Assessing the Effectiveness of Soil Parameters for Ground Response Characterization and Soil Classification

2008 ◽  
Vol 24 (3) ◽  
pp. 565-597 ◽  
Author(s):  
Simone Barani ◽  
Roberto De Ferrari ◽  
Gabriele Ferretti ◽  
Claudio Eva
Keyword(s):  
Response Spectrum ◽  
Soil Column ◽  
Soil Classification ◽  
Building Code ◽  
Soil Parameters ◽  
Ground Response ◽  
Velocity Response ◽  
Spectrum Intensity ◽  
Velocity Response Spectrum ◽  
Over The Top

The average shear wave velocity over the top 30 m of a soil profile ( VS,30) represents an usual parameter for soil classification in a modern building code for seismic design. In this work the ground response of about 100 soil profiles in Tuscany and Molise (Italy) is studied through 1-D numerical simulations in order to evaluate the reliability of European and Italian soil classifications based on the VS,30 criterion. The amplification factor, Fa, defined here as the ratio of the pseudo-velocity response spectrum intensity (Housner 1952) at the surface, S Is, to the pseudo-velocity response spectrum intensity at the rock outcrop, S Ir, is related to some soil parameters, such as VS,30, the fundamental frequency of vibration of the soil column, F0, and seismic impedance contrast, Iw. Analyzing the standard deviation of the residual obtained from regression analyses of Fa versus VS,30, F0, and Iw shows that F0 is the most helpful parameter for the prediction of Fa. Hence F0 appears to be more appropriate than VS,30 and Iw for the characterization of the seismic response of a site and, therefore, should not be disregarded in building code soil classifications.

scholarly journals Ultimate Seismic Resistance Capacity for Long Span Lattice Structures under Vertical Ground Motions

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Yoshiya Taniguchi
Keyword(s):  
Potential Energy ◽  
Response Spectrum ◽  
Estimation Method ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Frame Structures ◽  
Seismic Resistance ◽  
Long Span ◽  
Velocity Response ◽  
Velocity Response Spectrum

Seismic resistance capacities of frame structures have been discussed with equilibrium of energies among many researchers. The early one is the limit design presented by Housner, 1956; that is, frame structures should possess the plastic deformation ability equivalent to an earthquake input energy given by a velocity response spectrum. On such studies of response estimation by the energy equilibrium, the potential energy has been generally abandoned, since the effect of self-weight or fixed loads on the potential energy is negligible, while ordinary buildings usually sway in the horizontal direction. However, it could be said that the effect of gravity has to be considered for long span structures since the mass might be concerned with the vertical response. In this paper, as for ultimate seismic resistance capacity of long span structures, an estimation method considering the potential energy is discussed as for plane lattice beams and double-layer cylindrical lattice roofs. The method presented can be done with the information of static nonlinear behavior, natural periods, and velocity response spectrum of seismic motions; that is, any complicated nonlinear time history analysis is not required. The value estimated can be modified with the properties of strain energy absorption and the safety static factor.

Real-Time Prediction of Liquid Sloshing of Oil Storage Tank Based on Earthquake Early Warning

2009 ◽  
Author(s):  
Shinsaku Zama ◽  
Haruki Nishi ◽  
Minoru Yamada ◽  
Yoshihiro Hirokawa
Keyword(s):  
Real Time ◽  
Early Warning ◽  
Storage Tank ◽  
Response Spectrum ◽  
Liquid Sloshing ◽  
Time Prediction ◽  
Oil Storage ◽  
Oil Storage Tank ◽  
Velocity Response ◽  
Velocity Response Spectrum

For an efficient patrol to prevent and/or minimize secondary disaster such as fire breakout, diffusion of oil just after an earthquake, we investigated the possibility of real-time prediction of liquid sloshing of oil storage tank based on Earthquake Early Warning (EEW), and also investigated the estimation of volume of overflowed oil from a tank due to large liquid sloshing. As to velocity response spectrum prediction used in predicting liquid sloshing, we constructed the attenuation equation of spectral amplitude for far-field surface waves considering both the seismotectonics and the scaling law of the source characteristics. For estimation of the amount of overflowed oil, we executed experimental studies using a model tank of 7 m in diameter and proposed an empirical equation based on the velocity response spectrum and verified the validity of the formula for the past earthquakes. We applied these equations to the EEW in the 2008 Iwate/Miyagi inland earthquake (M7.2) for Sendai Oil Industrial Complex District, and obtained a good agreement between the predicted and the observed spectrum. Thus, it is expected that the information about the predicted sloshing behavior in a very early stage after a large earthquake using EEW, will be disseminated to person responsible for disaster countermeasures prior to communication congestion.

Study on Active Vibration Control of Seismic Isolation Structure With Variable Gain Using Spectrum Monitoring

2019 ◽  
Author(s):  
Ukyo Fujiwara ◽  
Nanako Miura ◽  
Akira Sone
Keyword(s):  
Seismic Wave ◽  
Seismic Isolation ◽  
Response Spectrum ◽  
Weighting Factor ◽  
Weighting Coefficient ◽  
Response Analysis ◽  
Time Varying ◽  
Long Period ◽  
Velocity Response ◽  
Velocity Response Spectrum

Abstract In this research, the seismic isolation structure which can switch the active control gains by the characteristics of the earthquake is proposed. As the number of high-rise buildings in urban areas in has increased in recent years, damage due to long-period earthquakes is expected to increase. In this paper, the focus is on the area of velocity response spectrum as an index of long-period earthquake. Then we design the time varying weighting coefficient from the area of the velocity response spectrum obtained from the seismic wave. The long periodicity of the earthquake is judged from the area of the velocity response spectrum calculated from the seismic wave arriving from moment to moment. In addition, we aim to improve the performance of the control system by inputting appropriate control power. We also aimed for energy saving of control by not performing control input within the range where the earthquake does not have a long period. We proposed a method of switching control using time varying weighting factor, designed time varying weighting factor, and confirmed its effectiveness by performing time history response analysis on actual seismic waves.

