for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> EARTH SCIENCES (Total: 579 journals)
    - EARTH SCIENCES (427 journals)
    - GEOLOGY (64 journals)
    - GEOPHYSICS (27 journals)
    - HYDROLOGY (17 journals)
    - OCEANOGRAPHY (44 journals)

EARTH SCIENCES (427 journals)            First | 1 2 3 4 5     

Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (3 followers)
New Journal of Physics     Open Access   (7 followers)
Newsletters on Stratigraphy     Full-text available via subscription   (6 followers)
Nonlinear Processes in Geophysics (NPG)     Open Access   (3 followers)
Ocean & Coastal Management     Hybrid Journal   (105 followers)
Ocean Development & International Law     Hybrid Journal   (11 followers)
Ocean Dynamics     Hybrid Journal   (5 followers)
Ocean Engineering     Hybrid Journal   (3 followers)
Ocean Modelling     Hybrid Journal   (4 followers)
Ocean Science (OS)     Open Access   (6 followers)
Ocean Science Discussions (OSD)     Open Access   (5 followers)
Ocean Science Journal     Hybrid Journal   (3 followers)
Open Journal of Soil Science     Open Access   (4 followers)
Ore Geology Reviews     Hybrid Journal   (3 followers)
Organic Geochemistry     Hybrid Journal   (7 followers)
Osterreichische Wasser- und Abfallwirtschaft     Hybrid Journal  
Paläontologische Zeitschrift     Hybrid Journal   (3 followers)
Papers on Global Change IGBP     Open Access   (1 follower)
Permafrost and Periglacial Processes     Hybrid Journal   (3 followers)
Pesquisas em Geociências     Open Access   (1 follower)
Petroleum Geoscience     Hybrid Journal   (5 followers)
Petrology     Hybrid Journal   (6 followers)
Photogrammetrie - Fernerkundung - Geoinformation     Full-text available via subscription  
Physical Geography     Hybrid Journal   (4 followers)
Physics in Medicine & Biology     Full-text available via subscription   (7 followers)
Physics of Life Reviews     Hybrid Journal   (1 follower)
Physics of Plasmas     Hybrid Journal   (6 followers)
Physics of the Earth and Planetary Interiors     Hybrid Journal   (10 followers)
Physics of the Solid State     Hybrid Journal   (3 followers)
Physics of Wave Phenomena     Hybrid Journal   (2 followers)
Physics World     Full-text available via subscription   (3 followers)
Physik in unserer Zeit     Hybrid Journal  
Pirineos     Open Access  
Planet     Open Access  
Plasma Physics and Controlled Fusion     Partially Free   (2 followers)
Plasma Physics Reports     Hybrid Journal   (2 followers)
Polish Polar Research     Open Access   (4 followers)
Positioning     Open Access   (1 follower)
Pramana     Open Access   (8 followers)
Precambrian Research     Hybrid Journal   (4 followers)
Preview     Hybrid Journal  
Procedia Earth and Planetary Science     Open Access   (4 followers)
Proceedings in Marine Science     Full-text available via subscription   (3 followers)
Proceedings of the Geologists' Association     Full-text available via subscription   (3 followers)
Proceedings of the Linnean Society of New South Wales     Full-text available via subscription  
Proceedings of the Yorkshire Geological Society     Hybrid Journal  
Pure and Applied Geophysics     Hybrid Journal   (8 followers)
Quarterly Journal of Engineering Geology and Hydrogeology     Hybrid Journal   (5 followers)
Quaternary Australasia     Full-text available via subscription  
Quaternary Geochronology     Hybrid Journal   (4 followers)
Quaternary International     Hybrid Journal   (9 followers)
Quaternary Research     Full-text available via subscription   (14 followers)
Quaternary Science Reviews     Hybrid Journal   (10 followers)
Radiocarbon     Open Access   (2 followers)
Raumforschung und Raumordnung     Hybrid Journal  
Remote Sensing     Open Access   (8 followers)
Remote Sensing Letters     Hybrid Journal   (8 followers)
Remote Sensing Science     Open Access   (1 follower)
Rendiconti Lincei     Hybrid Journal  
Reports on Mathematical Physics     Full-text available via subscription  
Reports on Progress in Physics     Full-text available via subscription   (2 followers)
Resource Geology     Hybrid Journal   (4 followers)
Reviews in Mineralogy and Geochemistry     Full-text available via subscription  
Reviews of Modern Physics     Full-text available via subscription   (15 followers)
Revista Boletín Ciencias de la Tierra     Open Access   (2 followers)
Revista Brasileira de Geofísica     Open Access   (4 followers)
Revista de Ingenieria Sismica     Open Access  
Revista de la Sociedad Entomologica Argentina     Open Access   (2 followers)
Revista de Topografía Azimut     Open Access   (1 follower)
Revista Eletrônica Científica Inovação e Tecnologia     Open Access  
Revista Geológica de Chile     Open Access   (2 followers)
River Systems     Full-text available via subscription   (3 followers)
Rock Mechanics and Rock Engineering     Hybrid Journal   (4 followers)
Rocks & Minerals     Hybrid Journal   (1 follower)
Russian Geology and Geophysics     Hybrid Journal   (2 followers)
Russian Journal of Mathematical Physics     Hybrid Journal   (1 follower)
Russian Journal of Pacific Geology     Hybrid Journal   (1 follower)
Russian Physics Journal     Hybrid Journal   (1 follower)
Science China Earth Sciences     Hybrid Journal   (2 followers)
Science News     Hybrid Journal   (13 followers)
Scientific Annals of Stefan cel Mare University of Suceava. Geography Series     Open Access  
Scientific Journal of Earth Science     Open Access  
Scientific Reports     Open Access   (10 followers)
Scottish Journal of Geology     Hybrid Journal   (5 followers)
Sedimentary Basins of the World     Full-text available via subscription   (2 followers)
Sedimentary Geology     Hybrid Journal   (10 followers)
Sedimentology     Hybrid Journal   (8 followers)
Seismic Instruments     Hybrid Journal   (1 follower)
Seismological Research Letters     Full-text available via subscription   (1 follower)
Soil Dynamics and Earthquake Engineering     Hybrid Journal   (7 followers)
Solid Earth     Open Access   (3 followers)
Solid Earth Discussions     Open Access   (1 follower)
Southern Forests: a Journal of Forest Science     Hybrid Journal   (4 followers)
Standort - Zeitschrift für angewandte Geographie     Hybrid Journal   (1 follower)
Stratigraphy and Geological Correlation     Hybrid Journal   (1 follower)
Studia Geophysica et Geodaetica     Hybrid Journal   (4 followers)
Studia Geotechnica et Mechanica     Open Access  
Studia Universitatis Babes-Bolyai, Geologia     Open Access   (1 follower)
Survey Review     Hybrid Journal   (4 followers)
Surveys in Geophysics     Hybrid Journal   (6 followers)

  First | 1 2 3 4 5     

Soil Dynamics and Earthquake Engineering    [9 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0267-7261
     Published by Elsevier Homepage  [2556 journals]   [SJR: 1.116]   [H-I: 39]
  • Assessment of railway vibrations using an efficient scoping model
    • Abstract: Publication date: March 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 58
      Author(s): D.P. Connolly , G. Kouroussis , A. Giannopoulos , O. Verlinden , P.K. Woodward , M.C. Forde
      Vibration assessments are required for new railroad lines to determine the effect of vibrations on local communities. Low accuracy assessments can significantly increase future project costs in the form of further detailed assessment or unexpected vibration abatement measures. This paper presents a new, high accuracy, initial assessment prediction tool for high speed lines. A key advantage of the new approach is that it is capable of including the effect of soil conditions in its calculation. This is novel because current scoping models ignore soil conditions, despite such characteristics being the most dominant factor in vibration propagation. The model also has zero run times thus allowing for the rapid assessment of vibration levels across rail networks. First, the development of the new tool is outlined. It is founded upon using a fully validated three dimensional finite element model to generate synthetic vibration records for a wide range of soil types. These records are analysed using a machine learning approach to map relationships between soil conditions, train speed and vibration levels. Its performance is tested through the prediction of two independent international vibration metrics on four European high speed lines and it is found to have high prediction accuracy. A key benefit from this increased prediction accuracy is that it potentially reduces the volume of detailed vibration analyses required for a new high speed train line. This avoids costly in-depth studies in the form of field experiments or large numerical models. Therefore the use of the new tool can result in cost savings.


