the inelastic behaviour of the r.c. frame members, while nonlinear force-displacement laws are considered for the elastomeric and sliding bearings. A pivot hysteretic model is assumed to predict the nonlinear force-displacement law of the equivalent diagonal strut adopted for modelling the MIs. Finally, near-fault ground motions with significant horizontal pulses are selected and scaled on the basis of the design hypotheses adopted for the test structures.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.025
      Issue No: Vol. 109 (2018)
       
  • Dynamic response of a finite beam resting on a Winkler foundation to a
           load moving on its surface with variable speed
    • Authors: Niki D. Beskou; Edmond V. Muho
      Pages: 222 - 226
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Niki D. Beskou, Edmond V. Muho
      The dynamic response of a simply supported elastic beam resting on an elastic foundation of Winkler's type with viscous damping to a point load moving with variable speed on the surface of the beam is obtained analytically/numerically. The beam is of the Bernoulli-Euler type with viscous damping. The load is concentrated and varies harmonically with time. The equation of lateral motion of the beam is solved by modal superposition analytically and computation of the resulting Duhamel's integrals is done numerically. The case of two loads representing the two axle system of a vehicle, is also treated here by following the same approach used for the single load. The effects of the various parameters, like foundation stiffness and damping, beam damping and especially acceleration or deceleration of the moving load or loads, on the response of the beam are assessed through extensive parametric studies and useful practical conclusions are presented.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.033
      Issue No: Vol. 109 (2018)
       
  • Method of accurate-fast magnitude estimation for earthquake early warning
           -----Trial and application for the 2008 Wenchuan earthquake
    • Authors: Zijun Wang; Boming Zhao
      Pages: 227 - 234
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Zijun Wang, Boming Zhao
      Earthquake early warning (EEW) system is one of the most useful tools to mitigate seismic hazards. Although EEW approaches have already been developed worldwide, the issues of improving the accuracy and applicability were still controversial. On the basis of the existing measurable parameters related to the earthquake magnitude, we proposed a method in terms of the squared integral displacement ( ID 2 ) to anticipate the magnitude in real-time for EEW purpose that can be used for large earthquakes. With the main-shock and aftershocks of the 2008 M s 8.0 Wenchuan earthquake, we investigated the regression relationships between the proposed ID 2 and earthquake magnitude, based on which the magnitude predication formula was derived. Then the predicated accuracy from ID 2 was compared with that from τ c and P d . By comparing the differences between the estimated and reported magnitudes, the proposed ID 2 method was of the highest accuracy among the investigated 3 parameters. Next we analysed the ground motion characteristics in the frequency domain and established the correlations between the Fourier amplitude and spectral intensity of the initial P wave with the magnitude estimation differences, based on which a revision method of reducing such differences was put forward and the saturation effects of predicting large magnitudes were well mitigated simultaneously.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.006
      Issue No: Vol. 109 (2018)
       
  • Experimental and numerical dynamic identification of a historic masonry
           bell tower accounting for different types of interaction
    • Authors: Filomena de Silva; Dimitris Pitilakis; Francesca Ceroni; Stefania Sica; Francesco Silvestri
      Pages: 235 - 250
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Filomena de Silva, Dimitris Pitilakis, Francesca Ceroni, Stefania Sica, Francesco Silvestri
      Advances in dynamic numerical analyses and investigation techniques nowadays allow to simulate the seismic behavior of structures through increasingly detailed models, calibrated on in-situ dynamic surveys. The different factors affecting the calibration procedure should, however, be well identified and properly represented in the model. Usually various forms of interaction may influence the building response (i.e. soil-structure, surrounding buildings, etc.) and so their single contribution on the overall response of the coupled system should properly be ascertained. In the paper, the results of numerical analyses and on-site dynamic identification are compared, to quantify the role exerted by the structure, the foundation, the soil and the adjacent buildings on the overall dynamic behavior of the highest tower in Napoli (Italy). The experimental frequencies and the corresponding deformed shapes were reproduced through a simplified model on springs, simulating the soil-foundation impedance. The inferred dynamic behavior of the tower was observed to be significantly influenced by the restraint exerted from adjacent buildings and by the interaction with the soil. The results were corroborated by the more refined predictions provided by a complete 3D Finite Difference model of soil, foundation and structure. In addition, a frequency detected from field records, which has not been identified in previous analyses on fixed base models, was found to be associated to the rocking response of the foundation.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.012
      Issue No: Vol. 109 (2018)
       
