共查询到20条相似文献，搜索用时 31 毫秒
1.
This article demonstrates how system identification techniques can be successfully applied to a soil-structure interaction system in conjunction with the results of the forced vibration tests on the Hualien large-scale seismic test structure which was recently built in Taiwan for an international joint research. The parameters identified are the shear moduli of several near-field soil regions as well as Young's moduli of the shell sections of the structure. The soil-structure interaction system is represented by the finite element method combined with infinite element formulation for the unbounded layered soil medium. Preliminary investigations are carried out on the results of the static stress analysis for the soil medium and the results of the in-situ tests to divide the soil-structure system into several regions with homogeneous properties and to determine the lower and upper bounds of the parameters for the purpose of identification. Then two sets of parameters are identified for two principal directions based on the forced vibration test data by minimizing the estimation error using the constrained steepest descent method. The simulated responses for the forced vibration tests using the identified parameters show excellent agreement with the test data. The present estimated parameters are also found to be well compared with the average value of those by other researchers in the joint project. 相似文献
2.
考虑各向异性的层土-盾构隧道地震反应数值模拟 总被引：3，自引：0，他引：3
在层状各向异性土体-盾构隧道地震反应分析中,引入了横观各向同性弹塑性模型理论,建立了适合于横观各向同性介质的双渐近-多向透射边界条件。针对地铁区间盾构隧道抗震设计的特点,基于横观各向同性弹塑性模型,研制了考虑层状土体各向异性和施工开挖效应,适合于盾构隧道动力计算的各向异性弹塑性动力有限元程序。在程序中对于不同的材料采用了不同的本构关系和不同的单元形式,并采用了关联流动法则和多种屈服准则,可同时进行各向异性土体与地下结构的二维平面应力、平面应变和轴对称问题的静力和动力数值分析。最后利用所研制的程序进行了上海地铁二号线石门一路站附近区间隧道在不同超越概率地震动输入下的隧道反应计算。结果表明,在层状土体-地铁区间隧道的抗震分析中考虑土体各向异性的影响是必要的,所提出的计算模型是可行的。 相似文献
3.
The effect of soil conditions on strength reduction factors (SRFs) is investigated. Both site effect and soil-structure interaction (SSI) effect are considered in the study with special emphasis on the latter effect. The structure is modeled as an elasto-plastic single degree of freedom (SDOF) system, whereas the underlying soil is considered as a homogeneous half-space. The half-space is also replaced by a simplified 3DOF system, based on the concept of Cone Models. The whole 4DOF model is then analyzed under a total of 54 strong motions recorded on different soil types. A parametric study is done for a wide range of non-dimensional parameters, which completely define the problem. It is concluded that SSI reduces the SRF values, especially for the case of buildings located on soft soil. Consequently, using the fixed-base SRFs for soil-structure systems lead to non-conservative design forces. Simplified expressions are proposed to estimate SRF for soil-structure systems. 相似文献
4.
5.
Andrea Marchi Domenico Gallese Davide Noè Gorini Paolo Franchin Luigi Callisto 《地震工程与结构动力学》2023,52(1):164-182
The seismic performance of integral abutment bridges (IABs) is affected by the interaction with the surrounding soil, and specifically by the development of interaction forces in the embankment-abutment and soil-piles systems. In principle, these effects could be evaluated by means of highly demanding numerical computations that, however, can be carried out only for detailed studies of specific cases. By contrast, a low-demanding analysis method is needed for a design-oriented assessment of the longitudinal seismic performance of IABs. To this purpose, the present paper describes a design technique in which the frequency- and amplitude-dependency of the soil-structure interaction is modelled in a simplified manner. Specifically, the method consists of a time-domain analysis of a simplified soil-bridge model, in which soil-structure interaction is simulated by means of distributed nonlinear springs connecting a free-field ground response analysis model to the structural system. The results of this simplified method are validated against the results of advanced numerical analyses, considering different seismic scenarios. In its present state of development, the proposed simplified nonlinear model can be used for an efficient evaluation of the longitudinal response of straight IABs and can constitute a starting point for a prospective generalisation to three-dimensional response. 相似文献
6.
