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1.
A novel time-domain identification technique is developed for the seismic response analysis of soil-structure interaction. A two-degree-of-freedom (2DOF) model with eight lumped parameters is adopted to model the frequency-dependent behavior of soils. For layered soil, the equivalent eight parameters of the 2DOF model arc identified by the extended Kalman filter (EKF) method using recorded seismic data. The polynomial approximations for derivation of state estimators are applied in the EKF procedure. A realistic identification example is given for the layered-soil of a building site in Anchorage, Alaska in the United States. Results of the example demonstrate the feasibility and practicality of the proposed identification technique. The 2DOF soil model and the identification technique can be used for nonlinear response analysis of soil-structure interaction in the time-domain for layered of complex soil conditions. The identified parameters can be stored in a database for use in other similar soil conditions. If a universal database that covers information related to most soil conditions is developed in the future, engineers could conveniently perform time history analyses of soil-structural interaction. 相似文献
2.
Two equivalent semi-discrete formulations are presented for the problem of the transient response of soil-structure interaction systems to seismic excitation, considering linear behaviour of the soil material and arbitrary non-linear structural properties. One formulation results in a direct method of analysis in which the motion in the structure and the entire soil medium, rendered finite by an artificial absorbing boundary, is determined simultaneously. The other represents a substructuring technique in which the structure and the soil are analysed separately. The forces induced in the discretized system by the incident seismic motion are obtained as part of the general formulation by using the free-field motion of the unaltered soil as the earthquake input. It is shown that these forces act within the soil region in the direct method, but only on the soil-structure interface in the substructure formulation. Both sets of forces, however, involve only the displacements and tractions acting on the fictitious surface in the unaltered (linear) soil which coincides with the soil-structure interface of the complete system. It is shown, further, that the free-field displacements alone define a minimal set of data for evaluating the seismic response of the structure, since the tractions and displacements on that surface are interrelated. In practice, the minimal set must be obtained by extrapolating the available information, as the free-field ground motion at a site is usually specified at a single reference point. 相似文献
3.
The contribution of the (linear) unbounded soil to the basic equation of motion of a non-linear analysis of soil-structure interaction consists of convolution integrals of the displacement-force relationship in the time domain and the history of the interaction forces. The former is calculated using the indirect boundary-element method, which is based on a weighted-residual technique and involves Green's functions. As an example of a non-linear soil-structure-interaction analysis, the partial uplift of the basemat of a structure is examined. As the convolution integrals have to be recalculated for each time step, the computational effort in this rigorous procedure is substantial. A reduction can be achieved by simplifying the Green's function by ‘concentrating’ the region of influence. Alternatively, assuming a specified wave pattern, a coupled system of springs and dashpots with frequency-independent coefficients can be used as an approximation. 相似文献
4.
Seismic response of underground utility tunnels: shaking table testing and FEM analysis 总被引：2，自引：1，他引：1
Underground utility tunnels are widely used in urban areas throughout the world for lifeline networks due to their easy maintenance
and environmental protection capabilities. However, knowledge about their seismic performance is still quite limited and seismic
design procedures are not included in current design codes. This paper describes a series of shaking table tests the authors
performed on a scaled utility tunnel model to explore its performance under earthquake excitation. Details of the experimental
setup are first presented focusing on aspects such as the design of the soil container, scaled structural model, sensor array
arrangement and test procedure. The main observations from the test program, including structural response, soil response,
soil-structure interaction and earth pressure, are summarized and discussed. Further, a finite element model (FEM) of the
test utility tunnel is established where the nonlinear soil properties are modeled by the Drucker-Prager constitutive model;
the master-slave surface mechanism is employed to simulate the soil-structure dynamic interaction; and the confining effect
of the laminar shear box to soil is considered by proper boundary modeling. The results from the numerical model are compared
with experiment measurements in terms of displacement, acceleration and amplification factor of the structural model and the
soil. The comparison shows that the numerical results match the experimental measurements quite well. The validated numerical
model can be adopted for further analysis. 相似文献
5.
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
6.
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
7.
三维土-结构动力相互作用的一种时域直接分析方法 总被引：1，自引：0，他引：1
本文提出了一种分析三维土-结构动力相互作用的时域直接方法。该方法采用集中质量显式有限元和透射人工边界模拟无限域地基,通过编制的FORTRAN程序实现;采用ANSYS软件对上部结构进行建模分析,并通过FORTRAN程序对ANSYS软件的调用,实现了土与结构系统在地震作用下的整体分析。该方法为显隐式相结合的方法,地基和上部结构可采用不同的时间步距进行分析,可大大提高效率。通过两算例,验证了该方法的可行性。 相似文献
8.