  • Effects of bond-slip and masonry infills interaction on seismic
           performance of older R/C frame structures
    • Authors: Aslam Faqeer Mohammad; Marco Faggella; Rosario Gigliotti; Enrico Spacone
      Pages: 251 - 265
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Aslam Faqeer Mohammad, Marco Faggella, Rosario Gigliotti, Enrico Spacone
      The seismic response of older R/C frames can be particularly sensitive to interaction with masonry infills, poor section detailing and smooth reinforcing bars. These aspects are quite often neglected in design and assessment both with linear and nonlinear models due to the modelling complexity and inherent increase in computational effort. This work presents a review of practical nonlinear models available in literature and quantifies, at the system performance level, the influence of bond-slip in critical plastic hinge locations and interaction effects with infill panels and shear deficient columns. Bond-slip effects are directly incorporated into the nonlinear fiber section models through a simplified approach and nonlinear shear behavior of columns is aggregated at the element level in conjunction to the common diagonal infill strut scheme. Three different infilled frame configurations are analyzed: a) bare frame, b) partially infilled frame (pilotis frame) and c) uniformly infilled frame. Static pushover analyses and Incremental Dynamic Nonlinear Response History Analyses (IDA) are performed spanning a wide range of hazard levels. Comparative analysis with concurrent incorporation of infill-induced shear damage and bond-slip quantify the loss of strength for the uniformly infilled configuration and the increased deformations for the bare frame and partially infilled configurations in terms of seismic performance parameters.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.027
      Issue No: Vol. 109 (2018)
       
  • Consistent damage model and performance-based assessment of structural
           members of different materials
    • Authors: Wei Huang; Ming Zou; Jiang Qian; Zhi Zhou
      Pages: 266 - 272
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Wei Huang, Ming Zou, Jiang Qian, Zhi Zhou
      Structural members of different materials in composite structures have different seismic damage performances. Consequently, a unified standard is required to evaluate the performance levels of structural members of a composite structure in order to determine the behavior and the damage process from member-level to structure-level. Based on the classical Park-Ang damage model, a consistent modification of that model is proposed for structural members of different materials. Furthermore, the specific limit values of this damage model at various performance levels are calculated. Obvious differences have been found between the limit values of different types of members. In order to unify the damage limits that correspond to predefined performance levels such that a comparison between different members can be made directly, normalizing parameters for the different types of members are introduced to build the unified damage model. The finite element method utilizing the proposed damage model and performance levels produces results in good agreement with those of testing.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.021
      Issue No: Vol. 109 (2018)
       
  • Performance of X-shaped and circular pile-improved ground subject to
           liquefaction-induced lateral spreading
    • Authors: Wenwen Li; Yumin Chen; Armin W. Stuedlein; Hanlong Liu; Xinlei Zhang; Yaohui Yang
      Pages: 273 - 281
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Wenwen Li, Yumin Chen, Armin W. Stuedlein, Hanlong Liu, Xinlei Zhang, Yaohui Yang
      Liquefaction-induced lateral spreading has caused severe damage and significant financial losses in major earthquakes distributed globally. Groups of piling installed in liquefaction- and lateral spreading-susceptible ground has been proven to be effective in reducing lateral displacements, but further investigation into the soil-structure interactions is required to elucidate the mechanisms for mitigation of displacement. Further, it is hypothesized that cross-, or X-shaped, piling may provide improved restraint on lateral flow deformations due the destructive interference of flow imposed by their cross-section. In this paper, the effectiveness of groups of X-shaped and circular piles to mitigate lateral spreading ground was investigated to improve the understanding of the mechanisms for improvement. Shake table tests were carried out to examine and compare the efficacy and efficiency of X-shaped and circular pile groups. Design parameters including the pile arrangement (square vs. triangular spacing) and orientation (X vs. +) of the X-shaped piling were also taken into consideration. The results demonstrate that the X-shaped pile groups can significantly reduce the lateral displacement and the areal extent of liquefied sand flow as compared to the unimproved and circular pile-improved ground, and that the spacing and orientation play a critical role in the deformation response. These findings will help inform the design of pile-improved ground as well as the design of structural piling adjacent to submerged, liquefiable slopes.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.022
      Issue No: Vol. 109 (2018)
       
  • Analysis of non-uniform piles driven into cohesive soils
    • Authors: Amin Sormeie; Mahmoud Ghazavi
      Pages: 282 - 285
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Amin Sormeie, Mahmoud Ghazavi
      In this paper, a theoretical method based on cavity expansion method (CEM) in conjunction with wave equation theory is used for analysis of driven tapered piles into cohesive soils. The results show that tapered piles are driven easier than cylindrical piles of the same length and volume. Also, with increasing the pile taper angle, the permanent pile displacement increases, which is significant in pile driving.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.014
      Issue No: Vol. 109 (2018)
       
  • Quantification of model uncertainty and variability in Newmark
           displacement analysis
    • Authors: Wenqi Du; Duruo Huang; Gang Wang
      Pages: 286 - 298
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Wenqi Du, Duruo Huang, Gang Wang
      Newmark displacement model has been extensively used to evaluate earthquake-induced displacement in earth systems. In this paper, model uncertainty and variability associated with the Newmark displacement analysis are systematically studied. Fourteen Newmark displacement models using scalar or vector intensity measures (IMs) as predictors are compared in this study. In general, model uncertainty for the vector-IM models is found smaller than that of the scalar-IM models, and remains consistent over different earthquake magnitude, distance and site conditions. Yet, the model uncertainty of these Newmark displacement models is still much larger than that of the ground-motion prediction equations (GMPEs) for IMs, indicating further development of the models is much needed. Considering the variabilities contributed from both GMPEs and Newmark displacement models, the total variability of the predicted Newmark displacements is rather consistent among the scalar- and vector-IM displacement models, due to extra sources of variability introduced by incorporating additional IMs. Finally, a logic tree scheme is implemented in the fully probabilistic Newmark displacement analysis to account for the model uncertainty and variability. Sensitivity analysis shows that specific weights would not significantly influence the displacement hazard curves as the results may be dominated by outlier models. Instead, selecting appropriate GMPEs and Newmark displacement models is more important in using the logic-tree framework.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.037
      Issue No: Vol. 109 (2018)
       
