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EARTH SCIENCES (469 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  [3041 journals]
  • Dynamic reliability analysis of slopes based on the probability density
           evolution method
    • Authors: Yu Huang; Min Xiong
      Pages: 1 - 6
      Abstract: Publication date: March 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 94
      Author(s): Yu Huang, Min Xiong
      Earthquake ground motions display random behavior; therefore, it is necessary to investigate the seismic response of engineering structures using stochastic analysis methods. The probability density evolution method (PDEM) is applied in stochastic seismic response analysis and dynamic reliability evaluation of slope stability. Combining PDEM with finite-element dynamic time-series analysis, this study analyses the stochastic seismic response of a slope under random earthquake ground motion. Comparison between the results of the Monte Carlo stochastic simulation and PDEM analysis demonstrates the effectiveness and high precision of the PDEM method. We assess the stability of the slope under earthquake conditions using the safety factor criterion to obtain the stability probability of the slope. Compared with traditional equilibrium methods, the reliability analysis can directly reflect the failure probability and degree of safety of the slope, demonstrating a novel approach to slope stability assessment using a random dynamic method.

      PubDate: 2017-01-07T00:30:07Z
      DOI: 10.1016/j.soildyn.2016.11.011
      Issue No: Vol. 94 (2017)
       
  • Influences of Biot's compressible parameters on dynamic response of
           vertically loaded multilayered poroelastic soils
    • Authors: Zhi Yong Ai; Li Hua Wang
      Pages: 7 - 12
      Abstract: Publication date: March 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 94
      Author(s): Zhi Yong Ai, Li Hua Wang
      The problem is formulated on the basis of Biot's theory and the analytical layer element method, and the global stiffness matrix for the multilayered soil is established by combining continuity conditions of adjacent layers and boundary conditions based on the analytical layer element for a single poroelastic saturated layer in the Hankel transformed domain. Solutions in frequency domain are obtained by taking the Hankel inverse transform. Selected numerical examples are performed to validate the correctness of the present method and to discuss the influences of compressibility parameters of soil grain and pore fluid as well as the influence of soil stratification on vertical displacement and pore pressure.

      PubDate: 2017-01-07T00:30:07Z
      DOI: 10.1016/j.soildyn.2016.12.010
      Issue No: Vol. 94 (2017)
       
  • Transient dynamic response of a shallow buried lined tunnel in saturated
           soil
    • Authors: Y. Wang; G.Y. Gao; J. Yang; X.Y. Bai
      Pages: 13 - 17
      Abstract: Publication date: March 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 94
      Author(s): Y. Wang, G.Y. Gao, J. Yang, X.Y. Bai
      Previous research has produced valuable results on the transient dynamic response of tunnels buried in full-space. However, a half-space model is of more practical interest because tunnels normally have finite buried depths. In this paper, the dynamic response of a lined tunnel is studied where the surrounding soil is described using Biot's theory and the lining is described by the theory of elastodynamics. The half-space straight boundary is approximately represented by a convex arc of large radius. In accordance with Graff's addition theorem, the general solutions in a rectangular coordinate system are converted to ones in a polar coordinate system. The solutions for displacements and stresses of both the soil and the lining as well as the pore pressure of the soil in the Laplace transform domain are derived based on boundary conditions. Time domain solutions are then obtained by the use of inverse Laplace transform. Numerical results are presented showing the distributions of peak values of ground displacements, stresses and pore pressures of the soil.

      PubDate: 2017-01-07T00:30:07Z
      DOI: 10.1016/j.soildyn.2016.12.011
      Issue No: Vol. 94 (2017)
       
  • A numerical procedure for the pushover analysis of masonry towers
    • Authors: Massimiliano Bocciarelli; Gaia Barbieri
      Pages: 162 - 171
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Massimiliano Bocciarelli, Gaia Barbieri
      In this paper, a numerical approach for the pushover analysis of masonry towers, having hollow arbitrary sections, is proposed. Masonry is considered a nonlinear softening material in compression and brittle in tension. The tower, modeled in the framework of the Euler-Bernoulli beam theory, is subjected to a predefined load distribution, but the problem is formulated as a displacement controlled analysis in order to follow the post peak descending branch of the structural response. Nonlinear geometric effects and nonlinear constraints (the latter due to surrounding buildings) are also considered. Benchmarking pushover analyses are performed with the commercial code Abaqus in relation to a real case (the Gabbia Tower in Mantua), which proved the accuracy and reliability of the results obtained with the present formulation and the noteworthy reduction of computing time.

      PubDate: 2017-01-07T00:30:07Z
      DOI: 10.1016/j.soildyn.2016.07.022
      Issue No: Vol. 93 (2017)
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93


      PubDate: 2017-01-07T00:30:07Z
       
  • Experimental study on effect of fly ash on liquefaction resistance of sand
    • Authors: Mahdi Keramatikerman; Amin Chegenizadeh; Hamid Nikraz
      Pages: 1 - 6
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Mahdi Keramatikerman, Amin Chegenizadeh, Hamid Nikraz
      A series of cyclic triaxial tests were performed to determine the liquefaction resistance of sand stabilised with fly ash (FA). In order to understand the cyclic behaviour of the FA stabilised sand, the effect of relative density (Dr), FA content, confining pressure (CP) and curing time liquefaction resistance were considered. In the first stage of the laboratory tests, specimens of sand mixed with 2% FA under 50 kPa CP and 0.2 CSR with relative density of 20%, 40%, 60%, and 80%, were tested and compared with untreated soil. The results indicated that mixtures of sand-FA in all relative densities have more resistance to liquefaction failure in comparison with untreated soil, and mixture of sand-FA for relative density of 80% has the greatest resistance value. In the second stage, two types of sand-FA mixture (i.e., 4% and 6% FA) with a relative density of 20% under three ranges of confining pressure, namely 50, 70 and 90 kPa, were tested. The results in this stage suggested that the addition of 6% FA to the sand led to an increase in the cyclic response of the soil to the liquefaction in comparison with the specimens of sand mixed with 4% FA in all tested confining pressures. In the last part of the study, variation of the CSR with the number of cycles to liquefaction for a mixture of sand and 2% FA with 20% relative density under 50, 70 and 90 kPa confining pressure were presented and results indicated that the specimens under greater CP liquefied at earlier cycle numbers and vice versa. In continuing to investigate the effect of curing time, the specimens containing 2% FA were cured for 14 and 28 days and tested under 50 kPa CP and 20% relative density. The result showed that an increase in curing time led to an increase in the liquefaction strength of the sand containing FA.

      PubDate: 2016-12-05T10:20:58Z
      DOI: 10.1016/j.soildyn.2016.11.012
      Issue No: Vol. 93 (2016)
       
  • Stress-strain behavior of soil-rock mixture at medium strain rates –
           Response to seismic dynamic loading
    • Authors: Y. Wang; X. Li; B. Zheng
      Pages: 7 - 17
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Y. Wang, X. Li, B. Zheng
      This paper aims to investigate the seismic dynamic responses of soil-rock mixtures (SRM) at medium loading strain rates. A total of 130 SRM specimens with four rock block percentage (RBP) of 20%, 30%, 40% and 50% were produced to conduct the uniaxial compressive strength test, at strain rates of 1×10−5 s−1, 5×10−4 s−1, 1×10−3 s−1, 5×10−3 s−1, and 1×10−2 s−1. From the experimental results, SRM presents particular rate-dependence characteristics that are different from each soil and rock material, the peak stress and peak strain first increase and then decrease with the increase of strain rate. The inflection points of rate-dependence are different for specimens with different RBP. The rate-dependence characteristic of SRM is strongly influenced by the rock blocks in the SRM specimen. In addition, crack initiation stress level σci/σf and crack damage stress level σcd/σf do not change with the increases of strain rate. What is more, the experimental results also show that the failure pattern of SRM performs as a spitting failure, shear failure, and conical failure at various strain rates. All the test results proved the particular seismic dynamic responses of SRM, and the interactions between the rock blocks and the soil matrix are the primary factor determining the dynamic response.