      PubDate: 2014-01-08T12:03:37Z
       
  • Comprehensive three dimensional finite element analysis, parametric study
           and sensitivity analysis on the seismic performance of
           soil–micropile-superstructure interaction
    • Abstract: Publication date: March 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 58
      Author(s): Ali Ghorbani , Hadi Hasanzadehshooiili , Elias Ghamari , Jurgis Medzvieckas
      A comprehensive dynamic three dimensional finite element model, which includes the effect of lots of important parameters on the micropiles seismic performance, has been presented. The validation of the built model has been carried out using remodeling a single degree of freedom shaking table test done by Mc Manus at the University of Canterbury. The gained results proved the accuracy of the constructed model. Then, using the parametric analysis, effects of all the earthquake characteristics, soil properties, superstructure and micropiles' cap and micropiles structure on the seismic performance of micropiles have been investigated by means of presenting internal forces and displacements which occurred as the main result of earthquake. Furthermore, using the data analysis, the most and the least influential parameters on internal forces are obtained based on the Cosine Amplitude Method (CAM).


      PubDate: 2014-01-04T12:05:45Z
       
  • In situ tests simulating traffic-load-induced settlement of alluvial silt
           subsoil
    • Abstract: Publication date: March 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 58
      Author(s): Xinzhuang Cui , Na Zhang , Jiong Zhang , Zhijun Gao
      In China, The Yellow River delta is the youngest large river delta, and the low liquid limit alluvial silt is widely distributed there. The silt is easy to liquefy so that the silt subsoil shows large settlement under traffic load. At present, few in situ model tests were conducted to study the traffic-load-induced settlement of silt subsoil. Therefore, a falling-weight simulation equipment of traffic load was developed. By adjusting the technical parameters such as the falling height of the weight, different types of traffic loads can be well simulated. With the equipment, in situ tests were carried out to study cumulative settlement of silt subsoil in the Yellow River delta. Tests indicate that the settlement and excess pore water pressures rapidly grow initially and then tend to be stable with increasing the number of load cycles, and they also increase with the magnitude of the traffic load. When the load attains a threshold value, liquefaction takes place in the silt subsoil. After terminating loading, the pore water pressure rapidly decreases and the settlement increases simultaneously, while after one hour they tend to stabilize. Based on Chai–Miura cumulative deformation model of soil, the traffic-load-induced cumulative settlement of silt subsoil was calculated and compared with the test results. The calculated cumulative settlement with increasing number of load cycles agrees well with the test results, except the initial phase of cyclic loading where the settlement observed in the situ tests is overestimated. This is mainly because Chai–Miura model assumes undrained conditions while the subsoil under traffic loads is partly drained.


      PubDate: 2013-12-31T13:30:35Z
       
  • Weighing the importance of model uncertainty against parameter uncertainty
           in earthquake loss assessments
    • Abstract: Publication date: March 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 58
      Author(s): Jeremy Rohmer , John Douglas , Didier Bertil , Daniel Monfort , Olivier Sedan
      Epistemic uncertainties can be classified into two major categories: parameter and model. While the first one stems from the difficulties in estimating the values of input model parameters, the second comes from the difficulties in selecting the appropriate type of model. Investigating their combined effects and ranking each of them in terms of their influence on the predicted losses can be useful in guiding future investigations. In this context, we propose a strategy relying on variance-based global sensitivity analysis, which is demonstrated using an earthquake loss assessment for Pointe-à-Pitre (Guadeloupe, France). For the considered assumptions, we show: that uncertainty of losses would be greatly reduced if all the models could be unambiguously selected; and that the most influential source of uncertainty (whether of parameter or model type) corresponds to the seismic activity group. Finally, a sampling strategy was proposed to test the influence of the experts’ weights on models and on the assumed coefficients of variation of parameter uncertainty. The former influenced the sensitivity measures of the model uncertainties, whereas the latter could completely change the importance rank of the uncertainties associated to the vulnerability assessment step.


      PubDate: 2013-12-31T13:30:35Z
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57




      PubDate: 2013-12-27T18:01:06Z
       
  • Behavior of a seismically isolated bridge crossing a fault rupture zone
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Alper Ucak , George P. Mavroeidis , Panos Tsopelas
      The effect of the fault rupture zone traversing a seismically isolated bridge is investigated utilizing a finite element model of a section of the Bolu Viaduct and a set of synthetic broadband strong ground motions simulated for the Bolu Viaduct site due to the 1999 Duzce earthquake. Both the original and a potential retrofit seismic isolation system designs are considered in the analyses. The results show double isolation system demands when fault crossing is considered, as compared to the case where fault crossing is ignored. The pier drift demands, however, remain comparable in both cases. Furthermore, the location of fault crossing along the bridge length, as well as the fault orientation with respect to the bridge longitudinal direction are shown to influence substantially the response of the seismically isolated bridge. Isolation system permanent displacements are greatly influenced by the restoring force capability of the isolation system when fault crossing effects in the excitations are ignored. In the case of fault crossing, the permanent displacements of the isolation system are dominated by the substantial permanent tectonic displacement along the fault trace which is imposed upon the structure. The results of this study contribute to developing a better understanding of how seismically isolated bridges respond when traversed by fault rupture zones. The lack of analyses and design guidelines for bridges crossing faults in international standards renders this study a useful reference for the profession.


      PubDate: 2013-12-15T19:25:54Z
       
  • Requirements for soil-specific correlation between shear wave velocity and
           liquefaction resistance of sands
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Mohammad Mehdi Ahmadi , Nima Akbari Paydar
      The application of the simplified method for evaluating the liquefaction potential based on shear wave velocity measurements has increased substantially due to its advantages, especially for microzonation of liquefaction potential. In the simplified method, a curve is proposed to correlate the cyclic resistance ratio (CRR) with overburden stress-corrected shear wave velocity (V s1). However, the uniqueness of this curve for all types of soils is questionable. The objective of this research is to study whether the correlation between CRR and V s1 is unique or not. Besides, the necessity of developing the soil-specific correlations is also investigated. Based on laboratory test data, a new semi-empirical method is proposed to establish the soil-specific CRR–V s1 correlation. To validate the proposed method, a number of undrained cyclic triaxial tests along with bender element tests were performed on two types of sands. Similar experimental data for six other types of sands reported in the literature was also compiled. Applying the proposed method, soil-specific CRR–V s1 correlation curves were developed for these eight types of sands. It is shown that the correlation is not unique for different types of sands and the boundary curve proposed in the available simplified method can only be used as an initial estimation of liquefaction resistance. Finally, using the results of this study as well as previous ones, a chart is suggested to be used in engineering practice showing the conditions for which a detailed soil-specific CRR–V s1 correlation study needs to be performed.


      PubDate: 2013-12-15T19:25:54Z
       
  • Seismic isolation foundations with effective attenuation zones
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Zhifei Shi , Zhibao Cheng , Hongjun Xiang
      In this paper, a new configuration of seismic isolation foundation containing several concrete layers and some rubber blocks is proposed. The concrete layers and the rubber blocks are placed periodically to form a periodic foundation. To study the isolation ability of this new configuration of periodic foundation, an equivalent analytical model is established. For practical applications, two very useful formulas are obtained. Using these formulas, the low bound frequency and the width of the first attenuation zone can be directly approximated without the calculation of dispersion structure. This new configuration of seismic isolation foundation enjoys the first attenuation zone between 2.15Hz and 15.01Hz, which means that the components of seismic waves with frequencies from 2.15Hz to 15.01Hz cannot propagate upward in the foundation. To illustrate the efficiency of this seismic isolation foundation, the seismic responses of a 6-story frame with three different foundations are simulated. Numerical simulations show that the seismic responses of the structure with the periodic foundation are greatly attenuated as compared with those of the structure with no isolation base or with traditional rubber bearings.


