Dynamic Behavior of Sand/Rubber Mixtures. Part I: Effect of Rubber Content and Duration of Confinement on Small-Strain Shear Modulus and Damping Ratio

2011 ◽  
pp. 221-247
Author(s):  
Anastasios Anastasiadis ◽  
Kostas Senetakis ◽  
Kyriazis Pitilakis ◽  
Chrysanthi Gargala ◽  
Iphigeneia Karakasi
Keyword(s):  
Shear Modulus ◽  
Dynamic Behavior ◽  
Damping Ratio ◽  
Small Strain ◽  
Rubber Content ◽  
Small Strain Shear Modulus

Dynamic Behavior of Sand/Rubber Mixtures. Part I: Effect of Rubber Content and Duration of Confinement on Small-Strain Shear Modulus and Damping Ratio

2012 ◽  
Vol 9 (2) ◽  
pp. 103680 ◽  
Author(s):  
Anastasios Anastasiadis ◽  
Kostas Senetakis ◽  
Kyriazis Pitilakis ◽  
Chrysanthi Gargala ◽  
Iphigeneia Karakasi ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Dynamic Behavior ◽  
Damping Ratio ◽  
Small Strain ◽  
Rubber Content ◽  
Small Strain Shear Modulus

Small-Strain Shear Modulus and Damping Ratio of Sand-Rubber and Gravel-Rubber Mixtures

2011 ◽  
Vol 30 (2) ◽  
pp. 363-382 ◽  
Author(s):  
Anastasios Anastasiadis ◽  
Kostas Senetakis ◽  
Kyriazis Pitilakis
Keyword(s):  
Shear Modulus ◽  
Damping Ratio ◽  
Small Strain ◽  
Small Strain Shear Modulus

Shear modulus and damping ratio of sensitive Eastern Canada clays

2020 ◽  
Author(s):  
Mustapha Abdellaziz ◽  
Mourad Karray ◽  
Mohamed Chekired ◽  
Marie-Christine Delisle ◽  
Pascal Locat ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Damping Ratio ◽  
Small Strain ◽  
Eastern Canada ◽  
Equivalent Viscous Damping ◽  
Small Strain Shear Modulus ◽  
Undisturbed Samples ◽  
Wide Range ◽  
Linear Behaviour ◽  
Equivalent Viscous Damping Ratio

The shear modulus and equivalent viscous damping ratio of three sensitive clays from the sediments of the Champlain Sea were investigated using a combined triaxial simple shear apparatus. The tests were conducted on undisturbed samples and were carried out on a wide range of shear strain from about 0.001% to 1%. The values of the small strain shear modulus of the tested clays were further confirmed through a series of piezoelectric ring actuator and MASW tests. Although the shear modulus and damping ratio of the sensitive eastern Canada clays follow some classic literature models, the results show that the examined clays exhibited more linear behaviour. Such behaviour may be attributed to their highly structured nature compared to other clays. The compilation of available data on the shear modulus and damping ratio of several sensitive eastern Canada clays confirmed this trend and showed that some literature models might not be representative.

Physical Hypotheses for Adjusting Coarse Profiles and Improving 1D Site-Response Estimation Assessed at 10 KiK-net Sites

2020 ◽  
Vol 110 (3) ◽  
pp. 1338-1358 ◽  
Author(s):  
James Kaklamanos ◽  
Brendon A. Bradley ◽  
Aiswarya N. Moolacattu ◽  
Bradley M. Picard
Keyword(s):  
Shear Modulus ◽  
Site Response ◽  
Damping Ratio ◽  
Constitutive Models ◽  
Small Strain ◽  
Significant Finding ◽  
Response Models ◽  
High Frequencies ◽  
Small Strain Shear Modulus ◽  
Nonlinear Site Response

ABSTRACT One-dimensional (1D) linear, equivalent-linear, and nonlinear site-response models have been shown to be biased toward underprediction at high frequencies in the aggregate, particularly at small-to-medium strains. Because this bias persists among various constitutive models, we hypothesize that breakdowns in the 1D site-response assumptions and/or poorly characterized soil properties are responsible for the consistent underpredictions. We test four physical hypotheses for this persistent bias using 398 ground motions at 10 selected sites in Japan’s Kiban–Kyoshin (KiK-net) database that are adequately modeled by 1D wave propagation. Specifically, we (1) apply a depth-dependent shear-wave velocity (VS) gradient within layers, (2) decrease the small-strain damping ratio by half, (3) increase the small-strain shear modulus by 10%, and (4) randomize the VS profile. We find that the application of a depth-dependent VS gradient and the reduction of the small-strain damping ratio most greatly reduce the high-frequency bias; that the randomized VS profiles sometimes improve predictions at the fundamental site frequency but often lead to greater underpredictions at high frequencies; and that the 10% adjustment of the small-strain shear modulus has a minimal effect. A significant finding of this study is that overly coarse VS profiles, which are inadequately sampled in depth, induce considerable underprediction bias in site-response models at high frequencies. With regard to 1D site-response model improvement, this study suggests that greater attention should be paid to the coarseness of VS profiles and excessive impedance contrasts, and that profile corrections using depth-dependent VS gradients may be warranted in some cases.

The Small-Strain Shear Modulus and Damping Ratio of Quartz and Volcanic Sands

2012 ◽  
Vol 35 (6) ◽  
pp. 20120073 ◽  
Author(s):  
Kostas Senetakis ◽  
Anastasios Anastasiadis ◽  
Kyriazis Pitilakis
Keyword(s):  
Shear Modulus ◽  
Damping Ratio ◽  
Small Strain ◽  
Small Strain Shear Modulus

Small strain shear modulus and damping ratio of two unsaturated lateritic sandy clays

2020 ◽  
Author(s):  
C.W.W. Ng ◽  
Obed Takyi Bentil ◽  
Chao Zhou
Keyword(s):  
Shear Modulus ◽  
Damping Ratio ◽  
Small Strain ◽  
Resonant Column ◽  
Column Tests ◽  
Small Strain Shear Modulus ◽  
Confining Pressures ◽  
The Difference ◽  
Elastic Threshold ◽  
Scanning Electron

In this study, resonant column tests carried out to investigate the influence of suction on the shear modulus and damping ratio of two compacted lateritic sandy clays from Ghana (GL) and Nigeria (NL) are reported. Each type of soils was tested under two confining pressures and at three suctions. The microstructure of the soils was also studied through a scanning electron microscope. It is found that the effects of suction on maximum shear modulus (G<u><sub></u>0<u></sub></u>) are about 10% larger for GL than NL, mainly due to the existence of smaller aggregates in GL. Moreover, an increase in suction from 0 to 300 kPa for both soils resulted in a lower elastic threshold shear strain, different from the behaviour of other soils reported in the literature. The uniqueness of lateritic soils is likely attributed to their high sesquioxide content and much larger aggregates, which shrink upon an increase in suction. Drying of specimens from 0 to 300 kPa resulted in an increase of about 22% and 100% in initial damping ratio (D<sub>0</sub>) for GL and NL, respectively. The difference in D<sub>0</sub> for GL and NL and is attributed to larger aggregation of NL because of its higher iron sesquioxide content, leading to more cladding

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