Analysis of Nonlinear Dynamic for Piles under Earthquake Loading

2013 ◽  
Vol 275-277 ◽  
pp. 1326-1329
Author(s):  
Jian Gen Lv ◽  
Jian Hui Qiu
Keyword(s):  
Dynamic Response ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Nonlinear Dynamic ◽  
Multiple Scales ◽  
Earthquake Loading ◽  
Soil Thickness ◽  
Nonlinear Dynamic Response ◽  
Seismic Force

The nonlinear dynamic response of piles in uniform foundation under earthquake loading is investigated. Based on the established nonlinear equations of motion of piles under earthquake loading, the approximate solution of the pile for the case of the resonance is obtained by the method of multiple scales. The effects of major parameters on seismic force are studied, such as, frequency ratio, shear wave velocity, soil thickness. And the effects of the major parameters on the frequency response curves of the pile in single layer soil are studied. Comparing with the non-resonant response of the pile, the effect of the resonance on the actual dynamic response is analyzed. The results shows that shear wave velocity and soil thickness have significant effect on the seismic force in soft clay, which have little effect on the seismic force in the other soil layers; soil thickness has the most important influence on the nonlinear dynamic response of pile and it is followed by the earthquake coefficient, the shear wave velocity in the effects.

Effects of Local Site Conditions on Seismic Responses of a Reactor Containment Structure

2006 ◽  
Author(s):  
Jian-Chu Chen
Keyword(s):  
Shear Wave ◽  
Half Space ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Response Spectra ◽  
Site Conditions ◽  
Pressurized Water ◽  
Soil Thickness ◽  
Local Site ◽  
Local Site Conditions

The effect of local site conditions on soil-structure interaction (SSI) responses of a pressurized water reactor (PWR) containment building founded on different site conditions was investigated using substructure SSI analysis procedure. The structure was analyzed for both surface and embedded foundation conditions for each site with an exception for one half-space site with shear wave velocity 5000 fps. Only the surface foundation was analyzed for this very stiff half-space site. A total of 23 analyses are presented in this paper. Responses including peak ground accelerations and response spectra at selected locations were compared. The results indicate that the local site conditions have a significant influence on SSI response particularly for the structure founded on the surface of shallow soil deposit overlying competent rock. For thick soil sites having shear wave velocity larger than 1000 fps and having soil thickness greater than 3.5 times the radius of the structure, the effect of the soil thickness is not important.

Seismic Site Classifications and Site Amplifications for the Urban Centres in the Shallow Overburden Deposits

2012 ◽  
Vol 3 (1) ◽  
pp. 86-108 ◽  
Author(s):  
P. Anbazhagan ◽  
M. Neaz Sheikh
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Classification System ◽  
Site Response ◽  
The United States ◽  
Site Classification ◽  
Soil Thickness ◽  
Soil Layers ◽  
China And India

This paper presents seismic site classification practices for urban centres in Australia, China, and India with special emphasis on their suitability for shallow soil sites. The geotechnical aspects of seismic site classifications play a critical role in the development of site response spectra, which is the basis for the seismic design of new structures and seismic assessment of existing structures. Seismic site classifications have used weighted average shear wave velocity of top 30 m soil layers, following the recommendations of National Earthquake Hazards Reduction Program (NEHRP) or International Building Code (IBC) site classification system. The site classification system is based on the studies carried out in the United States where soil layer may extend up to several hundred meters before reaching any distinct soil-bedrock interface. Most of the urban centers in Australia, China, and India are located on distinct bedrocks within few meter depth of soil deposits. For such shallow depth soil sites, NEHRP or IBC site classification system is not suitable. A new site classification based on average soil thickness, shear wave velocity up to engineering bedrock is proposed. The study shows that spectral value and amplification ratio estimated from site response study considering top 30 m soil layers are different from those determined considering soil thickness up to engineering bedrock.