      PubDate: 2013-12-15T19:25:54Z
       
  • Subsoil structure and site effects: A comparison between results from SPAC
           and HVSR in sites of complex geology
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Francisco J. Chávez-García , Maria V. Manakou , Dimitris G. Raptakis
      We present the results of the analysis of array recorded microtremors at 14 sites, close to the edges of the Mygdonian basin in northern Greece (Euroseistest). These measurements were made in order to better constrain the geometry and velocity structure of the basin as the soil layers taper out close to rock outcrop, where geology is complex and we may expect significant changes of the subsoil structure over short distances. The data were analysed using the SPAC method and HVSR. The first interprets the measurements as Rayleigh waves (for the vertical component we analysed) and allows to invert a phase velocity dispersion curve from computed correlation coefficients. The second estimates a local transfer function directly, from ratios of Fourier amplitude spectra. A phase velocity dispersion curve could be derived for 12 of the 14 measurement sites, and at three of the sites no resonant frequency was observed in the HVSR. It is encouraging that we obtained good results at most of our sites, in spite of the lateral heterogeneity expected close to the edges of Euroseistest. Our results allow us to obtain shear wave velocity models at most of the measurement sites (12 out of 14). They are also useful to explore the relation between size of the array and wavelength range for which a dispersion curve may be estimated, which in our case has strong limitations. We identify the frequency of resonance of the sediments as a small loss of coherency in SPAC’s correlation coefficients. Finally, we also consider the applicability of the joint inversion of the resonance frequency determined using HVSR and the phase velocity dispersion curve obtained from SPAC.


      PubDate: 2013-12-11T14:59:34Z
       
  • Exploring the feasibility of earthquake early warning using records of the
           2008 Wenchuan earthquake and its aftershocks
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Chaoyong Peng , Jiansi Yang , Bing Xue , Xiaoyi Zhu , Yang Chen
      Earthquake early warning system (EEWS) is one of the effective ways to mitigate earthquake damage and can provide few seconds to tens of seconds of advanced warning time of impending ground motions, allowing for mitigation measures to be taken in the short term. After the devastating Ms8.0 Wenchuan earthquake, hundreds of M4-6 earthquakes occurred with depth range of 2–24km. We explore a practical approach to earthquake early warning in Wenchuan area by determining a ground-motion period parameter τ c and a high-pass filtered vertical displacement amplitude parameter Pd from the initial 3s of the P waveforms of these aftershocks with M≥4.0. The empirical relationships both between τ c and M, and between Pd and peak ground velocity PGV for the Wenchuan area are presented. The τ c result shows that it is systematically greater for slow earthquakes, leading to a possible false alarm. The moment rate function is used to handle the fact that the Pd parameter alone miss the M=8.0 mainshock. These two relationships can be used to detect the occurrence of a major earthquake and provide onsite warning in the area around the station where onset of strong ground motions is expected within seconds after the arrival of the P wave. The robustness of onsite early warning can be increased by using multistation data when the station density is high or by combing τ c and Pd as a single indicator.


      PubDate: 2013-12-07T11:54:56Z
       
  • Experimental test of asymmetrical cable-stayed bridges using MR-damper for
           vibration control
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): G. Heo , C. Kim , C. Lee
      In this paper, a semi-active control by MR-damper is researched; its purpose is to effectively control vibration of asymmetrical cable-stayed bridges when earthquake is loaded on the type of bridge. For an experimental study, a model of 10.2m high and 28m long asymmetrical cable-stayed bridge structure was built being similar to a real one in size and function. A MR damper was also designed in proper size suitable for the control of the model. The experiment was performed in the way in which three piers were fixed on three shaking tables with 30% of El-centro earthquake wave, and a control device was placed on the lower part of its upper deck for horizontal control. As for control algorithms, Lyapunov and Clipped-optimal control algorithms were applied. The effectiveness of the semi-active control with MR damper for the asymmetrical cable-stayed bridge was measured under five control conditions: Un-control, Passive-off, Passive-on, Lyapunov Control, Clipped-optimal Control. The experiment showed that the semi-active control applying Lyapunov and Clipped-optimal algorithms effectively increased controllability almost in double, and decreased displacement 75% compared with the condition of passive-off. Therefore the semi-active method suggested in this paper is proven effective in controlling asymmetrical cable-stayed bridges.


      PubDate: 2013-12-07T11:54:56Z
       
  • Symmetric matrix-valued transmitting boundary formulation in the
           time-domain for soil–structure interaction problems
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Antonio Cazzani , Peter Ruge
      Time-domain formulations for soil–structure interaction problems with an unbounded soil-domain (the so-called far-field) including wave propagation require such time-domain formulations for both parts, soil and structure. For the structure (the near-field), typically treated by a finite element approach, the time-domain is used from the very beginning of the procedure. However, for the unbounded soil a representation by means of a frequency-dependent dynamic stiffness is usually available and it becomes necessary to devise techniques for switching from the frequency- to the time-domain. For various special cases in solid mechanics (e.g. plane, cylindrical and spherical waves) one-dimensional formulations in space have been used to derive scalar dynamical stiffness, to establish corresponding rational functions in the frequency-domain and transfer them into the time-domain in order to couple the near- and the far-field. A complete three-dimensional analysis for pile-groups through a linear homogeneous unbounded soil-domain and the corresponding description in the time-domain have already been treated by Cazzani and Ruge (2012, 2013) by means of a fully matrix-valued rational representation of a set of dynamic stiffness matrices K ( Ω ) , as a function of the angular frequency Ω . However, the symmetry of the input stiffness K ( Ω ) has not been maintained for the corresponding representation in the time-domain. This paper presents a fully matrix-valued rational formulation which does transfer the symmetry of K ( Ω ) to the corresponding formulation in the time-domain. Thus, the numerical treatment of the whole soil–structure interaction problem, coupling the far-field and near-field systems, can take advantage of algorithms for symmetric algebraic problems.


      PubDate: 2013-12-07T11:54:56Z
       
  • Yield acceleration and permanent displacement of a slope reinforced with a
           row of drilled shafts
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Arash Erfani Joorabchi , Robert Y. Liang , Lin Li , Hanlong Liu
      In this paper, a method for estimating yield acceleration of a slope reinforced with a row of equally spaced drilled shafts under a seismic excitation is presented. The method is based on a concept of soil arching due to rigid inclusions of drilled shafts on slope, which in turn reduces the driving force on the down-slope side of drilled shafts. Considering soil arching effects and earthquake-induced inertia forces, a limiting equilibrium based formulation was derived. A computer program was coded to allow for calculations of yield acceleration of a drilled shafts reinforced slope with complex slope geometry and soil profiles. Once yield acceleration is determined, then Newmark's method can be evoked to estimate permanent displacement of a slope reinforced with a row of drilled shafts under an earthquake excitation. A total of seven cases were presented to show that the proposed Newmark type calculation is adequate when compared to 3-D finite element analysis results.


      PubDate: 2013-12-07T11:54:56Z
       
  • Scaling of ground motions and its implications to plan-asymmetric
           structures
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Rana Roy , Pawan Thakur , Suvonkar Chakroborty
      Ground motions are often scaled to certain convenient target spectra in the response assessment of structures. While uniform hazard spectrum (UHS) is more widely used, conditional mean spectrum (CMS) is recently proposed as a more desirable target for scaling of real accelerograms. In this backdrop, the present study spectrally scales, using wavelets, a set of near-field and far-field ground motions to both the targets, viz., UHS and CMS. Relevance of a set of useful ground motion characteristics, viz., the peak ground acceleration-to-peak velocity ratio (a max /v max ), predominant period (T p ), Arias intensity (I a ), Housner intensity (I H ), cumulative absolute velocity (CAV) and significant duration (T d ⁎), is reviewed. Influence of ground motion scaling is discussed in terms of possible changes of such identified parameters. Seismic demand of horizontally irregular structures is assessed under both scaled and seed records recognizing strength dependent stiffness. Threshold of the scale factor, shown to have well-correlated with the change of ground motion characteristics, may be as high as ~10 to adequately estimate torsion-induced amplification in asymmetric system without any bias.


