for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> EARTH SCIENCES (Total: 649 journals)
    - EARTH SCIENCES (462 journals)
    - GEOLOGY (75 journals)
    - GEOPHYSICS (27 journals)
    - HYDROLOGY (21 journals)
    - OCEANOGRAPHY (64 journals)

EARTH SCIENCES (462 journals)

We no longer collect new content from this publisher because the publisher has forbidden systematic access to its RSS feeds.
Journal Cover Soil Dynamics and Earthquake Engineering
  [SJR: 1.516]   [H-I: 56]   [16 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0267-7261
   Published by Elsevier Homepage  [3089 journals]
  • An evolutionary power spectrum model of fully nonstationary seismic ground
           motion
    • Authors: Ding Wang; Zenglei Fan; Shengwang Hao; Dahai Zhao
      Pages: 1 - 10
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Ding Wang, Zenglei Fan, Shengwang Hao, Dahai Zhao
      A parametric evolutionary power spectrum model of fully nonstationary seismic ground motion is developed based on the evolutionary spectrum estimation method via generalized harmonic wavelets. The model consists of a frequency-domain energy distribution function and a series of normalized time-dependent envelop functions for different frequencies. The frequency-domain energy distribution function describes the spectral characteristics of the seismic ground motion. The nonstationarity is achieved by the normalized time-dependent envelope functions. For a specific seismic ground motion record, the evolutionary power spectral density (EPSD) is estimated via generalized harmonic wavelets. The parameters are identified by letting the model approximate to the estimated EPSD of the realistic ground motion. By using the spectral representation method, the proposed EPSD model can be used to synthesize the artificial seismic ground motion time histories for engineering purposes.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.014
      Issue No: Vol. 105 (2017)
       
  • Three-dimensional (3D) soil structure interaction with normal-plane P-wave
           incidence: Rigid foundation
    • Authors: Guanying Zhu; Vincent W. Lee
      Pages: 11 - 21
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Guanying Zhu, Vincent W. Lee
      This paper presents an analytic solution of a three-dimensional Soil-Structural Interaction (3D SSI) model in which the building and foundation are idealized as cylindrical thin-rod and rigid hemisphere. The ground is a stress-free elastic, isotropic, homogenous half-space, and excitation is vertically incident plane P-wave. Analytic three-dimensional (3D) solutions are presented which satisfy the stress-free boundary conditions at the half-space surface. Foundation motions, relative responses of building and surface displacement of soil around building are analyzed and discussed. A comparison with related two-dimensional (2D) SSI close-form solution is also described.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.016
      Issue No: Vol. 105 (2017)
       
  • Dynamic interaction between a partially corroded pipeline and saturated
           poroelastic medium under plane waves
    • Authors: Xue-Qian Fang; Bai-Lin Li
      Pages: 22 - 26
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Xue-Qian Fang, Bai-Lin Li
      A fundamentally based mathematical model of a partially corroded pipeline in a saturated poroelastic medium is presented, and the dynamic interaction around the pipeline under plane waves is derived. Based on Biot's poroelastic theory, the dynamic governing equations of the saturated poroelastic medium are decomposed. The wave fields around the corroded pipeline are expanded by using the wave function expansion method. The loose poroelastic medium in the corroded areas is simulated by the spring-type medium, and the thickness of pipeline is small. By introducing the different boundary conditions in the corroded and perfect areas, the expanded coefficients are solved. Through numerical examples, the jump of dynamic stress resulting from the corroded area under different wave frequencies is examined in detail.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.022
      Issue No: Vol. 105 (2017)
       
  • Soil-dependent optimum design of a new passive vibration control system
           combining seismic base isolation with tuned inerter damper
    • Authors: D. De Domenico; N. Impollonia; G. Ricciardi
      Pages: 37 - 53
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): D. De Domenico, N. Impollonia, G. Ricciardi
      The papers addresses a novel passive vibration control system combining seismic base isolation with a tuned inerter damper (TID) system. The latter, by analogy with the tuned mass damper (TMD), is a dynamic vibration absorber in which the physical mass of the TMD is partly or entirely replaced by an apparent mass, also called inertance, created by a particular arrangement of mechanical gearings—the inerter. By attaching a TID to the isolation floor, not only the displacement demand of base-isolated structures can be significantly reduced, but also the superstructure response (e.g. interstory drift, base shear) is effectively controlled. Optimum parameters of this system are found based on a simplified three degree-of-freedom model that reflects the dynamic properties of both the isolation system and the TID while accounting for the flexibility of the base-isolated superstructure. Within a probabilistic framework, the influence of soil conditions is investigated by modeling the seismic ground motion as a filtered Gaussian random process. Different filter parameters are considered that may be associated with firm, medium or soft soil conditions depending on the frequency content of the power spectral density function. A wide parametric study is performed in order to detect the optimal TID parameters depending on the soil conditions for a variety of isolation ratios, mass ratios and damping ratios of both the superstructure and the isolation system. Finally, a multi-story building equipped with the proposed passive vibration control system is examined. Effectiveness of the proposed system is assessed via the evaluation of the structural response in the time domain. Detuning effects are investigated via a sensitivity analysis. Comparison with alternative passive vibration control systems proposed in the literature and based on different arrangements of TMD and inerter-based device is discussed.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.023
      Issue No: Vol. 105 (2017)
       
  • A simplified analytical model of dynamic behavior of hybrid coupled wall
           systems with steel coupling beams
    • Authors: Mengde Pang; Guoqiang Li; Jian Jiang
      Pages: 54 - 67
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Mengde Pang, Guoqiang Li, Jian Jiang
      This paper proposes a simplified analytical model to estimate the seismic response of hybrid coupled walls (HCW). The model tends to consider the inelastic behavior of steel coupling beams (SCB) and elastic behavior of wall piers. The two wall piers are simplified to one cantilever beam with equivalent stiffness. The steel coupling beams were simulated by rotational springs, and their actions on the walls were represented by concentrated moments distributed along the height. A bilinear hysteretic model is used to represent the inelastic behavior of SCBs. The Rayleigh-Ritz method is adopted to determine the seismic response of the simplified model. The performance of the simplified model is verified against finite element analysis of a 20-storey HCW building. The comparison shows that the simplification is reasonable to capture the main dynamic characteristics of HCW systems. Parametric studies are conducted and the results show that the yielding level and post-yielding stiffness of SCBs have significant influence on the dynamic behavior of HCW systems. To achieve the optimum performance, it is recommended to reduce the yielding level of SCBs by 40–60%, and to design the post-yielding stiffness ratio of SCBs in the range of 0.4–0.6.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.001
      Issue No: Vol. 105 (2017)
       
