Influence of soil conditions on the seismic behaviour of two cable-stayed bridges

1995 ◽  
Vol 22 (5) ◽  
pp. 1021-1040 ◽  
Author(s):  
Mohamed Elassaly ◽  
Amin Ghali ◽  
Mamdouh M. Elbadry
Keyword(s):  
Soil Structure ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Seismic Behaviour ◽  
Internal Forces ◽  
Time Required ◽  
Cable Stayed Bridges

The results of a case study of the internal forces caused by earthquake in two examples of cable-stayed bridges are presented. A comparison is made between the behaviour of a model in which the structure is idealized without the foundation system and a model in which both the structure and the supporting foundation are idealized. The effects of varying the soil conditions on the seismic response are assessed. Also, the effects of out-of-phase support movements, caused by the lapse of time required for the seismic waves to travel from one support to the other, are considered. It is concluded that the effects of these parameters are significant and should not be ignored in the seismic analysis of cable-stayed bridges. Key words: bridges, cable-stayed, dynamic, earthquake, internal forces, seismic, soil–structure interaction.

scholarly journals Time Domain Implementation of Transmitting Boundaries in ABAQUS for Discrete Soil-structure Interaction Systems

2020 ◽  
Vol 5 (3) ◽  
pp. 447-462
Author(s):  
J. Rama Raju Patchamatla ◽  
P. K. Emani
Keyword(s):  
Time Domain ◽  
Soil Structure ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Discrete Models ◽  
Soil Structure Interaction ◽  
Finite Domain ◽  
Infinite Domains ◽  
Structure Interaction ◽  
Transmitting Boundaries

Soil-structure-interaction (SSI) analyses are essential to evaluate the seismic performance of important structures before finalizing their structural design. SSI under seismic condition involves much more complex interaction with soil compared to the dynamic loads having source on the structure. Seismic SSI analysis requires due consideration of site-specific and structure-specific properties to estimate the actual ground motion (scattered motion) experienced at the base of the structure, and subsequently the effects of the scattered motion on the structure. Most challenging aspect of seismic SSI analysis is to implement transmitting boundaries that absorb the artificial reflections of stress waves at the truncated interface of the finite and infinite domains, while allowing the seismic waves to enter the finite domain. In this paper, the time domain implementation of seismic analysis of a soil-structure system is presented using classical discrete models of structure and interactive force boundary conditions for soil. These models represent typical SSI systems- a single Degree of Freedom (DOF) of a spherical cavity with mass attached to its wall, a two DOF system consisting of a mass attached by a nonlinear spring to a semi-infinite rod on elastic foundation, and a three DOF system with additional DOFs for modelling the structural stiffness and damping. The convolution integral representing the force boundary condition on the truncated interface, is evaluated interactively using UAMP user-subroutine in ABAQUS and applied as concentrated forces at the interface (truncated interface) nodes of the bounded domain or generalized-structure domain. The verification problems presented in the paper show the satisfactory performance of the developed MATLAB code and ABAQUS implementation with FORTRAN user-subroutines. The classical phenomena associated with the dynamic soil-structure systems are discussed through the present work.

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.

Seismic Analysis Considering Soil-Structure Interaction

2004 ◽  
Author(s):  
Gangadhara Tilak Dulam ◽  
R. Sundaravadivelu
Keyword(s):  
Storage Tank ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Soil Structure Interaction ◽  
Single Pile ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Structure Interaction ◽  
Different Levels

The case study on LNG storage tank, Inchon, Korea which is supported by pile foundation system is carried out using Abaqus. The dynamic analysis is carried out on a single pile of this storage tank varying the ground accelerations, as 0.08g, 0.18g, 0.28g and 0.38g and maintaining the duration constant as 25 s. The spectral acceleration at the different levels of the piles are used to obtain the transfer function which is the ratio of spectral acceleration of the pile to ground acceleration. This paper will present the seismic response of single pile subjected to an earthquake at its bottom.

Effect of Soil Conditions on the Seismic Response of Spatial Structure

2011 ◽  
Vol 368-373 ◽  
pp. 2079-2083
Author(s):  
Su Duo Xue ◽  
Xiao Bing Luan ◽  
Xiong Yan Li
Keyword(s):  
Spatial Structure ◽  
Seismic Response ◽  
Axial Force ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Structure Interaction ◽  
Long Span

This paper is to study the seismic response of spatial structure incorporating the soil structure interaction (SSI). The SSI model for the long-span spatial structure with supporting substructure is proposed and the relevant soil parameters according to the IBC code are presented. A procedure for calculating the total damping ratios for one DOF system is used in the seismic analysis of spatial structure including SSI. The displacement and the axial force in the member under different soil conditions are compared and some important conclusions are drawn.