      PubDate: 2013-12-07T11:54:56Z
       
  • On effective characteristic of Rayleigh surface wave propagation in porous
           fluid-saturated media at low frequencies
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Yu Zhang , Yixian Xu , Jianghai Xia , Shuangxi Zhang , Ping Ping
      The analytical dispersion and waveform solutions of Rayleigh surface wave for the Biot fluid-saturated model are obtained at low frequencies for a homogeneous half space. The equivalent solution is also obtained by the equivalent-viscoelastic representation of the fluid-saturated model based on a single viscoelastic element for each wave modulus. The effective characteristics of the validations and limitations for the equivalent-viscoelastic model are analyzed by comparison of the numerical solutions of the fluid-saturated model and the equivalent model for the surface wave propagations. Our calculations show that the free boundary effects on the frequency dependent dispersion and time dependent dynamical waveforms of the surface wave in the Biot model are well fitted in a relative narrow low frequency band by the Zener elements in case of the frequency is much lower than the critical frequency f c of the porous material. The effective characteristics for air filled cases with a higher f c show a better result. Furthermore, if the critical frequency f c is low, always with high permeability κ under near surface condition, at low frequencies (e.g. the seismic frequency band <200Hz) the surface fluid drainage conditions influence Rayleigh-wave propagations obviously. The frequency range must hence be carefully checked for the viscoelastic representations. When the validated frequency range is defined, the viscoelastic elements can solve the transient surface wave propagation in porous media effectively. The convolution integral in wave modeling can be replaced by memory variables, which makes the field quantities calculated at every time step need not be stored. The effective representation saves the consumptions of computer time and storages, and supplies a more convenient approach to apply the surface wave considering poroelasticity.


      PubDate: 2013-12-07T11:54:56Z
       
  • Nonlinear dynamic analysis of Meloland Road Overpass using
           three-dimensional continuum modeling approach
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Amin Rahmani , Mahdi Taiebat , W.D. Liam Finn
      This paper presents a three-dimensional (3D) continuum nonlinear analysis of the Meloland Road Overpass (MRO) near El Centro, California. The modeling methodology and the computational tools are discussed in detail. The performance of the computational model is evaluated by comparing the computed responses with the responses recorded at the bridge site during the 1979 Imperial Valley and 2010 El Mayor-Cucapah earthquakes. Amongst the recorded earthquake events at the bridge site, these two events caused the strongest shaking. The comparison shows that the 3D model is potentially an effective tool for detailed analysis of a full bridge system including foundation soils, pile foundations, embankments, supporting columns, and the bridge structure itself in a unified system without relying on any ancillary models such as Winkler springs. Additional response parameters such as displacements, rockings, and bending moments are also evaluated although none of these was measured during the seismic events.


      PubDate: 2013-12-07T11:54:56Z
       
  • Geotechnical design with apparent seismic safety factors well-bellow 1
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): George Gazetas , Ioannis Anastasopoulos , Evangelia Garini
      The paper demonstrates that whereas often in seismic geotechnical design it is not realistically feasible to design with ample factor of safety against failure as is done in static design, an “engineering” apparent seismic factor of safety less than 1 does not imply failure. Examples from slope stability and foundation rocking illustrate the concept. It is also shown that in many cases it may be beneficial to under-design the foundation by accepting substantial uplifting and/or full mobilization of bearing capacity failure mechanisms.


      PubDate: 2013-11-25T12:02:01Z
       
  • Seismic performance of cylindrical
           latticed-intersected-three-dimensional-beam-system reticulated
           mega-structure with single-layer latticed-intersected-cylindrical-shell
           substructures
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Yongjun He , Xuhong Zhou , Jixin Wang
      This paper is focused on the research of seismic performance of cylindrical latticed-intersected-three-dimensional-beam-system (LITDBS) reticulated mega-structure with single-layer latticed-intersected-cylindrical-shell (LICS) substructures by time history method accounting for geometrical nonlinearity. The distribution laws of the dynamic internal forces and those of the ratios of the dynamic to static internal forces of members in this innovative structure are first studied. The behaviors of the structure under different multi-component seismic actions are analyzed, and the reasonable components of the seismic action that should be considered in design are thus obtained. Then taking the maximum dynamic internal force of the structure as the index, a series of parametric analyses are carried out, and the suitable values of several key form parameters are recommended. Additionally, the results by the response spectrum method with those by the time history method are compared, which indicates that the former is not on the safe side. Therefore, the mode-superposition response spectrum method can only be used to do preliminary seismic design of this kind of structure, and the results must be checked by the time history method at the end.


      PubDate: 2013-11-21T12:01:56Z
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56




      PubDate: 2013-11-21T12:01:56Z
       
  • Analytical solution of seismic pseudo-static active thrust acting on
           fascia retaining walls
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Venanzio R. Greco
      This paper presents a limit equilibrium method, based on the approach of Mononobe and Okabe, for calculating the active thrust on fascia retaining walls, where common methods cannot be used owing to the narrowness of the backfill which does not permit the development of the thrust wedge in the shape and sizes predicted by these methods. The proposed method examines three distinct failure mechanisms, called Mechanism 1, Mechanism 2 and Mechanism 3, where the thrust wedge is formed by one, two or three blocks, respectively; separated by plane slip surfaces. The seismic forces have been simulated with the pseudo-static method. For all three mechanisms, the active thrust is obtained in closed form: in particular, with a cubic equation for Mechanism 2, and with a system of two equations, one cubic and the other quartic, for Mechanism 3. Mechanisms with more than three blocks cannot have analytical solutions. The study is completed by an examination of some significant cases from which the higher attenuation of the seismic thrust, with respect to the static, emerges as the backfill width reduces.


      PubDate: 2013-11-21T12:01:56Z
       
  • A MATLAB toolbox for soil–structure interaction analysis with finite
           and boundary elements
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): P. Galvín , A. Romero
      In this work the numerical model SSIFiBo developed in MATLAB to study dynamic soil-structure interaction problems is presented. The model is based on a three dimensional boundary element-finite element coupled formulation in time domain. This model allows computing structural forced-vibrations, as well as seismic responses. Two numerical examples are solved with the proposed technique: ground-borne isolation with open and filled trench, and the seismic response of a tall chimney.


      PubDate: 2013-11-13T12:01:57Z
       
  • A power flow analysis of a double-deck circular tunnel embedded in a
           full-space
    • Abstract: Publication date: February 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 57
      Author(s): Arnau Clot , Jordi Romeu , Robert Arcos , Sara R. Martín
      The purpose of the present investigation is to obtain the mean power flow radiated by a double-deck circular tunnel and compares it to the one radiated by a simple circular tunnel. To achieve this, a harmonic line load is applied on the interior floor of the first one and at the bottom of the second one. For the double-deck tunnel, a new analytical model based on the receptance method is developed. The proposed model describes the dynamics of the interior floor using the thin plate theory and considers the Pipe in Pipe (PiP) model to describe the tunnel and soil coupled system. Plain strain conditions are assumed for both systems and conservative coupling is considered between them. Numerical results show significant differences between the power flow radiated by both tunnels, with the one radiated by the double-deck tunnel reaching much higher values. The effect of modifying the flexural rigidity of the interior floor is also presented.


      PubDate: 2013-11-13T12:01:57Z
       
  • Liquefaction characteristics of gap-graded gravelly soils in K0 condition
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): Wen-Jong Chang , Chi-Wen Chang , Jhang-Kai Zeng
      A series of undrained cyclic direct simple shear tests, which used a soil container with a membrane reinforced with stack rings to maintain the K 0 condition and integrated bender elements for shear wave velocity measurement, were performed to study the liquefaction characteristics of gap-graded gravelly soils with no fines content. The intergrain state concept was employed to categorize gap-graded sand–gravel mixtures as sand-like, gravel-like, and in-transition soils, which show different liquefaction characteristics. The testing results reveal that a linear relationship exists between the shear wave velocity and the minor fraction content for sand–gravel mixtures at a given skeleton void ratio of the major fraction particles. For gap-graded gravelly sand, the gravel content has a small effect on the liquefaction resistance, and the cyclic resistance ratio (CRR) of gap-graded gravelly sands can be evaluated using current techniques for sands with gravel content corrections. In addition, the results indicate that the current shear wave velocity (V s ) based correlation underestimates the liquefaction resistance for V s values less than 160m/s, and different correlations should be proposed for sand-like and gravel-like gravelly soils. Preliminary modifications to the correlations used in current evaluations of liquefaction resistance have thus been proposed.


