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EARTH SCIENCES (466 journals)

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Journal Cover Soil Dynamics and Earthquake Engineering
  [SJR: 1.516]   [H-I: 56]   [15 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0267-7261
   Published by Elsevier Homepage  [3043 journals]
  • A centrifuge-based experimental verification of Soil-Structure Interaction
           effects
    • Authors: Panagiotis Martakis; Damoun Taeseri; Eleni Chatzi; Jan Laue
      Pages: 1 - 14
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Panagiotis Martakis, Damoun Taeseri, Eleni Chatzi, Jan Laue
      A series of prototype dynamic centrifuge experiments is carried out to investigate the influence of soil properties and structural parameters on the Soil Structure Interaction (SSI) effect. Established analytical models are herein experimentally verified, and are proven accurate in estimating the system's natural frequency characteristics. It is observed that period elongation is strongly correlated to the relative superstructure-foundation stiffness. Although the present study deals exclusively with the small-strain near-linear range, the experimental response indicates occurrence of nonlinearity. The identified damping results remarkably larger than its analytical estimate and proves highly strain-dependent, raising questions on the reliability of existing analytical methods in capturing the actual dissipation mechanisms. An extended experimental dataset is formed under realistic stress and strain soil conditions, and is implemented, for the first time, for verification of existing analytical models offering valuable insight into the theory and serving as a benchmark for engineering practice.

      PubDate: 2017-09-27T16:20:50Z
      DOI: 10.1016/j.soildyn.2017.09.005
      Issue No: Vol. 103 (2017)
       
  • Seismic vulnerability assessment of stone masonry façade walls:
           Calibration using fragility-based results and observed damage
    • Authors: Tiago Miguel Ferreira; Rui Maio; Alexandre A. Costa; Romeu Vicente
      Pages: 21 - 37
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Tiago Miguel Ferreira, Rui Maio, Alexandre A. Costa, Romeu Vicente
      This paper is focused on the calibration of a simplified seismic vulnerability index method for masonry façade walls, through an innovative two-step calibration process based on two complementary approaches. The first one is based on a set of fragility curves constructed from out-of-plane damage limit states obtained from experimental data, which are used to calibrate the weights associated to the parameters of the vulnerability index method that rule the out-of-plane response of the masonry façade walls. The second approach, subsequently used to calibrate the weights of the remaining vulnerability parameters, is based on post-earthquake damage data collected after the seismic event that struck the Azores Archipelago in July 1998. The results obtained from such calibration are then presented and critically discussed taking into account not only the calibration itself, but also their reliability from the methodological point of view. Finally, the addition of three new evaluation parameters is further proposed and analysed. This two-step calibration process represents a valuable contribution for the current state-of-art of the simplified seismic vulnerability assessment methodologies which, up to the present, have been developed and calibrated only on the basis of empirical data.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.006
      Issue No: Vol. 103 (2017)
       
  • Performance-based, seismically-induced landslide hazard mapping of Western
           Oregon
    • Authors: Mahyar Sharifi-Mood; Michael J. Olsen; Daniel T. Gillins; Rubini Mahalingam
      Pages: 38 - 54
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Mahyar Sharifi-Mood, Michael J. Olsen, Daniel T. Gillins, Rubini Mahalingam
      Seismically-induced landslides can be detrimental to urban communities, often resulting in significant damage and repair costs, blockage of lifeline connection routes and utilities, environmental impacts, and potential for loss of life. Consistent, reliable hazard maps can assist agencies to efficiently allocate limited resources to prepare for these events. This paper presents methodology for evaluating and mapping seismically-induced landslide hazards across a large area utilizing performance-based design strategies. This approach scales site-specific seismic hazard curve analysis techniques to a regional scale evaluation by combining generally available data, including: previous landslide inventories, lidar and photogrammetric topographic data, geologic mapping, NEHRP site classifications based on shear wave velocity (VS30) measurements, and seismic hazard curves for the analysis. These maps can be combined with maps generated for other hazards (e.g., liquefaction) for a fully probabilistic, multi-hazard evaluation and risk assessment. To demonstrate the methodology, a series of landslide hazard maps showing the probabilities of exceeding different thresholds of movement (e.g., 0.1, 0.3, and 1.0m) were generated for western Oregon. The study area contains weak, wet soils that experience land sliding regularly even without significant seismic activity. The maps show reasonable agreement with landslide inventory and susceptibility maps.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.012
      Issue No: Vol. 103 (2017)
       
  • Influence of temperature and roughness of surrounding rocks on mechanical
           behavior of rock bolts
    • Authors: Fuhai Li; Hesong Jin; Dinghan Hu; Bo Wang; Yi Jia
      Pages: 55 - 63
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Fuhai Li, Hesong Jin, Dinghan Hu, Bo Wang, Yi Jia
      In order to solve the degradation problem of rock bolts and the safety of a support structure for a high geothermal tunnel in a dry heat environment, various tensile tests of rock bolts were conducted at different temperatures and different levels of roughness of the surrounding rocks in this paper. The roughness of the surrounding rocks was simulated through different types of steel tubes, and dry heat environment was simulated through different temperatures of a drying oven. Based on the first interface (bolt to grout interface) and the second interface (grout to pipe interface) pullout tests, the load-displacement curves of rock bolts were obtained at different temperatures and roughness. The results showed that temperature had little effects on the failure mode, but roughness of the surrounding rock had a great influence on the pullout strength. With an increase in roughness, the tensile strength increased, and the bolting effect was enhanced. For the non-threaded specimens, the interface bond strength of the first interface was larger than that of the second interface, and the second interface showed a kind of shear failure. Finally, it was revealed that the dependence of ultimate tensile force on temperature and roughness of surrounding rocks obeyed a cubic and quadratic polynomial function, respectively.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.011
      Issue No: Vol. 103 (2017)
       
  • Seismic behavior of novel partially connected buckling-restrained steel
           plate shear walls
    • Authors: Mu-Wang Wei; J.Y. Richard Liew; Yong Du; Xue-Yi Fu
      Pages: 64 - 75
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Mu-Wang Wei, J.Y. Richard Liew, Yong Du, Xue-Yi Fu
      A partially connected buckling-restrained steel plate shear wall (SPSW) consisting of an internal steel plate connected to two external reinforced concrete cover plates by bolts, is proposed. Only the four corners of the inner steel plate are connected to the boundary frame elements so that the steel plate can develop tension field action and to reduce potential damage to the surrounding frame elements under cyclic lateral loads. Two one-third scaled specimens were tested to quasi-static cyclic loading to investigate the hysteretic behavior of the proposed new lateral load resisting system. The test results show that the proposed partially connected buckling-restrained SPSW exhibits high initial stiffness, adequate ductility, good energy adsorption capacity, and stable hysteresis loop. Based on the observed failure modes and test results, a theoretical model in which the high-order shear buckling modes of the inner steel plate is developed to predict the shear resistance of the inner panel. The experimental results are compared with the predicted results in order to establish its accuracy in predicting the response behavior of the partially connected buckling-restrained SPSW under lateral loads.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.021
      Issue No: Vol. 103 (2017)
       
  • Seismic response of underwater fluid-conveying concrete pipes reinforced
           with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer
    • Authors: Mohammad Sharif Zarei; Reza Kolahchi; Mohammad Hadi Hajmohammad; Mostafa Maleki
      Pages: 76 - 85
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Mohammad Sharif Zarei, Reza Kolahchi, Mohammad Hadi Hajmohammad, Mostafa Maleki
      This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinforced with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer. The earthquake acceleration is consistent with the earthquake occurred in Tabas. It is assumed that the structure is subjected to external forces which exerted by inner and outer fluids. The force due to the inner fluid is evaluated using Navier-Stokes equation. Also, Mori-Tanaka model is employed to take into account the agglomeration effect of SiO2 nanoparticles. The mathematical model of the structure is developed based on the first order shear deformation theory (FSDT) and the governing equations are derived using energy method and Hamilton's principle. Finally, the problem is solved employing differential quadrature method (DQM) and Newmark method and the effect of different parameters like SiO2 nanoparticles agglomeration and volume percent, inner and outer fluids, various boundary conditions and geometric parameters on the dynamic deflection of the structure is studied. The results indicate that with increasing the thickness to radius ratio and volume fraction of SiO2 nanoparticles and also employing the NFRP layer, the dynamic deflection of the structure decreases while considering the effect of inner and outer fluids and agglomeration of SiO2 nanoparticles and increasing the length to thickness ratio increases the dynamic deflection of the structure.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.009
      Issue No: Vol. 103 (2017)
       