      PubDate: 2016-12-11T10:40:39Z
      DOI: 10.1016/j.soildyn.2016.10.020
      Issue No: Vol. 93 (2016)
       
  • Uncertainty quantification for seismic responses of bilinear SDOF systems:
           A semi-closed-form estimation
    • Authors: Peng Deng; Shiling Pei; John W. van de Lindt; Chao Zhang
      Pages: 18 - 28
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Peng Deng, Shiling Pei, John W. van de Lindt, Chao Zhang
      The ability to accurately quantify uncertainty in structural system seismic responses is a critical component of performance based earthquake engineering (PBEE). Currently, for nonlinear systems, this is achieved empirically using a large number of simulations with different excitation inputs (ground motion suites) and numerically randomized structural model samples. This study focused on one of the simplest nonlinear hysteretic systems, the bilinear single-degree-of-freedom (SDOF) oscillator, to develop a semi-closed-form solution for seismic response uncertainty as a function of 1) intensity-independent ground motion characteristics, 2) structural parameters, and 3) ground motion intensity level. This approach included the development of a parametric model for bilinear system IDA curves with intensity independent ground motion parameters and structural parameters. The accuracy of the proposed model was validated through nonlinear time history analysis (NLTHA) simulations.

      PubDate: 2016-12-11T10:40:39Z
      DOI: 10.1016/j.soildyn.2016.11.016
      Issue No: Vol. 93 (2016)
       
  • Extending the concept of energy-based pushover analysis to assess seismic
           demands of asymmetric-plan buildings
    • Authors: S. Soleimani; A. Aziminejad; A.S. Moghadam
      Pages: 29 - 41
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): S. Soleimani, A. Aziminejad, A.S. Moghadam
      The energy-based pushover analysis was developed in previous studies to address the issues regarding the distortion of capacity curve in conventional pushover procedures. Despite the conceptual superiority of an energy-based approach, its application is currently restricted to 2D structures. This study aims to extend the concept of this approach to asymmetric-plan buildings and bidirectional seismic excitation. For this purpose, a new energy-based multimode pushover analysis is developed. The overall procedure is quite similar to the well-known Modal Pushover Analysis (MPA). In contrast, however, the work done by lateral loads and torques here is used in preference to displacement of the roof center as an index to establish capacity curves. The efficiency of the proposed procedure is evaluated through seismic assessment of a set of one-way asymmetric (asymmetric around one axis) RC shear wall buildings. The results are compared with those of the MPA, ASCE41-13 pushover procedure, and the nonlinear response history analysis as a benchmark solution. Findings show that the proposed procedure can provide more accurate results than the MPA and ASCE41-13 procedures, in estimating the structural demands such as wall-hinge rotations and drift ratios.

      PubDate: 2016-12-11T10:40:39Z
      DOI: 10.1016/j.soildyn.2016.11.014
      Issue No: Vol. 93 (2016)
       
  • An extended modal pushover procedure for estimating the in-plane seismic
           responses of latticed arches
    • Authors: Yang Xiang; Yong-feng Luo; Zu-yan Shen
      Pages: 42 - 60
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Yang Xiang, Yong-feng Luo, Zu-yan Shen
      The vertical displacements induced by the in-plane vibrating modes of an arch formed structure are as important as the lateral ones. Therefore, the vertical response components should be considered in the modal pushover load patterns for the in-plane seismic performance evaluation of latticed arches. Since the equivalent force of the modal equivalent single-degree-of-freedom (ESDF) system is determined by the base shear in conventional modal pushover procedures, which could not reflect the vertical part of the pushover load, an extended modal pushover analysis (MPA) procedure is proposed in this paper. In the extended MPA, the modal ESDF system of the in-plane vibrating mode of a latticed arch is established by the aid of an energy-based structural stiffness parameter, and the equivalent load of theESDF system is obtained according to the static pushover load factor, instead of using the base shear or other kinds of support reactions. The extended MPA approach not only takes the vertical components of the pushover load patterns into consideration, but also maintains the conceptual understandability and simplicity exhibited by conventional MPA procedures. Numerical examples carried out on two latticed arches demonstrate that the proposed extended MPA is more accurate than the conventional MPA, because in the former, the displacement coupling between horizontal and vertical directions are reflected when the arches are excited by in-plane earthquake actions.
      Graphical abstract image

      PubDate: 2016-12-11T10:40:39Z
      DOI: 10.1016/j.soildyn.2016.12.005
      Issue No: Vol. 93 (2016)
       
  • Analysis of buried pipelines subjected to reverse fault motion using the
           vector form intrinsic finite element method
    • Authors: Leige Xu; Mian Lin
      Pages: 61 - 83
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Leige Xu, Mian Lin
      Buried pipelines crossing reverse faults is a common case in practice, while their mechanical responses are not very clear. To analyze buried pipelines subjected to reverse faults, a beam-shell coupling scheme is proposed based on the Vector Form Intrinsic Finite Element (VFIFE or V-5) method. Particular emphasis is given to identifying pipeline failure with three performance based limit states: the local buckling, the tensile strain limit and the flattening parameter limit. The critical fault displacements, at which the specified performance criteria are reached, are presented in diagram form. Effects of fault displacement, crossing angle, as well as fault dip angle on critical fault displacements are examined. This study shows that when the fault dip angle is 40°, the critical fault displacements of local buckling and pipe-wall rupture are the largest when a pipeline is oriented approximately parallel to a reverse fault plane. And for a perpendicularly crossing pipeline, the smaller the dip angle is, the more severe the cross-section distortion will be. Moreover, the critical strain of local buckling are obtained and compared with the recommendation of CSA Z662.

      PubDate: 2016-12-11T10:40:39Z
      DOI: 10.1016/j.soildyn.2016.12.004
      Issue No: Vol. 93 (2016)
       
  • Vulnerability assessment of reinforced concrete buildings at precarious
           slopes subjected to combined ground shaking and earthquake induced
           landslide
    • Authors: S.D. Fotopoulou; K.D. Pitilakis
      Pages: 84 - 98
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): S.D. Fotopoulou, K.D. Pitilakis
      At present, the seismic vulnerability of reinforced concrete (RC) buildings standing in the vicinity of the slope's crest is assessed ignoring, in most cases, the effect of topography and the potential slope instability. This study aspires to investigate these effects by proposing a methodological framework for assessing the vulnerability of typical RC buildings subjected to combined ground shaking and earthquake induced landslide hazards. The method is based on a two-step numerical analysis procedure. First, the acceleration time histories and the permanent differential ground displacement time histories are evaluated employing dynamic non-linear analysis. Then, a series of nonlinear dynamic and static time history analyses are performed for a reference low rise, code-conforming RC frame building located at varying distances from the slope's crest to compute the fragility curves for the two loading conditions i.e. ground shaking considering topographic amplification and seismic permanent landslide displacements. The derived fragility curves, described as a function of peak ground acceleration (PGA) at the rock outcrop, are compared to provide insight into the primary damage mechanism while, in the end, coupled fragility curves are generated to account for the combined potential damages due to ground shaking and seismically induced landslide considering or not the interaction between the two hazards. The proposed coupled fragility curves could be used within a probabilistic risk assessment framework to evaluate the structural vulnerability of specific RC building typologies at precarious slopes due to ground shaking and seismically induced slope displacements.

      PubDate: 2016-12-19T23:24:39Z
      DOI: 10.1016/j.soildyn.2016.12.007
      Issue No: Vol. 93 (2016)
       
  • Numerical study on the active vibration isolation by wave impeding block
           in saturated soils under vertical loading
    • Authors: Guangyun Gao; Juan Chen; Xiaoqiang Gu; Jian Song; Shaoyi Li; Ning Li
      Pages: 99 - 112
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Guangyun Gao, Juan Chen, Xiaoqiang Gu, Jian Song, Shaoyi Li, Ning Li
      Dynamic response in a saturated porous medium (i.e. two-phased medium) is significantly different from the commonly assumed single-phased elastic medium in vibration analyses. To investigate the ground vibration isolation by wave impeding block (WIB) in saturated layered soils under vertical loading, an improved three-dimensional (3D) boundary element model is established for analyzing the soil-foundation-WIB interaction problem. The equations of boundary element method (BEM) for saturated and layered soils were deduced using fundamental solution (Green's function) based on thin layer method (TLM), in order to account for the lamination characteristics of the ground. The vibration screening effectiveness of WIB with different thicknesses, equivalent diameters, shear module and embedded depths were systematically investigated and the results were compared with those in a single-phased elastic soil. The results show that the WIB can effectively reduce the vibration amplitude in the saturated ground and its effectiveness increases with increasing shear modulus, equivalent diameter, thickness, and decreasing embedded depth of the WIB. In addition, a significant amplification of the vibration is observed in the saturated soil when the dimensionless embedded depth is larger than or the dimensionless thickness is smaller than a threshold value.