  • Pile-grid foundations of onshore wind turbines considering
           soil-structure-interaction under seismic loading
    • Authors: Philipp Michel; Christoph Butenweg; Sven Klinkel
      Pages: 299 - 311
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Philipp Michel, Christoph Butenweg, Sven Klinkel
      In recent years, many onshore wind turbines are erected in seismic active regions and on soils with poor load bearing capacity, where pile grids are inevitable to transfer the loads into the ground. In this contribution, a realistic multi pile grid is designed to analyze the dynamics of a wind turbine tower including frequency dependent soil-structure-interaction. It turns out that different foundations on varying soil configurations heavily influence the vibration response. While the vibration amplitude is mostly attenuated, certain unfavorable combinations of structure and soil parameters lead to amplification in the range of the system's natural frequencies. This testifies the need for overall dynamic analysis in the assessment of the dynamic stability and the holistic frequency tuning of the turbines.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.009
      Issue No: Vol. 109 (2018)
       
  • Soil-buried wave barriers for vibration control of structures subjected to
           vertically incident shear waves
    • Authors: Amir Rezaie; Reza Rafiee-Dehkharghani; Kiarash M. Dolatshahi; Seyed Rasoul Mirghaderi
      Pages: 312 - 323
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Amir Rezaie, Reza Rafiee-Dehkharghani, Kiarash M. Dolatshahi, Seyed Rasoul Mirghaderi
      Traditionally, the effects of seismic forces on structures have been mitigated by installing supplemental energy dissipation systems. In this paper, a new approach is explored for the mitigation of earthquake-induced vibrations by obstructing the entrance of seismic energy to the structure through the insertion of some concrete wave barriers within the soil domain. To do so, genetic algorithm (GA) based adaptive optimization methodology is utilized that is capable of finding the efficient layout of the concrete barriers in a manipulated soil zone around the structure. The optimization methodology is coupled with finite element (FE) method for analyzing the complex wave propagation phenomenon in the medium. To investigate the effect of frequency, three single-degree-of-freedom (SDOF) structures with the natural frequencies of 1, 2, and 3 Hz are subjected to the time history ground motions with the predominant frequencies up to 8 Hz. The optimization analyses are performed in the frequency domain, and the efficiency of the obtained solutions is examined by applying time history ground motions in the time domain. The results show that the performance of the buried wave barriers is a complex function of the wave barriers layout, natural frequency of the structure, and the frequency content of the loading. It is observed that some optimal layouts of limited volume can attenuate the elastic demands of the structures to the extent of 30–80%.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.020
      Issue No: Vol. 109 (2018)
       
  • Nonlinear dynamic response of concrete gravity dams considering the
           deconvolution process
    • Authors: Masoud Khazaei Poul; Aspasia Zerva
      Pages: 324 - 338
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Masoud Khazaei Poul, Aspasia Zerva
      In order to model any physical system, including concrete dams, one needs to apply simplifications to the real system to make the modeling feasible. To study the dynamic response of concrete dams, relevant assumptions are made regarding foundation modeling, input motion mechanism, dam-reservoir interaction, and material behavior. Some of these simplifications may lead to more conservative and uneconomical outcomes. In this paper, nonlinear time-domain dynamic analyses are conducted to evaluate the effect of the input motion mechanism on the concrete gravity dam response. An ideal model of a dam-reservoir-foundation system, considering the inertia of the foundation, appropriate boundary conditions and precise deconvolved base motions, is selected as the reference model. The process of deconvolution of seismic waves through the frequency- and time-domain approaches is discussed, and suggestions for the selection of an appropriate damping model for the rock foundation are presented. The results are compared to those of the standard model of a massless foundation system as recommended by the US Army Corps of Engineers. The numerical results indicate that, generally, the nonlinear response of the two dam models follow similar patterns, but with a larger amplitude for the massless system. It is noted that the consequence of neglecting the dynamic effect of the foundation can be significant. Additionally, the results demonstrate that the degree of overestimation varies dramatically for the various seismic excitations. The average overestimation of the massless system for the crest displacement, crest acceleration, and the contact opening and sliding are 57%, 45%, 152%, and 90%, respectively. It is further shown that the use of the deconvolved input excitation at the base of the finite foundation derived from the frequency-domain approach can yield discrepancies between the target and convolved surface ground motions, which can also have a considerable effect on the dam response.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.025
      Issue No: Vol. 109 (2018)
       