  • Experimental and numerical investigation on the tensile fatigue properties
           of rocks using the cyclic flattened Brazilian disc method
    • Authors: Yi Liu; Feng Dai; Nuwen Xu; Tao Zhao; Peng Feng
      Pages: 68 - 82
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Yi Liu, Feng Dai, Nuwen Xu, Tao Zhao, Peng Feng
      Rock engineering structures are quite susceptible to cyclic tensile loading. Accurate characterizations of the tensile fatigue properties of rocks are crucial to the long-term stability assessment of rock structures. Using the cyclic flattened Brazilian disc (FBD) testing method, this study experimentally and numerically investigates the tensile fatigue response of brittle rocks to different cyclic loading conditions, involving three loading frequencies, three maximum loads and three amplitudes. Our experimental results systematically reveal the influence of the three cyclic loading parameters on the tensile fatigue properties of FBD specimens, including the fatigue deformation behavior, the tensile fatigue life and the fatigue failure mode. Under higher loading frequency or lower maximum load and amplitude, the FBD specimen is characterized by higher irreversible deformation and higher tensile fatigue life. Nevertheless, the fatigue failure modes of the tested FBD specimens are independent of cyclic loading parameters; all the cyclically failed specimens feature a prominent tensile failure. Furthermore, the progressive fracture behavior of the FBD specimen under representative cyclic tensile loading is numerically assessed via the three-dimensional DEM Code ESyS-Particle. The numerical results reveal that the cyclic FBD testing method indeed guarantees the central crack initiation of the disc specimen, which satisfies the prerequisite for a valid Brazilian-type tensile strength test. After the crack initiation, the central cracks further propagate along the vertical diameter of the FBD specimen, eventually triggering the tensile fatigue failure.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.025
      Issue No: Vol. 105 (2017)
       
  • The effect of sliding on the rocking instability of multi- rigid block
           assemblies under ground motion
    • Authors: Anthony N. Kounadis
      Pages: 1 - 14
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Anthony N. Kounadis
      The highly nonlinear differential equations describing the complex rocking-sliding instability of a freely standing on the ground multi-rigid block assembly under horizontal ground motion are analytically derived using an energy variational approach. A major step for deriving these equations is the evaluation of the displacements (horizontally and vertically) of the gravity centers of all rigid blocks of the assembly, after rocking initiation of the lower block and separation of all blocks to each other. This is conveniently achieved by combining the corresponding displacements of the same assembly without sliding (based on previous author's analyses) with the additional displacements due to slidings between consecutive blocks except the lower one with the ground. The increase of the magnitude of sliding along the height of the assembly (from bottom to the top) implies respective increase in the loss of energy. Thus, the beneficial effect of sliding on the minimum amplitude ground acceleration (leading to overturning) becomes more pronounced as the number of rigid blocks of the assembly increases. It was shown qualitatively and quantitatively that a very small sliding in a two-rigid block assembly may provoke a significant increase of the minimum amplitude ground acceleration (stabilizing considerably the assembly). It was also proved via a qualitative analysis that the number of configuration patterns to be examined can be substantially reduced which confines considerably the computational effort. Moreover, some new findings for the rocking-sliding response for one- rigid block systems are also presented contributing to the rocking-sliding analysis of multi-rigid block assemblies.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.03.035
      Issue No: Vol. 104 (2017)
       
  • Seismic behavior of irregular reinforced-concrete structures under
           multiple earthquake excitations
    • Authors: Resat Oyguc; Cagatay Toros; Adel E. Abdelnaby
      Pages: 15 - 32
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Resat Oyguc, Cagatay Toros, Adel E. Abdelnaby
      Reconnaissance studies on the recent Tohoku earthquake have reported collapse of structures due to multiple earthquake excitations in the earthquake-affected region. Strength and stiffness degradation is shown to be the primary reason for the observed damage. The present study aims to investigate the degrading behavior of irregularly built reinforced concrete structures subjected to the Tohoku ground motion sequences. Three-dimensional numerical models of three irregular reinforced concrete structures are developed. The structural characteristics of these buildings are then altered to achieve a regular case. The models contain appropriate damage features that can capture both the irregularity and material deterioration effects. The capacities of both cases are evaluated using the N2 and extended N2 procedures. The degrading models are then used for ground motion sequences measured at 23 selected stations. The results indicate that multiple earthquake effects are significant, and irregularity effects increase the dispersed damage under these excitation sequences.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.10.002
      Issue No: Vol. 104 (2017)
       
  • Porosity estimation of unsaturated soil using Brutsaert equation
    • Authors: Hyunwook Choo; Hwandon Jun; Hyung-Koo Yoon
      Pages: 33 - 39
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Hyunwook Choo, Hwandon Jun, Hyung-Koo Yoon
      Although the porosity is a crucial parameter for understanding the soil behavior under static and dynamic loading, estimating the porosity of unsaturated soil is difficult owing to the various input parameters required. The objective of this study is to suggest a technical method to obtain the level of porosity based on the elastic wave velocity in unsaturated soil. The Brutsaert model, which utilizes the theory of wave propagation, is applied to modify the proposed method in terms of the porosity of unsaturated soil. The soil compressional wave velocity is gathered through a seismic refraction survey, and the porosity distribution at different depths is estimated. A dynamic cone penetration test is applied to verify the converted porosity based on the compressional wave. The two porosities estimated through the wave propagation and penetration show similar trends. Furthermore, a special validation is performed to determine whether the energy dissipation can be ignored in the compressional wave propagations under this experiment condition. The results of this study indicate that the suggested technique is useful for obtaining the porosity in unsaturated soil.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.09.029
      Issue No: Vol. 104 (2017)
       
  • Investigation of ground vibrations induced by trains moving on saturated
           transversely isotropic ground
    • Authors: Guangyun Gao; Chenxiao Xu; Juan Chen; Jian Song
      Pages: 40 - 44
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Guangyun Gao, Chenxiao Xu, Juan Chen, Jian Song
      A 2.5D FEM (finite element method) is used to investigate the effects of soil parameters of transversely isotropic (cross anisotropic) saturated soil on ground vibrations and excess pore water pressures induced by moving train loads. The governing equations of transversely isotropic saturated soil are derived from the Boit's theory in frequency domain by applying the Fourier transform with respect to time, and 2.5D FE model is then established using Galerkin method. Correctness of the proposed model is validated with published data. Numerical results illustrate that the decrement of vibration amplitude and excess pore water pressure caused by the increment of vertical elastic modulus is more significant than that of the horizontal direction. Poisson ratios in both directions have little effect on ground vibrations, while an increase in horizontal Poisson ratio results in a significant increment in excess pore water pressure.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.09.030
      Issue No: Vol. 104 (2017)
       
  • Energy-based evaluation of liquefaction of fiber-reinforced sand using
           cyclic triaxial testing
    • Authors: P. Fardad Amini; R. Noorzad
      Pages: 45 - 53
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): P. Fardad Amini, R. Noorzad
      The present study reviews a series of cyclic triaxial tests to investigate the liquefaction characteristics of Babolsar sand reinforced with randomly distributed fibers using an energy-based approach. The effect of fiber content, fiber length, confining pressure, and relative density were studied. The test results revealed that the addition of fibers increased the number of cycles required to liquefaction, resulting in higher cumulative dissipated energy. This accounted for the higher cyclic shear resistance of reinforced sand compared to unreinforced sand. Capacity energy is defined as cumulative dissipated energy to onset of liquefaction. The test results showed that Wliq was significantly affected by the fiber inclusion. Comparative studies demonstrated that energy-based method is a good way to evaluate liquefaction potential of fiber-reinforced sands.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.09.026
      Issue No: Vol. 104 (2017)
       