Effect of Structure-Soil-Structure Interaction (SSSI) between Three Dissimilar Adjacent Bridges

2021 ◽  
Author(s):  
Mohanad Talal Alfach ◽  
Ashraf Ayoub
Keyword(s):  
Seismic Response ◽  
Seismic Behavior ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Numerical Analyses ◽  
Seismic Responses ◽  
Structure Interaction ◽  
Internal Forces ◽  
Isolated Bridge ◽  
Effect Of Structure

Abstract The present study assesses the effect of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar adjacent bridges by comparing their seismic responses with the seismic response of the isolated bridge including Soil-Structure-Interaction (SSI). To this end, an extensive series of numerical analyses have been carried out to elicit the effects of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar bridges with different superstructure masses. The studied bridges are based on groups of piles founded in nonlinear clay. A parametric study has been performed for configurations of three dissimilar bridges with superstructure masses ratios of 200% and 300%, concentrating on the influence of the inter-bridge spacing, and the geometrical position of the bridges towards each other and towards the seismic excitation direction. The numerical analyses have been conducted using a three-dimensional finite difference modeling software FLAC 3D (Fast Lagrangian analysis of continua in 3 dimensions). The results of the numerical simulations clearly show that the seismic responses of the dissimilar grouped bridges were strongly influenced by the neighboring bridges. In particular, the results reveal a salient positive impact on the acceleration of the superstructure by a considerable drop (up to 90.63%) and by (up to 91.27%) for the internal forces induced in the piles. Comparably, the influence of bridge arrangement towards the seismic loading were prominent on both of superstructure acceleration and the internal forces in the piles. The responses were as much as 27 times lesser for the acceleration and 11 times smaller for the internal forces than the response of the isolated bridge. Contrarily, the inter-bridge spacing has a limited effect on the seismic response of the grouped bridges.

scholarly journals Assessing soil-structure interaction during the 2016 Central Italy seismic sequence (Italy): preliminary results

2016 ◽  
Vol 59 ◽  
Author(s):  
Arrigo Caserta ◽  
Fawzi Doumaz ◽  
Antonio Costanzo ◽  
Anna Gervasi ◽  
William Thorossian ◽  
...  
Keyword(s):  
Soil Structure ◽  
Central Italy ◽  
Seismic Energy ◽  
Soil Structure Interaction ◽  
Seismic Sequence ◽  
Structure Interaction ◽  
Preliminary Results ◽  
The Church ◽  
Moderate Magnitude

<p><em>We used the moderate-magnitude aftershocks succeeding to the 2016 August 24<sup>th</sup>, Mw = 6.0, Amatrice (Italy) mainshok to asses, specially during an ongoing seismic sequence, the soil-structure interaction where cultural Heritage is involved. We have chosen as case study the</em><em> San Giovanni Battista</em><em> church (A.D. 1039)  in Acquasanta Terme town, about 20 Km northeast of Amatrice. First of all we studied the soil shaking features in order to characterize the input to the monument. Then, using the recordings in the church, we tried to figure out  how the input seismic energy is distributed over the different monument parts. Some preliminary results are shown and discussed.</em></p><p><em><br /></em></p>

scholarly journals SSI AND SSSI EFFECTS IN SEISMIC ANALYSIS OF TWIN BUILDINGS: DISCRETE MODEL CONCEPT

2012 ◽  
Vol 18 (6) ◽  
pp. 890-898 ◽  
Author(s):  
Sadegh Naserkhaki ◽  
Hassan Pourmohammad
Keyword(s):  
Discrete Model ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Numerical Study ◽  
Elastic Half Space ◽  
Soil Structure Interaction ◽  
Model Concept ◽  
Structure Interaction ◽  
Twin Buildings ◽  
Hard Soils

This paper presents a numerical study of soil-structure interaction (SSI) and structure-soil-structure interaction (SSSI) effects on response of twin buildings during earthquake excitations. The buildings are modeled as shear buildings and the soil is simulated by a discrete model representing a visco-elastic half-space subjected to earthquake acceleration. Equation of motion of twin buildings with different conditions, fixed based (FB), SSI and SSSI, are developed via an analytical procedure and solved numerically. Buildings responses are evaluated for aforementioned three conditions considering various soil types and compared together. One must say that soil causes change in distribution of responses throughout the buildings while ignoring soil interaction may lead to detrimental effects on buildings. Anyway, interaction between twin buildings with SSSI condition slightly mitigates soil unfavorable effects compare to one building with SSI condition. In addition, it is found that influence of soil is very significant for soft to stiff soils whereas negligible for hard soils.

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