scholarly journals DYNAMIC SOIL-STRUCTURE INTERACTION CONSIDERING SPATIAL VARIATION OF GROUND MOTION IN AN ALLUVIAL VALLEY

1995 ◽  
Vol 60 (475) ◽  
pp. 65-74 ◽  
Author(s):  
Yuzo SHINOZAKI
Keyword(s):  
Spatial Variation ◽  
Ground Motion ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Alluvial Valley ◽  
Structure Interaction

scholarly journals Seismic Analysis of a Curved Bridge Considering Soil-Structure Interactions Based on a Separated Foundation Model

2020 ◽  
Vol 10 (12) ◽  
pp. 4260
Author(s):  
Lixin Zhang ◽  
Yin Gu
Keyword(s):  
Spatial Variation ◽  
Seismic Response ◽  
Ground Motion ◽  
Soil Structure ◽  
Bending Moment ◽  
Soil Structure Interaction ◽  
Small Radius ◽  
Curved Bridge ◽  
Structure Interaction ◽  
Foundation Model

A separated foundation model was proposed in order to reduce the calculation scale of the numerical model for analyzing soil-bridge structure dynamics. The essence of the wave input analysis model considering soil-structure interaction was analyzed. Based on the large mass method, a one-dimensional time-domain algorithm of the free field was derived. This algorithm could simulate the specified ground motion input well. The displacement expansion solution of the free wave field was solved based on the propagation law of waves in a medium. By separating the soil foundations around the pile foundations of the bridge, the ground motion was transformed into an equivalent load applied on an artificial boundary. The separated foundation model could consider the incoherence effect and soil-structure interaction simultaneously; the number of model elements were reduced, and the computational efficiency was improved. In order to investigate the seismic response of a curved bridge considering soil-structure interaction under spatially varied earthquakes, a curved bridge with small radius was adopted in practical engineering. Spatially correlated multi-point ground motion time histories were generated, and the nonuniform ground motion field was simulated based on the wave input method on an artificial viscoelastic boundary. The effects of different apparent wave velocities, coherence values, and site conditions on the seismic response of the bridge were analyzed. The results showed that the spatial variation of seismic ground motion had a considerable effect on the bending moment and the torsion of the girder. The site effect had great influence on the bending moment of the pier bottom. When considering soil-structure interaction, the spatial variation of ground motion should be fully considered to avoid underestimating the structural response.

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.

Introduction of Shaking Table Test of Rigid Frame Bridge Model

2012 ◽  
Vol 256-259 ◽  
pp. 1492-1495
Author(s):  
Xiao Yu Yan
Keyword(s):  
Ground Motion ◽  
Soil Structure ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Rigid Frame ◽  
Bridge Model ◽  
Support Excitation ◽  
Rigid Frame Bridge

To investigate the seismic response of long-span rigid frame bridges with high-pier, the shaking table test of a 1/10 scaled rigid frame bridge model is introduced in this paper. Details about test equipment, model design, test arrangement, input ground motion waves and test principle are provided. The response of bridge model under the seismic excitation included the uniform excitation and the multi-support excitation is observed. The influence of the soil-structure interaction on the bridge is considered through the real-time dynamic hybrid testing method. The impact effect for different ground motion input during the test is discussed. The influence of multi-support excitation, soil-structure interaction and impact effect on structural seismic responses are studied based on the test results. The isolation effectiveness and the damping effect are discussed as well.

Case Study: Effect of Soil-Structure Interaction and Ground Motion Incoherency on Nuclear Power Plant Structures

2009 ◽  
Author(s):  
Jim Xu ◽  
Sujit Samaddar
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Response ◽  
Ground Motion ◽  
Nuclear Power ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Structure Interaction

The soil-structure interaction (SSI) has a significant impact on nuclear power plant (NPP) structures, especially for massive and rigid structures founded on soils, such as containments. The U.S. Nuclear Regulatory Commission’s (NRC) Standard Review Plan (SRP) provides the requirement and acceptance criteria for incorporating the SSI effect in the seismic design and analyses of NPP structures. The NRC staff uses the SRP for safety review of license applications. Recent studies have indicated that ground motions in recorded real earthquake events have exhibited spatial incoherency in high-frequency contents. Several techniques have been developed to incorporate the incoherency effect in the seismic response analyses. Section 3.7.2 of Revision 3 of the SRP also provided guidance for use in the safety evaluation of seismic analyses considering ground motion spatial incoherency effect. This paper describes a case study of the SSI and incoherency effects on seismic response analyses of NPP structures. The study selected a typical containment structure. The SSI model is generated based on the typical industry practice for SSI computation of containment structures. Specifically, a commercial version of SASSI was used for the study, which considered a surface-founded structure. The SSI model includes the foundation, represented with brick elements, and the superstructure, represented using lumped mass and beams. The study considered various soil conditions and ground motion coherency functions to investigate the effect of the range of soil stiffness and the ground motion incoherency effect on SSI in determining the seismic response of the structures. This paper describes the SSI model development and presents the analysis results as well as insights into the manner in which the SSI and incoherency effects are related to different soil conditions.

Empirical Spatial Coherency Functions for Application to Soil-Structure Interaction Analyses

1991 ◽  
Vol 7 (1) ◽  
pp. 1-27 ◽  
Author(s):  
N. A. Abrahamson ◽  
J. F. Schneider ◽  
J. C. Stepp
Keyword(s):  
Ground Motion ◽  
Soil Structure ◽  
Epicentral Distance ◽  
Strong Motion ◽  
Soil Structure Interaction ◽  
High Frequencies ◽  
S Waves ◽  
Structure Interaction ◽  
Strong Ground ◽  
Spatial Coherency

The spatial coherency of strong ground motion from fifteen earthquakes recorded by the Lotung LSST strong motion array is analyzed. The earthquakes range in magnitude from 3.7 to 7.8 and in epicentral distance from 5 to 80 km. In all, a total of 533 station pairs are used with station separations ranging from 6 to 85 meters. Empirical coherency functions for the horizontal component S-waves appropriate for use in engineering analyses are derived from these data. The derived coherency functions are applicable to all frequencies and to separation distances up to 100 m. For these short station separations, the coherency decreases much faster with increasing frequency than with increasing station separation. The computed coherencies indicate that at high frequencies (>10 Hz) over 25 percent of the power of the ground motion is random for station separations greater than 30 m.

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