  • Influence of the second-order effect of axial load on lateral dynamic
           response of a pipe pile in saturated soil layer
    • Authors: Xuanming Ding; Lubao Luan; Changjie Zheng; Wei Zhou
      Pages: 86 - 94
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Xuanming Ding, Lubao Luan, Changjie Zheng, Wei Zhou
      This paper presents lateral dynamic response of a pipe pile in saturated soil layer considering the second-order effect of axial loads. The horizontal vibrations of saturated soil layers are simulated by Biot's poroelastic theory. Based on the assumption of perfect contacts between the pipe pile and the saturated soil layers, the dynamic responses of the pipe pile are deduced, which yields the analytical forms of pile displacements, internal forces and complex impedances. Comparison with an existing solution is performed to validate the method proposed in this study. Numerical studies are carried out to clarify the influence of the second-order effect of axial loads and the permeability coefficient on horizontal dynamic responses of the pipe pile.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.007
      Issue No: Vol. 103 (2017)
       
  • Random-effects regression model for shear wave velocity as a function of
           standard penetration test resistance, vertical effective stress, fines
           content, and plasticity index
    • Authors: Mohammad Motalleb Nejad; Kalehiwot Nega Manahiloh; Mohammad Sadegh Momeni
      Pages: 95 - 104
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Mohammad Motalleb Nejad, Kalehiwot Nega Manahiloh, Mohammad Sadegh Momeni
      A random effect regression model is used to formulate a unified equation and estimate shear wave velocity (V s ). Standard penetration test (SPT) number, effective overburden pressure, plasticity index, and the fines content (F c ) are used as input parameters. First, a fixed model regression is used to obtain the regression parameters. SPT number and shear wave velocity are measured at 2m intervals up to a depth of 10m, for 71 boreholes, distributed evenly in Urmia city. Plasticity index and fines content are evaluated from laboratory tests that were performed on 355 samples obtained from the 71 boreholes (i.e., 5 samples from each borehole). Statistical analysis performed on the fixed effect model showed the need for examining the random effects arising from variable SPT test conditions in each borehole. A mixed effect regression model is employed to investigate such effects. The distribution of residuals is found to satisfy the normality criteria for the mixed effect model. A strong fit for the model is obtained, and through statistical evidence, it is implied that the proposed model is practical. The model's most prominent feature is the capability of unifying different soil types via the incorporation of plasticity index and fines content as inputs.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.09.022
      Issue No: Vol. 103 (2017)
       
  • Impedance functions of three-dimensional rectangular foundations embedded
           in multi-layered half-space
    • Authors: Jia Fu; Jianwen Liang; Bin Han
      Pages: 118 - 122
      Abstract: Publication date: December 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 103
      Author(s): Jia Fu, Jianwen Liang, Bin Han
      Although most of the building foundations are approximate to embedded three-dimensional rectangular foundations of different length-to-width ratios, the two-dimensional models or axis-symmetric models which ignore the influence of length-to-width ratios, are usually used for dynamic analysis due to less computational effort on impedance functions. The impedance functions of foundations characterized by different length-to-width ratios and depth-to-width ratios embedded in multi-layered half-space, are obtained by a boundary element method, combined with non-singular Green's functions of high efficiency. Results of high precision based on dense element meshing are presented on complete eight impedance functions (two horizontal, two coupled, two rocking, vertical and torsional impedance functions) for the practical values in the dynamic analysis of the buildings.

      PubDate: 2017-10-12T07:28:31Z
      DOI: 10.1016/j.soildyn.2017.09.024
      Issue No: Vol. 103 (2017)
       
  • Modelling the non-linear site response at the LSST down-hole accelerometer
           array in Lotung
    • Authors: Gaetano Elia; Mohamed Rouainia; Dimitrios Karofyllakis; Yusuf Guzel
      Pages: 1 - 14
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Gaetano Elia, Mohamed Rouainia, Dimitrios Karofyllakis, Yusuf Guzel
      Down-hole array observations are extremely useful to investigate site amplification effects and to validate numerical modelling techniques for site response. In this paper the ground response of the Lotung experiment site (Taiwan), measured along a down-hole accelerometer array during a weak and a strong motion event, is simulated using different numerical techniques of increasing level of complexity: 1) a simple equivalent-linear visco-elastic procedure, 2) a total stress time-domain scheme using a pressure-dependent hyperbolic model and 3) a fully-coupled approach implementing an advanced elasto-plastic soil model. The numerical models are calibrated against resonant column data and in-situ cross-hole measurements. The two horizontal components of the input motion are applied separately at bedrock level. The results of the simple and advanced numerical simulations are compared with the down-hole motions recorded in-situ during the investigated seismic events in terms of acceleration time histories and response spectra. The comparison between in-situ measurements and predicted results highlights the well-known limitations of the frequency-domain technique. It also shows some improved predictive capabilities of the total stress time-domain scheme and demonstrates the excellent performance of the fully-coupled advanced non-linear approach.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.08.007
      Issue No: Vol. 102 (2017)
       
  • Seismic vulnerability of gravity dams in near-fault areas
    • Authors: Yadollah Yazdani; Mohammad Alembagheri
      Pages: 15 - 24
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Yadollah Yazdani, Mohammad Alembagheri
      This research deals with seismic vulnerability assessment of gravity dams located in near-fault areas by proposing a probabilistic seismic demand model for gravity dams considering near-field earthquake ground motions. It is done by conducting a cloud analysis considering two sets of near-field ground motions including 75 pulse-like and 60 non-pulse-like ground motions. By establishing IM-EDP relations, it is attempted to identify optimal IM that is best able to predict the effects of near-field ground motions in terms of optimality criteria of efficiency, sufficiency, proficiency, and practicality. The model is applied to the tallest non-over-flow monolith of the Pine Flat gravity dam which is numerically modeled with its full reservoir using the finite element method. Finally, the seismic vulnerability of the dam is assessed by building its seismic fragility curves separately under the pulse-like and the non-pulse-like earthquakes.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.08.020
      Issue No: Vol. 102 (2017)
       
  • Response of railway track coupled with a stratified ground consisting of
           saturated interlayer to high-speed moving train load
    • Authors: Shi-Jin Feng; Yi-Cheng Li; Zhang-Long Chen; H.X. Chen
      Pages: 25 - 40
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Shi-Jin Feng, Yi-Cheng Li, Zhang-Long Chen, H.X. Chen
      A three-dimensional track-ground model is developed to study vibrations induced by high-speed train. The train loads are simplified as a series of moving point loads. The track system consists of rail, pads, sleeper and ballast. The ground consists of a treated soil layer, a crust, a saturated layer and semi-infinite bedrock, which considers the alternate distribution of viscoelastic and poroviscoelastic media. The ground is coupled with the track system according to the continuity conditions between the ballast and ground surface. Fourier transform is applied to solve the governing equations. Some adaptions are made on the basis of classical stiffness matrix method to give solution to the stratified ground. Semi-analytical solution to the coupling system is derived in the wavenumber domain. Solution in spatial and time domains is obtained with the aid of inverse fast Fourier transform (iFFT). The present method is verified against the published analysis results first. Dynamic responses of the coupling system such as displacement, acceleration and pore-water pressure, are then comprehensively investigated. The results indicate that the existence of ground water significantly influences the surface displacement of the ground while the influence on velocity and acceleration is weaker; ‘critical speeds’ for vertical displacement and acceleration exist for ground but the variations with distance from track center are complicated and depend on soil properties; load speed greatly influences pore-water pressure distribution while the influence of drainage condition is relatively small.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.08.018
      Issue No: Vol. 102 (2017)
       
  • Proposed mechanism for mid-span failure of pile supported river bridges
           during seismic liquefaction
    • Authors: Piyush Mohanty; S.C. Dutta; S. Bhattacharya
      Pages: 41 - 45
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Piyush Mohanty, S.C. Dutta, S. Bhattacharya
      Pile supported river bridge failures are still observed in liquefiable soils after most major earthquakes. One of the recurring observations is the mid span collapse of bridges (due to pier failure) with decks falling into the river while the piers close to the abutment and the abutment itself remain stable. This paper proposes a mechanism of the observed collapse. It has been shown previously through experiments and analytically that the natural period of bridge piers increases as soil liquefies. Due to the natural riverbed profile (i.e. increasingly higher water depth towards the centre of the river), the increase in natural period for the central piers is more as compared to the adjacent ones. Correspondingly, the displacement demand on the central pier also increases as soil progressively liquefies further promoting differential pier-cap displacements. If the pier-cap seating lengths for decks are inadequate, it may cause unseating of the decks leading to collapse. The collapse of Showa Bridge (1964 Niigata earthquake) is considered to demonstrate the mechanism. The study suggests that the bridge foundations need to be stiffened at the middle spans to reduce additional displacement demand.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2017.08.013
      Issue No: Vol. 102 (2017)
       