在土-结构的动力相互作用简化分析中,常采用双自由度集中参数模型简化土层.这种模型适合各向同性的单一土层,而实际工程场地的地基土多是各向异性的成层土层.为了将这一模型应用于此类土层,本文根据实际地震动记录,提出了一种变阻尼最小二乘反分析方法,可用来识别模型中的各个参数值.文中提出的方法具有适用范围广、计算精度较高的优点,并已通过编制FORTRAN程序加以实施和应用. 相似文献
7.
Green''''s functions for uniformly distributed loads acting on an inclined line in a poroelastic layered site 总被引：4，自引：0，他引：4
Based on one type of practical Biot's equation and the dynamic-stiffness matrices of a poroelastic soil layer and half-space, Green's functions were derived for uniformly distributed loads acting on an inclined line in a poroelastic layered site. This analysis overcomes significant problems in wave scattering due to local soil conditions and dynamic soil-structure interaction. The Green's functions can be reduced to the case of an elastic layered site developed by Wolf in 1985. Parametric studies are then carried out through two example problems. 相似文献
8.
This paper presents an input and system identification technique for a soil–structure interaction system using earthquake response data. Identification is carried out on the Hualien large‐scale seismic test structure, which was built in Taiwan for international joint research. The identified quantities are the input ground acceleration as well as the shear wave velocities of the near‐field soil regions and Young's moduli of the shell sections of the structure. The earthquake response analysis on the soil–structure interaction system is carried out using the finite element method incorporating the infinite element formulation for the unbounded layered soil medium and the substructured wave input technique. The criterion function for the parameter estimation is constructed using the frequency response amplitude ratios of the earthquake responses measured at several points of the structure, so that the information on the input motion may be excluded. The constrained steepest descent method is employed to obtain the revised parameters. The simulated earthquake responses using the identified parameters and input ground motion show excellent agreement with the measured responses. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
9.
We propose an effective and reliable time-domain substructure technique which takes soil-structure interaction effects into account and uses the flexibility coefficients of unbounded soil obtained in the frequency domain. Compared with previous methods, the frequency points to calculate flexibility coefficients, and computational loads in the calculation of time-domain interaction forces, are reduced. In the formulation, we have assumed the flexibility coefficient to be a periodic function, obtained within the bandlimited frequency range, which also includes the predominant frequencies of the structure and incident wave. Then we simulate the periodic flexibility coefficients using discrete impulse responses in the time-domain analyses. However, the real and imaginary parts of the bandlimited flexibility coefficients do not form a Hilbert transform pair; the discrete impulse responses should be modified to be causal for the time-domain analyses. We present various discrete impulse responses which have been obtained from only the real part, only the imaginary part and from both the real and imaginary parts of the frequency-domain flexibility coefficients by FFT with causality conditions. Through a numerical example the relationship between the modified discrete impulse responses and the validity of the time-domain substructure method is presented. 相似文献
10.
考虑土-结构相互作用和岩土参数不确定性的核电厂结构地震响应分析 总被引：2，自引：0，他引：2
针对核电厂结构,在考虑土-结构相互作用(SSI)的情况下进行随机地震反应分析,探讨地基岩土参数的不确定性对反应堆厂房楼层反应谱(FRS)的影响。运用ANSYS软件模块建立核电厂(NPP)结构有限元模型,通过设置边界弹簧单元和阻尼装置来考虑SSI效应;并且通过设置具有概率意义的弹簧刚度和阻尼系数,来模拟土特性参数的不确定性。随机响应分析与确定性分析的结果对比,揭示了岩性地基条件下SSI效应对核电厂FRS的影响以及地基岩土参数不确定性对FRS的影响程度。研究表明,在岩性地基条件下,亦不应忽略SSI效应;考虑SSI效应的随机分析模型同确定性模型相比,二者的分析结果较为接近,两方法都可用于NPP的FRS敏感性分析评估之中,并可进行相互比照。 相似文献
11.