  • Shear wave velocity and soil type microzonation using neural networks and
           geographic information system
    • Authors: Mohammad Motalleb Nejad; Mohammad Sadegh Momeni; Kalehiwot Nega Manahiloh
      Pages: 54 - 63
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Mohammad Motalleb Nejad, Mohammad Sadegh Momeni, Kalehiwot Nega Manahiloh
      Frequent casualties and massive infrastructure damages are strong indicators of the need for dynamic site characterization and systematic evaluation of a site's sustainability against hazards. Microzonation is one of the most popular techniques in assessing a site's hazard potential. Improving conventional macrozonation maps and generating detailed microzonation is a crucial step towards preparedness for hazardous events and their mitigation. In most geoscience studies, the direct measurement of parameters imposes a huge cost on projects. On one hand, field tests are expensive, time-consuming, and require specific high-level expertise. Laboratory methods, on the other hand, are faced with difficulties in perfect sampling. These limitations foster the need for the development of new numerical techniques that correlate simple-accessible data with parameters that can be used as inputs for site characterization. In this paper, a microzonation algorithm that combines neural networks (NNs) and geographic information system (GIS) is developed. In the field, standard penetration and downhole tests are conducted. Atterberg limit test and sieve analysis are performed on soil specimens retrieved during field-testing. The field and laboratory data are used as inputs, in the integrated NNs-GIS algorithm, for developing the microzonation of shear wave velocity and soil type of a selected site. The algorithm is equipped with the ability to automatically update the microzonation maps upon addition of new data.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.10.001
      Issue No: Vol. 104 (2017)
       
  • Simplified formulas for the seismic bearing capacity of shallow strip
           foundations
    • Authors: Riccardo Conti
      Pages: 64 - 74
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Riccardo Conti
      The seismic bearing capacity of shallow foundations is affected by inertia forces acting both on the structure and in the supporting soil. Even though the former have been recognised to play often the major role, by increasing the horizontal load and the overturning moment transferred to the foundation, both of them must be taken into account in the seismic design of foundations. Using a pseudostatic approach and based on the upper bound theorem of limit analysis, a comprehensive set of formulas is derived for the computation of the seismic bearing capacity of strip footings resting on cohesive-frictional and purely cohesive soils. Results are given in terms of: (i) reduction coefficients for the Terzaghi's equation of the vertical bearing capacity and (ii) ultimate failure envelopes in the space of normalised loading variables. These formulas extend to more general conditions other literature results, allowing to take into account easily the effects of inertia forces acting both on the superstructure (load inclination and eccentricity) and into the foundation soil. The reliability of the proposed equations, suitable for the design practice, is verified through a thorough comparison with other rigorous and approximate solutions.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.09.027
      Issue No: Vol. 104 (2017)
       
  • Effect of soil-structure interaction on inelastic displacement ratios of
           degrading structures
    • Authors: Nemat Hassani; Majid Bararnia; Gholamreza Ghodrati Amiri
      Pages: 75 - 87
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Nemat Hassani, Majid Bararnia, Gholamreza Ghodrati Amiri
      This study presents an evaluation of inelastic displacement ratios for degraded structures considering soil-structure interaction (SSI). In this regard, a wide variety of effective parameters of hysteresis models and soil-structure systems are considered. Four different hysteretic models a) bilinear, b) modified Clough, c) stiffness degrading, and d) strength-stiffness degrading, are assigned to represent force-displacement response of super-structure. The supporting soil is modeled using the concept of cone models. Inelastic displacement ratios were computed for 12,000 soil-structure models with periods between 0.1 and 5s when subjected to 19 strong ground motions recorded on NEHRP site class D. In addition, a parametric investigation is performed to evaluate the parameters that could affect nonlinear response of structures with strength-stiffness degrading hysteretic model. It is observed that generally SSI increases the inelastic displacement ratios with exception of very short period structures. Also, it is demonstrated that the soil-structure systems with stiffness degrading hysteresis model in short period range could experience larger inelastic displacement compare to those in non-degraded soil-structure systems. In particular, the SSI substantially increases inelastic displacement ratios of strength-stiffness degrading structures.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.10.004
      Issue No: Vol. 104 (2017)
       
  • A study on major seismological and fault-site parameters affecting
           near-fault directivity ground-motion demands for strike-slip faulting for
           their possible inclusion in seismic design codes
    • Authors: Sinan Akkar; Saed Moghimi; Yalın Arıcı
      Pages: 88 - 105
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Sinan Akkar, Saed Moghimi, Yalın Arıcı
      We investigate the role of major seismological (magnitude, pulse period, fault length, seismic activity, orientation of incident seismic wave with respect to fault-strike) and geometrical (fault-site geometry) parameters to understand the variations in ground-motion demands due to near-fault directivity (NFD) effects. To this end, we used a suite of probabilistic strike-slip earthquake scenarios and established the elastic spectral amplitude distributions conditioned on the above investigated parameters. The probabilistic earthquake scenarios also provided information on the sensitivity of directivity dominant near-fault (NF) ground motions to mean annual exceedance rates. We implemented different narrow-band directivity models to observe the significance of seismological modeling in the directivity dominant NF ground-motion amplitudes. The observations from these case studies suggest that each one of the above parameters have implications on the amplitude and spatial variation of directivity dominating NF ground-motion demands. The influence of each investigated parameter on NFD spectral amplitudes is dependent of the implemented directivity model. We also establish some rules to map the spatial extent of directivity dominant ground motions considering the variations in the investigated seismological parameters. The outcomes of the paper can be used to incorporate the NFD effects into design spectra representing different annual exceedance rates.

      PubDate: 2017-10-18T12:14:49Z
      DOI: 10.1016/j.soildyn.2017.09.023
      Issue No: Vol. 104 (2017)
       
  • Quantification of response spectra of pulse-like near-fault ground motions
    • Authors: Wuchuan Pu; Ming Wu; Bin Huang; Huajun Zhang
      Pages: 117 - 130
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Wuchuan Pu, Ming Wu, Bin Huang, Huajun Zhang
      This study aims to quantify the acceleration and displacement response spectra of pulse-like near-fault ground motions, which can be further employed to derive the seismic force demands of a structure system or structural member. The spectra are computed based on a set of pulse type ground motions, and the spectral shapes are derived by normalizing the spectra with the spectral values at the pulse periods. The normalized spectral values exhibit very small variations at periods larger than the pulse period but very large dispersions at periods shorter than the pulse periods. In a bi-normalization coordinate, an empirical function is developed for simulating the normalized spectral shape, in which the damping effect is included. Moreover, another empirical function for estimating the spectral value at the pulse period is constructed. The two-step procedure finally leads to a function for estimating acceleration spectral values based on the structural period, structural damping and pulse period of ground motion. The displacement spectra of high damping systems are further developed by employing the damping modification factors for acceleration and displacement spectra. On average, the spectra estimated by the proposed model are in agreement with the true spectra. Combined with the prediction of key parameters of ground motions in near-fault zones, the proposed record-based spectral model is expected to produce a design spectrum better than code-based design spectra.