  • Influence of index properties on shape of cyclic strength curve for
           clay-silt mixtures
    • Authors: Beena Ajmera; Thomas Brandon; Binod Tiwari
      Pages: 46 - 55
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Beena Ajmera, Thomas Brandon, Binod Tiwari
      Failures initiated in clay layers during recent earthquakes have emphasized the need to understand the cyclic behavior of clays. To systematically study the cyclic behavior, seventeen soils, prepared as mixtures of kaolinite and montmorillonite with quartz, and twelve natural soils were tested in a cyclic simple shear device. Cyclic strength curves were developed for 2.5%, 5% and 10% double amplitude shear strains. These curves were used to examine the influence of mineralogical composition, plasticity characteristics and shear strain on the cyclic resistance of the mixtures. A power function was used to represent the cyclic strength curves. Based on the results of this study, the mixtures were found to become increasingly resistant to cyclic loading as the plasticity index increased. Moreover, the soils with montmorillonite as the clay mineral were noted to have consistently higher cyclic resistance than the soils with kaolinite as the clay mineral. By examining the power functions, it was found that the cyclic strength curve became increasing flatter as the plasticity index increases in soils having kaolinite as the clay mineral. However, the opposite trend is observed in soils having montmorillonite as the clay mineral. The results presented in the literature for 37 soils were compared with those obtained in this study and found to be in good agreement.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.022
      Issue No: Vol. 102 (2017)
       
  • Investigation of liquefaction-induced lateral load on pile group behind
           quay wall
    • Authors: Chunhui Liu; Liang Tang; Xianzhang Ling; Lijun Deng; Lei Su; Xiaoyu Zhang
      Pages: 56 - 64
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Chunhui Liu, Liang Tang, Xianzhang Ling, Lijun Deng, Lei Su, Xiaoyu Zhang
      This paper presents the results of a shake-table test on a 2 × 2 pile group behind a quay wall. The main objective is to study the behavior of the pile group under the liquefaction-induced lateral spreading and the liquefied soil pressure exerted on the individual pile in the pile group. The test results are presented and discussed. Significant pile group effect is observed through a comparison of the monotonic bending moments of the individual pile in the pile group. In this regard, a simple finite element model is developed to evaluate the liquefied soil pressure on the individual pile in the pile group, in which, both the uniform and triangular soil pressures are calibrated based on the tested monotonic bending moments of the piles. The liquefied soil pressure on the pile near the quay wall is about twice as much as that on the pile far from the quay wall. Next, the liquefied soil pressure on the individual pile in the pile group is compared to that obtained from the shake-table test on single pile. Further, a parametric study is conducted to investigate the effect of the pile rotational stiffness and the pile diameter on the pile group response. Finally, the concluding remarks are drawn based upon the presented results.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.016
      Issue No: Vol. 102 (2017)
       
  • Empirical correlations between the effective number of cycles and other
           intensity measures of ground motions
    • Authors: Wenqi Du; Gang Wang
      Pages: 65 - 74
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Wenqi Du, Gang Wang
      The effective number of cycles is an important ground motion parameter for the assessment of liquefaction potential. In this paper, empirical correlations for two measures of the effective number of cycles with seven amplitude-, cumulative-, and duration-based intensity measures (IMs) are studied and compared, based on the NGA strong motion database and several ground motion prediction equations. The adopted definitions of the effective number of cycles include an absolute measure (N A ) and a relative measure (N R ). It is shown that N A is highly correlated with high-frequency IMs, such as spectral acceleration (SA) at short periods, Arias intensity, and negatively correlated with signification durations (Ds). On the other hand, N R shows generally negative correlations with both amplitude- and cumulative-based IMs. N R also exhibits small-to-moderate positive correlations with Ds, which are commonly regarded as similar parameters to the effect number of cycles. Simple parametric functions are provided to describe the N A -SA and N R -SA correlations for various cases. The importance of considering multiple IMs rather than SA only in ground-motion selection is also briefly demonstrated.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.014
      Issue No: Vol. 102 (2017)
       
  • ARCS: A one dimensional nonlinear soil model for ground response analysis
    • Authors: S. Yniesta; S.J. Brandenberg; A. Shafiee
      Pages: 75 - 85
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): S. Yniesta, S.J. Brandenberg, A. Shafiee
      This paper presents a one dimensional nonlinear stress-strain model called ARCS (Axis Rotation and Cubic Spline) capable of reproducing any user-input modulus reduction and damping curve. Unlike many previous nonlinear models, the ARCS model does not utilize Masing's rules, nor does it require a specific functional form for the backbone curve such as a hyperbola. Rather, the model matches the desired modulus reduction curve by fitting cubic splines to the implied stress-strain curve, and matches the damping curve by utilizing a coordinate transformation technique in which one axis lies along the secant shear modulus line with the other axis in the orthogonal direction for a particular unload-reload cycle. Damping is easily controlled in the transformed coordinate space. An inverse coordinate transformation returns the desired stress. The integration algorithm is independent of strain step size, meaning that the returned stress for a large strain increment is identical to the stress that would be returned by subdividing the strain increment into smaller increments. Small-strain damping may be modeled hysteretically, avoiding the need for supplemental viscous damping. The model is shown to match the results of laboratory cyclic simple shear tests involving deliberately irregular stain histories. The performance of the model is illustrated in a set of ground response simulations where its predictions are compared with those of existing models. The ARCS model does not explicitly account for rate effects, cyclic degradation, or pore pressure generation. However, the equations can potentially be adapted in more advanced constitutive models to capture these effects. Such implementations are reserved for future publications.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.015
      Issue No: Vol. 102 (2017)
       
  • Dynamic characteristics of expanded polystyrene composite soil under
           traffic loadings considering initial consolidation state
    • Authors: Hongmei Gao; Chunyao Bu; Zhihua Wang; Yanqing Shen; Guoxing Chen
      Pages: 86 - 98
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Hongmei Gao, Chunyao Bu, Zhihua Wang, Yanqing Shen, Guoxing Chen
      As a type of artificial filling material, the shear modulus and damping ratio of expanded polystyrene (EPS) composite soil are two key parameters used to analyze the dynamic stability of an embankment. Nineteen combined axial–torsional tests are conducted on hollow cylinder specimens of EPS composite soil to study its dynamic characteristics under the complex stress path induced by the simulated traffic loadings. The characteristics of skeleton curve, dynamic shear modulus and damping ratio for EPS composite soil are analyzed. It is found that EPS composite soil is characterized by typical dynamic nonlinearity, which is influenced by the mixing ratio and the initial stress state. The increasing cement content can effectively improve the dynamic strength of EPS composite soil. EPS bead content has a slight influence on the initial shear modulus of EPS composite soil as well as the cyclic stress-strain curve in the linear elastic stage. However, the increasing EPS bead content obviously reduces the dynamic strength. The initial shear modulus increases with increasing initial minor principal stress for the isotropic and anisotropic consolidated specimens. The characteristics of modulus attenuation are significantly influenced by the initial minor principal stress, EPS bead content and initial rotation angle of the major principal stress axis. The “structural damping” effect induced by the weak interface formed between EPS beads and cemented soil is an important component of the damping mechanism for the EPS composite soil. Based on the experimental results, this paper provides the empirical models to describe the skeleton curve, modulus attenuation and damping growth characteristics for EPS composite soil.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.012
      Issue No: Vol. 102 (2017)
       