A three-dimensional hybrid model for the analysis of soil-structure interaction under dynamic conditions is developed which takes advantage of the desirable features of the finite element and substructure methods and which minimizes their undesirable features. The modelling is achieved by partitioning the total soil-structure system into a near-field and a far-field with a hemispherical interface. The near-field, which consists of the structure to be analysed and a finite region of soil around it, is modelled by finite elements. The semi-infinite far-field is modelled by distributed impedance functions at the interface which are determined by system identification methods. Numerical results indicate that the proposed model makes possible realistic and economical assessment of three-dimensional soil-structure interaction for both surface and embedded structures. 相似文献
12.
Toyoaki Nogami 《Soil Dynamics and Earthquake Engineering》1996,15(7):419-429
A simple mechanical model is presented for the three-dimensional dynamic soil-structure interaction analysis of surface foundations. The model is made of one-dimensional vertical beams with distributed mass and horizontal springs which interconnect the two adjacent beams. Its parameters are rather uniquely related with the soil properties alone and thus are minimally dependent on the loading condition and the foundation conditions like geometry, flexibility and size. Formulations are provided to determine the model parameters from the soil properties. Solving the governing equations of this model, expressions for the subgrade behavior in response to the applied load and soil-foundation interaction are developed in analytical forms for various cases. The dynamic and static response of three-dimensional surface foundations are computed by these expressions. It is verified that the model is well capable of reproducing the three-dimensional soil-structure interaction behavior. 相似文献
13.
This paper investigates the effects of foundation embedment on the seismic behavior of fluid-elevated tank-foundation–soil system with a structural frame supporting the fluid containing tank. Six different soil types defined in the well-known seismic codes were considered. Both the sloshing effects of the fluid and soil-structure interaction of the elevated tanks located on these six different soils were included in the analyses. Fluid-elevated tank-foundation–soil systems were modeled with the finite element (FE) technique. The fluid-structure interaction was taken into account using Lagrangian fluid FE approximation implemented in the general purpose structural analysis computer program, ANSYS. FE model with viscous boundary was used to include elevated tank-foundation–soil interaction effects. The models were analyzed for the foundations with and without embedment. It was found that the tank roof displacements were affected significantly by the embedment in soft soil, however, this effect was smaller for stiff soil types. Except for soft soil types, embedment did not affect the other response parameters, such as sloshing displacement, of the systems considered in this study. 相似文献
14.
Green＇s functions for uniformly distributed loads acting on an inclined line in a poroelastic layered site 总被引：2，自引：1，他引：1
Based on one type of practical Biot＇s equation and the dynamic-stiffness matrices ofa poroelastic soil layer and half-space, Green＇s functions were derived for unitformly distributed loads acting on an inclined line in a poroelastie layered site. This analysis overcomes significant problems in wave scattering due to local soil conditions and dynamic soil-structure interaction. The Green＇s functions can be reduced to the case of an elastic layered site developed by Wolf in 1985. Parametric studies are then carried out through two example problems. 相似文献
15.
Cheng-Hsing Chen Yang-Jye Lee Wen-Yu Jean Ikuo Katayama Joseph Penzien 《地震工程与结构动力学》1990,19(7):993-1024
The hybrid modelling method is presented herein along with the equivalent linearization method to take account of the strain-dependent non-linearity of soils in a soil-structure interaction (SSI) seismic analysis. A refined substructuring of the soil-structure system is utilized and two separate analyses are made to determine the soil free-field and SSI motions induced by earthquake excitation. This method is used to predict the seismic response of a 1/4-scale containment model built in the seismically active area of Lotung, Taiwan. The results obtained show excellent correlation with the field test results. 相似文献
16.
考虑土-结构相互作用双层柱面网壳在多点输入下的地震反应分析 总被引：3，自引：0，他引：3
目前对于网壳结构的地震反应研究大部分仍然采用一致输入,特别是没有考虑土-结构相互作用对网壳结构的影响。本文通过对大型有限元分析软件MSC.Nastran的二次开发,用等效线性化方法考虑土体的非线性,对土体采用三维实体单元建模,并对土体在基岩面上采用地震动的多点输入,计算分析了大跨度双层柱面网壳的动力反应,并且与一致地震动输入下网壳结构的地震反应进行了对比,考察了两者之间的差异,深入分析了考虑土-结构相互作用下,双层柱面网壳结构在多点输入和一致输入下的地震反应规律,并得出了一些重要结论。 相似文献
17.