      PubDate: 2017-10-26T11:22:13Z
      DOI: 10.1016/j.soildyn.2017.10.005
      Issue No: Vol. 104 (2017)
       
  • Interpretation of the velocity measured in buildings by seismic
           interferometry based on Timoshenko beam theory under weak and moderate
           motion
    • Authors: Clotaire Michel; Philippe Guéguen
      Pages: 131 - 142
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Clotaire Michel, Philippe Guéguen
      Application of seismic interferometry in buildings gained interest in the recent years for structural health monitoring. It allows us to derive the shear wave velocity for an equivalent homogeneous medium representing the structure. Previous authors suggested using a shear beam model to compute the fundamental frequency of the structure out of this velocity. This model is however not adapted to a large part of existing buildings having different behaviors. In this paper, we propose a correction factor from shear beam and based on the Timoshenko beam to link the fundamental frequencies with the observed pulse velocity and the relative effects of shear and bending. This factor provides corrections up to 60% in frequency with respect to the shear beam model. The proposed correction factor shows that the higher velocities observed in the literature for shear wall buildings compared to frame buildings is compensated by their bending flexibility, resulting in resonance frequencies scaling similarly with building height. This model is applied to an 18-story reinforced concrete shear wall building (Ophite tower). The observed pulse velocity obtained by seismic interferometry in this building was about 500m/s correlated to the resonance frequency by the correction factor. We show that variations of velocity in this structure and the well-studied Factor building (California), related to non-linear behavior at low-strains (down to 10−5), can be retrieved with seismic interferometry, demonstrating that this method is sensitive enough for structural health monitoring.

      PubDate: 2017-10-26T11:22:13Z
      DOI: 10.1016/j.soildyn.2017.09.031
      Issue No: Vol. 104 (2017)
       
  • Application of UBCSAND to the LEAP centrifuge experiments
    • Authors: Michael H. Beaty
      Pages: 143 - 153
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Michael H. Beaty
      UBCSAND is an effective-stress constitutive model for estimating shear-induced deformations resulting from liquefaction. It is a practice-oriented tool that balances simplicity of formulation and use with the ability to address key aspects of the liquefaction problem. This paper discusses the challenges of applying a FLAC-UBCSAND modeling approach to Class-A, B, and C predictions of the LEAP centrifuge tests. Attention is given to typical model calibration procedures and difficulties in using these procedures for the LEAP evaluations. A comparison of the analysis predictions to the centrifuge measurements is provided.

      PubDate: 2017-10-26T11:22:13Z
      DOI: 10.1016/j.soildyn.2017.10.006
      Issue No: Vol. 104 (2017)
       
  • Reply to Authors on “Assessment of earthquake damage considering the
           characteristics of past events in South America”
    • Authors: Mario Ordaz; Mario A. Salgado-Gálvez; Omar D. Cardona
      Pages: 154 - 155
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Mario Ordaz, Mario A. Salgado-Gálvez, Omar D. Cardona


      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.08.025
      Issue No: Vol. 104 (2017)
       
  • Revisiting the 1995 MW 6.4 Aigion, Greece, earthquake: Simulation of
           broadband strong ground motion and site response analysis
    • Authors: George P. Mavroeidis; Yang Ding; Negar Moharrami
      Pages: 156 - 173
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): George P. Mavroeidis, Yang Ding, Negar Moharrami
      The 1995 M W 6.4 Aigion earthquake is one of the largest and most destructive seismic events that have occurred in Greece over the past few decades. The ground shaking in the near-fault region was recorded by a strong-motion accelerograph in the city of Aigion, at a distance of about 16km from the epicenter. The recorded horizontal ground acceleration exceeded 0.5g, whereas the horizontal components of ground velocity exhibited pulse-like motions of large amplitude. These ground-motion characteristics have been attributed to forward rupture directivity combined with the effects of soil and topography. In this article, broadband synthetic ground motions are generated at selected locations and at a dense grid of observation points extending over the causative fault of the 1995 Aigion earthquake using a hybrid deterministic-stochastic method. The low-frequency components of the synthetic ground motion are simulated using the discrete wavenumber method and the generalized transmission and reflection coefficient technique, whereas the high-frequency components of the synthetic ground motion are generated using the stochastic modeling approach and the specific barrier model. The two independently derived ground-motion components are then combined using matched filtering at a crossover frequency of 2Hz to generate broadband ground-motion time histories and response spectra. The effects of soil and topography on the simulated ground motion in the city of Aigion are also investigated through site response analysis. In addition, the strong motion recorded at Aigion is corrected for crustal anisotropy using the cross-correlation technique, thus further enhancing the alignment of recorded and synthetic ground-motion time histories. Finally, the synthetic ground motions are compared with ground-motion estimates obtained from observed geotechnical damage, USGS ShakeMaps, and ground-motion prediction equations.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.08.023
      Issue No: Vol. 104 (2017)
       
  • Modeling added spatial variability due to soil improvement: Coupling FEM
           with binary random fields for seismic risk analysis
    • Authors: Silvana Montoya-Noguera; Fernando Lopez-Caballero
      Pages: 174 - 185
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Silvana Montoya-Noguera, Fernando Lopez-Caballero
      A binary mixture homogenization model is proposed for predicting the effects on liquefaction-induced settlement after soil improvement based on the consideration of the added spatial variability between the natural and the treated soil. A 2D finite element model of an inelastic structure founded on a shallow foundation was coupled with a binary random field. Nonlinear soil behavior is used and the model is tested for different mesh size, model parameters and input motions. Historical evidence as well as physical and numerical modeling indicate that improved sites present less liquefaction and ground deformation. In most cases this improvement is modeled as homogeneous; however, in-situ measurements evidence the high level of heterogeneity in the deposit. Inherent spatial variability in the soil and the application of some soil improvement techniques such as biogrouting and Bentonite permeations will necessary introduce heterogeneity in the soil deposit shown as clusters of the treated material in the natural soil. Hence, in this study, improvement zones are regarded as a two-phase mixture that will present a nonlinear relation due to the level of complexity of seismic liquefaction and the consequent settlement in a structure. This relation is greatly affected by the mechanical behavior of the soils used and the input motion. The effect on the latter can be efficiently related to the equivalent wave period as the proposed homogenization model depends on the stiffness demand of the input motion.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.009
      Issue No: Vol. 104 (2017)
       
  • Study on the effect of the motion state of interface on the damping
           characteristics of SSI system
    • Authors: Zhiying Zhang; Hongyang Wei; Qiji Ze
      Pages: 186 - 195
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Zhiying Zhang, Hongyang Wei, Qiji Ze
      Based on the theory of discontinuous dynamical systems, this paper investigates the effect of the motion state of interface on the damping characteristics of SSI system through the phase plane analysis method. The necessary and sufficient conditions for the coordinated motion state of interface between soil and structure are obtained. The relationship between the motion state of interface and the damping system is investigated via the shaking table test. It is verified that the coordinated motion state of interface is the decisive factor for the identification of damping system. The phase trajectories of the interface and the transfer functions of the system after the different magnitudes of vibration are further given. The test results show that the motion coordination mechanism is developed between soil and structure. The coordination mechanism enables soil and structure to have a unified and collaborative motion state after a small magnitude of the vibration. The SSI system can be viewed as an approximately classical damping system under a certain dynamic excitation.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.008
      Issue No: Vol. 104 (2017)
       