  • Seismic performance of a building affected by moderate liquefaction during
           the Christchurch earthquake
    • Authors: Jonathan D. Bray; Roberto Luque
      Pages: 99 - 111
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Jonathan D. Bray, Roberto Luque
      The seismic performance of an important structure in Christchurch, New Zealand was well-documented during the 2010–2011 Canterbury earthquake sequence. Minor ground deformation and negligible-to-minor structural damage occurred during the primary events of the sequence, except for the 22 February 2011Mw6.2 Christchurch earthquake, which produced differential movement of the basement mat and architectural and structural damage. This case history is evaluated to garner insights. Static settlements are estimated to establish the pre-seismic conditions of the building. Dynamic nonlinear effective stress soil-structure-interaction analysis are performed for the primary events of the Canterbury earthquake sequence using FLAC2D with the PM4Sand constitutive model to capture the cyclic response of the key soil units. The analytical results indicate the post-Canterbury earthquake sequence measured differential mat movements were primarily due to the earthquake events. A thin liquefiable layer, which historic maps indicate is now a buried stream deposit, is largely responsible for the ground movements. A medium dense sandy gravel also appeared to contribute significantly to the observed foundation movements.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.011
      Issue No: Vol. 102 (2017)
       
  • Experimental investigation on the cyclic behaviors of corroded coastal
           bridge piers with transfer of plastic hinge due to non-uniform corrosion
    • Authors: Wei Yuan; Anxin Guo; Hui Li
      Pages: 112 - 123
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Wei Yuan, Anxin Guo, Hui Li
      Coastal bridge piers exposed to marine environments always suffer from non-uniform corrosion along the elevation. Severe degradation in the splash and tidal zone would significantly affect the seismic performance of the structure with a specific phenomenon of the plastic hinge transferring from the column end to the splash and tidal zone. In a companion paper of the authors [1], a theoretical method to identify the time-dependent failure mode and equivalent plastic hinge length of the aging bridge piers under seismic excitation in the whole life cycle was conducted. In this study, cyclic loading tests of six reinforced concrete circular bridge piers with different levels of corrosion are carried out to investigate the seismic performance of such types of structures and validate the proposed method. The test specimens and the experimental setup are first introduced. Based on the measured hysteretic curves, the experimental results of the curvature distributions, hysteretic characteristics, loading-resistance capacity, ductility, energy dissipation, equivalent viscous damping ratio and equivalent plastic hinge length are analyzed and discussed. The test results demonstrate the accuracy of the analysis results for the seismic failure modes presented in the companion paper. It is also indicated that the seismic performance of the non-uniformly corroded columns exhibited a small variation before the transfer of the plastic hinge location, while an obvious reduction was observed for moderately and severely corroded structures.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.019
      Issue No: Vol. 102 (2017)
       
  • Site response analysis of vertical ground motion in consideration of soil
           nonlinearity
    • Authors: Chi-Chin Tsai; Hsing-Wen Liu in
      Pages: 124 - 136
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Chi-Chin Tsai, Hsing-Wen Liu in
      Vertical ground motion significantly affects the seismic response of engineering structures, particularly nuclear power plants and dams. However, most ground motion predictions or site response analyses focus on horizontal ground motion. As a result, knowledge of the characteristics of vertical ground motions is inadequate. In this study, a benchmark approach for equivalent linear vertical site response analyses is developed, with focus on the modeling of soil nonlinearity. The modeled soil exhibits different nonlinear behavior in the vertical direction depending on the saturation condition (i.e., above or below the groundwater table). Moreover, the vertical nonlinearity is different from that observed in the horizontal direction. The vertical ground responses predicted by the proposed approach are generally consistent with downhole measurements associated with different geological conditions, groundwater tables, and shaking intensities.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.024
      Issue No: Vol. 102 (2017)
       
  • Scaling of Fourier Spectra of strong earthquake ground motion in western
           Himalaya and northeastern India
    • Authors: I.D. Gupta; M.D. Trifunac
      Pages: 137 - 159
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): I.D. Gupta, M.D. Trifunac
      It is necessary to develop scaling models of various functionals of ground motions for different seismic regions to obtain region-specific motion characterizations for the design of structures and for seismic hazard studies. Until recently, a paucity of strong-motion data has limited such work in seismic regions in India. In this study, scaling of Fourier spectrum amplitudes is attempted for the western Himalayan and northeast regions of India in terms of magnitude, source-to-station distance, component orientation, and geological and soil site conditions. The scaling model considered is similar to that of Trifunac and co-workers for the California region in the 1980s and 1990s. A database of 1236 recorded accelerograms for both regions of India is used with the assumption that dependence on earthquake magnitude, site geology, site soil and component direction is the same. Separate attenuation models are then developed for the western Himalayan and northeast Indian regions in the period range of 0.03–3.0s. The assumption of identical dependence of Fourier amplitudes on earthquake magnitude in the western Himalaya and northeast India region is found to be consistent with the actual data. These amplitudes grow with magnitude, reaching a maximum for magnitude around 7.0 for periods below 0.1s and for magnitude exceeding 8.0 for longer periods. The Fourier amplitudes are amplified on sediments (with respect to basement rocks) at periods longer than 0.24s, which are also amplified on “stiff soil” (with respect to the “rock” soil sites) at periods longer than 0.2s. Extension of the proposed models to shorter and longer periods is also presented using the available techniques and validated by establishing their consistency with the independent estimates of seismic moment, stress drop, and radiated wave energy in both western Himalaya and northeast India.

      PubDate: 2017-09-09T08:27:09Z
      DOI: 10.1016/j.soildyn.2017.08.010
      Issue No: Vol. 102 (2017)
       
  • Modelling seismic fragility of a rock mountain tunnel based on support
           vector machine
    • Authors: Guang Huang; Wenge Qiu; Junru Zhang
      Pages: 160 - 171
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Guang Huang, Wenge Qiu, Junru Zhang
      In the paper, an analytical method is proposed to develop seismic fragility analysis for rock mountain tunnels. We consider four types of uncertainties in the fragility analysis including different ground motions, tunnel depths, rock mass and lining thickness. By using the uniform design method (UDM), numerical experiment samples are generated. The verified dynamic numerical simulation (DNS) model is carried out to develop probabilistic seismic demand models. To optimize conventional methodology, a prediction technique support vector machine (SVM) is employed. The SVM model could help to reduce calculation resource. It is concluded that (1) the proposed uniform design-dynamic numerical simulation-support vector machine (UDM-DNS-SVM) method could provide accurate estimated fragility curves considering multiple uncertainties; (2) comparisons among the proposed fragility curves, case studies and empirical curves verified feasibility of proposed fragility curves.

      PubDate: 2017-09-14T20:02:54Z
      DOI: 10.1016/j.soildyn.2017.09.002
      Issue No: Vol. 102 (2017)
       
  • 2D dynamic structure-soil-structure interaction for twin buildings in
           layered half-space I: Incident SH-waves
    • Authors: Jianwen Liang; Bing Han; Maria I. Todorovska; Mihailo D. Trifunac
      Pages: 172 - 194
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Jianwen Liang, Bing Han, Maria I. Todorovska, Mihailo D. Trifunac
      Structure-soil-structure interaction (SSSI) is investigated using a model of two shear walls supported by rigid foundations embedded in a soft layer over elastic bedrock. Solution is presented for the model response to incident plane SH-wave based on indirect boundary element method (IBEM). The analysis focuses on the effects of the soil layer. Although the dominant features in the response of flexible structures are those related to the structural resonances, the SSSI effects are not negligible. Further, the SSSI effect are enhanced by the soil layering, and are more pronounced for shallower layer and stiffer bedrock. It is shown that for closely spaced structures, reduction of the peak response occurs, which may reach 30–45%, while, for certain combinations of frequency and separation distance, amplification occurs, which may reach 45–50%, as compared to the stand-alone structure. For inclined wave incidence, the SSSI effects occur for larger separation distances than for vertical incidence. The results may be useful for interpretation of observed response in buildings and seismic response estimation in general.