      PubDate: 2013-11-09T13:30:15Z
       
  • Seismic microzonation studies for the city of Ragusa (Italy)
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): S. Grasso , M. Maugeri
      The seismic history of the city of Ragusa (Italy), the geotechnical characterisation of the subsoil and the site response analysis should be correctly evaluated for the definition of the Seismic Geotechnical Hazard of the city of Ragusa, through geo-settled seismic microzoning maps. Basing on the seismic history of the city of Ragusa, the following earthquake scenarios have been considered: the “Val di Noto” earthquake of January 11, 1693 (with intensity X–XI on MCS scale, magnitude M W =7.41 and epicentral distance of about 53km); the “Etna” earthquake of February 20, 1818 (with intensity IX on MCS scale, magnitude M W =6.23 and epicentral distance of about 64km); the Vizzini earthquake of April 13, 1895 (with intensity I=VII–VIII on MCS scale, magnitude M W =5.86 and epicentral distance of about 26km); the “Modica” earthquake of January 23, 1980 (with intensity I=V–VI on MCS scale, magnitude M W =4.58 and epicentral distance of about 10km); the “Sicilian” earthquake of December 13, 1990 (with intensity I=VII on MCS scale, magnitude M W =5.64 and epicentral distance of about 50km). Geotechnical characterisation has been performed by in situ and laboratory tests, with the definition of shear wave velocity profiles in the upper 30m of soil. Soil response analyses have been evaluated for about 120 borings location by some non-linear 1-D models. Finally the seismic microzonation of the city of Ragusa has been obtained in terms of maps with different peak ground acceleration at the surface; shaking maps for the central area of the city of Ragusa were generated via GIS for the earthquake scenarios.


      PubDate: 2013-11-09T13:30:15Z
       
  • Editorial Board / Aims and Scope
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55




      PubDate: 2013-11-05T12:06:55Z
       
  • Methodology for estimating seismic coefficients for performance-based
           design of earthdams and tall embankments
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): Achilleas G. Papadimitriou , George D. Bouckovalas , Konstantinos I. Andrianopoulos
      Following an overview of pertinent literature, this paper presents a new methodology for estimating seismic coefficients for the performance-based design of earth dams and tall embankments. The methodology is based on statistical regression of (decoupled) numerical data for 1084 potential sliding masses, originating from 110 non-linear seismic response analyses of 2D cross sections with height ranging from 20 to 120m. At first, the methodology estimates the peak value of the seismic coefficient k hmax as a function of: the peak ground acceleration at the free field, the predominant period of the seismic excitation, the non-linear fundamental period of dam vibration, the stiffness of the firm foundation soil or rock layer, as well as the geometrical characteristics and the location (upstream or downstream) of the potentially sliding mass. Then, it proceeds to the estimation of an effective value of the seismic coefficient k hE, as a percentile of k hmax, to be used with a requirement for pseudo-static factor of safety greater or equal to 1.0. The estimation of k hE is based on allowable permanent down-slope deviatoric displacement and a conservative consideration of sliding block analysis.


      PubDate: 2013-11-05T12:06:55Z
       
  • Spatial zonations for regional assessment of seismic site effects in the
           Seoul metropolitan area
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): Chang-Guk Sun , Han-Saem Kim , Choong-Ki Chung , Heon-Cheol Chi
      Earthquake-induced hazards are profoundly affected by site effects related to the amplification of ground motions, which are strongly influenced by local geologic conditions such as soil thickness or bedrock depth and soil stiffness. In this study, an integrated geographic information system (GIS)-based system for geotechnical data, called the geotechnical information system (GTIS), was developed to establish a regional counterplan against earthquake ground motions in the Seoul metropolitan area. In particular, to reliably predict spatial geotechnical information, a procedural methodology for building the GTIS within a GIS framework was developed and applied to the Seoul area in Korea. To build the GTIS, pre-existing geotechnical data were collected in and around the study area, and then a walk-over site survey was conducted to acquire surface geo-knowledge data. In addition, the representative shear wave velocities for geotechnical layers were derived by statistically analyzing many seismic test data in Korea. The GTIS was used in a practical application to estimate site effects in the study area; seismic zoning maps of geotechnical earthquake parameters, such as the depth to bedrock and the site period, were created and presented as a regional synthetic strategy for earthquake risk assessment. Furthermore, seismic zonation of site classification was also performed to determine the site amplification coefficients for seismic design and seismic performance evaluation at any site and administrative sub-unit in the study area. The methodology and results of the case study of seismic zonations in the Seoul area verified that the GIS-based GTIS can be very useful for the regional estimation of seismic risk and also to support decisions regarding seismic hazard mitigation, particularly in the metropolitan area.


      PubDate: 2013-11-01T12:01:48Z
       
  • Simplified approximate method for analysis of rocking systems accounting
           for soil inelasticity and foundation uplifting
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): I. Anastasopoulos , Th. Kontoroupi
      A simplified approximate method to analyze the rocking response of SDOF systems lying on compliant soil is introduced, accounting for soil inelasticity and foundation uplifting. The soil–foundation system is replaced by a nonlinear rotational spring, accompanied by a linear rotational dashpot, and linear horizontal and vertical springs and dashpots. Considering a square footing on clay under undrained conditions, the necessary moment–rotation (M–θ) relations are computed through monotonic pushover finite element (FE) analyses, employing a thoroughly-validated constitutive model. Cyclic pushover analyses are performed to compute the damping–rotation (C R –θ) relations, necessary to calibrate the rotational dashpot, and the settlement–rotation (Δw–θ) relations, required to estimate the dynamic settlement. The effectiveness of the simplified method is verified through dynamic time history analyses, comparing its predictions with the results of 3D FE analyses. The simplified method is shown to capture the entire rotation time history θ(t) with adequate accuracy. The latter is used to compute the time history of dynamic settlement w(t), employing a simplified approximate procedure. The proposed simplified method should, by no means, be considered a substitute for more sophisticated analysis methods. However, despite its limitations, it may be utilized for (at least preliminary) design purposes.


      PubDate: 2013-10-24T11:06:10Z
       
  • A model for the seismic analysis of a periodic viaduct when considering
           the pile–soil–structure interaction
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): Jian-Fei Lu , Cheng-Yong He
      In this study, a new model is developed for the aseismic design of a periodic viaduct when the pile–soil–structure interaction is considered. To account for the influence of the pile–soil–structure interaction, a wavenumber domain boundary element method (WDBEM) model for the periodic pile row supporting the viaduct is developed using the sequence Fourier transform as well as the boundary element method for the elastic medium. By using the WDBEM model for the pile row, the transfer matrices for the beams and piers, the joint conditions at the beam–beam–pier (BBP) junction as well as the periodicity condition for the viaduct, the wavenumber domain response of the periodic viaduct to spatially harmonic waves is determined. Based on the wavenumber domain response of the viaduct, the space-domain response of the viaduct to an arbitrary seismic wave can be obtained by invoking the inverse sequence Fourier transform method. Numerical results show that when the periodic viaduct is exposed to the spatially harmonic wave, resonances may occur at the bounding frequencies of the passbands of the characteristic waves of the viaduct. Also, it is found that the coincidence between the traveling seismic wave and characteristic waves of the viaduct will generate additional resonant frequencies located in passbands of the characteristic waves.