      PubDate: 2016-12-19T23:24:39Z
      DOI: 10.1016/j.soildyn.2016.12.006
      Issue No: Vol. 93 (2016)
       
  • Site response in a representative region of Manzanillo, Colima, Mexico,
           and a comparison between spectra from real records and spectra from
           normative
    • Authors: Reyes Tonatiuh Dominguez; Héctor E. Rodríguez-Lozoya; Mario Cabrera Sandoval; Eva Sanchez Sanchez; Armando Aguilar Meléndez; Héctor E. Rodríguez- Leyva; R. Amelia Campos
      Pages: 113 - 120
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Reyes Tonatiuh Dominguez, Héctor E. Rodríguez-Lozoya, Mario Cabrera Sandoval, Eva Sanchez Sanchez, Armando Aguilar Meléndez, Héctor E. Rodríguez- Leyva, R. Amelia Campos
      The October 1995 Mw=8.0 Colima-Jalisco earthquake triggered damage in buildings located in Manzanillo city (Tena, A, 1997) [1]. Great damages were reported in different regions of that city. It was also observed liquefaction in the Manzanillo port. In order to improve the knowledge of the subsoil of Manzanillo, Rayleigh waves were inverted applying spatial autocorrelation (SPAC) to array measurements of microtremors at five representative sites of the city. This procedure allowed us to obtain a shallow S-wave velocity profile at each site. We compute the transfer function for each profile and correlate the results with geology. We calculate theoretical surface records. For this purpose, we used a numerical simulation of wave propagation of an input signal (Green function) through the structure. In this case, records of two great subduction earthquakes were used as Green functions. We use these surface signals to estimate response spectra for each site. On the other hand, design spectra according to the manual of seismic design of the Federal Commission of Electricity 2008 edition (MOC-CFE) [2] were obtained and compared with previous results. We observed important differences between the seismic responses in different regions of Manzanillo. For instance, the response at site 5 (alluvial deposits) for a period of 0.25s is twice the response of site 4 (sand deposits) for the same period. Therefore, the site effects are relevant in Manzanillo. For the majority of the cases we observe a reasonable agreement between the values of the dominant periods computed according to the MOC-CFE [2] normative and those obtained directly from Transfer Function (TF). On the other hand, we found significant differences between design spectra and response spectra obtained from seismic records for the 0.1–0.6s interval. Amplitudes are underestimated for the first ones.

      PubDate: 2016-12-19T23:24:39Z
      DOI: 10.1016/j.soildyn.2016.11.013
      Issue No: Vol. 93 (2016)
       
  • An approach for synthesizing tri-component ground motions compatible with
           hazard-consistent target spectrum - Italian aseismic code application
    • Authors: S. Trovato; E. D'Amore; Q. Yue; P.D. Spanos
      Pages: 121 - 134
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): S. Trovato, E. D'Amore, Q. Yue, P.D. Spanos
      A versatile approach for synthesizing non-stationary multicomponent ground motions compatible with a given target response spectrum is presented. In conjunction with performance-based structural design, the proposed approach combines a scenario-based procedure to select the target spectra of the three components of the motion, and a stochastic scheme, with an iterative wavelet-based method to generate the artificial time histories. In this context, the selection of an appropriate target spectrum is mandatory to synthesizing accelerograms with proper frequency content, input-energy, effective duration, and inelastic demand. In the scenario-based assessments, the target spectrum is derived directly from an earthquake scenario defined by seismic hazard disaggregation and strong ground-motion attenuation relationships. Firstly, the design spectrum specified by aseismic code provisions is replaced by a set of conditional mean spectra (CMS) for each of the ground motion components. Subsequently, an inverse stochastic dynamics problem, defined by a set of parametric evolutionary power spectra (EPS), is formulated and solved in a point-wise format for each CMS and for the three components of the motion. To improve the matching between the response spectrum of the simulated records and the CMS, an iterative procedure involving the family of harmonic wavelets is then employed. Post-processing for a proper baseline correction of the records is performed to synthesize ground-motions yielding realistic velocity and displacement traces. To illustrate the effectiveness of the approach, extensive numerical results pertaining to the Italian aseismic code provisions are included in this paper. In this regard, Monte Carlo simulations are undertaken to relate the CMSs to the evolutionary power spectrum. In particular, non-constant peak factor expressions via regression analysis are derived for various ground-motion durations. Finally, the nonlinear responses of elasto-plastic SDOF oscillators with different values of the yield strength reduction factor are considered. The oscillators subjected to artificially generated records and a set of natural unscaled and spectrum-compatible accelerograms, are examined in terms of ductility demand and equivalent number of yield cycles.

      PubDate: 2016-12-19T23:24:39Z
      DOI: 10.1016/j.soildyn.2016.12.003
      Issue No: Vol. 93 (2016)
       
  • Seismic failure mode of coastal bridge piers considering the effects of
           corrosion-induced damage
    • Authors: Wei Yuan; Anxin Guo; Hui Li
      Pages: 135 - 146
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): Wei Yuan, Anxin Guo, Hui Li
      Coastal bridges exposed to an aggressive environment are vulnerable to corrosion damage, which reduces the seismic resisting capacity of the structures. Focusing on the corrosion varying along the column height of the coastal bridge piers, this paper investigates the time-dependent failure mode and equivalent plastic hinge length of the aging bridge piers under seismic excitation in the whole life cycle. First, the possible seismic failure modes and the method to estimate the equivalent plastic hinge length are analyzed and discussed. Then, the corrosion initiation time and performance deterioration of the reinforcement are presented. After that, the finite element models of the sound and aging bridge piers are introduced based on the OpenSees software package and the time-dependent constitutive models of the reinforcement. According to the proposed flowchart of the computational procedure, a numerical simulation is conducted to investigate the plastic hinge evolution process of the coastal bridge pier. The analysis results indicate that the seismic failure mode of the continuously corroded bridge pier varies with the service time, and the plastic hinge has the possibility of transferring from the column end to the bottom of the splash and tidal zone.
      Graphical abstract image

      PubDate: 2016-12-19T23:24:39Z
      DOI: 10.1016/j.soildyn.2016.12.002
      Issue No: Vol. 93 (2016)
       
  • Scoping assessment of building vibration induced by railway traffic
    • Authors: D. López-Mendoza; A. Romero; D.P. Connolly; P. Galvín
      Pages: 147 - 161
      Abstract: Publication date: February 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 93
      Author(s): D. López-Mendoza, A. Romero, D.P. Connolly, P. Galvín
      This work presents a scoping model to predict ground-borne railway vibration levels within buildings considering soil-structure interaction (SSI). It can predict the response of arbitrarily complex buildings in a fraction of the time typically required to analyse a complex SSI problem, and thus provides a practical tool to rapidly analyse the vibration response of numerous structures near railway lines. The tool is designed for use in cases where the ground-borne vibration is known, and thus can be used as model input. Therefore in practice, for the case of a new line, the ground motion can be computed numerically, or alternatively, for the case of new buildings to be constructed near an existing line, it can be recorded directly (e.g. using accelerometers) and used as model input. To achieve these large reductions in computational time, the model discretises the ground-borne vibration in the free field into a frequency range corresponding to the modes that characterize the dynamic building response. After the ground-borne response spectra that corresponds with the incident wave field is estimated, structural vibration levels are computed using modal superposition, thus avoiding intensive soil-structure interaction computations. The model is validated using a SSI problem and by comparing results against a more complex finite element-boundary element model. Finally, the new scoping model is then used to analyse the effect of soil properties, building height, train speed and distance between the building and the track on structural-borne vibration. The results show that the scoping model provides a powerful tool for use during the early design stages of a railway system when a large number of structures require analysis.