  • Ground motion prediction equations for distant subduction interface
           earthquakes based on empirical data in the Malay Peninsula and Japan
    • Authors: Abdollah Vaez Shoushtari; Azlan Bin Adnan; Mehdi Zare
      Pages: 339 - 353
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Abdollah Vaez Shoushtari, Azlan Bin Adnan, Mehdi Zare
      Ground motion prediction equations (GMPEs) for earthquakes that occur in subduction zones, including both interface and slab parts, have a major impact on seismic hazard analysis in many parts of the world. For example, in the Sumatran subduction region, there could be a remarkable hazard for the Malay Peninsula due to the large megathrust earthquakes that occur far from the region along the subduction interface. This study has developed new empirical spectral GMPEs for long-distance subduction interface earthquakes based on the recorded ground motion data in the Malay Peninsula and Japan. The compiled ground motion database is from hundreds of ground motion recordings due to twenty five reliably identified subduction interface events with moment magnitude [M] of 5.0–9.1 and hypocentral distance (R hyp) up to 1300 km. The data from the large megathrust earthquakes with M ≥ 7.0 such as 2011 M 9.1 Tohoku-Japan, the 2007 M 8.5 earthquake near Bengkulu in Sumatra Island, 2005 M 8.6 Nias-Sumatra, and 2004 M 9.0 Aceh-Sumatra earthquakes were included in the database. The proposed GMPEs are able to predict peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped pseudo-spectral acceleration (PSA) for four different site classes based on the National Earthquake Hazards Reduction Program (NEHRP) site classification. The results of this study could be applied to develop logic tree frameworks for seismic hazard analyses of Peninsular Malaysia as well as the regions affected by large and distant subduction interface earthquake events.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.024
      Issue No: Vol. 109 (2018)
       
  • Seismic hazard assessment at micro level in Gandhinagar (the capital of
           Gujarat, India) considering soil effects
    • Authors: Kapil Mohan; B.K. Rastogi; Vasu Pancholi; Drasti Gandhi
      Pages: 354 - 370
      Abstract: Publication date: June 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 109
      Author(s): Kapil Mohan, B.K. Rastogi, Vasu Pancholi, Drasti Gandhi
      Gandhinagar City (the Capital of Gujarat, India) falls under Zone III on the seismic zoning map of India where an earthquake of magnitude 6 can be expected. It is a well established fact that the site amplification/ shaking and damage is large in soil covered areas. To estimate the effect of soil on ground motion and to estimate the strong ground motion parameters at surface, soil modeling and the ground response analysis have been conducted along uniformly distributed 14 boreholes drilled upto a depth of 50 m. The methodology is divided into three parts (i) Estimation of depth of Engineering Bed layer (EBL) (a layer with a shear wave velocity 400 m/s ≤ Vs ≤ 750 m/s, N value >80 and minimum soil variation below it) through soil modeling, (ii) Estimation of Ground Motion at EBL due to scenario earthquake at nearby active fault and (iii) Estimation of surface strong ground motion using 1D ground response analysis through SHAKE 2000 program. The EBL is found at a depth of 21–33 m (shallower in central part and deeper in northern and southern parts). The Near-Field scenario earthquake (Eq.) of magnitude Mw 6.0 has been considered along East Cambay Fault (normal fault, 60° dip) located at about ~ 20 km east and Far Field scenario Eq. of Mw 7.6 is considered along Kachchh Mainland Fault located ~270 km west. The Peak Ground acceleration (PGA) of 0.172–0.237 g have been estimated at surface due to near field earthquake scenario. The mean spectral acceleration maps for 0.1–0.4 s, 0.4–0.7 s, 0.7–1.0 s and 1.0–1.5 s have also been computed. The mean spectral acceleration for the period of 0.1–0.4 s has been varying from 0.330 g to 0.508 g, for period of 0.4–0.7 Sec, it has been varying from 0.151 g to 0.161 g and for period between 1.0 and 1.5 Sec, it has been found from 0.83 g to 0.09 g. The PGA is found increased by 5–38% in the first subsurface soil layer in Gandhinagar city. The PGA of the order of 0.059–0.072 g and peak Spectral acceleration of the order of 0.187–0.259 g have been computed (with predominant periods of ~0.1 s and 0.31 s) due to Far-Field Eq. scenario and are found less than Indian code. The PGA and Spectral acceleration (Sa) values are found higher than the Indian code in the period range of 0.1–0.4 s (one to four storey buildings) for Near Field Eq. Scenario.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.03.007
      Issue No: Vol. 109 (2018)
       