      PubDate: 2013-10-24T11:06:10Z
       
  • The performance of inclined secant micro-pile walls as active vibration
           barriers
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): A. Turan , D. Hafez , M.H. El Naggar
      The isolation of vibrations from the surroundings is one of the important problems in the design of machine foundations. The use of open trenches, infilled trenches, single and multiple pile rows have been widely studied. In this paper, the vibration screening efficiency of an inclined secant micro-pile wall positioned as an active vibration barrier is investigated. The study is performed using three-dimensional time domain finite element analyses. Various parameters such as barrier depth, inclination, barrier distance and load excitation frequency were studied. The results show that inclined secant micro-pile walls are a viable vibration isolation option for a multitude of vibration problems. It is shown that varying barrier inclination angle from 90° to 120° improved vibration isolation performance as high as 44% relative to the vertical barrier for the active isolation case. The effectiveness of the barrier increases as its depth increases and also as the excitation frequency increases. The orientation of the inclined barrier towards or against vibration source is shown to be a fundamental design consideration.


      PubDate: 2013-10-20T11:02:29Z
       
  • Seismic performance of earth-core and concrete-faced rock-fill dams by
           large-scale shaking table tests
    • Abstract: Publication date: January 2014
      Source:Soil Dynamics and Earthquake Engineering, Volume 56
      Author(s): Linjuan Yuan , Xiaosheng Liu , Xiaogang Wang , Yusheng Yang , Zhengquan Yang
      Two of China's highest earth-core rock-fill dams (ECRDs) and concrete-faced rock-fill dams (CFRDs) were simulated by large-scale earthquake simulation shaking table tests in this work. A series of staged tests were performed, including white noise, different types of earthquake excitations with different magnitudes etc. The seismic performance of the ECRD and CFRD models were analyzed and investigated. The test results indicated that reservoir impoundment influenced the structure and seismic characteristics of the ECRD model much more than the CFRD model. The average fundamental frequency of the CFRD decreased less than the ECRD model when subjected to strong excitation. The acceleration amplification factors decreased as the input peak acceleration increased. The maximum acceleration occurred at the top of the ECRD model, while it occurred at 0.6–0.9dam height of the CFRD model. Seismic residual deformations of the two models were very small. When subjected to strong earthquake excitation, the residual deformation of the CFRD model was smaller than that of the ECRD model. The dominant failure pattern of the two models was shallow sliding at the height of 3/4 on the downstream slope. The above analysis indicated that seismic performance of CFRD was superior to ECRD.


      PubDate: 2013-10-20T11:02:29Z
       
  • Seismic soil–pile–structure kinematic and inertial
           interaction—A new beam approach
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): A.E. Kampitsis , E.J. Sapountzakis , S.K. Giannakos , N.A. Gerolymos
      The main purpose of this study is to investigate the accuracy of an advanced beam model for the soil–pile–structure kinematic and inertial interaction and demonstrate its efficiency and advantages compared to other commonly used beam or solid models. Within this context, a Beam on Nonlinear Winkler Foundation model is adopted based on the Boundary Element Method (BEM), accounting for the effects induced by geometrical nonlinearity, rotary inertia and shear deformation, employing the concept of shear deformation coefficients. The soil nonlinearity is taken into consideration by means of a hybrid spring configuration consisting of a nonlinear (p–y) spring connected in series to an elastic spring–damper model. The nonlinear spring captures the near-field plastification of the soil while the spring–damper system (Kelvin–Voigt element) represents the far-field viscoelastic character of the soil. An extensive case study is carried out on a pile-column–deck system of a bridge, found in two cohesive layers of sharply different stiffness and subjected to various earthquake excitations, providing insight to several phenomena. The results of the proposed model are compared with those obtained from a Beam-FE solution as well as from a rigorous fully three-dimensional (3-D) continuum FE scheme.


      PubDate: 2013-10-20T11:02:29Z
       
  • Modified fish-bone model: A simplified MDOF model for simulation of
           seismic responses of moment resisting frames
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): A.R. Khaloo , H. Khosravi
      This paper presents a simplified Multi-Degree-Of-Freedom (MDOF) model through modification of fish-bone model (or generic frame). Modified Fish-Bone (MFB) model is developed through three enhancements: (i) the moment of inertia for half-beams is reduced slightly to modify the assumption of equal rotation at each story joints, (ii) a number of truss elements are inserted to the fish-bone model to simulate flexural deformation of moment frames due to axial elongation and contraction of columns, and (iii) moment–rotation relationship of representative rotational springs is supposed to be bilinear instead of trilinear in order to consider simultaneous yielding at both ends of the beam in moment frames. The proposed model is evaluated with respect to nonlinear dynamic analysis results of three classic moment resisting frames subjected to 94 records of FEMA-440 ground motion data set. Moreover, the adequacy of this model is compared with the fish-bone model and two predictors of nonlinear seismic demand. The statistical study of predicted interstory drift demonstrates the superiority of the proposed model over the fish-bone model and both seismic demand predictors.


      PubDate: 2013-10-16T12:35:41Z
       
  • Winkler model for dynamic response of composite caisson-piles foundations:
           Lateral response
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Rui Zhong , Maosong Huang
      As the first part of a sequence focusing on the dynamic response of composite caisson-piles foundations (CCPFs 1 1 CCPF: composite caisson-piles foundation ), this paper develops a simplified method for the lateral response of these foundations. A Winkler model for the lateral vibration of the CCPF is created by joining the two components, the caisson and the pile group, where the four-spring Winkler model is utilized for the caisson and axial–lateral coupled vibration equations are derived for the pile group. For determining the coefficients of the four-spring Winkler model for the caissons, embedded footing impedance is used and a modification on the rotational embedment factor is made for the sake of the geometrical difference between shallow footings and caissons. Comparisons against results from finite element simulations demonstrate the reliability of this modified four-spring Winkler model for caissons in both homogenous and layered soils. The proposed simplified method for the lateral vibration of CCPFs is verified also by 3D finite element modeling. Finally, through an example, the idea of adding piles beneath the caisson is proved to be of great significance to enhance the resistance of the foundation against lateral dynamic loads.


      PubDate: 2013-10-16T12:35:41Z
       
  • Stochastic strong ground motion simulations in sparsely-monitored regions:
           A validation and sensitivity study on the 13 March 1992 Erzincan (Turkey)
           earthquake
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Aysegul Askan , F. Nurten Sisman , Beliz Ugurhan
      Stochastic simulations have recently become quite popular for estimating synthetic ground motion time histories. For seismically active regions that are not well-monitored or studied extensively, input parameters of the simulations should be carefully selected as the reliability of the simulation results directly depends on the accuracy of the input parameters. In the first part of this study, 13 March 1992 Erzincan (eastern Turkey) earthquake (Mw=6.6), which is recorded at only three strong ground motion stations, is simulated using the stochastic finite-fault method. The source and regional path parameters for this event are adopted from previously validated studies whereas the local site parameters are derived herein. In the second part of the paper, sensitivity of the simulation results with respect to small changes in selected input seismic parameters is investigated. The parameters for which sensitivities are computed include stress drop, crustal shear-wave quality factor and kappa operator. A change of 20% in stress drop value results in 14% change in PGA, whereas a 20% difference in the Q 0 value causes 17% change in PGA, and a 20% variation in kappa leads to 15% difference in PGA. Numerical experiments presented in this study prove that the ground motion simulations are prone to trade-off between the source, path and site filters. Hence, input models must be implemented carefully for reliable synthetic ground motions.


      PubDate: 2013-10-16T12:35:41Z
       
  • Centrifuge model tests on liquefaction-induced settlement and pore water
           migration in non-homogeneous soil deposits
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Manika Maharjan , Akihiro Takahashi
      This paper presents the results of dynamic centrifuge model tests conducted to investigate the liquefaction mechanism in non-homogeneous soil deposits. Four types of model tests were conducted: one model test involved a uniform soil deposit; one involved continuous layered soil deposit; and two involved discontinuous layered soil deposits. Non-homogeneity in the tests was incorporated by including periodically distributed discontinuous silty sand patches. It was found that more excess pore water pressure (EPWP) remains for a longer period of time in the discontinuous region in non-homogeneous soil deposits compared with the continuous layered and uniform soil deposits. The generation of pore water pressure ceases the supply of a new mass of water after seismic excitation; therefore the dissipation of EPWP becomes the dominant factor for settlement after seismic excitation. The rapid dissipation of EPWP through the discontinuous part in the non-homogeneous soil deposits manifests as a larger settlement in the discontinuous part, causing non-uniform settlements.


