Partitioned analysis of nonlinear soil-structure interaction using iterative coupling

Jahromi, H. Zolghadr,Izzuddin, B.A.,Zdravkovic, L. Techno-Press 2008 Interaction and multiscale mechanics Vol.1 No.1

This paper investigates the modelling of coupled soil-structure interaction problems by domain decomposition techniques. It is assumed that the soil-structure system is physically partitioned into soil and structure subdomains, which are independently modelled. Coupling of the separately modelled partitioned subdomains is undertaken with various algorithms based on the sequential iterative Dirichlet-Neumann sub-structuring method, which ensures compatibility and equilibrium at the interface boundaries of the subdomains. A number of mathematical and computational characteristics of the coupling algorithms, including the convergence conditions and choice of algorithmic parameters leading to enhanced convergence of the iterative method, are discussed. Based on the presented coupling algorithms a simulation environment, utilizing discipline-oriented solvers for nonlinear structural and geotechnical analysis, is developed which is used here to demonstrate the performance characteristics and benefits of various algorithms. Finally, the developed tool is used in a case study involving nonlinear soil-structure interaction analysis between a plane frame and soil subjected to ground excavation. This study highlights the relative performance of the various considered coupling algorithms in modelling real soil-structure interaction problems, in which nonlinearity arises in both the structure and the soil, and leads to important conclusions regarding their adequacy for such problems as well as the prospects for further enhancements.

Seismic equivalent linear response of a structure by considering soil-structure interaction: Analytical and numerical analysis

Maroua Lagaguine,Badreddine Sbartai 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.87 No.2

For a given structural geometry, the stiffness and damping parameters of the soil and the dynamic response of the structure may change in the face of an equivalent linear soil behavior caused by a strong earthquake. Therefore, the influence of equivalent linear soil behavior on the impedance functions form and the seismic response of the soil-structure system has been investigated. Through the substructure method, the seismic response of the selected structure was obtained by an analytical formulation based on the dynamic equilibrium of the soil-structure system modeled by an analog model with three degrees of freedom. Also, the dynamic response of the soil-structure system for a nonlinear soil behavior and for the two types of impedance function forms was also analyzed by 2D finite element modeling using ABAQUS software. The numerical results were compared with those of the analytical solution. After the investigation, the effect of soil nonlinearity clearly showed the critical role of soil stiffness loss under strong shaking, which is more complex than the linear elastic soil behavior, where the energy dissipation depends on the seismic motion amplitude and its frequency, the impedance function types, the shear modulus reduction and the damping increase. Excellent agreement between finite element analysis and analytical results has been obtained due to the reasonable representation of the model.

Lateral seismic response of building frames considering dynamic soil-structure interaction effects

S. Hamid RezaTabatabaiefar,Behzad Fatahi,Bijan Samali 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3

In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures,including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.

Evaluation of numerical procedures to determine seismic response of structures under influence of soil-structure interaction

Hamid Reza Tabatabaiefar,Behzad Fatahi,Kazem Ghabraie,Wan-Huan Zhou 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.56 No.1

In this study, the accuracy and reliability of fully nonlinear method against equivalent linear method for dynamic analysis of soil-structure interaction is investigated comparing the predicted results of both numerical procedures with the results of experimental shaking table tests. An enhanced numerical soil-structure model has been developed which treats the behaviour of the soil and the structure with equal rigour. The soil-structural model comprises a 15 storey structural model resting on a soft soil inside a laminar soil container. The structural model was analysed under three different conditions: (i) fixed base model performing conventional time history dynamic analysis, (ii) flexible base model (considering full soil-structure interaction) conducting equivalent linear dynamic analysis, and (iii) flexible base model performing fully nonlinear dynamic analysis. The results of the above mentioned three cases in terms of lateral storey deflections and inter-storey drifts are determined and compared with the experimental results of shaking table tests. Comparing the experimental results with the numerical analysis predictions, it is noted that equivalent linear method of dynamic analysis underestimates the inelastic seismic response of mid-rise moment resisting building frames resting on soft soils in comparison to the fully nonlinear dynamic analysis method. Thus, inelastic design procedure, using equivalent linear method, cannot adequately guarantee the structural safety for mid-rise building frames resting on soft soils. However, results obtained from the fully nonlinear method of analysis fit the experimental results reasonably well. Therefore, this method is recommended to be used by practicing engineers.