      PubDate: 2017-09-14T20:02:54Z
      DOI: 10.1016/j.soildyn.2017.08.017
      Issue No: Vol. 102 (2017)
       
  • In situ experimental study on high speed train induced ground vibrations
           with the ballast-less track
    • Authors: Shi-Jin Feng; Xiao-Lei Zhang; Lei Wang; Qi-Teng Zheng; Feng-Lei Du; Zhi-Lu Wang
      Pages: 195 - 214
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Shi-Jin Feng, Xiao-Lei Zhang, Lei Wang, Qi-Teng Zheng, Feng-Lei Du, Zhi-Lu Wang
      Many conveniences and efficiencies have been brought to the passengers with the rapid growth and application of High Speed Train (HST), especially in China. However, the vibrations induced by HST can cause adverse influences on the surrounding environment, which arouses increasing concerns from researchers and governments. In this paper, in-situ HST generated ground vibrations were measured in the embankment, culvert, viaduct and transition sections of Beijing-Shanghai high speed railway (HSR) in China. The acceleration responses of the free field in three directions (x, y, z) were recorded with a train operation speed of around 250–350km/h. The characteristics of the three directional free field responses in time and frequency domains are then be acquired. Moreover, the variations of vibration amplitude and its vibration level with the distance from the track centerline and train speed are investigated, respectively. Ground dynamic impact coefficient (GDIC) and ground remaining dominant frequency (GRDF) are first introduced and defined to identify the ground vibration performances. It is found that the vertical acceleration response is typically the largest in the near field, while in the far field the largest one is the transverse acceleration response. When a culvert or viaduct is included, the longitudinal vibration would be dominant in the near field. Typically, an obvious vibration amplification zone can be observed in the field around 20m due to the wave interference. In all four measurement scenarios, the dominant frequencies of the free field are typically n times the characteristic frequencies, which have a strong relation to the train's geometry dimension and unevenness of the rail. The first dominant frequency of the free field is generally determined by the distance between wheelsets, bogies and the ground fundamental frequency. Some useful recommendations are also provided in this paper and the results are valuable for validating numerical prediction of HST induced vibration and ground-borne vibration mitigation.

      PubDate: 2017-09-20T20:16:04Z
      DOI: 10.1016/j.soildyn.2017.09.001
      Issue No: Vol. 102 (2017)
       
  • 6th Ishihara lecture: Simplified procedure for estimating
           liquefaction-induced building settlement
    • Authors: Jonathan D. Bray; Jorge Macedo
      Pages: 215 - 231
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Jonathan D. Bray, Jorge Macedo
      Significant settlement and damage may occur due to liquefaction of soils beneath shallow-founded buildings. The primary mechanisms of liquefaction-induced building settlement are shear-induced, volumetric-induced, and ejecta-induced ground deformation. Volumetric-induced free-field ground deformation may be estimated with available empirical procedures. Although challenging to estimate, ground failure indices and experience can be used to estimate roughly ejecta-induced building settlement. Nonlinear dynamic soil-structure interaction (SSI) effective stress analyses are required to estimate shear-induced ground deformation. Results from over 1300 analyses identified earthquake, site, and building characteristics that largely control liquefaction-induced building settlement during strong shaking. A simplified procedure is developed based on the results of these analyses to estimate the shear-induced component of liquefaction building settlement. The standardized cumulative absolute velocity and 5%-damped spectral acceleration at 1s period capture the ground shaking. The liquefaction building settlement index, which is based on the shear strain potential of the site, captures in situ ground conditions. Building contact pressure and width capture the building characteristics. Field case histories and centrifuge test results validate the proposed simplified procedure. Recommendations and an example for evaluating building performance at liquefiable sites are shared.

      PubDate: 2017-09-20T20:16:04Z
      DOI: 10.1016/j.soildyn.2017.08.026
      Issue No: Vol. 102 (2017)
       
  • Characterization of the small-strain dynamic behaviour of silty sands;
           contribution of silica non-plastic fines content
    • Authors: Meghdad Payan; Kostas Senetakis; Arman Khoshghalb; Nasser Khalili
      Pages: 232 - 240
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Meghdad Payan, Kostas Senetakis, Arman Khoshghalb, Nasser Khalili
      Dynamic properties of soils at very small strains are of particular interest for geotechnical engineers for the characterization of the behaviour of earth structures subjected to a variety of static and dynamic stress states. This study reports on the small-strain dynamic properties of silty sand with particular emphasis on the effect of non-plastic fines content on the small-strain shear modulus ( G max ) and material damping ( D s , min ). Several clean sands with a wide range of grain size distribution and particle shape are mixed with different percentages of a silica non-plastic silt. The laboratory created samples are subjected to torsional resonant column tests with small-strain shear moduli and damping ratios measured along an isotropic stress path. It is shown that at low percentages of fines content, there is a significant difference between the dynamic properties of the various samples due to the different characteristics of the sand portion of the mixtures. However this variance diminishes as the fines content increases and the soil behaviour becomes mainly silt-dominant, rendering no significant influence of different sand properties on the small-strain shear modulus and damping ratio. Using the experimental results, new expressions for the prediction of small-strain shear modulus and small-strain damping ratio of non-plastic silty sands are developed accounting for the percentage of silt and the characteristics of the sand portion.

      PubDate: 2017-09-27T16:20:50Z
      DOI: 10.1016/j.soildyn.2017.08.008
      Issue No: Vol. 102 (2017)
       
  • Effective soil-stiffness validation: Shaker excitation of an in-situ
           monopile foundation
    • Authors: W.G. Versteijlen; F.W. Renting; P.L.C. van der Valk; J. Bongers; K.N. van Dalen; A.V. Metrikine
      Pages: 241 - 262
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): W.G. Versteijlen, F.W. Renting, P.L.C. van der Valk, J. Bongers, K.N. van Dalen, A.V. Metrikine
      In an attempt to decrease the modelling uncertainty associated with the soil-structure interaction of large-diameter monopile foundations, a hydraulic shaker was used to excite a real-sized, in-situ monopile foundation in stiff, sandy soil in a near-shore wind farm. The response in terms of natural frequency and damping of a pile-only system is significantly more influenced by the soil than a full offshore wind turbine structure, and therefore ensures a higher degree of certainty regarding the assessment of the soil reaction. Steady-state vibration amplitudes with frequencies between 1 and 9Hz were retrieved from strain gauges vertically spaced along the embedded pile, and accelerometers attached to the top of the pile and to the shaker. The measured response is used to validate an effective 1D stiffness method, which is applied as a smart initial guess for a model-based identification of the effective soil-structure interaction properties in terms of stiffness, damping and soil inertia. The performance of the stiffness method is compared to the currently employed p-y stiffness design method. While the effective stiffness method seems to overestimate the actual low-frequency stiffness with about 20%, the p-y method appears to underestimate this stiffness with 140%. The assumption of linear soil behaviour for most of the occurring pile displacements is shown to be acceptable. A damping ratio of 20% (critical) is identified as effective soil damping for the monopile, which is estimated to correspond to a 0.14% damping ratio contribution from the soil for the full structure. The unique measurement setup yielded a ‘first-off’ opportunity to validate a soil-structure interaction model for a rigidly behaving pile. We have shown that indeed such a pile reacts stiffer than predicted by the p-y curve method, and that its response can be modeled more accurately with our recently developed effective stiffness method.

      PubDate: 2017-09-27T16:20:50Z
      DOI: 10.1016/j.soildyn.2017.08.003
      Issue No: Vol. 102 (2017)
       
  • A Discussion of the paper: “Ant colony optimization of tuned mass
           dampers for earthquake oscillations of high-rise structures including
           soil–structure interaction” [Soil Dyn. Earthq. Eng. 51 (2013) 14–22]
           
    • Authors: Ali Reza Rahai; Hossein Saberi; Hassan Saberi
      Pages: 263 - 265
      Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102
      Author(s): Ali Reza Rahai, Hossein Saberi, Hassan Saberi
      This discussion is based on the paper by Farshidianfar and Soheili [1]. In this paper, the authors consider Soil–Structure Interaction effects (SSI) and optimize parameters of Tuned Mass Dampers (TMD) to decrease the earthquake vibrations of tall buildings. They also develop a mathematical model based on the time domain analysis. In this discussion we show that the offered model is not accurate enough and we rectify the model.

      PubDate: 2017-10-05T06:43:05Z
      DOI: 10.1016/j.soildyn.2016.03.011
      Issue No: Vol. 102 (2017)
       
  • Performance-based assessment of protection measures for buried pipes at
           strike-slip fault crossings
    • Authors: Vasileios E. Melissianos; Dimitrios Vamvatsikos; Charis J. Gantes
      Pages: 1 - 11
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Vasileios E. Melissianos, Dimitrios Vamvatsikos, Charis J. Gantes
      Onshore buried steel pipelines are vulnerable to fault rupture, where large ground displacements are imposed on the crossing pipe and thus protection measures are often necessary to avoid failure. A three-step methodology based on the framework of performance-based earthquake engineering is presented on assessing the effectiveness of protection measures against the consequences of strike-slip faulting on pipes. Firstly, the randomness of the fault movement is quantified, next the pipeline mechanical behavior is numerically assessed and finally the results are combined to extract the strain hazard curves, which are easy-to-handle engineering decision making tools. The various protection measures used in engineering practice or proposed in the literature are evaluated through the mean annual rate of exceeding strain values, also including a simple safety checking format at the strain level. Conclusions are extracted from the proposed assessment methodology on the efficiency of measures with reference to engineering practice and safety requirements of the pipeline operator.

