Effect of Ground Motion Characteristics on Seismic Soil-Foundation-Structure Interaction

2015 ◽  
Vol 31 (3) ◽  
pp. 1789-1812 ◽  
Author(s):  
Majid Ghayoomi ◽  
Shideh Dashti
Keyword(s):  
Ground Motion ◽  
Free Field ◽  
Time History ◽  
Natural Period ◽  
Dense Sand ◽  
Structure Interaction ◽  
Flexible Base ◽  
Soil Foundation ◽  
Motion Characteristics ◽  
Foundation Structure

A series of dynamic centrifuge experiments involving a soil-structure model were performed to investigate the influence of ground motion characteristics on site performance and soil-foundation-structure interaction (SFSI) on medium-dense sand. When investigating kinematic SFSI, the translational component of the foundation motion was observed to de-amplify compared to the free-field in terms of most intensity parameters primarily during intense shaking and at higher frequencies. The building's fundamental rocking frequency was strongly influenced by the predominant frequency of the base motion. When investigating inertial SFSI, increasing the shaking intensity was observed to increase the flexible-base natural period of the structure. Spectral accelerations at the foundation level were significantly amplified near the building's flexible-base natural period. Structural settlements were greater than those in the free-field, and their rate followed the rate of the Arias intensity time history of the base motion. More holistic ground motion parameters, such as Arias and Housner Intensities, demonstrated a strong and consistent influence on SFSI and site performance.

scholarly journals Effects of Stratification on Soil–Foundation–Structure Interaction: Centrifugal Observation and Numerical Simulation

2021 ◽  
Vol 11 (2) ◽  
pp. 623
Author(s):  
Van-Linh Ngo ◽  
Changho Lee ◽  
Jae-Min Kim
Keyword(s):  
Soft Soil ◽  
Free Field ◽  
Soil Layer ◽  
Structure Interaction ◽  
Centrifuge Tests ◽  
Shear Beam ◽  
Soil Foundation ◽  
Input Motion ◽  
Layered Ground ◽  
Foundation Structure

It is essential to reduce structural damages caused by earthquakes in severe conditions, such as layered ground, especially when a soft soil layer is close to the surface. In this study, the kinematic and inertial interactions, two mechanisms of soil–foundation–structure interaction (SFSI), of different soil–foundation–structure systems (SFS) were investigated on uniform and layered grounds. Two layered soil profiles composed of a low stiffness layer laid over another were prepared in an equivalent shear beam container. Nine centrifuge experiments were carried out for three structures located on the surface of each ground and exposed to the Hachinohe earthquake while increasing the peak acceleration of the input motion. Numerical simulations were performed to simulate the centrifuge tests. It was found that roof motion (RM) of the tall structure increased in layered profile even though the free-field motion (FFM) decreased compared to homogeneous ground. The appearance of a soft layer beneath structures modifies the SFS system’s stiffness that causes kinematic and inertial interactions to alter to those on uniform soil profile.

The effect of soil-structure interaction on seismometer readings

1978 ◽  
Vol 68 (3) ◽  
pp. 823-843
Author(s):  
G. N. Bycroft
Keyword(s):  
Ground Motion ◽  
Soil Structure ◽  
Free Field ◽  
Soil Structure Interaction ◽  
Rigid Sphere ◽  
Elastic Space ◽  
Structure Interaction ◽  
Frequency Components ◽  
Low Shear

abstract Rocking and vertical and horizontal translations of typical “free-field” seismometer installations lead to magnification of the ground motion record. This magnification can be significant for the higher frequency components if the terrain has a relatively low shear-wave velocity. Seismometers placed on foundations which cover a significant part of a wavelength of a horizontally incident wave, experience an attenuated ground motion. A method of correcting the seismograms for these effects is given. Compliance functions for a rigid sphere in a full elastic space are derived and are used to show that, in practical cases, down-hole seismometer installations are not significantly affected by interaction. These compliance functions should be useful in discussing the soil structure interaction of structures erected on bulbous piles. They may be also used as the basis of a method of determining elastic constants of ground at depth, in situ, and at different frequencies.

Predictive Equations to Quantify the Impact of Spectral Matching on Ground Motion Characteristics

2016 ◽  
Vol 32 (1) ◽  
pp. 125-142 ◽  
Author(s):  
Clinton Carlson ◽  
Dimitrios Zekkos ◽  
Adda Athanasopoulos-Zekkos
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Time History ◽  
Peak Ground Velocity ◽  
Spectral Matching ◽  
Predictive Equations ◽  
Earthquake Scenarios ◽  
Cumulative Absolute Velocity ◽  
Motion Characteristics ◽  
The Impact

Spectral matching, the process of modifying a seed acceleration time history in intensity and frequency content until its acceleration response spectrum matches a target spectrum, is used extensively in practice. Predictive equations that quantify the impact of spectral matching on the peak ground velocity, peak ground displacement, Arias intensity, and cumulative absolute velocity of a scaled seed time history have been developed and validated on the basis of thousands of matched motions, three different earthquake scenarios, and numerous target spectra. It is found that spectral mismatch is the most critical factor affecting the changes in ground motion characteristics. The technique used for modification (e.g., time domain or frequency domain) is in many cases not critical. Based on the results, recommendations in order to minimize the impact of matching on the ground motion characteristics are provided.

Soil-Foundation-Structure Behavior at the Oakland Outer Harbor Wharf

1996 ◽  
Vol 1546 (1) ◽  
pp. 100-111
Author(s):  
G. Norris ◽  
R. Siddharthan ◽  
Z. Zafir ◽  
S. Abdel-Ghaffar ◽  
P. Gowda
Keyword(s):  
Pile Foundation ◽  
Free Field ◽  
Strong Motion ◽  
Structural Failure ◽  
Loma Prieta ◽  
Soil Foundation ◽  
Batter Piles ◽  
Foundation Structure

The California Strong Motion Instrumentation Program's Loma Prieta records at Oakland Outer Harbor Wharf maybe used to study the free-field motions, the possible softening of soils surrounding the piles supporting the instrumented wharf, the determination of the motion on the instrumented wharf using free-field motion input and deflection-compatible lateral and vertical pile foundation stiffnesses, and conditions under which a soil-foundation interaction failure or structural failure of the batter piles might have developed.

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