The effects of foundation size on the seismic performance of buildings considering the soil-foundation-structure interaction

Quoc Van Nguyen,Behzad Fatahi,Aslan S. Hokmabadi 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.6

Shallow footings are one of the most common types of foundations used to support mid-rise buildings in high risk seismic zones. Recent findings have revealed that the dynamic interaction between the soil, foundation, and the superstructure can influence the seismic response of the building during earthquakes. Accordingly, the properties of a foundation can alter the dynamic characteristics (natural frequency and damping) of the soil-foundation-structure system. In this paper the influence that shallow foundations have on the seismic response of a mid-rise moment resisting building is investigated. For this purpose, a fifteen storey moment resisting frame sitting on shallow footings with different sizes was simulated numerically using ABAQUS software. By adopting a direct calculation method, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behaviour of soil, foundation, and structure under seismic excitations. This three-dimensional numerical model accounts for the nonlinear behaviour of the soil medium and structural elements. Infinite boundary conditions were assigned to the numerical model to simulate free field boundaries, and appropriate contact elements capable of modelling sliding and separation between the foundation and soil elements are also considered. The influence of foundation size on the natural frequency of the system and structural response spectrum was also studied. The numerical results for cases of soil-foundation-structure systems with different sized foundations and fixed base conditions (excluding soil-foundation-structure interaction) in terms of lateral deformations, inter-storey drifts, rocking, and shear force distribution of the structure were then compared. Due to natural period lengthening, there was a significant reduction in the base shears when the size of the foundation was reduced. It was concluded that the size of a shallow foundation influences the dynamic characteristics and the seismic response of the building due to interaction between the soil, foundation, and structure, and therefore design engineer should carefully consider these parameters in order to ensure a safe and cost effective seismic design.

Lateral seismic response of building frames considering dynamic soil-structure interaction effects

RezaTabatabaiefar, S. Hamid,Fatahi, Behzad,Samali, Bijan Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3

In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes $C_e$, $D_e$ and $E_e$, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.

지반-구조물 상호작용을 고려한 장대교량의 동적 거동

임채민,박장호,신영석 한국안전학회 2004 한국안전학회지 Vol.19 No.2

The effect of soil-structure interaction becomes important in the design of civil structures such as long-span bridges, which are constructed in the site composed of soft soil. Many methodologies have been developed to account for the proper consideration of soil-structure interaction effect. However, it is difficult to estimate soil-structure interaction effect accurately because of many uncertainties. This paper presents the results of study on soil-structure interaction and dynamic response of a long-span bridge designed in the site composed of soft soil. The effect of the soft soil was evaluated by the use of computer program SASSI and a long-span bridge structure was modeled by finite elements. Dynamic response characteristics of a long-span bridge considering soil-structure interaction were investigated.

Soil-structure interaction and axial force effect in structural vibration

Gao, H.,Kwok, K.C.S.,Samali, B. Techno-Press 1997 Structural Engineering and Mechanics, An Int'l Jou Vol.5 No.1

A numerical procedure for dynamic analysis of structures including lateral-torsional coupling, axial force effect and soil-structure interaction is presented in this study. A simple soil-structure system model has been designed for microcomputer applications capable of reflecting both kinematic and inertial soil-foundation interaction as well as the effect of this interaction on the superstructure response. A parametric study focusing on inertial soil-structure interaction is carried out through a simplified nine-degree of freedom building model with different foundation conditions. The inertial soil-structure interaction and axial force effects on a 20-storey building excited by an Australian earthquake is analysed through its top floor displacement time history and envelope values of structural maximum displacement and shear force.

복잡한 지반 형상을 고려한 비선형 지반-구조물 상호작용 해석

박장호 ( Jang Ho Park ) 한국안전학회(구-한국산업안전학회) 2011 한국안전학회지 Vol.26 No.1

This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an unaligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil- structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach

Dynamic Soil-Structure Interaction Analysis for Complex Soil Profiles using Unaligned Mesh Generation and Nonlinear Modeling Approach

박장호,추프랑솨,조정래 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.4

Even if numerous studies were dedicated to propose soil-structure interaction analysis methods, most of these methods introduce several assumptions to circumvent the difficulties encountered in modeling and reduce computational efforts. The complex spatial configuration of the soil-foundation interface or the distribution of the soil medium are often simplified using flat-layered soil profiles and, the nonlinearity of the soil medium is generally dealt through an equivalent linear model. However, real soil profiles are featured by complex shapes, inclusion of discontinuities and nonlinear characteristics of soil. Accordingly, this paper presents a soil-structure interaction analysis method considering the characteristics of the structure, soil-structure interface and complex nonlinear distribution of the soil that could not be accurately modeled in previous methods. The proposed method adopts unaligned mesh generation and nonlinear modeling approach to model complex soil profiles. The validity and applicability of the nonlinear soil-structure interaction analysis method are verified through a numerical example.