      PubDate: 2016-12-26T23:49:27Z
      DOI: 10.1016/j.soildyn.2016.12.008
      Issue No: Vol. 93 (2016)
       
  • Harmonic response of layered halfspace using reduced finite element model
           with perfectly-matched layer boundaries
    • Authors: Simon Jones
      Pages: 1 - 8
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Simon Jones
      The current paper investigates the use of perfectly-matched layers (PML) as absorbing elements for a finite element (FE) model simulating a semi-infinite medium. Due to the formulation of the FE-PML model, it is also possible to use a Craig-Bampton reduction to significantly reduce the number of degrees-of-freedom in the model, in an attempt to improve the computational efficiency of the simulation. The perfectly-matched layers use a complex-valued function to numerically stretch the apparent size of PML elements while allowing them to remain nominally small. The results from this investigation suggest the PML elements worked seamlessly with the FE elements to approximate the elastodynamic response of a 3D halfspace subjected to a surface load; the wave energy is completely absorbed by the PMLs regardless of incident angle or wavelength. Furthermore, the size of the model was reduced by approximately 32% using a Craig-Bampton reduction (CBR). The CBR transforms the system into a mixed set of coordinates, including both modal and spatial coordinates. The model reduction is accomplished by neglecting modal frequencies for the system above two and a half times the maximum forcing frequency of interest. By only transforming the frequency-independent FE section into modal coordinates, and leaving the frequency-dependent PML elements as spatial degrees-of-freedom, the mode-shapes must only be solved once and can then be reused for different forcing frequencies. The results from this investigation suggest this could provide computational benefits if a number of cases are being computed for different frequencies.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.08.023
      Issue No: Vol. 92 (2016)
       
  • Studying the uncertainties in the seismic risk assessment at urban scale
           applying the Capacity Spectrum Method: The case of Thessaloniki
    • Authors: Evi Riga; Anna Karatzetzou; Aikaterini Mara; Kyriazis Pitilakis
      Pages: 9 - 24
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Evi Riga, Anna Karatzetzou, Aikaterini Mara, Kyriazis Pitilakis
      Seismic risk assessment and loss estimation are of major importance for decision-making with respect to the reduction of earthquake-induced losses in large urban areas. However, the methodological chain of seismic risk assessment, from seismic hazard assessment to evaluation of potential losses, encompasses numerous uncertainties, both aleatory and epistemic, associated with different sources. The present study is a comprehensive application of the Capacity Spectrum Method to the seismic risk assessment of the city of Thessaloniki, aiming to give an insight into epistemic uncertainties involved in the above methodology, owing to hazard modelling, structural capacity, fragility and damping, as well as shaking duration. To quantify and discuss the uncertainties, a logic tree approach is used. A sensitivity analysis of the computed seismic risk results is performed to determine the input parameters having the greatest impact. The analyses were carried out for the building stock of the city of Thessaloniki, Greece, for which detailed building inventory and very good knowledge of the soil conditions are available. Only physical losses due to the structural damage of the building stock were considered. Considerable scatter in the risk estimates was observed due to epistemic uncertainties. The sensitivity analyses demonstrated that the most influencing parameters when applying the Capacity Spectrum Method are the selection of the fragility curves for the buildings and the seismic hazard model adopted in the analysis. The decision-making process with respect to seismic risk assessment should therefore carefully account for uncertainties and pay attention to the most influencing parameters regardless of the methodology used.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.043
      Issue No: Vol. 92 (2016)
       
  • Efficient model updating of a multi-story frame and its foundation
           stiffness from earthquake records using a timoshenko beam model
    • Authors: E. Taciroglu; S.F. Ghahari; F. Abazarsa
      Pages: 25 - 35
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): E. Taciroglu, S.F. Ghahari, F. Abazarsa
      We present a new approach to estimate the dynamic stiffnesses of soil-foundation systems using earthquake-induced response signals recorded on multi-story buildings with sparsely instrumentation. Identification of soil-foundation dynamic stiffness parameters from real-life data, especially earthquake-induced response signals, is arguably one of the most challenging problems in structural/geotechnical earthquake engineering. This is because the said parameters are frequency-dependent, and the non-stationary input excitation is not measurable due to soil-structure interaction effects. It is possible to identify these parameters using recently developed blind source separation techniques, provided that a finite element model of the superstructure is available. However, developing and updating a finite element model is usually a laborious undertaking, and its success strongly depends on the spatial density of measurements. In the present study, we offer a new method that is based on the use of a Timoshenko beam model to represent the superstructure. In this method, key parameters of the Timoshenko beam model – and those of its soil-foundation system – are adjusted through a systematic procedure, until the systems’ overall (flexible-based) modal properties match those identified from real-life data. The proposed method is robust against sensor sparseness, and yields accurate results even if the foundation rocking is not measured. The proposed procedure is first verified using a synthetic problem, and subsequently applied to real-life data recorded at the Millikan Library building, which is located at the Caltech campus in Pasadena, California.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.041
      Issue No: Vol. 92 (2016)
       
  • A design spectrum model for flexible soil sites in regions of
           low-to-moderate seismicity
    • Authors: H.H. Tsang; J.L. Wilson; N.T.K. Lam; R.K.L. Su
      Pages: 36 - 45
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): H.H. Tsang, J.L. Wilson, N.T.K. Lam, R.K.L. Su
      Design spectrum (DS) models in major codes of practice for structural design of buildings typically stipulate empirical site factors for each of the five, or six, site classes. Although the phenomenon of resonant like amplification behaviour of the structure caused by multiple wave reflections is well known, the potentials for such periodic amplification behaviour are not explicitly considered in code models. This is partly because of expert opinion that such effects are very “localised” in the frequency domain and can be suppressed readily by damping. However, investigations into the risk of collapse of non-ductile, and irregular structural systems, common in regions of low-to-moderate seismicity, revealed the extensive influence of periodic base excitations on flexible soil sites (with initial small-strain natural period T i >0.5s). In this paper, an alternative DS model which addresses the important phenomenon of soil resonance without the need of computational site response analysis of the subsurface model of the site is introduced.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.035
      Issue No: Vol. 92 (2016)
       
  • An experimental study of high strain-rate properties of clay under high
           consolidation stress
    • Authors: Renshu Yang; Jun Chen; Liyun Yang; Shizheng Fang; Ju Liu
      Pages: 46 - 51
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Renshu Yang, Jun Chen, Liyun Yang, Shizheng Fang, Ju Liu
      A split Hopkinson pressure bar (SHPB) combined with high pressure consolidation apparatus and high speed camera was used to obtain dynamic compressive stress-strain curves of clay whose over consolidation stress state in the process of formation was properly considered. The stress-strain relationship at various high strain rates from 60s−1 to 600s−1 was obtained. The strain rate and degree of consolidation effects on the compressive response of the consolidated clay were determined. The results show that the dynamic mechanical properties of clay in high pressure consolidation is sensitive to strain rate, and parameters like dynamic strength, failure strain and so on are significantly improved compared with unconsolidated clay which indicate that the initial stress history of the soil materials is also one of the most important factors that affect the dynamic mechanical response.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.036
      Issue No: Vol. 92 (2016)
       
  • Soil-structure interaction effects in single bridge piers founded on
           inclined pile groups
    • Authors: Sandro Carbonari; Michele Morici; Francesca Dezi; Fabrizio Gara; Graziano Leoni
      Pages: 52 - 67
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Sandro Carbonari, Michele Morici, Francesca Dezi, Fabrizio Gara, Graziano Leoni
      This paper investigates the seismic response of bridge piers founded on inclined pile groups in different soil deposits, evaluating effects of soil-structure interaction induced by different pile group geometries and piles inclinations. Analyses are performed in the frequency domain by means of the direct approach taking advantage of a numerical model developed by the authors for the analysis of inclined pile groups. Both the superstructure and piles are modelled with beam elements and the soil is schematized as a visco-elastic medium constituted by independent infinite horizontal layers. The soil-pile and the pile-soil-pile interaction are captured in the frequency domain by means of elastodynamic Green's functions that also allow including the hysteretic and radiation damping. The significance of kinematic stress resultants in piles, the foundation filtering effect and the rotational component of the input motion due to the coupled roto-translational behaviour of the soil-foundation system are also investigated; to this purpose kinematic interaction analyses are performed. These analyses revealed essential for the understanding of the general phenomena governing the dynamic response of the whole soil-foundation-superstructure systems. Results of numerical investigations highlight that conventional design approaches suggested by codes do not provide reliable predictions of the superstructure displacements and stress resultants.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.10.005
      Issue No: Vol. 92 (2016)
       
  • Flow deformation and cyclic resistance of saturated loose sand considering
           initial static shear effect
    • Authors: Z.X. Yang; K. Pan
      Pages: 68 - 78
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Z.X. Yang, K. Pan
      In practical engineering, a driving stress often exists and acts on the soil elements, and this stress may have a significant effect on the deformational characteristics and liquefaction resistance of sand when the sand is subjected to seismic loadings. This paper presents a systematic experimental investigation into the undrained cyclic behavior of saturated loose sand with the static shear under both triaxial compression and extension conditions. Various combinations of the magnitude of static stresses and cyclic stresses were considered in the triaxial tests. The results indicate that different static shear stress conditions lead to two distinct failure modes, namely, flow liquefaction and residual deformation failure. The required number of loading cycles for the onset of flow deformation and failure are both related to two stress parameters, i.e., cyclic stress ratio (CSR) and static stress ratio (SSR). In viewing the failure envelope established against the two stress variables CSR and SSR, a critical SSR that identifies the role of the presence of initial static shear stress is obtained: when SSR is less than that critical value, the resistance may increase, whereas the resistance may decrease as SSR becomes larger. In addition, the triggering conditions of flow deformation under cyclic loading can be interpreted with the instability response of sand under monotonic loading. Combined with the observation on the cyclic deviatoric strains developed during and after the flow deformation, a unified interpretation is made to quantify the effects of both the SSR and CSR on the cyclic resistance of loose sand.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.002
      Issue No: Vol. 92 (2016)
       