  • Effect of super-structure frequency on the seismic behavior of pile-raft
           foundation using physical modeling
    • Authors: Mohammad Hassan Baziar; Fahime Rafiee; Alireza Saeedi Azizkandi; Chung Jung Lee
      Pages: 196 - 209
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Mohammad Hassan Baziar, Fahime Rafiee, Alireza Saeedi Azizkandi, Chung Jung Lee
      This paper presents the results of two physical test series, including shaking table and centrifuge modeling, on two super-structures with different frequencies and supported by piled raft foundations in a dry sand bed. While the height and weight of two super-structures were kept constant, the axial force and bending moment of piles, as well as horizontal displacement of super-structures were recorded during seismic loadings. The input seismic loadings were given different amplitudes and frequencies. The shaking table and the centrifuge test results indicated that the super-structure frequency strongly affected the pile-raft system responses. Based on the centrifuge test results, the super-structure had larger horizontal displacement, when the excitation frequency was close to system frequency with low base acceleration (0.14g), while subsequently, axial force and bending moment of piles increased. In high input base acceleration (0.4g), excitation frequency dominated the super-structure response, and larger responses occurred at smaller (1Hz) input excitation frequency.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.09.028
      Issue No: Vol. 104 (2017)
       
  • An investigation about seismic behavior of piled raft foundation for oil
           storage tanks using centrifuge modelling
    • Authors: Seyed Mohammad Sadegh Sahraeian; Jiro Takemura; Sakae Seki
      Pages: 210 - 227
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Seyed Mohammad Sadegh Sahraeian, Jiro Takemura, Sakae Seki
      Some level of settlement is allowed in the design of oil tank if the uneven settlement can be controlled in an allowable value. Considering a critical condition of piled raft foundation (PRF), that is, secure contact of raft base to the ground surface, and the expected function of piles to impose additional resistance against the local settlement, PRF is considered as one of the rational foundation systems for the oil tanks. However, PRF has a complex interaction with soil under horizontal seismic loading, especially if the tank rests on a liquefiable soil, which may cause an extreme change of the soil stiffness underneath the tank. In this study, a series of centrifuge model tests was performed to investigate the mechanical behavior of oil tank supported by piled raft foundation on liquefiable saturated sand and non-liquefiable dry sand. In the tests, two types of foundation were modelled; a slab foundation, and a piled raft foundation. Using the observed results, such as accelerations of the tank and ground, dynamic and permanent displacement of the foundation, and excess pore water pressures of the ground, advantages and limitations of piled raft foundation for application to oil tanks on sandy soil are discussed.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.010
      Issue No: Vol. 104 (2017)
       
  • Feasibility of ambient vibration screening by periodic geofoam-filled
           trenches
    • Authors: Xingbo Pu; Zhifei Shi; Hongjun Xiang
      Pages: 228 - 235
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Xingbo Pu, Zhifei Shi, Hongjun Xiang
      Single in-filled trench barriers have been widely investigated to mitigate ground vibrations. However, investigations on the application of multiple rows of in-filled trenches are very limited. This paper investigates the attenuation of surface waves by periodic geofoam-filled trenches in single-phased elastic soil deposits. First, a field test of train-induced ground vibration is carried out, from which the corresponding acceleration record and main frequency are obtained. Second, attenuation zones for surface waves in periodic geofoam-filled trenches are studied based on the periodic theory of solid-state physics. Finally, a numerical model for ambient vibration isolation is built under the conditions of plane strain, and the responses are performed both in frequency domain and in time domain by finite element method. The screening effectiveness of the proposed wave barrier is studied by conducting an extensive dimensionless parameter investigation. Results show that the proposed periodic geofoam-filled trenches can attenuate surface waves effectively, when the frequencies of surface waves are located in the attenuation zones. The present study provides a new concept for designing periodic in-filled trench barriers to mitigate ground vibrations.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.022
      Issue No: Vol. 104 (2017)
       
  • Incremental dynamic analysis of nonlinear rocking soil-structure systems
    • Authors: Hamid Masaeli; Faramarz Khoshnoudian; Saman Musician
      Pages: 236 - 249
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Hamid Masaeli, Faramarz Khoshnoudian, Saman Musician
      Rocking isolation effect on seismic demands of shear-building structures rested on shallow foundation is investigated in this paper. Building structures with surface raft foundations of various geometrical and structural properties located on soft-to-very dense sites are studied. Two types of near-fault pulses, i.e. fling step and forward directivity, are considered as input excitation. Results show that nonlinear SSI effect is governed by static vertical safety factor of foundation (F S ) that is varied in this study. Evidently, it is not necessary to excessively decrease the F S factor. So that rocking isolation is achieved as F S factor is around 2.0. On the other hand, nonlinear SSI effect is strongly correlated with normalized period of the incident near-fault pulse (T p /T). The most significant effects of nonlinear SSI on mitigating structural demands occur at T p /T near to unity. It is observed that rocking isolation has the same drawbacks of conventional synthetic translational isolators that work in sway directions. The first drawback is deficiency of rocking isolation subjected to long-period near-fault pulses and the latter is in case of high-rise superstructures.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.09.013
      Issue No: Vol. 104 (2017)
       
  • Shear wave velocity profiles of fill dams
    • Authors: DongSoon Park; Tadahiro Kishida
      Pages: 250 - 258
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): DongSoon Park, Tadahiro Kishida
      The shear stiffness (Gmax), which is determined from the shear wave velocity (Vs), is an essential parameter in dynamic analyses of fill dams. In this study, Vs profiles were collected and interpreted after comprehensive in situ geophysical seismic surveys of 28 fill dams. The Vs profiles were compared with the empirical formula proposed by Sawada and Takahashi, which was found to overestimate the shear stiffness of a core layer and underestimate that of a shell layer. Regression equations for Vs and Gmax profiles as functions of effective stress were developed for both the core and shell materials. A regression analysis including the mixed effect model was performed to account for the potential bias of data depending on the material types, survey methods, locations, and repeatability. The presented results will improve the prediction of Vs and the reliability of dynamic analyses of fill dams.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.013
      Issue No: Vol. 104 (2017)
       
  • Vertical ductility demand and residual displacement of roof-type steel
           structures subjected to vertical earthquake ground motions
    • Authors: Yang Xiang; Yong-feng Luo; Qing-long Huang; Zu-yan Shen
      Pages: 259 - 275
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Yang Xiang, Yong-feng Luo, Qing-long Huang, Zu-yan Shen
      The vertical component of seismic ground motions (VGM) may induce severe responses in roof-type structures such as mega canopies, large floors, etc. This paper proposes a ductility-based approach for estimating the inelastic responses of roof-type steel structures under VGMs. Due to the pre-loaded gravity, a roof-type steel structure exhibits obvious asymmetric hysteresis properties in the vertical direction. Accordingly, this kind of structure could be idealized as “one-side yielding” systems which only yield in the lower side of vibration, wherein the gravity effect and the VGM effect positively super-positions with each other. Based on the idealized model, the vertical ductility demand spectra and the vertical residual displacement spectra for roof-type steel structures are computed using 53 recorded strong near-fault VGMs. Taking into account the vertical strength reduction factor and the vertical post-yielding stiffness ratio, a vertical ductility demand model in the μ-T format is proposed for roof-type steel structures under VGMs. Meanwhile, the vertical residual displacement model is derived from the vertical ductility demand model, since the vertical residual displacement could be computed as the peak vertical displacement subtracted by the recoverable elastic displacement. An application of these proposed models is given in the paper. The vertical seismic responses of a large-span steel floor under VGMs are predicted based on the proposed models, and the obtained results (including both the peak and the residual responses in the vertical direction) show good accuracy as compared with the results given by nonlinear response history analysis.

