Vibration Control of Soil-structure Systems and Pile-soil-structure Systems

Lihua Zou,Leiqing Fang,Kai Huang,Liyuan Wang 대한토목학회 2012 KSCE JOURNAL OF CIVIL ENGINEERING Vol.16 No.5

The purpose of this paper is to investigate the influence of Soil-Structure Interaction (SSI) and Pile-Soil-Structure Interaction (PSSI) on vibration control effect. Assuming the ground as an isotropic elastic half space and the soil around the foundation as a horizontal and rotational spring-dashpot system, a SSI model for buildings with rigid shallow foundations is established. Based on Penzien model, a PSSI model for structures with pile-foundations is also set up. Then, after the motion and control equations of the SSI system and PSSI system are derived, the influences of SSI and PSSI on vibration control are investigated. Important parameters of soil and structures are studied. Numerical results show that the SSI and PSSI have an obvious influence on the control effect of structures. Parameters such as shear-wave velocity, embedded depth of soil and stiffness of superstructure and pile, play a significant role in vibration control. The influences of SSI and PSSI mainly depend on characteristics of the upper soil layer, hence, the SSI influence on buildings with rigid foundations is more obvious than that of PSSI on buildings with pile foundations.

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.

반복법을 이용한 면진적용 원전구조물의 지반-구조물 상호작용 해석

한승룡,남민준,서춘교,이상훈 한국지진공학회 2015 한국지진공학회논문집 Vol.19 No.1

The nuclear accident due to the recent earthquake in Japan has triggered awareness of the importance of safety with regard to nuclear power plants (NPPs). An earthquake is one of the most important parameters which governs the safety of NPPs among external events. Application of a base isolation system for NPPs can reduce the risk for earthquakes. At present, a soil-structure interaction (SSI) analysis is essential in the seismic design of NPPs in consideration of the ground structure interaction. In the seismic analysis of the base-isolated NPP, it is restrictive to consider the nonlinear properties of seismic isolation devices due to the linear analysis of the SSI analysis programs, such as SASSI. Thus, in this study, SSI analyses are performed using an iterative approach considering the material nonlinearity of the isolators. By performing the SSI analysis using an iterative approach, the nonlinear properties of isolators can be considered. The difference between the SSI analysis results without iteration and SSI with iteration using SASSI is noticeable. The results of the SSI analysis using an effective linear (non-iterative) approach underestimate the spectral acceleration because the effective linear model cannot consider the nonlinear properties of isolators. The results of the SSI analysis show that the horizontal response of the base-isolated NPP is significantly reduced.

유한요소법을 이용한 동적 지진하중을 받는 교량의 구조물-유체-지반 상호작용해석

류희룡,박영택,이재영 한국농공학회 2008 한국농공학회논문집 Vol.50 No.4

In construction facilities such as bridges, the fluid boundary layer(or water film) is formed at the structure-soil interface by the inflow into the system due to rainfall or/and rising ground-water. As a result, the structure-soil interaction(SSI) state changes into the structure-fluid-soil interaction(SFSI) state. In general, construction facilities may be endangered by the inflow of water into the soil foundation. Thus, it is important to predict the dynamic SFSI responses accurately so that the facilities may be properly designed against such dangers. It is desired to have the robust tools of attaining such a purpose. However, there has not been any report of a method for the SFSI analyses. The objective of this study is to propose an efficient method of finite element modelling using the new interface element named hybrid interface element capable of giving reasonable predictions of the dynamic SFSI response. This element enables the simulation of the limited normal tensile resistance and the tangential hydro-plane behaviour, which has not been preceded in the previous studies. The hybrid interface element was tested numerically for its validity and employed in the analysis of SFSI responses of the continuous bridge subjected to seismic load under rainfall or/and rising ground-water condition. It showed that dynamic responses of the continuous bridge resting on direct foundation may be amplified under rainfall condition and consequently lead to significant variation of stresses.

반복법을 이용한 면진적용 원전구조물의 지반-구조물 상호작용 해석

한승룡,남민준,서춘교,이상훈 한국지진공학회 2015 한국지진공학회논문집 Vol.19 No.1

The nuclear accident due to the recent earthquake in Japan has triggered awareness of the importance of safety with regard to nuclear power plants (NPPs). An earthquake is one of the most important parameters which governs the safety of NPPs among external events. Application of a base isolation system for NPPs can reduce the risk for earthquakes. At present, a soil-structure interaction (SSI) analysis is essential in the seismic design of NPPs in consideration of the ground structure interaction. In the seismic analysis of the base-isolated NPP, it is restrictive to consider the nonlinear properties of seismic isolation devices due to the linear analysis of the SSI analysis programs, such as SASSI. Thus, in this study, SSI analyses are performed using an iterative approach considering the material nonlinearity of the isolators. By performing the SSI analysis using an iterative approach, the nonlinear properties of isolators can be considered. The difference between the SSI analysis results without iteration and SSI with iteration using SASSI is noticeable. The results of the SSI analysis using an effective linear (non-iterative) approach underestimate the spectral acceleration because the effective linear model cannot consider the nonlinear properties of isolators. The results of the SSI analysis show that the horizontal response of the base-isolated NPP is significantly reduced.

