scholarly journals Inelastic Response Spectra Due to the Weak Earthquakes Considering the Nonlinear Soft Soil Layer

2003 ◽  
Vol 7 (4) ◽  
pp. 15-22
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Response Spectra ◽  
Inelastic Response ◽  
Weak Earthquakes

Amplification Effects of Thin Soft-Surface Layers

2016 ◽  
Vol 32 (4) ◽  
pp. 2109-2126 ◽  
Author(s):  
W. D. Liam Finn ◽  
Francisco Ruz
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Tohoku Earthquake ◽  
Response Spectra ◽  
Surface Layers ◽  
Soft Layer ◽  
The 2011 Tohoku Earthquake ◽  
Amplification Factors ◽  
Soft Surface ◽  
Using Data

The amplification effects of shallow soft-surface layers with respect to an underlying hard-soil layer or rock are studied using data recorded from the 2011 Tohoku earthquake. Twenty-four sites have been studied with depths to rock ranging from 4–30 m. At each site, two records were available: one in rock at the bottom of the borehole at depths of 100–500 m and one on the surface of the soft-soil layer. Analyses of the soil-rock columns were conducted using the program SHAKE. Good agreement was found between calculated and recorded surface spectra, which demonstrated the reliability of SHAKE analyses for the sites under study. Therefore, SHAKE analyses were used to determine the outcrop motions at the top of rock. Amplification factors were determined by comparing characteristics of the surface and outcrop motions such as Fourier and response spectra. Computed amplification factors were correlated with V S30, V soil, and soft layer period, T = 4 H/ V soil. The results show clearly that the most reliable correlations for estimating the amplification of soft shallow surface layers less than 30 m are those based on V S30 and soft layer period, T.

Research on Inelastic Response Spectra for Asymmetric Plan Systems Subjected to Bi-Directional Earthquake Motions

2012 ◽  
Vol 166-169 ◽  
pp. 2332-2336
Author(s):  
Feng Wang ◽  
Hong Nan Li ◽  
Ting Hua Yi
Keyword(s):  
Soft Soil ◽  
Rotation Frequency ◽  
Response Spectra ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Inelastic Response ◽  
Surface Plasticity ◽  
Soil Site ◽  
Spectral Equation

The limitations of traditional inelastic response spectra are discussed. Considering a one-storey asymmetric plan system subjected to perpendicular bi-directional earthquake motions, the inelastic multi-dimensional strength reduction factor spectra is presented. The yield rule of the asymmetric plan system is determined by two-dimensional yield-surface plasticity function. The spectral equation is simplified by the relationship of strength reduction factors between x-direction and y-direction.The multi-dimensional spectra are analyzed based on 30 pair strong earthquake motion records for hard soil site, intermediate soil site and soft soil site. Analytic results shows that the strength reduction factor mean spectra for each soil site has its own characteristics, and the strength reduction factor spectra is affected strongly by ductility, normalized stiffness eccentricity, period and rotation frequency ratio.

Erdbebenantwortspektren einer weichen Bodenschicht auf einem Halbraum/Earthquake response spectra of a soft soil layer underlain by a halfspace

Bauingenieur ◽  
2016 ◽  
Vol 91 (04) ◽  
pp. 131-139
Author(s):  
Horst Werkle
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Response Spectra ◽  
Earthquake Response ◽  
Earthquake Response Spectra

Weiche Bodenschichten, wie sie beispielsweise als Tonschichten über steifen Sedimentböden auftreten, beeinflussen die Form eines horizontalen Erdbeben-Antwortspektrums aufgrund von resonanzartigen Effekten der einfallenden SH-Wellen erheblich. Daher werden etwa im EC 8 (deutsches NAD) für weiche Böden mit Scherwellengeschwindigkeiten unter 150 m/s besondere Untersuchungen gefordert. Auf der Grundlage einer intensiven Parameterstudie wurden für das Modell einer homogenen viskoelastischen Bodenschicht auf einem homogenen viskoelastischen Halbraum Gleichungen zur Beschreibung des zugehörigen horizontalen Beschleunigungsantwortspektrums entwickelt. An der Oberfläche des Halbraums wurde ein Antwortspektrum nach EC 8, Boden-/Untergrundklasse C-S angenommen. Die mit den Gleichungen erhaltenen Antwortspektren stimmen mit den nach der Theorie für eindimensionale Scherwellen erhaltenen Ergebnissen gut überein. Sie können unmittelbar zur Ermittlung der Erdbebenbeanspruchungen von Gebäuden auf einer weichen Bodenschicht nach EC 8 verwendet werden.

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

scholarly journals CONCERNING THE EXTRACTION OF A SLACK SOIL LAYER FROM COMPRESSIBLE THICKNESS OF FOUNDATION STRATUM OF FINITE WIDTH FOUNDATIONS

2019 ◽  
Vol 7 (4) ◽  
pp. 49-56
Author(s):  
Zaven Ter-Martirosyan ◽  
Armen Ter-martirosyan ◽  
Valery DEMYANENKO
Keyword(s):  
Analytical Solutions ◽  
Soft Soil ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Creep Model ◽  
Shear Stresses ◽  
Finite Width ◽  
Relative Depth ◽  
Weak Layer ◽  
Horizontal Displacements

The paper provides a quantitative assessment of the deflected mode of foundation stratum of finite width foundation, in the compressible thickness of which there is a slack clay soil layer. A number of criteria for assessing the possibility or impossibility of extruding a slack layer depending on its strength and rheological properties, as well as the relative thickness of the layer to its length (h/l) and the relative depth of the layer (h/d) have been given. Closed analytical solutions are given to determine the rate of Foundation precipitation depending on the rate of extrusion of the weak layer, including taking into account the damped and undamped creep. The analytical solutions in the article are supported by the graphical part made with the help of the Mathcad program. Plots of changes in shear stresses in the layer along the x axis at different distances from the axis and at different values 0, contours of horizontal displacement velocities in the weak layer at different distances from the x axis, plots of horizontal displacement velocities in the middle of the weak layer and plots of horizontal displacement velocities in the weak layer at different distances from the x axis are given. As a calculation model for describing the creep of a slack layer, rheological ones of the soil using power and hyperbolic functions and their modifications have been considered. In addition, most modern rheological models that take into account soil hardening during creep have been considered. Based on these models, the problem is solved by means analytical and numerical methods using the Mathcad PC and the PLAXIS PC according to the Soft Soil Creep model. The graphical part shows the isofields of horizontal displacements for 300 days and 600 days and the corresponding contours of horizontal displacements.

Model Test of Bearing Capacity of WasteTire Assembly Foundation on Soft Soil Layer

2021 ◽  
Vol 69 (7) ◽  
pp. 263-269
Author(s):  
Me ti ◽  
Tri Harianto ◽  
Abdul Rachman Djamaluddin ◽  
Achmad Bakri Muhiddin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soft Soil ◽  
Soil Layer

Soft soil layer-tunnel interaction under seismic loading

2020 ◽  
Vol 98 ◽  
pp. 103329 ◽  
Author(s):  
Qiangqiang Sun ◽  
Daniel Dias ◽  
Luis Ribeiro e Sousa
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Seismic Loading
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