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.10.019
      Issue No: Vol. 104 (2017)
       
  • Support vector machine based reliability analysis of concrete dams
    • Authors: Mohammad Amin Hariri-Ardebili; Farhad Pourkamali-Anaraki
      Pages: 276 - 295
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Mohammad Amin Hariri-Ardebili, Farhad Pourkamali-Anaraki
      This paper presents possible combination of structural responses of concrete dams with machine learning techniques. Support vector machine (SVM) method is adopted and two broad applications are presented: one for a simplified flood reliability assessment of gravity dams and the other for detailed nonlinear seismic finite element method (FEM) based analysis. Up to seventeen random variables are considered in the former example and the results of SVM contrasted with classical reliability analyses techniques (i.e., first- and second-order reliability methods, Monte Carlo simulation, Latin Hypercube and importance sampling techniques). For the latter example, a FEM-SVM based hybrid methodology is proposed for reduction of number of nonlinear analyses. A discussion is provided on the relation between the optimal earthquake intensity measures, the damage states and the accuracy of prediction. It is found that the family of SVM (i.e. standard, least squares, multi-class and regression) is an useful and effective tool for classification, response prediction and reliability analysis of the concrete dams with reasonable accuracy.
      Graphical abstract image Highlights fx1

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.09.016
      Issue No: Vol. 104 (2017)
       
  • Statistical analysis of the additional amplification in deep basins
           relative to the 1D approach
    • Authors: Chuanbin Zhu; David Thambiratnam; Chaminda Gallage
      Pages: 296 - 306
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Chuanbin Zhu, David Thambiratnam, Chaminda Gallage
      To bridge the 1D to the multidimensional site response analysis, aggravation factor at a certain surface point is defined as the ratio of its response spectrum computed using a multidimensional model to that computed using its local 1D model. Zhu et al. (2017a) quantified the aggravation factor in 2D shallow basins. As an extension to Zhu et al. (2017a), this paper aims to quantify, in a statistical sense, the aggravation factor in 2D deep basins using the numerical approach. We thus configure a total of 32 heterogeneous deep basin formations (half-width less than approximately five times basin depth) constructed based mainly on real 1D soil profiles. Nine seismic motions recorded on rock site are taken as vertically propagating SH waves. Both 1D and 2D ground motions of each basin model are simulated and averaged over the nine input motions. 2D ground motions in these deep basins are found to be significantly aggravated relative to 1D results within the period range from 0.1s to T h across the whole basin width by a factor of which the 16th and 84th percentile are 1.3 and 1.8 respectively (T h is the fundamental period of the soil column at the deepest portion of a basin).

      PubDate: 2017-11-10T08:12:37Z
      DOI: 10.1016/j.soildyn.2017.09.003
      Issue No: Vol. 104 (2017)
       
  • 2.5D coupled FEM-SBFEM analysis of ground vibrations induced by train
           movement
    • Authors: A. Yaseri; M.H. Bazyar; S. Javady
      Pages: 307 - 318
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): A. Yaseri, M.H. Bazyar, S. Javady
      2.5D models are efficient tools for dynamic analysis of structures that are longitudinally invariant. In this work, a two-and-a-half dimensional (2.5D) coupled finite element method-scaled boundary finite-element method (FEM-SBFEM) is utilized to study the induced ground vibration of passing trains. By applying Fourier transformation in the longitudinal direction, the SBFE equations in the frequency-wave number domain is presented. The unbounded domain is simulated by SBFEM. The coupling with the 2.5D FEM is straightforward. The bounded domain is modelled by FEM and the track with the use of Euler–Bernoulli beam. A number of available analytical solution results are used to verify accuracy of proposed methods in both time and frequency domains. The results were in good agreement with the analytical solution. The effect of speed of the moving load on the ground response is shown. Also 2.5D FEM-SBFEM is used in the analysis of underground train-induced ground vibrations. 2.5D results are in reasonable agreement with 3D results.

      PubDate: 2017-11-16T08:28:16Z
      DOI: 10.1016/j.soildyn.2017.10.021
      Issue No: Vol. 104 (2017)
       
  • Cyclic behavior of saturated soft clay under stress path with
           bidirectional shear stresses
    • Authors: Xiuqing Hu; Yan Zhang; Lin Guo; Jun Wang; Yuanqiang Cai; Hongtao Fu; Ying Cai
      Pages: 319 - 328
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Xiuqing Hu, Yan Zhang, Lin Guo, Jun Wang, Yuanqiang Cai, Hongtao Fu, Ying Cai
      Under seismic loading, soil layers experience multidirectional cyclic shear stresses with different amplitudes and frequencies. Therefore, the deformation behavior of soft clay under complex stress paths is practically relevant. In this study, cyclic tests are performed on normally consolidated soft clay. To simulate the situation induced by seismic load, the complex figure-eight-shaped stress path is realized by applying shear stresses in two directions simultaneously. Under the figure-eight-shaped shear stress path, the cyclic strain, cyclic modulus, and cyclic strength of soft clay are found to be significantly dependent on the CSR (cyclic shear stress ratio) and the bidirectional shear frequencies. With an increase in the CSR and a decrease in the shear frequency, the dynamic shear modulus decreases and cyclic strain accumulation increases with an increasing number of cycles. Based on the test results, an empirical formula was presented to predict the cyclic strength under different shear frequencies.

      PubDate: 2017-11-16T08:28:16Z
      DOI: 10.1016/j.soildyn.2017.10.016
      Issue No: Vol. 104 (2017)
       
  • Comparison of different models for high damping rubber bearings in
           seismically isolated bridges
    • Authors: E. Tubaldi; S.A. Mitoulis; H. Ahmadi
      Pages: 329 - 345
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): E. Tubaldi, S.A. Mitoulis, H. Ahmadi
      Steel-reinforced high damping natural rubber (HDNR) bearings are widely employed in seismic isolation applications to protect structures from earthquake excitations. In multi-span simply supported bridges, the HDNR bearings are typically placed in two lines of support, eccentric with respect to the pier axis. This configuration induces a coupled horizontal-vertical response of the bearings, mainly due to the rotation of the pier caps. Although simplified and computationally efficient models are available, which neglect the coupling between the horizontal and vertical response, their accuracy has not been investigated to date. In this paper, the dynamic behaviour and seismic response of a benchmark three-span bridge are analysed by using an advanced HDNR bearing model recently developed and capable of accounting for the coupled horizontal and vertical responses, as well as for significant features of the hysteretic shear response of these isolation devices. The results of the analyses shed light on the importance of the bearing vertical stiffness and how it modifies the seismic performance of isolated bridges. Successively, the seismic response estimates obtained by using simplified bearing models, whose use is well established and also suggested by design codes, are compared against the corresponding estimates obtained by using the advanced bearing model, to evaluate their accuracy for the current design practice.