Gin-Show Liou 《地震工程与结构动力学》1989,18(5):667-686
The total system studied in this paper is a layered soil stratum with a rigid bedrock and a cylindrical cavity on the surface. Analytic solutions for the layered medium with prescribed harmonic displacement time history on the surface of the cylindrical cavity are presented. The whole soil domain is divided into interior and exterior domains. The interior domain is the projection of the cylindrical cavity down to the rigid bedrock, whereas the exterior domain is then the soil medium complement to the interior domain. The displacement and stress fields in both domains are expanded as an infinite series of Fourier components with respect to the azimuth. For each Fourier component in the infinite series, the solutions for both domains are found independently by solving the general differential equations of wave propagation satisfying the boundary conditions of the top surface and the lower rigid boundary. Displacement and stress continuity conditions are then imposed on the vertical interface between the two domains using the formulation of a weighted residual. For the soil-structure interaction problem, the impedance matrix at the interface between the structure and the soil medium can be easily generated using the analytic solutions, which can then be combined with the finite element model of the structure. A simple example is presented to demonstrate the effectiveness of the procedure presented. 相似文献
18.
A seismic free field input formulation of the coupling procedure of the finite element (FE) and the scaled boundary finite-element
(SBFE) is proposed to perform the unbounded soil-structure interaction analysis in time domain. Based on the substructure
technique, seismic excitation of the soil-structure system is represented by the free-field motion of an elastic half-space.
To reduce the computational effort, the acceleration unit-impulse response function of the unbounded soil is decomposed into
two functions; linear and residual. The latter converges to zero and can be truncated as required. With the prescribed tolerance
parameter, the balance between accuracy and efficiency of the procedure can be controlled. The validity of the model is verified
by the scattering analysis of a hemi-spherical canyon subjected to plane harmonic P, SV and SH wave incidence. Numerical results
show that the new procedure is very efficient for seismic problems within a normal range of frequency. The coupling procedure
presented herein can be applied to linear and nonlinear earthquake response analysis of practical structures which are built
on unbounded soil.
Supproted by: the National Key Basic Research and Development Program under Grant No. 2002CB412709 相似文献
19.
为实现地震作用下土-结构动力相互作用问题的有限元模拟,需要在人工边界上完成地震动的有效输入,目前工程和科研中常用的地震动输入方法有两种:波动输入方法和振动输入方法。波动输入方法的模拟精度高,但实施上相对复杂且耗时,而振动输入方法处理简单,但模拟精度较低。针对应力型人工边界提出一种在人工边界上实现地震动输入的新方法,该方法通过对土-结构有限元模型中由人工边界节点及相邻节点组成的局部子结构施加自由波场位移时程并进行动力分析,从而直接获得可实现地震波动有效输入的等效地震荷载,然后在土-结构有限元模型的人工边界节点上施加等效输入地震荷载并完成动力计算,由此完成土-结构动力相互作用问题的地震动输入和地震反应计算。与原有波动输入方法相比,新方法避免了原方法需分别计算人工边界上自由场应力和由引入人工边界条件引起的附加力,以及需要根据不同人工边界面的外法线方向确定荷载作用方向等较为复杂的处理过程,具有等效地震荷载计算简便、地震动输入过程更易于实施的特点。采用均匀弹性半空间和成层弹性半空间一维地震反应算例初步验证新方法的正确性和可靠性。 相似文献
20.
大型结构地震反应值模拟中的波动输入 总被引：11，自引：6，他引：11
解耦的时域有限元数值模拟技术在考虑土－结构相互作用的大型结构地震反应分析中的应用日趋成熟。为完善其中的波动输入技术，本提出 了一种波动输入时步数值模拟的简便方法，替换对自由场的频域计算，从而使结构反应分析可以完全通过时步数值模拟实现。同时，通过数值实现，对这一实施方案的有效性进行了检验。 相似文献