      PubDate: 2013-10-16T12:35:41Z
       
  • Earthquake parameters affecting the performance of an RC frame with
           friction damper
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Semra Sirin Kiris , M. Hasan Boduroglu
      In this paper, correlation between the ground motion parameters and the peak displacement demand of a reinforced concrete single degree of freedom system retrofitted by friction dampers is investigated. The aim is to reveal the best parameters that are used in selecting earthquake records for nonlinear dynamic analysis of the system. Performing numerous nonlinear time history analyses, it is observed that different earthquake parameters play role in peak displacement demand related to the ranges formed by the different periods of a reinforced concrete frame, the strength ratio of total system at slip displacement and the stiff/soft soil profiles. For the both soil types, out of sixteen ground motion parameters, the eight, Spectral Response Acceleration, Peak Ground Acceleration, Effective Peak Acceleration, Maximum Incremental Velocity, Peak Ground Velocity, Arias Intensity, Arias Intensity-based Parameter and Effective Peak Velocity correlate better with peak displacement demand.


      PubDate: 2013-10-16T12:35:41Z
       
  • A simplified empirical method for assessing seismic soil-structure
           interaction effects on ordinary shear-type buildings
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Stefano Renzi , Claudia Madiai , Giovanni Vannucchi
      The beneficial or detrimental effect of seismic soil-structure interaction (SSI) is still a controversial issue. A parametric analysis of the seismic SSI effects of a large number of idealised ordinary shear-type buildings was carried out with some simplifying assumptions. Results were compared to the corresponding classical fixed-base solutions. Structures were modelled as generalised single degree of freedom systems using the principle of virtual displacements and shallow squared foundations resting on different soil types were assumed. The outcomes of the numerical analyses were used as a statistical base in order to obtain simple analytical and non-dimensional relationships for estimating seismic SSI effects in terms of modified period and damping. The proposed approximated method can be used by consultants in an immediate and simplified manner in order to obtain a preliminary evaluation of SSI effects and seismic demand without devoting resources to complex analyses.


      PubDate: 2013-10-12T11:02:02Z
       
  • Validation and improvement of N1 method for pushover analysis
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Paolo Giorgi , Roberto Scotta
      Many of the non-linear static methods for seismic assessment of buildings according to modern structural codes are based on the well-known N2 procedure. A more intuitive pushover procedure, N1, has recently been proposed. Its main advantage is that the explicit evaluation of an equivalent SDOF system is not required. The N1 method has been proved to provide the same accuracy as N2, but only when a lateral load distribution proportional to the first mode shape is involved. After a brief description of the main differences between the two methods, an improved version, the N1 corrected method, is presented here. It is more consistent with N2, also when constant acceleration lateral load patterns are applied. The N1 corrected method is validated according to an extensive parametric investigation of a set of case studies on steel and R/C frames, with regular and irregular mass distribution in height.


      PubDate: 2013-10-12T11:02:02Z
       
  • Small-strain constrained elastic modulus of clean quartz sand with various
           grain size distribution
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): T. Wichtmann , T. Triantafyllidis
      Approx. 120 resonant column (RC) tests with additional P-wave velocity measurements using piezoelectric elements have been performed on 19 clean quartz sands with piecewise linear, gap-graded, S-shaped or other smoothly shaped grain size distribution curves. For each material different pressures and densities were tested. It is demonstrated that the extended empirical equations for the small-strain constrained elastic modulus proposed by the authors in an earlier paper work well also for most of the more complex grain size distribution curves tested in the present study. These equations considering the influence of the uniformity coefficient of the grain size distribution curve were developed based on the data from tests on linear gradations. A further improvement of the prediction for the more complex grain size distributions can be achieved if the correlation equations are applied with a specially defined average inclination of the grain size distribution curve. Such an improvement is demonstrated not only for the small-strain constrained elastic modulus, but also for small-strain shear modulus, modulus degradation and Poisson's ratio.


      PubDate: 2013-10-12T11:02:02Z
       
  • Estimation of shear wave velocity of earth dam materials using artificial
           blasting test
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Ik-Soo Ha
      The objective of this study is to estimate the shear wave velocity of earth dam materials using the vibration generated from artificial blasting events, and to verify its applicability. In this study, near-field artificial blast testing and monitoring were carried out at the Seongdeok dam, Korea, as the first blasting tests to be carried out on an existing dam in Korea. Vibrations were induced by four different types of blasting, using various explosive charge weights and depths of blasting bore-holes. During the tests, acceleration time histories were measured at the rock outcrop adjacent to the point of the explosion, and at the crest of the dam. The fundamental frequency of the target dam was computed from the frequency analysis of measured acceleration histories. Numerical analyses were carried out, varying the shear modulus of the earth fill zone and using the acceleration histories measured at the rock outcrop as input ground motions. From a comparison between the fundamental frequencies calculated by numerical analyses and those of measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be estimated. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible, and that shear wave velocity can be consistently evaluated. Furthermore, by comparing the evaluated shear wave velocity with empirical formulae from previous research, the applicability of the method was verified. Therefore, in cases of mid-to-small earth dams, where the earthquake record is not available, the shear wave velocity of earth fill materials can be reasonably evaluated using blasting vibration records obtained at the site adjacent to the dam.


      PubDate: 2013-10-12T11:02:02Z
       
  • Influence of fines content on liquefied strength of silty sands
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Abouzar Sadrekarimi
      Critical state soil mechanics is a useful framework to understand sand behavior. In this paper, a relationship is developed for estimating undrained critical shear strength of sands based on the critical state framework. The relationship is validated by comparison with laboratory test results and sand liquefied strength from field liquefaction failure case histories. Using this relationship, the influence of fines content on undrained critical shear strength is studied for different combinations of effective stress and density. The parametric study indicates that depending on soil void ratio, effective stress, and the shape and mineralogy of the fine particles, undrained critical strength may increase, remain the same, or decrease as the amount of fines content increases. Both the susceptibility to liquefaction and the severity of strain-softening are affected by adding fines. It is suggested that the critical state parameter is inadequate for describing the behavior of liquefiable sands and sand shearing-compressibility should be taken into account in liquefaction analysis.


      PubDate: 2013-10-12T11:02:02Z
       
  • Phasing issues in the seismic response of yielding, gravity-type earth
           retaining walls – Overview and results from a FEM study
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): A. Athanasopoulos -Zekkos , V.S. Vlachakis , G.A. Athanasopoulos
      An overview of past and recent developments on the subject of seismic earth pressures on yielding, gravity-type walls, retaining cohesionless backfill, is first presented, focusing on available data on the issue of phase difference that develops between the peak values of wall inertia and seismic earth thrust increment. The results of a FEM parametric study are next presented regarding the dependence on the resulting dynamic earth thrust reduction – acting on the time of peak wall inertia – on backfill rigidity, wall height, and shaking characteristics. The reliability of the numerical analyses was verified by modeling centrifuge tests reported by Nakamura [24] and successfully comparing measured vs. computed behavior. The results of the parametric analyses indicate that the seismic active earth thrust, acting on the wall at the time of maximum wall inertia, is significantly reduced (compared to its peak value) with increasing shaking intensity of backfill, increasing wall displacements, increasing wall height, and decreasing backfill rigidity. No systematic dependence on the ratio of input motion frequency to the natural frequency of the backfill (f/f 1) was observed. The above findings: (1) verify earlier experimental and numerical results, (2) explain the reported lack of damage to retaining walls under strong ground shaking, and (3) indicate the need for revising the pertinent provisions of current seismic codes. Graphs summarizing the results of the numerical analyses are presented which may be used as a guide for selecting the magnitude of seismic active earth thrust that needs to be taken into account in the design of the examined type of earth retaining walls.