scholarly journals Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Yaniv Darvasi ◽  
Amotz Agnon
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dead Sea ◽  
Attenuation Curve ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Moderate Seismicity ◽  
Local Point ◽  
The Dead

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

scholarly journals Multi-method site characterization to verify the hard rock (Site Class A) assumption at 25 seismograph stations across Eastern Canada

2021 ◽  
pp. 875529302110010
Author(s):  
Sameer Ladak ◽  
Sheri Molnar ◽  
Samantha Palmer
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Hard Rock ◽  
Site Characterization ◽  
Eastern Canada ◽  
Site Class ◽  
Paleozoic Rock ◽  
Rock Types ◽  
Site Period

Site characterization is a crucial component in assessing seismic hazard, typically involving in situ shear-wave velocity ( VS) depth profiling, and measurement of site amplification including site period. Noninvasive methods are ideal for soil sites and become challenging in terms of field logistics and interpretation in more complex geologic settings including rock sites. Multiple noninvasive active- and passive-seismic techniques are applied at 25 seismograph stations across Eastern Canada. It is typically assumed that these stations are installed on hard rock. We investigate which site characterization methods are suitable at rock sites as well as confirm the hard rock assumption by providing VS profiles. Active-source compression-wave refraction and surface wave array techniques consistently provide velocity measurements at rock sites; passive-source array testing is less consistent but it is our most suitable method in constraining the rock VS. Bayesian inversion of Rayleigh wave dispersion curves provides quantitative uncertainty in the rock VS. We succeed in estimating rock VS at 16 stations, with constrained rock VS estimates at 7 stations that are consistent with previous estimates for Precambrian and Paleozoic rock types. The National Building Code of Canada uses solely the time-averaged shear-wave velocity of the upper 30 m ( VS30) to classify rock sites. We determine a mean VS30 of ∼ 1600 m/s for 16 Eastern Canada stations; the hard rock assumption is correct (>1500 m/s) but not as hard as often assumed (∼2000 m/s). Mean variability in VS30 is ∼400 m/s and can lead to softer rock classifications, in particular, for Paleozoic rock types with lower average rock VS near the hard/soft rock boundary. Microtremor and earthquake horizontal-to-vertical spectral ratios are obtained and provide site period classifications as an alternative to VS30.

scholarly journals The Polito Surface Wave flat-file Database (PSWD): statistical properties of test results and some inter-method comparisons

2021 ◽  
Vol 19 (6) ◽  
pp. 2343-2370
Author(s):  
Federico Passeri ◽  
Cesare Comina ◽  
Sebastiano Foti ◽  
Laura Valentina Socco
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Active Surface ◽  
Statistical Properties ◽  
Test Results ◽  
Flat File ◽  
Research Fields ◽  
Database Content

AbstractThe compilation and maintenance of experimental databases are of crucial importance in all research fields, allowing for researchers to develop and test new methodologies. In this work, we present a flat-file database of experimental dispersion curves and shear wave velocity profiles, mainly from active surface wave testing, but including also data from passive surface wave testing and invasive methods. The Polito Surface Wave flat-file Database (PSWD) is a gathering of experimental measurements collected within the past 25 years at different Italian sites. Discussion on the database content is reported in this paper to evaluate some statistical properties of surface wave test results. Comparisons with other methods for shear wave velocity measurements are also considered. The main novelty of this work is the homogeneity of the PSWD in terms of processing and interpretation methods. A common processing strategy and a new inversion approach were applied to all the data in the PSWD to guarantee consistency. The PSWD can be useful for further correlation studies and is made available as a reference benchmark for the validation and verification of novel interpretation procedures by other researchers.

Shear Strength Monitoring System Based on Measurement of Shear Wave Velocity and Moisture Content

2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Shear Wave ◽  
Monitoring System ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Elements ◽  
Strength Measurement ◽  
Soil Shear Strength ◽  
The Relationship

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.

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