      PubDate: 2017-07-24T12:37:51Z
      DOI: 10.1016/j.soildyn.2017.07.004
      Issue No: Vol. 101 (2017)
       
  • Coupled influence of content, gradation and shape characteristics of silts
           on static liquefaction of loose silty sands
    • Authors: Mehmet Murat Monkul; Ehsan Etminan; Aykut Şenol
      Pages: 12 - 26
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Mehmet Murat Monkul, Ehsan Etminan, Aykut Şenol
      Static liquefaction is a challenging problem of geotechnical engineering as its consequences are generally catastrophic when they occur on site. Previous laboratory studies focused on various factors that could influence the static liquefaction potential of silty sands. Most popular of those investigated factors are stress conditions, deposition method and fines content. The purpose of the present study is to investigate the other possible factors, of which very little is known, mainly focusing on the silt characteristics including grain size distribution, relative size, and shape effects of the silt grain matrix within the sand. Undrained monotonic triaxial compression tests were conducted on thirty sands with varying fines contents, which were prepared by mixing three base sands (Sile Sands 20/30, 50/55, 80/100) with same geologic origin but with different gradations and three different non-plastic silts (IZ, SI and TT silts) with different gradations and shape characteristics. The experimental results revealed that each of the mentioned factors had their own influence on static liquefaction behavior of sands. The static liquefaction potential of all the three sands in this study was observed to increase with decreasing coefficient of uniformities of the silt grain matrix (CUsilt) in sands. For a particular base sand, static liquefaction potential was observed to increase with decreasing mean grain diameter ratio (D50-sand/d50-silt) due to change of silt gradation. However, shape characteristics of the silt grains are also found to be another important factor, in certain cases observed to have a greater influence than mean grain diameter ratio criterion. As an example, it was shown that at the same FC, base sand, depositional energy and consolidation stress, angular nature of TT silt potentially caused more meta-stable contacts (weaker grain contacts that promote excess pore pressure generation during shearing) within the specimens than sub-rounded SI silt, which caused specimens with TT silt to be more liquefiable than their counterparts with SI silt. Moreover, it was found that there is a coupled relationship between the fines content and investigated silt characteristics (gradation, mean size, shape effects) on the static liquefaction behavior of sands. The unexpected trend regarding the last finding is that the mentioned influence of silt characteristics (i.e. gradation, size and shape) on static liquefaction of sands becomes more considerable with decreasing fines content at loose states.

      PubDate: 2017-08-02T23:57:33Z
      DOI: 10.1016/j.soildyn.2017.06.023
      Issue No: Vol. 101 (2017)
       
  • Newmark sliding block model for predicting the seismic performance of
           vegetated slopes
    • Authors: T. Liang; J.A. Knappett
      Pages: 27 - 40
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): T. Liang, J.A. Knappett
      This paper presents a simplified procedure for predicting the seismic slip of a vegetated slope. This is important for more precise estimation of the hazard associated with seismic landslip of naturally vegetated slopes, and also as a design tool for determining performance improvement when planting is to be used as a protective measure. The analysis procedure consists of two main components. Firstly, Discontinuity Layout Optimisation (DLO) analysis is used to determine the critical seismic slope failure mechanism and estimate the corresponding yield acceleration of a given slope. In DLO analysis, a modified rigid perfectly plastic (Mohr–Coulomb) model is employed to approximate small permanent deformations which may accrue in non-associative materials when subjected to ground motions with relatively low peak ground acceleration. The contribution of the vegetation to enhancing the yield acceleration is obtained via subtraction of the fallow slope yield acceleration. The second stage of the analysis incorporates the vegetation contribution to the slope's yield acceleration from DLO into modified limit equilibrium equations to further account for the geometric hardening of the slope under increasing soil movement. Thereby, the method can predict the permanent settlement at the crest of the slope via a slip-dependent Newmark sliding block approach. This procedure is validated against a series of centrifuge tests to be highly effective for both fallow and vegetated slopes and is subsequently used to provide further insights into the stabilising mechanisms controlling the seismic behaviour of vegetated slopes.

      PubDate: 2017-08-02T23:57:33Z
      DOI: 10.1016/j.soildyn.2017.07.010
      Issue No: Vol. 101 (2017)
       
  • Framework for the vulnerability assessment of structure under
           mainshock-aftershock sequences
    • Authors: Weiping Wen; Changhai Zhai; Duofa Ji; Shuang Li; Lili Xie
      Pages: 41 - 52
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Weiping Wen, Changhai Zhai, Duofa Ji, Shuang Li, Lili Xie
      Many earthquakes have indicated that the mainshock-damaged structures may be more vulnerable to severe damage and collapse during the subsequent aftershocks. This manuscript presents a framework for the vulnerability assessment of structure under the mainshock-aftershock sequences. In this framework, the engineering demand parameter (EDP) which can more effectively characterized the additional damage of structure induced by aftershock, and the intensity measure (IM) having the higher correlation with the additional damage of structure are selected and used. The versatility of the proposed framework is demonstrated on a case-study reinforced concrete (RC) frame structure with 5 stories. The influences of aftershocks on the fragility of structure are studied for different limit states. The effects of aftershocks on the fragility of structure are more obvious for the case that mainshock fragility changes from 30% to 60%, and the maximum influence of aftershock can exceed 15%. The results in this study can be used to evaluate the vulnerability of structure under the seismic sequence in the pre-earthquake environment.

      PubDate: 2017-08-02T23:57:33Z
      DOI: 10.1016/j.soildyn.2017.07.002
      Issue No: Vol. 101 (2017)
       
  • Response of steel moment and braced frames subjected to near-source
           
    • Authors: Pouria Ayough; Seiyed Ali Haj Seiyed Taghia
      Pages: 53 - 66
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Pouria Ayough, Seiyed Ali Haj Seiyed Taghia
      Most seismic regulations are usually associated with fixed-base structures, assuming that elimination of this phenomenon leads to conservative results and engineers are not obliged to use near-fault earthquakes. This study investigates the effect of soil–structure interaction on the inelastic response of MDOF steel structures by using well known Cone method. In order to achieve this, three dimensional multi-storey steel structures with moment and braced frame are analyzed using non-linear time history method under the action of 40 near-fault records. Seismic response parameters, such as base shear, performance of structures, ductility demand and displacement demand ratios of structures subjected to different frequency-contents of near-fault records including pulse type and high-frequency components are investigated. The results elucidate that the flexibility of soil strongly affects the seismic response of steel frames. soil – structure interaction can increase seismic demands of structures. Also, soil has approximately increasing and mitigating effects on structural responses subjected to the pulse type and high frequency components. A threshold period exists below which can highly change the ductility demand for short period structures subjected to near-fault records.

      PubDate: 2017-08-02T23:57:33Z
      DOI: 10.1016/j.soildyn.2017.07.013
      Issue No: Vol. 101 (2017)
       
  • Optimum earthquake-tuned TMDs: Seismic performance and new design concept
           of balance of split effective modal masses
    • Authors: Jonathan Salvi; Egidio Rizzi
      Pages: 67 - 80
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Jonathan Salvi, Egidio Rizzi
      The present paper, concerning the performance of optimum TMDs in seismic engineering, is composed of two parts. First, Part I deals with a comprehensive investigation on the effectiveness of an optimum seismic-tuned TMD towards reducing the earthquake response of linear frame structures, which is set up by a dedicated optimisation algorithm, allowing to achieve the best control device for a specific structural system and earthquake event. First, a representative set of 16 primary structures and 18 selected earthquakes has been considered, for a total of 288 cases. Second, additional trials based on a benchmark 10-storey frame and on a codified set of far-field earthquakes (FEMA P695 database), composed of 2×22=44 records, have been developed, for a further assessment. The presented outcomes provide extensive information about the TMD performance in the seismic engineering scenario, for a-priori known seismic input. Then, Part II reports a comprehensive post-processing and interpretation analysis of the results above. Specifically, connections between seismic TMD performance and modal structural properties are envisaged. Cross-comparisons, presented here through typical sample cases, analyse the changes of the structural characteristics after TMD insertion and monitor the associated effects on the seismic response reduction. The crucial role of achieving a balanced split of effective modal masses on the tuned mode is investigated, and highlighted as an essential ingredient to rely on a high TMD effectiveness in the seismic context. This criterion may be implemented within the tuning process, as a basic true structure-based concept for TMD design in Earthquake Engineering applications, thus for a-priori unknown seismic input.

