scholarly journals Effect of soil-structure interaction on the response of reactor structures to seismic ground motion. Final report

1970 ◽  
Author(s):  
R. Chiapetta
1978 ◽  
Vol 68 (3) ◽  
pp. 823-843
Author(s):  
G. N. Bycroft

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.


2012 ◽  
Vol 256-259 ◽  
pp. 1492-1495
Author(s):  
Xiao Yu Yan

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.


Author(s):  
Jim Xu ◽  
Sujit Samaddar

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.


1991 ◽  
Vol 7 (1) ◽  
pp. 1-27 ◽  
Author(s):  
N. A. Abrahamson ◽  
J. F. Schneider ◽  
J. C. Stepp

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
B. R. Jayalekshmi ◽  
S. V. Jisha ◽  
R. Shivashankar ◽  
S. Soorya Narayana

This paper presents numerical analysis of soil-structure-interaction (SSI) of tall reinforced concrete chimneys with piled raft foundation subjected to El Centro ground motion (1940) using finite element method. Seismic analysis in time domain was performed on the basis of direct method of SSI on the three-dimensional SSI system. The chimney, foundation, and soil were assumed to be linearly elastic in the analysis. The stress resultants and settlement of raft of piled raft foundation were evaluated under different soil properties and different geometrical features of raft and chimney. Soil properties were selected based on the shear wave velocity corresponding to sand in the loose to dense range. Chimneys with different elevations of 100 m, 200 m, and 400 m were taken with a ratio of height to base diameter of chimney of 17. Raft of different thickness was considered to evaluate the effect of stiffness of foundation. Results were analysed to assess the significance of characteristic of the ground motion. It is found that the response in the raft depends on the different parameters of chimney, foundation, and soil. It is also found that the higher modes of SSI system are significant in determining the response in the raft.


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