  • Efficient random field modeling of soil deposits properties
    • Authors: Qingxia Yue; Jingru Yao; Alfredo H.-S. Ang; Pol D. Spanos
      Pages: 1 - 12
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Qingxia Yue, Jingru Yao, Alfredo H.-S. Ang, Pol D. Spanos
      The autocorrelation function (ACF) of the soil profile in some sites in Shandong province, China is studied using cone penetration test (CPT) data. This is done in the context of a random field modeling of the soil deposits. It is found that the different types of soil profile have different stochastic parameters, and there is no obvious trend along the depth of the soil profile. Thus, the soil profile is examined within each layer. Numerical values for three existing analytical (ACF) models are derived by the least squares fitting approach for the different types of soil. Further, comparisons of the autocorrelation function between the tip resistance and sleeve friction were examined. Based on the autocorrelation data analysis, a new autocorrelation model, named linear-exponential-cosine (LNCS), is considered with differentiability at the origin of the spatial lag axis, and alternating sign along this axis. For all of the four ACF models, a related integral equation is numerically solved for determining the associated Karhunen-Loeve (K-L) representation. In this regard, it is noted that the new model is not only more physics-consistent, but also yields quite good computational efficiency. In the end, the random field of the soil profile is modeled using a two-dimensional K-L expansion with the new model, assuming separability in two dimensions.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.01.036
      Issue No: Vol. 108 (2018)
       
  • Cyclic undrained behavior and liquefaction resistance of transparent sand
           manufactured by fused quartz
    • Authors: Gangqiang Kong; Hui Li; Qing Yang; Yongdong Meng; Xiaoliang Xu
      Pages: 13 - 17
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Gangqiang Kong, Hui Li, Qing Yang, Yongdong Meng, Xiaoliang Xu
      In this paper, a series of cyclic torsional shear tests (TST) were used to study the cyclic undrained behavior and liquefaction resistance of saturated transparent sand manufactured by fused quartz. It was found that the saturated transparent sand has the similar cyclic undrained behavior with saturated natural sands. The mobilized angle of shearing resistance of saturated transparent sand is around 42.6° within the range of saturated natural sands which have angular shape. The saturated transparent sand has a similar trend of shear stress ratio versus number of cycles, but the liquefaction resistance is a little of higher than saturated natural sands.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.015
      Issue No: Vol. 108 (2018)
       
  • Upper bound analysis of 3D static and seismic active earth pressure
    • Authors: Xiao-Li Yang; Zheng-Wei Li
      Pages: 18 - 28
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Xiao-Li Yang, Zheng-Wei Li
      This paper adopts a three-dimensional (3D) rotational failure mechanism to calculate the static and seismic active earth pressure acting on rigid retaining walls within the framework of the kinematic approach of limit analysis. The failure mechanism can be generated through rotating a varying circle defined by two log-spirals, and a plane strain block is inserted into the mechanism for consideration of retaining walls with different widths. Quasi-static representation using the seismic coefficient concept is applied to consider horizontal earthquake effects for the seismic active earth pressure calculation. Two cases with the different points of action of resultant earth pressure are included in this study. In the realm of soil plasticity, the new expressions about 3D active earth pressure are educed from the work-energy balance equation. The critical solution is obtained from an optimization scheme where the maximum of active earth pressure is obtained. Numerical results for different parameters are calculated and presented in the forms of graphs and tables, which may serve as a useful tool for practical application. Compared with existing 2D and 3D solutions, the validity of the proposed method is shown. A parametric study is conducted to investigate the effects of different parameters on the static and seismic active earth pressure under 3D conditions.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.006
      Issue No: Vol. 108 (2018)
       
  • Shaking table test and numerical simulation on a combined retaining
           structure response to earthquake loading
    • Authors: Yu-liang Lin; Xue-ming Cheng; Guo-lin Yang
      Pages: 29 - 45
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Yu-liang Lin, Xue-ming Cheng, Guo-lin Yang
      The combined retaining structure is widely used in high slope supporting engineering. In this paper, shaking table test and numerical simulation are carried out on the seismic response of a combined retaining structure where a gravity wall and an anchoring frame beam are used as a lower structure and an upper structure, respectively. The shaking events of Wenchuan, Da-Rui and Kobe ground motions with different amplitudes are applied in both horizontal and vertical directions. The horizontal and vertical acceleration responses are studied in time domain and frequency domain based on shaking table test, and the results are compared with those obtained from numerical simulation. The axial stress response of anchor and the element state of combined retaining structure subjected to earthquake loading are supplemented and studied by using numerical simulation. Both horizontal and vertical acceleration responses near the bottom of frame beam are significantly magnified, which results in a dramatic increment in acceleration amplification. The acceleration response behind the frame beam is more intensive than that at the back of the gravity wall. The high-frequency component of seismic ground motion is weakened by the combined retaining structure, and the vertical acceleration response presents a wider frequency band. The axial stress of anchor is greatly increased by seismic excitation, and the increment is mainly induced within the excitation period of great acceleration amplitude. Shear failure, tension failure, or both are observed at different positions of combined retaining structure during seismic excitation.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.008
      Issue No: Vol. 108 (2018)
       