      PubDate: 2017-11-16T08:28:16Z
      DOI: 10.1016/j.soildyn.2017.09.017
      Issue No: Vol. 104 (2017)
       
  • Influence of ground motion characteristics on the optimal single concave
           sliding bearing properties for base-isolated structures
    • Authors: P. Castaldo; E. Tubaldi
      Pages: 346 - 364
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): P. Castaldo, E. Tubaldi
      This study examines the influence of ground motion characteristics on the optimal friction properties of single concave sliding bearings employed for the seismic isolation of structural systems. The evaluation of the optimal properties is carried out by considering a non-dimensional formulation which employs the peak ground acceleration (PGA) and the peak ground acceleration-to-velocity (PGA/PGV) ratio as ground motion parameters. A two-degree-of-freedom (2dof) model is employed to describe the isolated system and two different families of records representative respectively of near fault and far field seismic inputs are considered. Following the nondimensionalization of the equation of motion for the proposed ground motion parameters, it is shown that the non-dimensional responses obtained for the two types of seismic inputs are similar. This result confirms that PGA/PGV is a good indicator of the frequency content and of other characteristics of ground motion records, helping to reduce the scatter in the response. Regression expressions are also obtained for the optimal values of the friction coefficient that minimizes the superstructure displacements relative to the base as a function of the abovementioned ground motion parameter and of the dimensionless system parameters. These expressions can be used for the preliminary estimation of the optimal properties of isolation bearings with a single concave sliding surface or double concave sliding surfaces with equal friction coefficient.

      PubDate: 2017-11-16T08:28:16Z
      DOI: 10.1016/j.soildyn.2017.09.025
      Issue No: Vol. 104 (2017)
       
  • Influence of soil type on damping reduction factor: A stochastic analysis
           based on peak theory
    • Authors: Rita Greco; Alessandra Fiore; Bruno Briseghella
      Pages: 365 - 368
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Rita Greco, Alessandra Fiore, Bruno Briseghella
      Damping reduction factor plays a central role both in scientific literature and seismic codes, but still now proposed formulations show a quite large scatter. The main goal of the present work is to explore a new definition of the damping reduction factor. The concept of stochastic response spectrum is adopted in order to predict the earthquake response of a linear SDoF system, on the basis of the random vibration theory for non-stationary process. The peak of the response of a SDoF system under a non-stationary stochastic process is used to define the stochastic displacement spectrum. The damping reduction factor is thus evaluated as the ratio between the maximum displacement of systems with a given damping and a conventional one subject to the same earthquake.

      PubDate: 2017-11-16T08:28:16Z
      DOI: 10.1016/j.soildyn.2017.10.020
      Issue No: Vol. 104 (2017)
       
  • Liquefaction resistance of fibre reinforced low-plasticity silt
    • Authors: Amin Chegenizadeh; Mahdi Keramatikerman; Hamid Nikraz
      Pages: 372 - 377
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Amin Chegenizadeh, Mahdi Keramatikerman, Hamid Nikraz
      This study sought to investigate the effect of bulk continuous filament (BCF) on the liquefaction resistance of low plasticity silt by performing a series of cyclic triaxial tests on the reference (unreinforced) and reinforced specimens. The effects of BCF contents and length (BL), relative density (D r ), and effective confining pressure (σ' 3 ) on the liquefaction strength of the reinforced specimens were investigated and the results were compared with the reference tests. The results showed that increasing the BCF content improved the liquefaction resistance of the silt. Also, it was noted that increasing the fibre length from 5-mm, to 10-mm and 15-mm respectively, increased the liquefaction resistance of the specimens. The results in the next stage showed that by increasing the relative density (D r ), liquefaction resistance of a reinforced specimen is more pronounced than that of an unreinforced specimen. Finally, investigations on the effect of effective confining pressure (σ' 3 ) on the liquefaction resistance of the reinforced specimens showed that increasing the effective confining pressure reduced the liquefaction resistance of the specimens due to suppression of the dilatancy.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.004
      Issue No: Vol. 104 (2017)
       
  • An orthogonal Hilbert-Huang transform and its application in the spectral
           representation of earthquake accelerograms
    • Authors: Tian-Li Huang; Meng-Lin Lou; Hua-Peng Chen; Ning-Bo Wang
      Pages: 378 - 389
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Tian-Li Huang, Meng-Lin Lou, Hua-Peng Chen, Ning-Bo Wang
      This paper first discusses the limitation that the intrinsic mode functions (IMFs) decomposed by the empirical mode decomposition (EMD) in Hilbert-Huang transform (HHT) are not orthogonal. As an improvement to the HHT method, three orthogonal techniques (the forward, backward and arbitrary sequence orthogonalization algorithms) based on the Gram-Schmidt method are then proposed to obtain the completely orthogonal IMFs. According to the orthogonal index and the energy index, the effectiveness of the proposed technique and algorithms is validated through a synthetic signal generated by the combination of three sinusoidal waves with different frequencies and the El Centro (1940, N-S) earthquake accelerogram. By taking the El Centro (1940, N-S) earthquake accelerogram as an example, the problem that whether the orthogonal IMFs satisfy the requirements of IMF is discussed, then the backward and the arbitrary sequence orthogonalization algorithms are recommended. Three historic earthquake accelerograms are analyzed by using the recommended orthogonalization algorithms combined with the Hilbert spectral analysis. The results show that the orthogonal Hilbert spectrum and the orthogonal Hilbert marginal spectrum can produce more faithful representation of earthquake accelerograms than the Hilbert spectrum and the Hilbert marginal spectrum, and they can be used to quantitatively characterize the energy distribution of earthquake accelerograms at different frequency regions.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.005
      Issue No: Vol. 104 (2017)
       
  • Effect of geotextile reinforcement on cyclic undrained behavior of sand
    • Authors: Reza Ziaie Moayed; Mahdi Alibolandi
      Pages: 395 - 402
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Reza Ziaie Moayed, Mahdi Alibolandi
      Dynamic behavior of reinforced soil are evaluated relative to a number of factors including: strain level, density, number of cycles, material type, fine content, geosynthetic inclusion, saturation, and effective stress. This paper investigates the dynamic behavior of saturated reinforced sand under cyclic stress condition. The cyclic triaxial tests are conducted on remolded specimens under various cyclic stress ratios (CSR) which reinforced by different arrangement of non-woven geotextile. Aforementioned tests simulate field reinforced saturated deposits during earthquake or other cyclic loadings. This analysis revealed that the geotextile arrangement played dominant role on dynamic soil behavior and as geotextile close to top of specimen, the liquefaction resistance increased. Meanwhile, the results demonstrate that the effects of arrangement of reinforcement layers on deformation and shear modulus are considerable.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.013
      Issue No: Vol. 104 (2017)
       
  • Static and seismic earth pressure coefficients for vertical walls with
           horizontal backfill
    • Authors: K. Krabbenhoft
      Pages: 403 - 407
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): K. Krabbenhoft
      The seismic earth pressure problem is considered for the special case of a vertical wall with horizontal backfill. Using upper and lower bound finite element limit analysis, earth pressure coefficients are derived for a range of seismic coefficients and soil-wall interface friction angles. The coefficients presented have a verifiable error of at most ± 1 % . Finally, the earth pressure coefficients are applied in a limit equilibrium framework to the design of various embedded retaining structures. For the resulting designs, factors of safety are computed using upper and lower bound strength reduction finite element analysis and it is concluded that the limit equilibrium approach, using the new earth pressure coefficients, is fairly accurate, albeit slightly unconservative.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.011
      Issue No: Vol. 104 (2017)
       