      PubDate: 2017-08-02T23:57:33Z
      DOI: 10.1016/j.soildyn.2017.05.029
      Issue No: Vol. 101 (2017)
       
  • On the behavior factor of masonry towers
    • Authors: Massimiliano Bocciarelli
      Pages: 81 - 89
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Massimiliano Bocciarelli
      A recently proposed numerical algorithm, for the pushover analysis of masonry towers, is here adopted for the evaluation of the behavior factor, entering the simplified seismic analysis of masonry towers, suggested in the Italian Directive for the assessment and reduction of the seismic risk of the cultural heritage. In order to consider, within a probabilistic context, the uncertainty of the mechanical and structural parameters involved, Monte Carlo method is adopted. The study indicated that the reduction factor of the seismic forces depends mainly on the acting stress over compressive resistance ratio. It is shown that the actual value proposed in the Italian Directive may be unsafe for high values of this ratio. Finally, an empirical formula based on the different Monte Carlo simulations is calibrated for the prediction of the behavior factor.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.05.027
      Issue No: Vol. 101 (2017)
       
  • Near-fault fling-step ground motions: Characteristics and simulation
    • Authors: Kshitij K. Yadav; Vinay K. Gupta
      Pages: 90 - 104
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Kshitij K. Yadav, Vinay K. Gupta
      The presence of long-period pulses in the near-fault pulse-type ground motions increases the damage potential of such ground motions, particularly for the flexible structures like bridges. It is necessary to carry out nonlinear analyses of structural systems for ensuring their safety in the near-source regions. This study considers the simulation of fling-step motions under the assumption that a fling-step accelerogram can be decomposed into a pulse component and a component without any pulse. Fling-step pulses are extracted from a database of 20 recorded fling-step accelerograms through smoothening via the five-point moving average method and are base-line adjusted for zero velocity and permanent displacement at the end of the pulse time-window. The velocity waveform of these pulses is modelled by a mathematical function characterized by three parameters related to amplitude, duration and location of the pulse. The amplitude and duration parameters are proposed to be estimated for an anticipated motion in terms of the closest distance of site from the fault for a given magnitude and faulting mechanism, while the location parameter is proposed to be taken same as the location of peak ground acceleration in the non-pulse component. It is shown through a numerical study that the proposed method of simulation works well provided the amplitude parameter of the pulse is chosen with care.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.06.022
      Issue No: Vol. 101 (2017)
       
  • Numerical modeling of the interaction of pressurized large diameter gas
           buried pipelines with normal fault ruptures
    • Authors: AG Özcebe; R. Paolucci; S. Mariani
      Pages: 105 - 115
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): AG Özcebe, R. Paolucci, S. Mariani
      There is a growing attention towards the seismic response of large diameter pipelines, owing to the potential adverse impact on economy and civilized life of a structural collapse under earthquake effects, such as strong ground shaking, and other earthquake related effects such as fault rupture, landsliding and liquefaction. The intersection of a fault rupture with a pipeline is of special concern, because the safety verification is affected by significant uncertainties in the loading condition, related to the unknown exact location where the fault offset may occur, the unknown amount of the offset itself, as well as the intersection angle of the fault rupture with the pipe axis. Besides, the inherent analytical/numerical complexity of the problem may require 3D finite element models with non-linear constitutive laws and large deformations. In this paper a summary is presented of a comprehensive set of 3D numerical simulations of the interaction of a large diameter gas pipeline with a normal fault rupture, with the main objectives of: 1) throwing light on the pipeline performance under increasing levels of fault offset, including cross-sectional buckling and ovalization; 2) providing a parametric set of results, including the variability of the fault-pipe intersection angles, of the mechanical properties of the pipe-soil interface, as well as of the operating conditions, in terms of internal gas pressure and temperature variations.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.017
      Issue No: Vol. 101 (2017)
       
  • Rocking spectrum intensity measures for seismic assessment of rocking
           rigid blocks
    • Authors: Ioannis E. Kavvadias; Georgios A. Papachatzakis; Kosmas E. Bantilas; Lazaros K. Vasiliadis; Anaxagoras Elenas
      Pages: 116 - 124
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Ioannis E. Kavvadias, Georgios A. Papachatzakis, Kosmas E. Bantilas, Lazaros K. Vasiliadis, Anaxagoras Elenas
      In this study two novel spectral ground motion intensity measures (IMs) are presented. The proposed IMs are calculated throughout the rocking rotational and the angular velocity spectra which are illustrated as 3D surface graphs, with the slenderness α and the period parameter T, the two horizontal axes. Thus, the IMs are defined as the volume under the spectra, evaluated throughout integration. The proposed IMs are intended to have a strong correlation with the rocking response of free standing blocks. Several rocking rigid blocks subjected to multiple ground motion records are assumed in order to identify the capability of the IMs to predict the rocking response concerning the variability of the block dimensions. The selection of the dimensions was made in order to correspond to slender rocking structures such as electrical equipment, ancient monolithic columns and bridges piers. The evaluation of the IMs was also made by examining characteristics such as efficiency, proficiency and sufficiency. Furthermore, the performance of the proposed IMs are compared with the performance of other well-known ground motion parameters to highlight the adequacy of the former in predicting the rocking seismic response.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.021
      Issue No: Vol. 101 (2017)
       
  • Evaluation of approximate methods for estimating maximum displacement
           response of MDOF systems
    • Authors: Saman Yaghmaei-Sabegh; Shabnam Neekmanesh; Jorge Ruiz-García
      Pages: 125 - 136
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Saman Yaghmaei-Sabegh, Shabnam Neekmanesh, Jorge Ruiz-García
      This study evaluates the accuracy of seven approximate methods to estimate nonlinear maximum roof displacement and the maximum inter-story drift ratio of multi-degree-of-freedom systems. The approximate methods were classified in three groups. The first group includes methods based on equivalent single-degree-of-freedom systems; the second group contains methods based on displacement amplification factors, while the third group includes methods based on equivalent linearization. The accuracy of the approximate methods is evaluated from displacement demands computed by rigorous nonlinear time history (NLTH) analysis of a family of RC frames subjected to sets of far-field and near-field earthquake ground motions. Results obtained from this investigation showed that the average relative error between the estimated maximum roof displacement and that obtained from NLTH analysis was greater than about 31% for the first and second group of methods, while average relative error was less than 25.5% for the third group, for the range of periods of vibration considered in this study. The average relative error of all methods for estimating maximum inter-story drift ratio was in the range of 32–35% for far-field earthquake ground motion records. For near-field earthquake ground motion records, the average relative error of the first and second group was more than about 35%, while it was less than about 30% for the third group. According to the results, the third group of methods provides reasonable estimates of maximum roof displacement and interstory drift demands, which is particularly true for the near-field earthquake ground motion records.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.020
      Issue No: Vol. 101 (2017)
       
  • Equivalent-linear pile head impedance functions using a hybrid method
    • Authors: Hooman Torabi; Mohammad T. Rayhani
      Pages: 137 - 152
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Hooman Torabi, Mohammad T. Rayhani
      Majority of available solutions for determination of pile head dynamic stiffness and damping for use in substructure analysis of soil-pile interaction are based on linear elastic soil behavior and perfect contact at soil-pile interface. This paper presents a hybrid numerical-analytical methodology for equivalent-linear (EL) characterization of pile head impedance functions under inelastic soil-pile interaction. Inelastic continuum modeling, frequency-domain substructure formulation and closed-form derivation of impedance functions, based on Winkler assumption, are ingredients of the proposed approach. Results from three-dimensional (3D) nonlinear finite element (FE) analyses of single piles under dynamic pile head loading are used as input to the derivation algorithm. A new mathematical procedure for polynomial representation of the impedance functions is introduced, which allows for derivation of the EL impedances for “short-type” lateral behavior of an end-bearing pile, especially in the rock-socketed piles. The back-calculated impedances demonstrate variation of the pile head stiffness and damping in frequency domain as the inelasticity increases. They also reveal significant influence of inelastic interface (gap) and soil deformation on reduction of pile head stiffness, in particular radiation damping.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.014
      Issue No: Vol. 101 (2017)
       