  • Finite-difference modeling and characteristics analysis of Rayleigh waves
           in anisotropic-viscoelastic media
    • Authors: Shichuan Yuan; Xianhai Song; Xueqiang Zhang; Sutao Zhao; Peiqiang Zhao; Wei Cai; Dongkai Yu
      Pages: 46 - 57
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Shichuan Yuan, Xianhai Song, Xueqiang Zhang, Sutao Zhao, Peiqiang Zhao, Wei Cai, Dongkai Yu
      Effects of anisotropy and viscoelasticity of Earth media on Rayleigh waves propagation are studied by numerical simulation based on a finite-difference (FD) scheme, which calculates the spatial derivatives via a 12th-order staggered grid difference operator and the time derivatives through the fourth-order Runge-Kutta method. In the homogeneous half-space, the accuracy of FD algorithm is tested against the isotropic-elastic (IE) analytical solution; the calculation method of the theoretical phase velocities of the anisotropic-viscoelastic (AV) Rayleigh waves is developed to verify the correctness of modeling results; the characteristics of Rayleigh-wave are analyzed by comparisons among IE, anisotropic-elastic (AE) and AV modeling results in terms of the wave field snapshots, the synthetic seismograms, and the dispersive images, respectively. Then, the two-layer models and the four-layer models are utilized to further analyze the characteristics of Rayleigh waves in the AV layered media. Results show the substantial differences among these three kinds of media. Anisotropy of medium leads to the significant changes of Rayleigh-wave in amplitude, waveform and phase velocity due to anisotropy of velocity, but does not cause the phase velocity dispersion of Rayleigh-wave. Viscoelasticity of media arouses the amplitude attenuation and phase velocity dispersion of Rayleigh-wave. This is the first report for FD modeling and characteristics analysis of Rayleigh-wave in the AV media, which will provide a valuable reference for near-surface geophysical investigation.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.004
      Issue No: Vol. 108 (2018)
       
  • An energy-based pushover-analysis with torque-effects in assessment of the
           structures with asymmetric plan
    • Authors: Reza Zare Bidoki; Mohsenali Shayanfar
      Pages: 58 - 68
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Reza Zare Bidoki, Mohsenali Shayanfar
      The current paper aims to investigate the pushover schemes for buildings with asymmetric plan in nonlinear static procedures (NSPs). Moreover, this paper will propose an extension of the energy-based adaptive pushover analysis (EAPA) procedure for the seismic design/assessment of 3D irregular structures, which will be denoted as energy-based pushover-analysis with torque-effects (EPT). This innovative single-run adaptive method is proposed based on the work done produced by modal force in each step of analysis; and is validated on 3D steel structures with asymmetric plan composed from moment-resisting frames. EPT uses the concepts of energy to produce an incremental, adaptive load pattern that takes into account the effects of structural deterioration due to seismic loads, the higher modes of vibration, and the characteristics of the frequency content of the excitations. Also, an innovative MDOF-to-SDOF transformation method is proposed based on energy concept, removing the ambiguity of choosing a controlling point in asymmetric plan buildings. The seismic response obtained from nonlinear analyses under 20 earthquake excitations are plotted over the height of the structures. The results of the analytical studies of these buildings show that the EPT method provides a good prediction of maximum inter-story drifts and displacements over the height of the structures.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.005
      Issue No: Vol. 108 (2018)
       
  • Response Spectrum Method for integrated and differential spatial seismic
           ground motions
    • Authors: Yuri P. Nazarov; Elena Poznyak
      Pages: 69 - 78
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Yuri P. Nazarov, Elena Poznyak
      The Response Spectrum Method (RSM) is a widely known method for solving linear dynamic problem in earthquake engineering. However, it is often believed that the RSM can only be applied to the integrated (or averaged over the base of the building) seismic ground motion, when a ground base moves like a rigid body. In this paper we show how to apply spectral technique not only to the integrated six-component seismic motion that is included three translational and three rotational components, but also to the differential seismic motion, when each support point of structure makes individual spatial motion. The RSM is a quasistatic modal method, in which the modal seismic forces are defined as static loads that depend on spectral accelerations. To use the RSM for the differential seismic motion it is necessary to solve two key problems: firstly, correctly define the relative motion of a structure about the moving points of the ground and, secondly, determine the spatial distribution of spectral accelerations. These problems are solved by introducing an influence matrix (it relates the generalized coordinates of the support points and the generalized coordinates of the structure) and a matrix of spatial variations of intensity. The use of these matrices allows to obtain the equations of relative differential motion which are similar to the equations of the integrated seismic ground motion. Therefore, it's easy to apply the RSM to them. This article presents a theory of spectral technique for the general cases of the integrated and differential ground motions. To illustrate the application of the RSM, we consider a simple spatial structure (a rigid plate with shifted flexural center on four steel columns under two-component seismic action, the m-file with solution is attached in the Appendix) for the integrated and differential ground motions.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.014
      Issue No: Vol. 108 (2018)
       
  • Influence of site dynamic characteristics on dynamic soil-structure
           interaction: Comparison between 3D model and 2D models
    • Authors: Jianwen Liang; Bing Han; Jia Fu; Run Liu
      Pages: 79 - 95
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Jianwen Liang, Bing Han, Jia Fu, Run Liu
      The influence of site dynamic characteristics on dynamic soil-structure interaction (SSI) is studied using a three-dimensional (3D) model of a single-degree-of-freedom (SDOF) oscillator on an embedded foundation in a layered elastic half-space. The foundation has hemispherical shape, and the excitation consists of incident P, SH and SV waves. A nonsingular indirect boundary element method (IBEM) is used, with Green's functions computed for distributed loads on inclined planes. Results are shown in both frequency and time domains. The results for the 3D model are compared with those for 2D models with the same cross-section. It is shown that, the site dynamic characteristics have significant influence on the system response, and that the 2D model exaggerates their effects. 2D simplification is potentially risky in the seismic analysis of SSI, with the error of resonant-frequency estimation up to 92.3% and with the underestimation of response peak value up to 73.2% for the example in this study.