  • Evaluation of power substation equipment seismic vulnerability by
           multivariate fragility analysis: A case study on a 420kV circuit breaker
    • Authors: Seyed Alireza Zareei; Mahmood Hosseini; Mohsen Ghafory-Ashtiany
      Pages: 79 - 94
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Seyed Alireza Zareei, Mahmood Hosseini, Mohsen Ghafory-Ashtiany
      Recent earthquakes have shown that Electrical Power Substations apparatuses are seismically vulnerable. This causes to disrupt the power supply in many cases, and therefore their seismic evaluation with high reliability is significantly important. Using fragility curves is a common practice for assessing seismic vulnerability. In general, fragility curves are based on only one intensity measure (IM), such as peak ground acceleration (PGA). This study has attempted to propose multivariate fragility analysis. One of the major advantages of this developed multivariate fragility analysis is to more reliably determine the seismic vulnerability of a region. A 420kV circuit breaker (CB) was modeled and analyzed by using finite element technique. The results show that by adding another IM as peak ground velocity (PGV) the dispersion of the created data decreases to a great extent and therefore, the developed fragility surfaces helps conducting the seismic risk evaluation of electric power system components with higher level of reliability. Based on the obtained numerical results it can be expressed that for moderate damage state the fragility values are not much dependent on the PGV variation, while for severe damage state the dependence of fragility values on PGV is noticeable, particularly for PGA values in range of 0.1–0.7g.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.026
      Issue No: Vol. 92 (2016)
       
  • A modal shear-based pushover procedure for estimating the seismic demands
           of tall building structures
    • Authors: Mohammad Hossein Vafaee; Hamed Saffari
      Pages: 95 - 108
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Mohammad Hossein Vafaee, Hamed Saffari
      Non-linear static procedure (NSP) has been considered as a popular method to predict seismic force and deformation demands for performance evaluation of the structures, in recent years. However, this evaluation tool is restricted to low-rise and regular buildings in which the fundamental vibration mode dominates the structural behavior. Recently, some advanced procedures have been presented to oversee these conventional procedure deficiencies. In the current study, a new nonlinear static procedure considering the effects of higher modes in structural responses is presented. This approach assigns a contribution factor for each mode based on modal shear distribution. The offered contribution factor can be applied for determining the importance of each mode in lateral load pattern formation. In order to verify the results, some other types of pushover-based analysis are also performed and the responses obtained from each NSP are compared with those of rigorous non-linear response history analysis (NL-RHA). Results demonstrated the efficiency of the proposed method in accurate prediction of the seismic demands of high-rise buildings.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.033
      Issue No: Vol. 92 (2016)
       
  • System identification and modal analysis of an arch dam based on
           earthquake response records
    • Authors: Jian Yang; Feng Jin; Jin-Ting Wang; Li-Hang Kou
      Pages: 109 - 121
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Jian Yang, Feng Jin, Jin-Ting Wang, Li-Hang Kou
      The true dynamic characteristics of dams, namely, natural frequencies, damping ratios, and mode shapes, are important to earthquake-resistant design. Thus, system identification based on in-site measurements is useful for numerical analysis and health monitoring. The well-instrumented strong motion array on an arch dam in Southwestern China recorded some seismic response data. The dynamic properties of the dam are identified from records of the top five strongest earthquake motions using power spectral density functions, transfer functions, and the ARX model. The identified modal parameters of the different seismic events are compared, and the stability of the stiffness of the dam system from 2002 to 2008 and the nonuniformity in the input ground motion are indicated. A linear finite element model of the dam and a nonlinear model that considers contraction joints are constructed and calibrated to reproduce the frequencies determined from the system identification. The modal analysis highlights potential information about the dynamic characteristics of the dam. The comparison of the results of the system identification and calibration shows that the use of the nonlinear model may be reasonable in simulating the dynamic response of the Ertan Dam.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.039
      Issue No: Vol. 92 (2016)
       
  • Design of monopiles for offshore wind turbines in 10 steps
    • Authors: Laszlo Arany; S. Bhattacharya; John Macdonald; S.J. Hogan
      Pages: 126 - 152
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Laszlo Arany, S. Bhattacharya, John Macdonald, S.J. Hogan
      A simplified design procedure for foundations of offshore wind turbines is often useful as it can provide the types and sizes of foundation required to carry out financial viability analysis of a project and can also be used for tender design. This paper presents a simplified way of carrying out the design of monopiles based on necessary data (i.e. the least amount of data), namely site characteristics (wind speed at reference height, wind turbulence intensity, water depth, wave height and wave period), turbine characteristics (rated power, rated wind speed, rotor diameter, cut-in and cut-out speed, mass of the rotor-nacelle-assembly) and ground profile (soil stiffness variation with depth and soil stiffness at one diameter depth). Other data that may be required for final detailed design are also discussed. A flowchart of the design process is also presented for visualisation of the rather complex multi-disciplinary analysis. Where possible, validation of the proposed method is carried out based on field data and references/guidance are also drawn from codes of practice and certification bodies. The calculation procedures that are required can be easily carried out either through a series of spreadsheets or simple hand calculations. An example problem emulating the design of foundations for London Array wind farm is taken to demonstrate the proposed calculation procedure. The data used for the calculations are obtained from publicly available sources and the example shows that the simplified method arrives at a similar foundation to the one actually used in the project.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.024
      Issue No: Vol. 92 (2016)
       
  • Liquefaction assessments at shallow foundation building sites in the
           Central Business District of Christchurch, New Zealand
    • Authors: Jonathan D. Bray; Christopher S. Markham; Misko Cubrinovski
      Pages: 153 - 164
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Jonathan D. Bray, Christopher S. Markham, Misko Cubrinovski
      The 2010–2011 Canterbury earthquake sequence provides an exceptional opportunity to investigate the effects of varying degrees of liquefaction on the built environment. Significant ground settlements and building damage in the Central Business District (CBD) were observed for the Christchurch earthquake. The results of CPTs and soil index tests from exploratory borings performed in the CBD are combined with cyclic triaxial (CTX) test results to characterize the soil deposits at several buildings sites. Conventional one-dimensional liquefaction-induced ground settlement procedures do not capture shear-induced deformation mechanisms and the effects of ground loss due to sediment ejecta. Improved procedures are required. Nonlinear effective stress analyses using robust soil constitutive models calibrated through CTX tests provide a means for developing these procedures. The CTX tests estimate generally consistent cyclic resistances as the CPT-based methods for medium dense sands and silty sands; however, the CTX tests provide useful insights regarding pore water pressure response and strain development. Correlations and CTX tests performed on loose clean sands indicate that these specimens were disturbed by the sampling process. Interim findings from this ongoing study are presented, and preliminary recommendations for evaluating the seismic performance of buildings with shallow foundations at sites with liquefiable soils are provided.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.049
      Issue No: Vol. 92 (2016)
       
  • A model for estimating horizontal aftershock ground motions for active
           crustal regions
    • Authors: Byungmin Kim; Moochul Shin
      Pages: 165 - 175
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Byungmin Kim, Moochul Shin
      Inconsistent observations on the characteristics of ground motions from aftershocks have been found, while there is increasing attention to effects of aftershock ground motions on structural behaviors. This study examines differences in ground motions from main shock and aftershock earthquakes using the NGA-West2 database, and propose an empirical model to estimate the average horizontal components of peak ground acceleration (PGA), and peak ground velocity (PGV), and 5% damped pseudo spectral acceleration (PSA) at various spectral periods of aftershock earthquakes for tectonically active crustal regions, as a function of aftershock to main shock magnitude ratio, distance ratio, and time-averaged shear-wave velocity in the upper 30m of soil deposits (V S30). Spectral accelerations from aftershock earthquakes are smaller than those from main shock earthquakes given the same magnitude, especially at short periods. Performance of the proposed model is evaluated using a mixed-effects residuals analysis. Period-dependent standard deviation of residuals is also presented.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.040
      Issue No: Vol. 92 (2016)
       