  • SH waves in a moon-shaped valley
    • Authors: Thang Le; Vincent W. Lee; Mihailo D. Trifunac
      Pages: 162 - 175
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Thang Le, Vincent W. Lee, Mihailo D. Trifunac
      The analytical solution of a two-dimensional moon-shaped alluvial valley embedded in an elastic half-space is analyzed for incident plane SH waves, using the wave function expansion and the Discrete Cosine Transform (DCT). A series of solutions with different depth-to-radius ratios have been computed, analyzed, and discussed. It is shown that amplification of incident motions along the thinning valley segment can be significant. The phenomena of combined action of the waves resulting from (a) turning (reversing the direction of propagation), (b) focusing, and (c) diffraction from the half space into the valley have been examined with an emphasis on the significance for surface-motion amplification and the power to damage man-made structures.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.06.019
      Issue No: Vol. 101 (2017)
       
  • Seismic response of pile groups supporting long-span cable-stayed bridge
           subjected to multi-support excitations
    • Authors: Fayun Liang; Yajie Jia; Limin Sun; Wen Xie; Haibing Chen
      Pages: 182 - 203
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Fayun Liang, Yajie Jia, Limin Sun, Wen Xie, Haibing Chen
      Long-span cable-stayed bridge is one of the main structures for highways and railways crossing wide rivers. Seismic response of an integral 1:70 scaled model for a long-span cable-stayed bridge was studied with multifunctional shake tables. The bridge model includes synthetic soil, pile groups and long span cable-stayed bridge structure. Seismic responses of pile groups supporting bridge structural systems of different stiffness, namely the floating system, the elastically constrained system and the supporting pier system are studied considering the seismic soil-pile-structure interaction (SSPSI). The accelerations, bending moments and displacements of piles supporting pylons, auxiliary piers and transition piers are discussed. The wave passage effect on pile foundation supporting long-span cable-stayed bridge is studied by tests for the first time. Results showed that compared with the floating system and the elastically constrained system, the bridge girder of long natural period has larger impact on pile foundations in the supporting pier system under uniform excitations. When subjected to non-uniform excitations, different seismic load generates from the superstructure and acts on the substructure. As a result, seismic response of pile foundation supporting long span bridge under non-uniform excitations is different from that under uniform excitations. The wave passage effect has little influence on seismic response of piles in the floating system and the elastically constrained system. However, in the supporting pier system, with shear wave velocity decreased from infinity to 1000m/s, the Fourier amplitudes of pile accelerations, bending moments and relative displacements at 3.50Hz decreased dramatically. The peak bending moments at the head of piles supporting auxiliary piles decreased about 50%.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.019
      Issue No: Vol. 101 (2017)
       
  • Seismic response of clay-pile-raft-superstructure systems subjected to
           far-field ground motions
    • Authors: Lei Zhang; Huabei Liu
      Pages: 209 - 224
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Lei Zhang, Huabei Liu
      A series of three-dimensional (3D) finite element analyses incorporated with a hyperbolic-hysteretic soil model were performed to investigate the seismic response of pile-raft-superstructure systems constructed on soft clay stratum, focusing on the seismic pile bending moment and superstructural responses. The seismic pile bending moment results suggested that using a lumped mass to represent the superstructure, which has been widely used in many other studies, could only perform well for a relatively low-rise superstructure; on the other hand, the seismic response of superstructure was found to be significantly affected by the soil-structure interaction, and both the detrimental and beneficial effects of dynamic soil-structure interaction were observed. Hence, coupled soil-foundation-superstructure analyses were primarily performed in this study. The influences of peak base acceleration, pile flexural rigidity and the configuration of superstructure on both the pile bending moment and superstructural responses were studied. Furthermore, some correlations were derived to relate the maximum pile bending moment to the influencing factors, which can be used as useful tools for obtaining preliminary and first-order estimates of the maximum pile bending moment for pile-raft-superstructure systems constructed on soft clay deposits.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.08.004
      Issue No: Vol. 101 (2017)
       
  • Seismic response of hunchbacked block type gravity quay walls
    • Authors: Z. Tugce Yuksel; Yalcin Yuksel; K. Onder Cetin; Esin Cevik
      Pages: 225 - 233
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Z. Tugce Yuksel, Yalcin Yuksel, K. Onder Cetin, Esin Cevik
      Earthquakes near major cities may cause big social and economic impacts. Damages to port facilities may cripple the economy. The past twenty years’ experience has proven the high vulnerability of the port facilities. This fact, along with the economic importance of port structures, indicates the need for better seismic design approaches for berth structures and cargo handling facilities. In the recent decades, there have been many incidences of failure of gravity type quay walls. These failures have stimulated research interest in the development of performance-based design methods. In this paper, two different hunchbacked block type quay walls with different back face shape were studied. A series of 1-g shaking tank tests was performed using a 1/10 scaled block type quay wall with gravel backfill materials on firm non-liquefiable sea bed conditions subjected to different harmonic loads. The shaking tank tests provided insight into the wall displacements and the total dynamic pressures by analyzing pressure components at the contact surface between the saturated gravel backfill soil and the wall. It is concluded that the back-face shape of the walls is an important factor and the larger positive slope of the wall improves the overall seismic stability.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.08.002
      Issue No: Vol. 101 (2017)
       
  • Single and multi-hazard capacity functions for concrete dams
    • Authors: M.A. Hariri-Ardebili; V.E. Saouma
      Pages: 234 - 249
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): M.A. Hariri-Ardebili, V.E. Saouma
      In the context of performance-based engineering (PBE), it is essential to determine a functional relationship for the response in terms of externally (such as hydraulic or seismic) or internally (such as alkali silica reaction)-imposed stressors. The importance of nonlinear analyses for each of the critical load cases (or stressors) or combinations thereof, as well as the final safety assessment are discussed. This extensive survey paper reviews an extensive body of literature in multiple disciplines. This article aims to present all relevant methods (specially those not tailored for dams) in a more palpable way to dam engineers. Finally as a result of this extensive study new multi hazard capacity functions are introduced.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.009
      Issue No: Vol. 101 (2017)
       
  • Strain accumulation due to packages of cycles with varying amplitude
           and/or average stress – On the bundling of cycles and the loss of the
           cyclic preloading memory
    • Authors: T. Wichtmann; T. Triantafyllidis
      Pages: 250 - 263
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): T. Wichtmann, T. Triantafyllidis
      In order to predict permanent deformations by means of a high-cycle accumulation (HCA) model, a random cyclic loading, i.e. a loading with frequently changing amplitudes, has to be grouped into packages of cycles each with a constant amplitude. Based on a series of drained triaxial tests on fine sand, in which the same cycles have been applied either in an order with frequently changing amplitudes or in packages of cycles, it is demonstrated that such bundling is conservative. Predictions by the HCA model of Niemunis et al. [19] are confronted with experimental data and with other approaches for the prediction of permanent deformations under packages of cycles, among them the frequently cited procedure of Stewart [26]. An effect not captured in the HCA model or in any other approach yet has been detected in another series of tests with a change of the average stress between bundles of cycles: The monotonic loading associated with this change can partially or fully erase the memory of the sand regarding its cyclic preloading history.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.012
      Issue No: Vol. 101 (2017)
       
  • Dynamic behavior of fiber-reinforced soil under freeze-thaw cycles
    • Authors: Muge Elif Orakoglu; Jiankun Liu; Fujun Niu
      Pages: 269 - 284
      Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101
      Author(s): Muge Elif Orakoglu, Jiankun Liu, Fujun Niu
      This research presents the dynamic behavior of fiber-reinforced soil exposed to freeze-thaw cycles. The series of dynamic triaxial tests were conducted on fine-grained soil mixed with different percentages of basalt and glass fibers subjected to freeze-thaw cycles. The results showed that after freeze-thaw cycles, with the addition of basalt and glass fibers, the damping ratio and the shear modulus increased at a constant confining pressure because of the increase of stiffness, but the shear modulus decreased with increasing shear strain. Moreover, the theoretical analytical formulations were developed to define for dynamic shear stress and dynamic shear modulus. The parameters were predicted by Hardin-Drnevich model and Kondner-Zelasko model. The shear modulus was expressed as a function of freeze-thaw cycles, fiber contents, confining pressure and initial water content. Finally, ten coefficients were calibrated by analyzing the experimental results and then employed to describe dynamic shear modulus of the fiber-reinforced soil.

      PubDate: 2017-09-02T14:05:26Z
      DOI: 10.1016/j.soildyn.2017.07.022
      Issue No: Vol. 101 (2017)
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: November 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 102


      PubDate: 2017-10-05T06:43:05Z
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: October 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 101


      PubDate: 2017-09-02T14:05:26Z
       
 
 
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