One-Dimensional Dynamic Ground Response Analyses

1982 ◽  
Vol 108 (7) ◽  
pp. 935-952 ◽  
Author(s):  
Philippe P. Martin ◽  
H. Bolton Seed
2018 ◽  
Vol 7 (4.20) ◽  
pp. 45
Author(s):  
Heba Kamal

New Damietta City is situated in a locale of moderate notable seismicity about M6.25 have happened. These dangerous tremors started from the Mediterranean subduction zone among African and Eurasian plates and is underlain by soaked late Holocene stores. In this examination, the city of New Damietta was assessed regarding site intensification and site period. Geographical and geotechnical examination including information base of 543 boreholes were gathered from past geotechnical reports and corroborative exhausting logs were executed by the Lodging and Building national Exploration focus. These information were incorporated to decide the variety of the dirt profile and in addition the qualities of the dirt layers inside the investigation site. One dimensional ground response close examination using corresponding straight system and nonlinear procedure have been done. Nonlinear examinations' results were differentiated and those of the indistinguishable direct method, and both of the similarities and differences are discussed. It is assumed that because of nonlinearity of soil under strong ground developments, 1-D parallel direct showing overestimates the strengthening structures the extent that add up to upgrade level, and can't viably speak to full frequencies and hysteric soil lead. Along these lines, more reasonable and suitable numerical strategies for ground reaction examination ought to be reviewed  


Author(s):  
Tam Larkin ◽  
John Marsh

This paper presents the results of computer studies of the seismic site response of two dimensional alluvial valleys with a variety of geometries and material properties. The alluvial material is modelled as a nonlinear hysteretic solid and results are presented to illustrate the effect of material nonlinearity on surface ground response. Comparative studies with one dimensional analyses are presented and conclusions drawn as to ground conditions that are appropriate to one dimensional site analyses.


Author(s):  
Devdeep Basu ◽  
Arindam Dey ◽  
Shiv Shankar Kumar

Ground response analysis (GRA) helps to assess the influence of the soil medium on the propagating shear waves and indicates about the characteristics of the waves reaching the ground surface from the bedrock level. Such a study becomes imperative for the urbanized alluvial banks of North-Eastern region of India, which is located in the highest seismic zone of the country. Conventionally, GRA is carried out based equivalent linear approach, which being a simplistic approach is unable to capture the nonlinear characteristics of saturated silty sands subjected to seismic shaking. This article presents the outcome of seismic one-dimensional nonlinear GRA of IIT Guwahati (located on a varying geology in the saturated alluvial banks of River Brahmaputra) considering pore-water pressure dissipation characteristics and non-Masing unload-reload criteria. Various ground response parameters obtained from the study helps in the accurate identification of the earthquake intensity based site amplification of the region expressed through a 2-D mapping.


Author(s):  
Samuel Yniesta ◽  
Mallak Janati-Idrissi

During an earthquake, strain-rate effects affect both the stiffness and damping behaviour of soils, yet existing constitutive models for ground response analysis are typically formulated within a rate-independent framework. In this paper, a one-dimensional viscoplastic stress-strain model is presented to introduce strain rate effects in ground response analysis. Its constitutive equations are based on a model that uses a cubic spline fit of the modulus reduction curve and a coordinate transformation technique to match any input modulus reduction and damping curve. A viscous stress component is added to model the effect of strain rate on the mechanical behaviour of soils using a single input parameter. The model is able to reproduce the linear increase in shear strength with the logarithm of shear strain rate, and allows to introduce viscous effects in 1D ground response analysis with control over damping and modulus reduction behaviour. The model is implemented in a software for ground response analysis and used to predict the results of a centrifuge test modeling one-dimensional wave propagation. The results show that the model predicts accurately the amplification and attenuation of shear waves, in a context where strain rates impact significantly the response of the model.


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