지반-기초-구조물 상호작용을 고려한 말뚝 기초 구조물에서의 지진 하중 평가

유민택,하정곤,조성배,김동수 한국지진공학회 2014 한국지진공학회논문집 Vol.18 No.3

In this study, a series of dynamic centrifuge tests were performed for a soil-foundation-structural interaction system in dry sand with various embedded depths and superstructure conditions. Sinusoidal wave, sweep wave and real earthquake were used as input motion with various input acceleration and frequencies. Based on the results, a natural period and an earthquake load for soil-structure interaction system were evaluated by comparing the free-field and foundation accelerations . The natural period of free field is longer than that of the soil-foundation-structure system. In addition, it is confirmed that the earthquake load for soil-foundation-structure system is smaller than that of free-field in short period region. In contrast, the earthquake load for soil-foundation-structure interaction system is larger than that of free-field in long period region. Therefore, the current seismic design method, applying seismic loading of free-field to foundation, could overly underestimate seismic load and cause unsafe design for long period structures, such as high-rise buildings.

현장자료를 사용한 지반-구조물 상호작용에 대한 경험적 연구

김승현 한국지반공학회 2005 한국지반공학회논문집 Vol.21 No.2

In the field of earthquake engineering, recent improvements in many areas, such as seismological source modeling, analysis of travel path effects, and characterization of local site effects on strong shaking, have led to significant advances in both code-based and more advanced procedures for evaluating earthquake ground motions. A missing link, however, is empirically verified design procedures for assessing the effects of soil-structure interaction (SSI). Available Soil-Structure Interaction (SSI) analysis techniques range from simple substructure-type procedures to relatively sophisticated finite element procedures. The most common substructure approach for foundation-soil interaction is to use a frequency-dependent and complex-valued impedance function. This study uniquely evaluates impedance functions for two well-instrumented sites with significant inertial SSI effects using a system identification technique. The system identification analysis results are then compared to predictions from a simple theoretical model to gain insight into the intertial interaction effect in the subject sites.

유한요소법을 이용한 지진하중을 받는 교량의 구조물-유체-지반 동적 상호작용해석

류희룡,박영택,이재영,You, Hee-Yong,Park, Young-Tack,Lee, Jae-Young 한국농공학회 2008 한국농공학회논문집 Vol.50 No.4

In construction facilities such as bridges, the fluid boundary layer(or water film) is formed at the structure-soil interface by the inflow into the system due to rainfall or/and rising ground-water. As a result, the structure-soil interaction(SSI) state changes into the structure-fluid-soil interaction(SFSI) state. In general, construction facilities may be endangered by the inflow of water into the soil foundation. Thus, it is important to predict the dynamic SFSI responses accurately so that the facilities may be properly designed against such dangers. It is desired to have the robust tools of attaining such a purpose. However, there has not been any report of a method for the SFSI analyses. The objective of this study is to propose an efficient method of finite element modelling using the new interface element named hybrid interface element capable of giving reasonable predictions of the dynamic SFSI response. This element enables the simulation of the limited normal tensile resistance and the tangential hydro-plane behaviour, which has not been preceded in the previous studies. The hybrid interface element was tested numerically for its validity and employed in the analysis of SFSI responses of the continuous bridge subjected to seismic load under rainfall or/and rising ground-water condition. It showed that dynamic responses of the continuous bridge resting on direct foundation may be amplified under rainfall condition and consequently lead to significant variation of stresses.

Mitigation of the seismic response of a cable-stayed bridge with soil-structure-interaction effect using tuned mass dampers

Denise-Penelope N. Kontoni,Ahmed Abdelraheem Farghaly 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.6

A cable-stayed bridge (CSB) is one of the most complicated structures, especially when subjected to earthquakes and taking into consideration the effect of soil-structure-interaction (SSI). A CSB of a 500 m mid-span was modeled by the SAP2000 software and was subjected to four different earthquakes. To mitigate the harmful effect of the vibration generated from each earthquake, four mitigation schemes were used and compared with the non-mitigation model to determine the effectiveness of each scheme, when applying on the SSI or fixed CSB models. For earthquake mitigation, tuned mass damper (TMD) systems and spring dampers with different placements were used to help reduce the seismic response of the CBS model. The pylons, the mid-span of the deck and the pylon-deck connections are the best TMDs and spring dampers placements to achieve an effective reduction of the earthquake response on such bridges.

지진하중을 받는 교량 말뚝 기초부의 동적거동

마호성(Ho-beong Mha),박병진(Byung Jin Park),이덕주(Duk Ju Lee) 호서대학교 공업기술연구소 2007 공업기술연구 논문집 Vol.26 No.1

The dynamic behaviors of the pile-foundation of a bridge under earthquakes is analyzed to see the effect of the near-by soil foundation to the pile, using the commercial code MIDAS GTS . The soil-structure interaction(SSI) is examined by comparing the results of pile-foundation from both models with and without including the upper bridge mass. The displacements and accelerations of the pile at the different depths are evaluated and the maximum values obtained from time-histories of each value are depicted. The amplification and effect of SSI can be seen from the results.