  • Role of conditioning intensity measure in the influence of ground motion
           duration on the structural response
    • Authors: Jalal Kiani; Charles Camp; Shahram Pezeshk
      Pages: 408 - 417
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Jalal Kiani, Charles Camp, Shahram Pezeshk
      Although several research studies have examined some effects of ground motion (GM) duration on the structural responses, many questions in this field remain unexplored and unaddressed. One area that remains a topic of debate in this field is that no outcomes can be found with regard to the effect of GM duration on structural responses when considering different choices of conditioning intensity measures (IMs). This study examines the role of the conditioning IM in the degree that GM duration influences the structural responses. To this end, the seismic demand in three different structural systems from low- to high-rise buildings are estimated using multiple stripe analyses subjected to different sets of GMs from shallow crustal seismic zone. It is found that duration of GMs from shallow events affects the structural response but not as much as that reported for GMs from subductions events. The results also reveal that the importance of GM duration mainly depends on the considered conditioning IM. Specifically, GM duration does not substantially affect the structural responses in terms of probability of collapse if peak ground acceleration, peak ground velocity, spectrum intensity, spectral acceleration at higher modes are implemented as the conditioning IMs. On the other hand, in the case of cumulative absolute velocity and spectral acceleration at the fundamental and lengthened periods, the structural responses are considerably affected by GM duration.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.021
      Issue No: Vol. 104 (2017)
       
  • Earthquake-induced settlement of a clay layer
    • Authors: Hidemasa Sato; Tran Thanh Nhan; Hiroshi Matsuda
      Pages: 418 - 431
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Hidemasa Sato, Tran Thanh Nhan, Hiroshi Matsuda
      A model for pore water pressure accumulation and settlement of saturated clay layer induced by uniform and irregular cyclic shear strains was developed by concerning the direction of cyclic shear strain. To apply this model to any kinds of clay, the effects of Atterberg's limits of cohesive clay on the cyclic shear-induced pore water pressure and the settlement were observed by using the strain-controlled cyclic simple shear test apparatus which can control the cyclic shear direction. In conclusion, the effects of Atterberg's limits of clay on the cyclic shear-induced pore water pressure accumulation and settlement were clarified by using the cumulative shear strain. Based on the experimental results, estimation methods for the pore water pressure accumulation and post-cyclic settlement of clay with a wide range of Atterberg's limits were developed. Furthermore, to apply the proposed methods to the earthquake-induced ground motions, a transformation procedure of irregular cyclic shears to the equivalent uniform ones including the effect of cyclic shear direction was developed and the practical applicability was confirmed.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.006
      Issue No: Vol. 104 (2017)
       
  • Seismic fragility for high CFRDs based on deformation and damage index
           through incremental dynamic analysis
    • Authors: Rui Pang; Bin Xu; Xianjing Kong; Degao Zou
      Pages: 432 - 436
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Rui Pang, Bin Xu, Xianjing Kong, Degao Zou
      In this paper, a seismic fragility analysis method based on incremental dynamic analysis (IDA) is extended to evaluate the seismic performance of high concrete face rockfill dams (CFRDs). Permanent deformation and face-slab damage index using a modified generalized plasticity model for rockfills and a plastic-damage model for face-slabs are considered to be dam damage measures (DMs) after defining a new face-slab damage index. The verification to damage index through the Zipingpu CFRD and previous research indicates that the grading standards are reasonable. Fragility curves and the probabilities are determined for each DM under different earthquake intensities. The results of fragility analysis demonstrate that this method can provide a strong scientific basis for predicting the earthquake destruction and loss of high CFRDs.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.017
      Issue No: Vol. 104 (2017)
       
  • The effect of variation of soil conditions along the pipeline in the
           fault-crossing zone
    • Authors: Oleg V. Trifonov
      Pages: 437 - 448
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): Oleg V. Trifonov
      In the paper, buried steel pipelines crossing strike-slip and normal-slip faults are considered within analytical and numerical approaches. The effect of variation of the backfill soil properties along the pipeline in the fault-crossing zone on the stress-strain state of the pipeline is analyzed. The analytical model developed in the previous publications is substantially reworked to take into account the variation of soil conditions along the pipeline length and the effect of internal pressure on the deformed pipe geometry. A complete set of analytical solutions for the axial pipeline-soil interaction force taking into account two zones along the pipeline length with different soil conditions, plastic behavior of the pipeline and soil, initial stress in the pipeline has been derived and introduced into the model. The effect of special (loose sand) backfill segment length on the pipeline response under strike-slip and normal-slip fault actions is studied. It is shown that the extension of the special backfill length has an advantageous effect in case of substantial axial fault displacement component. In this case, the reduction of soil constraining effect on a larger distance substantially reduces the maximal tensile strains in the pipeline. In contrast, under bending-dominant behavior of the pipeline, the elongation of the special backfill zone has no positive effect on the maximal strains.

      PubDate: 2017-12-12T12:34:01Z
      DOI: 10.1016/j.soildyn.2017.11.008
      Issue No: Vol. 104 (2017)
       
  • An incremental model for cyclic compaction of sand
    • Authors: Paul
      Abstract: Publication date: February 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 105
      Author(s): Paul Hölscher
      This paper presents an incremental objective model for the compaction of sand under cyclic triaxial loading. The model is derived on the assumption that on the long-term a cyclic loading will lead to the maximal attainable density, irrespective of the amplitude. To obtain an objective model, an incremental description is essential. It turns out that a model with three state variables is able to describe the observed behavior over the full time scale. These three state variables together define two compaction processes: a fast one and a slow one. The proposed model is tested against the empirical data obtained by Wichtmann and Triantafyllidis [1] and short term tests by Deltares. It is shown that the model also describes the observed behavior in short term tests and tests with multiple loading stages [2].
      Graphical abstract image Highlights fx1

      PubDate: 2017-12-12T12:34:01Z
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104


      PubDate: 2017-12-12T12:34:01Z
       
  • Discussion on “The effect of sliding on the rocking instability of
           multi-rigid block assemblies under ground motion” by A.N. Kounadis [Soil
           Dyn Earthq Eng 104 (2018) 1–14]
    • Authors: Gazetas
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): G. Gazetas


      PubDate: 2017-12-12T12:34:01Z
       
  • Discussion on “The effect of sliding on the rocking instability of
           multi-rigid block assemblies under ground motion” by A.N. Kounadis [Soil
           Dyn Earthq Eng 104 (2018) 1–14]
    • Authors: Dassios
      Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104
      Author(s): G. Dassios


      PubDate: 2017-12-12T12:34:01Z
       
  • Author's reply to discussers on “The effect of sliding on the rocking
           instability of multi-rigid block assemblies under ground motion” by A.N.
           Kounadis [Soil Dyn Earthq Eng 104(2018) 1–14]
    • Abstract: Publication date: January 2018
      Source:Soil Dynamics and Earthquake Engineering, Volume 104


      PubDate: 2017-12-12T12:34:01Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.90.92.204
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016