Preliminary Analysis of Correlation between Ground Response and Subsoil Softening

2011 ◽  
Vol 368-373 ◽  
pp. 2904-2907
Author(s):  
Long Wei Chen ◽  
Xian Zhang Ling ◽  
Xiao Ming Yuan
Keyword(s):  
Ground Motion ◽  
Preliminary Analysis ◽  
Response Spectrum ◽  
Velocity Ratio ◽  
Ground Response ◽  
Long Period ◽  
Long Span ◽  
1D Model ◽  
Spectrum Intensity ◽  
Changing Rate

Ground motion is closely related with subsoil properties. Under dynamic loading, subsoil tends to soften. Using a 1D model to simulate horizontal stratum, the correlation between ground motion and subsoil softening is investigated. Subsoil softening mainly influences ground motion, especially for long period components. Response spectrum intensity relative changing rate is proposed as an index for evaluating the influence of subsoil softening on ground motion. Response spectrum intensity relative changing rate keeps constant when shear wave velocity ratio v’/v0 is greater than 0.2 but increases dramatically with decreasing v’/v0 when v’/v0 is smaller than 0.2. Comparing to subsoil nonlinearity, subsoil liquefaction greatly increases long-period component energy which affects long period structures such as high rising buildings, long span structures

Statistical Analysis for Platform Height Ratio of Horizontal Components in Bedrock Seismic Oscillation Velocity Response Spectrum

2014 ◽  
Vol 624 ◽  
pp. 639-642
Author(s):  
Yu Yang Kong ◽  
Chao Lian ◽  
Chen Song
Keyword(s):  
Strong Ground Motion ◽  
Response Spectrum ◽  
Earthquake Magnitude ◽  
Far Field ◽  
Height Ratio ◽  
Velocity Response ◽  
Oscillation Velocity ◽  
Velocity Response Spectrum ◽  
Ground Motion Records ◽  
Strong Ground

Based on the strong ground motion records of the bedrock, the overall feature of ratio (H1/H2) of the platform height of two horizontal components in velocity response spectrum was analyzed. The results show that: (1) The platform height values of two horizontal components are different from each other; (2) H1/H2 decreases with the increasing of earthquake magnitude, decreases with the increasing of epicenter distance, and tends to be 1 in far field.

Research on the Damage Fracture of Rock Blasting Based on Velocity Response Spectrum

2011 ◽  
Vol 105-107 ◽  
pp. 1521-1527 ◽  
Author(s):  
Xin Jian Sun ◽  
Jian Sheng Sun
Keyword(s):  
Relative Velocity ◽  
Response Spectrum ◽  
Damage Effect ◽  
Blasting Vibration ◽  
Rock Blasting ◽  
Duration Time ◽  
Complex Process ◽  
Velocity Response ◽  
Velocity Response Spectrum ◽  
Two Parameter

The damage caused by blasting vibration on rock mass is an extremely complex process, and has certain impact on the mechanical properties and bearing capacity of the rock, which will affect the overall stability and safe operation of the construction. Therefore, studying on the damage effect of blasting vibration is very necessary. Taking Laxiwa hydropower station project as a background, the paper computed relative velocity response spectrum using monitoring and measuring blasting velocity as an excitation, then analysis was carried out to study the relationship between the depth of rock blasting and the integral value of relative velocity response spectrum as well as the index of cooperation of the integral value and the blast vibration’s duration time. The results show that using three-parameter (velocity, frequency, duration time) was clearly superior to two-parameter (velocity, frequency) on studying the damage fracture of rock blasting, and two-parameter was better than one-parameter (velocity) by analogy.

scholarly journals Stochastic Nonlinear Ground Response Analysis Considering Existing Boreholes Locations by the Geostatistical Method

2021 ◽  
Author(s):  
A.H. Amjadi ◽  
Ali johari
Keyword(s):  
Random Field ◽  
Mean Value ◽  
Response Analysis ◽  
Soil Parameters ◽  
Seismic Responses ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Geostatistical Method ◽  
Stationary Random Field

Abstract The field and laboratory evidence of nonlinear soil behavior, even at small strains, emphasizes the ‎importance of employing nonlinear methods in seismic ground response analysis. Additionally, ‎determination of dynamic characteristics of soil layers always includes some degree of uncertainty. Most of ‎previous stochastic studies of ground response analysis have focused only on uncertainties of soil ‎parameters, and the effect of soil sample location has been mostly ignored. This study attempts to couple ‎nonlinear time-domain ground response analysis with uncertainty of soil parameters considering existing ‎boreholes’ ‎location through a geostatistical method using a program written in MATLAB. To evaluate ‎the efficiency of the proposed method, stochastic seismic ground responses at construction location were compared with those of the non-stationary random ‎field method‎ through real site data. The ‎results demonstrate that applying the boreholes’ ‎location significantly affects not only the ground ‎responses but also their Coefficient Of Variation (COV). Furthermore, the mean value of the seismic ‎responses is affected more considerably by the values of soil parameters at the vicinity of the construction location. It is also inferred that considering boreholes’ location may reduce the COV of the seismic ‎responses. Among the surface responses in the studied site, the values of Peak Ground Displacement (PGD) ‎and Peak Ground Acceleration (PGA) reflect the highest and ‎lowest dispersion due to uncertainties of soil ‎properties through both non-stationary random field and geostatistical methods.

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