      PubDate: 2018-02-25T22:50:11Z
      DOI: 10.1016/j.soildyn.2018.02.011
      Issue No: Vol. 108 (2018)
       
  • Influence of connection and constructional details on masonry-infilled RC
           frames under cyclic loading
    • Authors: Quanmin Peng; Xiaojie Zhou; Chenghao Yang
      Pages: 96 - 110
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Quanmin Peng, Xiaojie Zhou, Chenghao Yang
      Infill walls significantly affect the dynamic characteristics and the seismic performance of reinforced concrete (RC) frames. To evaluate the influence of connection type and constructional details of infill on the cyclic response of RC frames, a quasi-static test was performed on four infilled frame specimens and a bare frame specimen. The infilled frames were constructed with rigid connection or flexible connection between frames and infills, and the infill walls were constructed with or without core columns. The test results show that the presence of the masonry infill wall increased the lateral strength, stiffness, ductility and energy dissipation capacity of the RC frame. The contribution of connection type and core column were analyzed and compared. Additionally, finite element (FE) modeling was conducted and validated with the experimental observations.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.009
      Issue No: Vol. 108 (2018)
       
  • Seismic demand of base-isolated irregular structures subjected to
           pulse-type earthquakes
    • Authors: Fabio Mazza
      Pages: 111 - 129
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Fabio Mazza
      Base-isolated structures may be subjected to severe seismic demand in the superstructure and/or in the isolation system at sites located near an active fault. Forward directivity effects with long-period horizontal pulses in the fault-normal velocity signals are the main cause of this behaviour. However, recent studies have identified pulses in arbitrary orientations along with false-positive classification of pulse-type ground motions. The aim of the present work is to evaluate the reliability of elastomeric (i.e. high-damping-laminated-rubber bearings, HDLRBs) and sliding (i.e. curved surface sliding bearings, CSSBs) base-isolation systems for the seismic retrofitting of in-plan irregular buildings located in the near-fault area. To this end, a five-storey reinforced concrete (r.c.) framed structure, with an asymmetric-plan and bays of different length, is chosen from benchmark structures of the Re.L.U.I.S. project. Attention is focused on the pulse-type and non-pulse-type nature of near-fault earthquakes and moderately-soft and soft subsoil conditions. First, a comparison between algorithms based on wavelet signal processing, that can identify pulses at a single (e.g. fault-normal) or arbitrary orientation in multicomponent near-fault ground motions, is carried out to classify records of recent events in central Italy and worldwide. Then, nonlinear seismic analysis of the fixed-base and base-isolated test structures is performed by using a lumped plasticity model to describe the inelastic behaviour of the r.c. frame members. Nonlinear force-displacement laws are considered for the HDLRBs and CSSBs, including coupled bi-directional motions in the horizontal directions and coupling of vertical and horizontal motions.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2017.11.030
      Issue No: Vol. 108 (2018)
       
  • Dynamic interaction between adjacent buildings through nonlinear soil
           during earthquakes
    • Authors: Felipe Vicencio; Nicholas A. Alexander
      Pages: 130 - 141
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Felipe Vicencio, Nicholas A. Alexander
      This paper evaluates the effect of Structure-Soil-Structure Interaction (SSSI) between two buildings given different parameters of the buildings, inter-building spacing, and soil type. A two-dimensional simple discrete nonlinear model is proposed that is described by a set of nonlinear differential equations of motion. A nonlinear phenomenological Bouc-Wen model, for the soil directly underneath the foundations, linear rotational interaction spring between buildings and linear behaviour of buildings are assumed. The seismic ground motion employed is spectrally matched with EC8 elastic spectra. The results showed that there are both unfavourable and beneficial configurations of the two buildings that produce important differences between nonlinear SSSI and nonlinear SSI (the uncoupled building case). Importantly it is demonstrated that the adverse effects of SSSI can be more pronounced when the nonlinear soil behaviour is assumed.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2017.11.031
      Issue No: Vol. 108 (2018)
       
  • CAV site-effect assessment: A case study of Taipei Basin
    • Authors: J.P. Wang; Xu Yun; H. Kuo-Chen; Yih-Min Wu
      Pages: 142 - 149
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): J.P. Wang, Xu Yun, H. Kuo-Chen, Yih-Min Wu
      Recent studies have shown that structural damage exhibits stronger correlations with cumulative absolute velocity (CAV) than other ground motion intensity measures (e.g., PGA). This paper presents a CAV site-effect assessment for the Taipei areas for the first time. The study was based on more than 1200 strong-motion data from 47 major earthquakes that had occurred around Taiwan. The results show that the site effects are more conspicuous in the western Taipei than the eastern areas, and it is also obvious that the site effect is strong in locations close to the rims of the basin, where seismic waves could be easily reflected, refracted and superimposed. Subsequently, a map showing the areas in Taipei subject to severe CAV amplification and/or high variability was developed for site-effect microzonation for the study area, on the basis of CAV that was considered better correlated with structural damage under earthquake condition.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.028
      Issue No: Vol. 108 (2018)
       