  • A fast and accurate method to compute dispersion spectra for layered media
           using a modified Kausel-Roësset stiffness matrix approach
    • Authors: Jyant Kumar; Tarun Naskar
      Pages: 176 - 182
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Jyant Kumar, Tarun Naskar
      This brief article presents a simple modification to the widely-used Kausel-Roësset Stiffness Matrix Method (SMM), and in particular to its implementation in the context of the Thin-Layer Method (TLM). This modification allows making fast and accurate computations of wavenumber spectra even for layered media underlain by infinitely deep half-spaces. As is well known, the TLM uses a finite element expansion in the depth direction, which in principle disallows exact representations of infinitely deep media other than through Paraxial Approximations or Perfectly Matched Layers. However, with the modification presented herein, that obstacle is removed. The very simple method is first presented and then demonstrated by means of examples involving layered half-spaces.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.042
      Issue No: Vol. 92 (2016)
       
  • Effect of ground motion filtering on the dynamic response of a seismically
           isolated bridge with and without fault crossing considerations
    • Authors: Shuo Yang; George P. Mavroeidis; Alper Ucak; Panos Tsopelas
      Pages: 183 - 191
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Shuo Yang, George P. Mavroeidis, Alper Ucak, Panos Tsopelas
      High-pass filtering not only removes the low-frequency noise from the near-fault ground motion records, but also eliminates the permanent ground displacement and reduces the dynamic ground displacement. This may considerably influence the calculated seismic response of a spatially extended engineering structure crossing a fault rupture zone. To demonstrate the importance of incorporating permanent ground displacements in the analysis and design of extended structures under specific fault crossing conditions, the dynamic response of a seismically isolated bridge located in the vicinity of a surface fault rupture (“Case A”) or crossing a fault rupture zone (“Case B”) is calculated by utilizing a near-fault ground motion record processed with and without a displacement offset. The seismically isolated bridge considered in this study is a 10-span continuous structure supported by 11 piers, resembling a typical segment of the 2.3km long Bolu Viaduct 1 located in west-central Turkey. The Lucerne Valley record from the 1992 M w 7.2 Landers earthquake, which preserves a permanent ground displacement in the fault-parallel direction and exhibits a large velocity pulse in the fault-normal direction, is used as the basis for investigating the effect of high-pass filtering on the dynamic response of the bridge. For the seismically isolated bridge located in the vicinity of the surface fault rupture (“Case A”), the utilization of the high-pass filtered ground motion leads to underestimating the demands of pier top, pier bottom and deck displacements. However, the demands of isolation displacement, isolation permanent displacement and pier drift are almost identical for both the unfiltered and filtered versions of the ground motion record. On the other hand, for the seismically isolated bridge traversed by a fault rupture zone (“Case B”), all response quantities are significantly underestimated when the high-pass filtered ground motion is used. These results, though limited to a single bridge structure and a single ground motion input, clearly indicate the importance of permanent ground displacement on the dynamic response of spatially extended engineering structures crossing fault rupture zones.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.10.001
      Issue No: Vol. 92 (2016)
       
  • Modal and nodal impedance functions for truncated semi-infinite soil
           domains
    • Authors: E. Esmaeilzadeh Seylabi; C. Jeong; E. Taciroglu
      Pages: 192 - 202
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): E. Esmaeilzadeh Seylabi, C. Jeong, E. Taciroglu
      A general methodology for numerically extracting the impedance functions of flexible soil-foundation interfaces (SFIs) in both physical (nodal) and modal domains is provided, which can also be applied to any truncated semi-infinite elastic media. A recently developed finite element method that features perfectly matched layers as absorbing boundary conditions is used to compute the wave responses within the semi-infinite soil domain. Using this tool, the impedance functions are obtained by prescribing the known nodal or modal displacement along the SFI and computing the corresponding reactions. The modal approach has the advantage of only computing the impedance functions for the most important mode shapes that control the behavior of the interface with a reduced computational cost. The accuracy of the proposed method is investigated through forced-vibration analysis of a strip foundation on surface of an elastic half-space. It is found that reduced-order modal impedance matrices can be as accurate as their nodal counterparts as long as a set of appropriate mode shapes is retained. Moreover, depending on the type of the applied loading and its frequency content, higher (flexible) mode shapes will be activated, and therefore, the substructure methods that are based on rigid or winkler-type impedance functions may predict the actual response of the foundation poorly.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.037
      Issue No: Vol. 92 (2016)
       
  • Ductility demands of MRF structures on soft soils considering
           soil-structure interaction
    • Authors: M. Ghandil; F. Behnamfar
      Pages: 203 - 214
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): M. Ghandil, F. Behnamfar
      The problem of nonlinear response of moment resisting frames on nonlinear soft soils is investigated. The soil-structure interaction (SSI) is considered using the direct method. The direct method consists of concurrent modeling of structure and its supporting soil to the bedrock. The soil medium is usually modeled using the equivalent linear method where the shear modulus and damping ratio of soil are replaced with values representative of the nonlinear soil behavior. A correction of this method with regard to very large strains of soil at and around foundations is proposed in this study. The nonlinear behavior of the frame elements of structure is assumed to be concentrated at plastic hinges at the ends of members. Drifts, shear forces and ductility demands of stories of the studied buildings are calculated once assuming a rigid base and then a soft supporting soil for the structure with nonlinear time-history analysis. It is shown that SSI increases the drifts and ductility demands of the lower stories. Interim modification factors being ratios of ductility demands with SSI to those without SSI (fixed-base cases) are presented as checking tools for when SSI is important for nonlinear dynamic response calculation of structures.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.051
      Issue No: Vol. 92 (2016)
       
  • Identification of soil dynamic properties of sites subjected to
           bi-directional excitation
    • Authors: Vicente Mercado; Waleed El-Sekelly; Mourad Zeghal; Tarek Abdoun
      Pages: 215 - 228
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Vicente Mercado, Waleed El-Sekelly, Mourad Zeghal, Tarek Abdoun
      Accurate evaluation of soil dynamic properties is essential for seismic response analyses of sites. In a number of studies, site properties have been identified using one-dimensional analyses. Such analyses uncouple the two-dimensional (horizontal) response of soil deposits, which is inherently coupled. This paper presents a system identification technique that takes into account the coupled two-directional response of soil deposits. The technique employs non-parametric estimates of the shear stresses derived from acceleration records provided by a vertical (downhole) array. A multi-yield surface plasticity approach is used to model the multi-dimensional stress-strain relation. The identification technique is first verified using finite elements computational simulations. This technique was then used to assess the coupled response of the Wildlife liquefaction research site (Imperial Valley, California). The identified shear moduli and shear wave velocities were found to be in a very good agreement with those measured in the field using crosshole seismic testing.

      PubDate: 2016-10-23T18:06:44Z
      DOI: 10.1016/j.soildyn.2016.09.038
      Issue No: Vol. 92 (2016)
       
  • A modified dynamic shear modulus model for rockfill materials under a wide
           range of shear strain amplitudes
    • Authors: Wei Zhou; Yuan Chen; Gang Ma; Lifu Yang; Xiaolin Chang
      Pages: 229 - 238
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Wei Zhou, Yuan Chen, Gang Ma, Lifu Yang, Xiaolin Chang
      High rockfill dams experience a wide range of shear strain amplitudes during earthquakes. To provide more reliable material property descriptions for earthquake response analysis of high rockfill dams, this study investigates the dynamic properties of rockfill materials in a wide strain range by large-scale cyclic triaxial testing with a high-sensitivity laser sensor. The results reveal the considerable increase of shear modulus and decrease of damping ratio with increasing confining pressure for a given initial stress ratio and the significant effect of the initial stress ratio on the small-strain shear modulus and normalized shear modulus. Previously proposed equations were found to imprecisely depict the variation of the dynamic shear modulus of rockfill materials for a wide strain range. Furthermore, the dynamic shear modulus is dependent on the Initial stress ratio in the anisotropic stress condition. Based on the existing hyperbolic model, a modified model for rockfill materials is suggested to accurately estimate the nonlinear behavior. The applicability of the modified model and previous studies for rockfill materials are assessed in the estimation of the normalized shear modulus. The results provide a reference for evaluating the accurate shear modulus in a wide strain range for strong earthquake motions.