      PubDate: 2013-10-08T11:02:21Z
       
  • Vibration analysis of pile-supported embankments under high-speed train
           passage
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Pham-Ngoc Thach , Han-Long Liu , Gang-Qiang Kong
      Soft ground improvement using piles has increasingly been used as a rapid construction technique for railway and highway embankments over soft soil areas. While most studies conducted so far have addressed only issues of stability and settlement of pile-supported embankments under static loading, very limited attention has been paid to understanding their behaviors under transient loading of moving vehicles. In this study, vibration behaviors of this embankment system under high-speed train passage are investigated through three-dimensional finite element simulation. They include (1) characteristics of the surface wave field at high train speeds, (2) the dependence of vibration amplitude on the train speed and the phenomenon of critical speed, and (3) response at some typical locations in the system when the train moves at the critical speed. The study shows that there are breaks in the simulated wave fronts as transiting between different materials due to the difference in the Rayleigh wave speed among the materials relative to the train speed, and that the increase in train speed is accompanied by the increase in phase shift between the train load and the displacement pattern beneath the load. It is shown that the critical speed of the system is governed by the embankment, instead of the soft soil as commonly observed in previous studies in which the ground is not improved. Namely the vibration amplitude is maximally amplified when the train speed approaches the characteristic Rayleigh wave speed of the embankment material. In addition, the results also suggest that the sloping surfaces on the ballast and embankment along with the piles form a ‘trapping’ effect by which most of the train-induced waves, especially higher-frequency waves, incident to the sloping surfaces are trapped and dissipated within the pile-supported embankment system, and thus significantly reducing vibration amplitudes outside the embankment.


      PubDate: 2013-10-08T11:02:21Z
       
  • Static and cyclic behavior of North Coast calcareous sand in Egypt
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Manal Salem , Hussein Elmamlouk , Shehab Agaiby
      This research studies the behavior of calcareous sand located in the North Coast of Egypt, Dabaa area, under static and cyclic loading. The study is performed through a series of monotonic and cyclic undrained triaxial tests conducted on two relative densities and different effective confining pressures. The cyclic tests were carried out at different cyclic stress ratios. Failure under cyclic loading was found to be governed by the gradual development of excess pore water pressure until liquefaction is reached, rather than cumulative development of axial strain (cyclic mobility). The cyclic strength of the tested sand is compared with other calcareous and siliceous sands reported in the literature. The test results indicate that loose Dabaa calcareous sand has higher cyclic strength compared to other siliceous sands, probably due to the existence of different shapes of calcareous sand particles within the tested soil. Relationship between cyclic resistance ratio, effective confining pressure, and relative density was developed for the tested sand.


      PubDate: 2013-10-08T11:02:21Z
       
  • Evaluation of the performance of the face slab of a CFRD during earthquake
           excitation
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Yalin Arici
      The primary goal of this study was to examine the cracking behavior of the face plate of a CFRD during earthquake excitation. Analyses of the impounding stage and earthquake loading were conducted in sequential phases using a 2-D plane-strain model with the appropriate non-linear constitutive relationships for the dam constituents. The effect of rockfill stiffness and the face plate design properties on the seismic performance of the face plate was investigated. The crack widths on the plate increased with earthquake shaking. Settlement of the fill during intense seismic excitation counteracted this phenomenon by causing compression on the plate at some locations.


      PubDate: 2013-10-08T11:02:21Z
       
  • Non-linear static analysis of masonry buildings based on a strut-and-tie
           modeling
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Paolo Foraboschi , Alessia Vanin
      This paper presents an analytical method for evaluating the capacity curve of masonry buildings according to non-linear static analysis. This method splits the building into stories, and the vertical structures of each story into masonry panels, which are analyzed individually by a new push-over analysis. The behavior of each panel is reproduced with an evolutive strut-and-tie model, which simulates the uncracked and cracked behavior of the panel subjected to a vertical constant force and a lateral force that increases up to the complete development of the failure mechanism. The strut-and-tie model provides the capacity curve of the panel. The composition of the capacity curves of all the panels of a story provides the capacity curve of this story. The capacity curves of all the stories of the building can be used to obtain either the maximum drift that the building can withstand or the behavior factor of the structure. Either outcome allows the specific dissipation capacity and overstrength of the masonry building to be considered in the seismic analyses, which provides ultimate limit state verifications with more reliability. The proposed method is applied to a school building. The comparison between seismic safety assessed with this method and with a linear dynamic analysis, all other parameters being equal, shows that the latter approach is overly-conservative and misleading. In fact, the specific inelastic capacity, which only the former approach can consider, influences greatly the seismic behavior of the case study.


      PubDate: 2013-10-04T11:02:18Z
       
  • A two-rigid block model for sliding gravity retaining walls
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Riccardo Conti , Giulia M.B. Viggiani , Simone Cavallo
      This paper presents a new two-rigid block model for sliding gravity retaining walls. Some conceptual limitations of a direct application of Newmark's sliding block method to the case of retaining walls are discussed with reference to a simple scheme of two interacting rigid blocks on an inclined plane. In particular, it is shown that both the internal force between the blocks and their absolute acceleration are not constant during sliding, and must be computed by direct consideration of the dynamic equilibrium and the kinematic constraints for the whole system. The same concepts are extended to the analysis of the active soil wedge–wall system, leading to an extremely simple procedure for computing the relative displacements of the wall when subjected to base accelerations exceeding the critical value. A comparison with the results of numerical analyses demonstrates that the proposed method is capable of describing fully the kinematics of the soil wedge–wall system under dynamic loading. On the contrary, direct application of Newmark's method may lead to inaccurate predictions of the final displacements, in excess or in defect depending on a coefficient which emerges from direct consideration of the dynamic equilibrium of the whole system. This coefficient can be viewed as a corrective factor for the horizontal relative acceleration of the wall, related to the mechanical and geometrical properties of the soil–wall system.


      PubDate: 2013-10-04T11:02:18Z
       
  • Modeling of spatially correlated, site-reflected, and nonstationary ground
           motions compatible with response spectrum
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): De-Yi Zhang , Wei Liu , Wei-Chau Xie , Mahesh D. Pandey
      Seismic risk analysis and mitigation of spatially extended structures require the synthesis of spatially varying ground motions in the response history analysis of these structures. These synthetic motions are usually desired to be spatially correlated, site reflected, nonstationary, and compatible with target design response spectra. In this paper, a method is presented for simulating spatially varying ground motions considering the nonstationarity, local site effects, and compatibility of response spectra. The scheme for generating spatially varying and response spectra compatible ground motions is first established for spatial locations on the ground surface with varying site conditions. The design response spectrum is introduced as the “power” spectrum at the base rock. The site amplification approach is then derived based on the deterministic wave propagation theory, by assuming that the base rock motions consist of out-of-plane SH wave or in-plane combined P and SV waves propagating into the site with assumed incident angles, from which tri-directional spatial ground motions can be generated. The phase difference spectrum is employed to model ground motions exhibiting nonstationarity in both frequency and time domains with different site conditions. The proposed scheme is demonstrated with numerical examples.


      PubDate: 2013-09-26T15:31:40Z
       
  • Uniform hazard spectra in western Balkan Peninsula
    • Abstract: Publication date: December 2013
      Source:Soil Dynamics and Earthquake Engineering, Volume 55
      Author(s): Vincent Lee , Marijan Herak , Davorka Herak , Mihailo Trifunac
      Earthquake design codes, which are based on the performance-based design principles, aim to satisfy both the operational continuity and safety requirements for the designed structures. This calls for the design for at least two very different levels of strong earthquake shaking, and thus requires the amplitudes and the shapes of the elastic acceleration spectra to vary with geographic coordinates, and with the probabilities of exceedance. The traditional code procedures, which scale the design spectra in terms of peak ground acceleration and fixed shape spectra cannot meet these objectives. In this paper we show how the performance based design principles can be satisfied if the Uniform Hazard Spectral (UHS) method is used for scaling the design spectra. We illustrate this method for seismic zoning of the northwestern segment of the Bosnia and Herzegovina area, centered at Banja Luka in the Republic of Srpska. The method we present in this paper can be implemented in essentially all seismic regions of the world.


      PubDate: 2013-09-16T11:03:34Z
       
 
 
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
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2014