  • Multi-point shaking table test for long tunnels subjected to non-uniform
           seismic loadings – Part I: Theory and validation
    • Authors: Yong Yuan; Haitao Yu; Chong Li; Xiao Yan; Juyun Yuan
      Pages: 177 - 186
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Yong Yuan, Haitao Yu, Chong Li, Xiao Yan, Juyun Yuan
      The spatially varying ground motions can significantly influence the dynamic response of extended structures such as tunnels. However, current knowledge on the effects of non-uniform seismic excitations on long tunnels is limited to analytical or numerical methods and lack of experimental or field data. This paper presents a confirmatory experimental method for long tunnels subjected to non-uniform excitations, using four independent shaking tables worked in coordination as a large linear shaking table array. The discrete multi-point input mechanism is deemed critical to accomplish a continuous and coordinated excitation over a long tunnel. A 40m-long segmental model container is developed to realize the equivalent transformation from the four independent shaking tables into continuous excitations. The dimension of the segmental model container as well as the connection between each of its components is determined after significant analytical and numerical simulations. A series of tests are conducted to investigate the wave passage effect along the length of the segmental model container. Results show that the wave passage effect is accurately reproduced with the test setup and the acceleration input scheme, and thus the validation of the design of the multi-point test system is approved.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2016.08.017
      Issue No: Vol. 108 (2018)
       
  • Multi-point shaking table test for long tunnels subjected to non-uniform
           seismic loadings - part II: Application to the HZM immersed tunnel
    • Authors: Haitao Yu; Yong Yuan; Guoping Xu; Quanke Su; Xiao Yan; Chong Li
      Pages: 187 - 195
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Haitao Yu, Yong Yuan, Guoping Xu, Quanke Su, Xiao Yan, Chong Li
      A series of multi-point shaking table tests are conducted on a long immersed tunnel designed for the Hongkong-Zhuhai-Macau linkage (HMZ linkage) under non-uniform seismic excitations. Details of experimental setup are first presented with particular focuses on: shaking table array of the four independent shaking tables; dynamic similitude design between scale model of soil and tunnel structure and prototype model; design and fabrication of the scaled model tunnel and model soil; and procedure for simulation of non-uniform seismic waves. A series of testing cases of the shaking tables are carried out on the model tunnel using input motions with different seismic amplitudes. Dynamic responses measured from the experiment include acceleration of soil stratum and model tunnel, as well as extension and closure of immersion joints. Acceleration and deformation responses in the tunnel segments and their connecting joints are investigated and analyzed in the test cases under both uniform and non-uniform seismic loadings, and the capacity of critical structural components, such as extension of joints is evaluated. Results show that the non-uniform seismic excitation significantly aggravates the extension of immersion joints compared to the uniform excitation, and thus the non-uniform seismic effect should be considered in the design of immersed tunnels.

      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2016.08.018
      Issue No: Vol. 108 (2018)
       
  • Discussion of “An orthogonal Hilbert-Huang transform and its application
           in the spectral representation of earthquake accelerograms” by Tian-Li
           Huang, Meng-Lin Lou, Hua-Peng Chen, Ning-Bo Wanga [Soil Dyn. Earthq. Eng.
           104 (2018), 378–389]
    • Authors: Pushpendra Singh
      First page: 196
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Pushpendra Singh


      PubDate: 2018-04-10T20:50:41Z
      DOI: 10.1016/j.soildyn.2018.02.031
      Issue No: Vol. 108 (2018)
       
  • Nonlinear soil-structure interaction analysis in poroelastic soil using
           mid-point integrated finite elements and perfectly matched discrete layers
           
    • Authors: Jin Lee
      Abstract: Publication date: May 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 108
      Author(s): Jin Ho Lee
      A numerical approach for a nonlinear analysis of soil-structure interaction in poroelastic soil is proposed. Nonlinear behavior in the near-field region of soil is considered by conventional finite elements. The far-field region of soil is represented by mid-point integrated finite elements and perfectly matched discrete layers (PMDLs) in order to consider the energy radiation into infinity. The mid-point integrated finite elements can be formulated identically to conventional finite elements. Thus, PMDLs for poroelastic media are formulated in this study. A means by which to represent a layered poroelastic half-space with conventional finite elements, mid-point integrated finite elements, and the developed PMDLs is proposed. The proposed numerical approach is verified from various perspectives. The approach is applied to a nonlinear analysis of the earthquake responses of a structural system on poroelastic soil. It is demonstrated via the application that the proposed approach can be applied successfully to nonlinear dynamic soil-structure interaction problems.

      PubDate: 2018-04-10T20:50:41Z
       
 
 
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