      PubDate: 2016-10-30T21:54:39Z
      DOI: 10.1016/j.soildyn.2016.10.027
      Issue No: Vol. 92 (2016)
       
  • 3D integrated numerical model for Fluid-Structures-Seabed Interaction
           (FSSI): Loosely deposited seabed foundation
    • Authors: Jianhong Ye; D.-S. Jeng; A.H.C. Chan; R. Wang; Q.C. Zhu
      Pages: 239 - 252
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Jianhong Ye, D.-S. Jeng, A.H.C. Chan, R. Wang, Q.C. Zhu
      In the past several decades, a great number of offshore structures have been constructed on loosely deposited seabed foundation because sometimes there would be no a dense seabed floor could be chosen in planned sites, for example, the breakwaters and oil platforms in the Yellow River estunary area, China. Wave-induced residual liquefaction is easy to occur in loosely deposited seabed, which brings great risk to the stability of offshore structures. In this study, we focus our attention on the 3D interaction mechanism between ocean wave, a caisson breakwater and its loosely deposited seabed foundation. A three-dimensional integrated numerical model FSSI-CAS 3D is taken as the computational tool; and the soil constitutive model: Pastor-Zienkiewicz Mark III (PZIII) proposed by Pastor et al. [16] is adopted to describe the wave-induced dynamic behavior of loose seabed soil. The numerical results indicate that the developed integrated numerical model FSSI-CAS 3D is capable of capturing a series of nonlinear phenomena, such as tilting, subsiding of breakwater, as well as residual liquefaction in loose seabed foundation etc., in the interaction process between ocean wave, a caisson breakwater and its loose seabed foundation. The purpose of this study is to provide coastal engineers with comprehensive understanding of FSSI problme involving loosely deposited seabed soil; and propose a reliable computational method to engineers involved in the design of offshore structures on loose seabed foundation.

      PubDate: 2016-11-21T01:52:47Z
      DOI: 10.1016/j.soildyn.2016.10.026
      Issue No: Vol. 92 (2016)
       
  • Optimal Caughey series representation of classical damping matrices
    • Authors: J. Enrique Luco; Armando Lanzi
      Pages: 253 - 265
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): J. Enrique Luco, Armando Lanzi
      A least squares approach to determine the coefficients in a Caughey series representation of a classical damping matrix is presented. Instead of solving an ill-conditioned Vandermonde system of equations involving the modal damping ratios at a set of pivots, the procedure uses a least squares fit between the polynomial representing the damping ratios and the assumed known frequency dependence of the damping ratios. The proposed approach eliminates the large fluctuations of the damping ratios associated with the standard approach. Three alternative procedures are presented: (i) analytical application of the least squares approach for an expansion into power series, (ii) numerical solution of the least squares equations for a dense set of pivots, and (iii) expansion of the damping matrix into series of Legendre polynomials of matrices. In each alternative, the cases of series including or excluding the mass-proportional term are considered separately.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.028
      Issue No: Vol. 92 (2016)
       
  • Estimation method for ground deformation of granular soils caused by
           dynamic compaction
    • Authors: Wei Wang; Jin-Jian Chen; Jian-Hua Wang
      Pages: 266 - 278
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Wei Wang, Jin-Jian Chen, Jian-Hua Wang
      A numerical investigation into the performance of ground deformation due to dynamic compaction (DC), and a developed method of estimating ground deformation of granular soils caused by DC are presented. Firstly, a 2D numerical model is created in LS-DYNA and the result is verified by variables measured in a real field case using DC treatment. A simplified model for describing ground deformation is presented. Five deformation variables, δ v m , d δ v =0 , d δ u m , δ u m , d δ u =0.01% W t H , are defined to describe characteristics of ground surface deformation. An extensive parametric study is then conducted to investigate the effect of each parameter on the five deformation variables. Finally, based on the results obtained, a forecast model is produced to describe ground deformation under DC. The applicability of the proposed procedure is then illustrated by comparing its predictions with a case of DC applied in the field. The results of this comparison indicate that the predictions using the developed method are reasonably realistic. This suggested method can provide some easy and convenient guidelines to determine ground deformation of granular soils due to dynamic compaction.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.09.015
      Issue No: Vol. 92 (2016)
       
  • Dynamic pile impedances for laterally–loaded piles using improved Tajimi
           and Winkler formulations
    • Authors: George Anoyatis; Anne Lemnitzer
      Pages: 279 - 297
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): George Anoyatis, Anne Lemnitzer
      Lateral dynamic soil–pile interaction is investigated through an improved Tajimi type solution. The soil is treated as a continuum with hysteretic material damping as previously proposed by the authors, and the pile is modelled as beam using traditional strength-of-materials solutions. Following the pioneering work of Novak and Nogami, a more accurate analytical model for the static and harmonic response of a pile in a soil layer overlying rock is proposed, and closed form expressions for pile head stiffness are derived. Results are validated through comparisons against rigorous solutions from literature. Hereafter, the Winkler model was considered as a simple alternative for predicting pile head stiffness and damping. An extensive review of available Winkler moduli demonstrated that the Winkler model performance strongly depends on the selection of the respective moduli but found to be satisfactory in static conditions. Most existing expressions for dynamic Winkler moduli were found to render the model incapable of capturing resonant effects. Consequently, a new expression for a dynamic Winkler modulus is derived based on a modification of the classic dynamic plane strain modulus of Baranov–Novak. Implemented in the Winkler model this expression is capable of accurately computing dynamic stiffness attenuation and damping increase for frequencies up to the first resonance over a wide range of pile slenderness ratios.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.09.020
      Issue No: Vol. 92 (2016)
       
  • Damage-based strength reduction factor for nonlinear structures subjected
           to sequence-type ground motions
    • Authors: Yongqun Zhang; Jun Chen; Chaoxu Sun
      Pages: 298 - 311
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Yongqun Zhang, Jun Chen, Chaoxu Sun
      This paper investigates the strength reduction factor of single-degree-of-freedom (SDOF) system subjected to the mainshock–aftershock sequence-type ground motions. Both displacement ductility and cumulative damage are considered in the reduction factor. Records of mainshock-aftershock earthquakes were collected and classified according to site properties. The aftershock ground motions in sequence are scaled to five relative intensity levels. Based on the nonlinear time-history analysis of inelastic SDOF systems, the effects of natural period, ductility factor, damage index and aftershock have been studied statistically. The results indicate that the aftershock ground motion has significant influences on strength reduction factors, and the damage-based strength reduction factor is about 0.6–0.9 times of the ductility-based strength reduction factor. Finally, an empirical expression for strength reduction factor was established by regression analysis.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.002
      Issue No: Vol. 92 (2016)
       
  • A study on a MR damping system with lumped mass for a two-span bridge to
           diminish its earthquake-induced longitudinal vibration
    • Authors: G. Heo; C. Kim; S. Jeon; C. Lee; S. Seo
      Pages: 312 - 329
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): G. Heo, C. Kim, S. Jeon, C. Lee, S. Seo
      This paper examines the effectiveness of a MR damping system with lumped mass for a longitudinal vibration control of two-span bridge, preventing spans from pounding each other and mitigating its seismic responses when earthquake-induced load is inflicted. The MR damping system with lumped mass proposed in this study it was constituted by three components: a MR damper (30kN) which connected two spans of a bridge and two spans themselves made different mass and stiffness. Its function was designed to impose an effective check on relative displacement and pounding. In order to prove its effectiveness, a two-span bridge (8.3m long) was constructed with a MR damper installed beneath the two spans. First, a mathematical model of the bridge was derived; also, a model of the MR damper was verified through a separate test on its performance. Next, shaking table tests were carried out by inflicting 150% of El-centro earthquake and 60% of Kobe earthquake to see how effective the system would be in mitigating seismic responses. All the tests were done under various conditions (un-control, passive off, passive on, Lyapunov control, and Clipped-optional control) in order to closely examine and analyze under which condition mitigation could be maximized and how mitigation could be effected. As a result of the tests, it was found that the MR damping system with lumped mass was effective in preventing two spans from pounding each other and its active performance decreased the relative displacement of the bridge structure. Therefore, it was proven to be effective in attenuating the seismic responses of two-span bridge in longitudinal direction.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.004
      Issue No: Vol. 92 (2016)
       
  • Determination of seismic compression of sand subjected to two horizontal
           components of earthquake ground motions
    • Authors: Chun-Xiao Nie; Qing-Sheng Chen; Guang-Yun Gao; Jun Yang
      Pages: 330 - 333
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Chun-Xiao Nie, Qing-Sheng Chen, Guang-Yun Gao, Jun Yang
      The objective of this Technical Note is to investigate the ratio of seismic compression of sand subjected to two mutually perpendicular horizontal components of earthquake ground motions simultaneously to its counterpart for single component of horizontal motions. By using a verified, fully coupled and inelastic finite element procedure, sand specimens with various relative densities (Dr=45%, 60% and 100%) are subjected to each of the horizontal components of motion separately, and then simultaneously, with the vertical strains and corresponding ratio computed for each case. In total, 296 shallow crustal horizontal motions (i.e. 148 sets of horizontal motions) with various earthquake magnitudes, site to source distances, durations, and site conditions recorded in active tectonic regions are used in the analyses. The results showed that the ratio generally ranges from 1.52 to 2.32, and it increases with earthquake magnitude and relative density of sand but decreases with epicentral distance. These results can be used in conjunction with seismic compression correlations for single component of motion to estimate its counterpart for multiple components of motion, thereby increasing the accuracy in predicting the severity of seismic compression under multi-directional seismic motions.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.007
      Issue No: Vol. 92 (2016)
       
  • Local amplification and subsoil structure at a difficult site:
           Understanding site effects from different measurements
    • Authors: Francisco J. Chávez-García; Dimitris Raptakis
      Pages: 334 - 344
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Francisco J. Chávez-García, Dimitris Raptakis
      We present a detailed site effects study at a site (TYF) close to the Thermaikos gulf coast in Thessaloniki, northern Greece. Different types of data recorded by different instruments are analyzed. Empirical amplification is estimated using spectral ratios relative to a reference station (SSR) and horizontal to vertical spectral ratios (HVSR) using earthquake data. In addition, seismic noise records from different arrays were analyzed using HVSR. Our results show that earthquake data SSR fails for our data. The reason is the poor signal to noise ratio of our records. Better results were obtained using HVSR for earthquake data. Seismic noise HVSR were not useful due to the particular soil profile at TYF, with the exception of HVSR of seismic noise recorded in one of our arrays that were able to reflect a significant change in the coast line at our site. Although amplification at site TYF is relatively small, it is large enough to originate a difference of one intensity unit relative to firm ground motion. Amplification at TYF is caused by a deep soil structure (over 350m in depth) and therefore cannot be captured using measures like Vs30.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.008
      Issue No: Vol. 92 (2016)
       
  • Evaluation of the seismic earth pressure for inverted T-shape stiff
           retaining wall in cohesionless soils via dynamic centrifuge
    • Authors: Seong-Bae Jo; Jeong-Gon Ha; Jin-Sun Lee; Dong-Soo Kim
      Pages: 345 - 357
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Seong-Bae Jo, Jeong-Gon Ha, Jin-Sun Lee, Dong-Soo Kim
      In the design procedure of a retaining wall, the pseudo-static method has been extensively used and the dynamic earth pressure has been calculated based on force equilibrium using the Mononobe–Okabe method that is an extension of the Coulomb's earth pressure theory. According to the Mononobe–Okabe method, the resultant total dynamic thrust would act at a height of 0.33H. The Seed and Whitman method that is a modification of the Mononobe–Okabe method, suggests that the dynamic thrust would be applied at 0.6H above the base. There is no clear empirical basis for the distribution of the dynamic earth pressure, and recent experimental research studies have shown that the dynamic earth pressure has a triangular shape, and that the dynamic thrust is applied at 0.33H above the base. Moreover, pseudo-static methods do not consider the effects of the inertial force of the wall itself on the structural behavior. Two dynamic centrifuge tests were designed and conducted to evaluate the magnitude and distribution of the dynamic earth pressure and the inertial effect of the wall itself on an inverted, T-shape, stiff retaining wall with a dry medium sand backfill. Results from two sets of dynamic centrifuge experiments show that the dynamic earth pressure has a triangular shape for critical states during the earthquake, and that the inertial force of the wall significantly influences the structural moment. Moreover, the deformation pattern, the rigidity of the retaining wall, and the frequency contents of the input motions cause the phase difference between the wall and the soil. Correspondingly, this phase difference influences the dynamic earth pressure.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.009
      Issue No: Vol. 92 (2016)
       
  • Recorded seismic response of the Samoa Channel Bridge-foundation system
           and adjacent downhole array
    • Authors: Ning Wang; Ahmed Elgamal; Thomas Shantz
      Pages: 358 - 376
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Ning Wang, Ahmed Elgamal, Thomas Shantz
      A large set of earthquake records from the highly instrumented Samoa Channel bridge-ground system has been compiled and made available by the California Geological Survey. During six seismic events, more than 30 data channels have been documenting the seismic response of the bridge, abutments, and adjacent ground surface. Of special interest is the response of one of the bridge piers with records at the deck level, pile cap and within the underlying pile foundation. Response of this pile foundation is compared to that of the ground as documented by the nearby Eureka geotechnical downhole array. In this paper, records from the strongest to date 2010 Ferndale earthquake (PGA of about 0.16g), along with other available low-amplitude events (2007–2014) are employed to evaluate the ground, pile foundation, and overall bridge seismic response. Spatial variation of the recorded motions is examined. Linear and nonlinear response of the ground and the bridge are assessed using system identification techniques. During the strong shaking phase of the 2010 Ferndale Earthquake, a clear and significant stiffness reduction was observed in the column as well as in the foundation of the instrumented pier.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.09.034
      Issue No: Vol. 92 (2016)
       
  • Numerical modelling method for inelastic and frequency-dependent behavior
           of shallow foundations
    • Authors: Seok hyeon Chai; Amir Reza Ghaemmaghami; Oh-Sung Kwon
      Pages: 377 - 387
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Seok hyeon Chai, Amir Reza Ghaemmaghami, Oh-Sung Kwon
      This paper presents a novel framework with which the inelastic behavior and the frequency-dependent dynamic characteristics of soil-foundation system can be represented with a computationally efficient numerical model. The inelastic behavior of soil in the vicinity of a shallow foundation is represented with a macro-element which is based on the classical plasticity theory. The frequency-dependent property of soil-foundation system is represented with a recursive parameter model. The framework allows integration of both models such that both the inelastic behavior and the frequency-dependent characteristics can be captured. The proposed method is verified against FE analysis of a shallow foundation in the two dimensional parametric space of frequency and inelasticity. The verification shows that the model using the proposed framework can fully represent the inelastic cyclic behavior at low frequency excitation and the dynamic response at high frequency excitation. The method provides an approximate solution for the cases in-between, e.g. a foundation subjected large amplitude high-frequency excitation. As an application example, the method is applied to an analysis of a bridge pier subjected to earthquake loading.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.030
      Issue No: Vol. 92 (2016)
       
  • Liquefaction characteristics of gravelly soil under cyclic loading with
           constant strain amplitude by experimental and numerical investigations
    • Authors: Yong Wang; Yan-Li Wang
      Pages: 388 - 396
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Yong Wang, Yan-Li Wang
      In order to investigate the liquefaction behavior and meso-mechanism of gravelly soil under cyclic loading with constant strain amplitude, the undrained dynamic triaxial test, CT scan test and numerical simulations by discrete element method (DEM) are performed. Effects of gravel content and the evolution of liquefaction nmeso-mechanism are analyzed respectively. Test Results show that the liquefaction resistance of gravelly soil increases considerably with the increasing gravel content due to growing in number of gravel-to-gravel contact. DEM simulations reflect the macro mechanical property of saturated gravelly soil in the cyclic triaxial test, and show anisotropy is the most important mechanical properties of gravelly soil liquefaction under cyclic loading with constant strain amplitude. In process of the liquefaction, the backbone force-chain is gradually destroyed, and magnitude of normal contact force decreases to zero until initial liquefaction. Both of the fabric and force-chain evolution demonstrate a consistent deflection of the principal stress axis.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.029
      Issue No: Vol. 92 (2016)
       
  • Reliability assessment on earthquake early warning: A case study from
           Taiwan
    • Authors: Yun Xu; J.P. Wang; Yih-Min Wu; Hao Kuo-Chen
      Pages: 397 - 407
      Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92
      Author(s): Yun Xu, J.P. Wang, Yih-Min Wu, Hao Kuo-Chen
      Earthquake early warning (EEW) has been implemented in several regions around the world. However, because of natural randomness and uncertainty, false alarm and missed alarm can be expected in EEW. The key scope of this study is to evaluate the reliability of an on-site EEW in Taiwan, by testing the system's algorithm with 17,836 earthquake data from 1999 to 2013. The analysis shows that the on-site EEW system, empirically speaking, should have a false-alarm probability of 2.5%, and a missed-alarm probability of 14.1%. Considering missed alarm should be more critical to EEW, a new algorithm that could reduce the system's missed-alarm occurrences to 6% is also discussed in this paper.

      PubDate: 2016-11-06T22:13:55Z
      DOI: 10.1016/j.soildyn.2016.10.015
      Issue No: Vol. 92 (2016)
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: January 2017
      Source:Soil Dynamics and Earthquake Engineering, Volume 92


      PubDate: 2016-12-11T10:40:39Z
       
 
 
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