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
9.
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
10.
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
11.
A method of coupling finite elements (FE), boundary elements (BE) and infinite boundary elements (IBE) in the frequency domain is presented for wave propagation and soil-structure interaction problems. The procedure has the advantage of being suitable for considering non-homogeneous materials in the near region and the radiation condition at the far field. At the same time, the displacement field on the traction free boundary of the semi-plane is simulated by the IBE rather than by additional discretization of the ground surface as is required in the normal BE procedure. Verification examples show that excellent accuracy is achieved compared with the results by Wong18 who used the generalized inverse method. Finally, the proposed procedure is employed to obtain the response of a semi-elliptical rock canyon-alluvial deposit under seismic P and SV waves. Amplification behaviour due to the alluvial soil is observed to be significant for the given geometric dimensions of the canyon and the mechanical properties of the media under the excitation of the El Centro and Parkfield earthquakes. 相似文献
12.
Evaluation of FEMA-440 for including soil-structure interaction 总被引：1，自引：1，他引：0
Replacing the entire soil-structure system with a fixed base oscillator to consider the effect of soil-structure interaction
(SSI) is a common analysis method in seismic design. This technique has been included in design procedures such as NEHRP,
ASCE, etc. by defining an equivalent fundamental period and damping ratio that can modify the response of the structure. However,
recent studies indicate that the effects of SSI should be reconsidered when a structure undergoes a nonlinear displacement
demand. In recent documents on Nonlinear Static Procedures (NSPs), FEMA-440 (2005), a modified damping ratio of the replacement
oscillator was proposed by introducing the ductility of the soil-structure system obtained from pushover analysis. In this
paper, the damping defined in FEMA-440 to include the soil-structure interaction effect is evaluated, and the accuracy of
the Coefficient Method given in FEMA-440 and the Equivalent Linearization Method is studied. Although the improvements for
Nonlinear Static Procedures (NSPs) in FEMA-440 are achieved for a fixed base SDOF structure, the soil effects are not perfectly
obtained. Furthermore, the damping definition of a soil-structure system is extended to structures to consider bilinear behavior. 相似文献
13.
In a bounded domain elasto-plastic wave propagation can be modelled accurately using the finite-element method. As is even the case for an elastic analysis, an unbounded domain, e.g. a semi-infinite soil or fluid, can, however, not be represented in this manner, as any spatial discretization has to be avoided. For one-dimensional wave propagation with a bi-linear elasto-plastic material law involving one stress component an analytical solution exists. The latter is used in modelling the non-linear far field of an unbounded medium using a rigorous bookkeeping procedure of the generated elastic and plastic waves propagating in both directions. The need for a non-linear model of the far field arises, as in a two-dimensional representation of soil-structure interaction the surface waves do not decay. 相似文献
14.
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
15.
16.
地下结构的地震响应主要取决于由地震波传播产生的土体变形与土结相互作用。剪切波传播过程中将会引起隧道衬砌的椭圆化变形,进而降低衬砌有效承载力。剪切波作用下的深埋圆形隧道可认为处于均质的纯剪状态,基于相对刚度法的拟静力解析解可充分考虑土结相互作用对隧道结构内力的影响。基于此,本文将通过有限元数值分析获得的自由场地地基变形引入不滑移状态下深埋圆形隧道内力求解公式,并结合二维和三维数值模拟途径,将动力分析结果与解析解结果进行对比分析,以评价各种解析方法的适用性和数值途径的可靠性。 相似文献
17.
Behnoud Ganjavi 《地震工程与工程振动(英文版)》2012,11(2):205-220
It is known that structural stiffness and strength distributions have an important role in the seismic response of buildings.The effect of using different code-specified lateral load patterns on the seismic performance of fixed-base buildings has been investigated by researchers during the past two decades.However,no investigation has yet been carried out for the case of soil-structure systems.In the present study,through intensive parametric analyses of 21,600 linear and nonlinear MDOF systems and considering five different shear strength and stiffness distribution patterns,including three code-specified patterns as well as uniform and concentric patterns subjected to a group of earthquakes recorded on alluvium and soft soils,the effect of structural characteristics distribution on the strength demand and ductility reduction factor of MDOF fixed-base and soil-structure systems are parametrically investigated.The results of this study show that depending on the level of inelasticity,soil flexibility and number of degrees-of-freedoms(DOFs),structural characteristics distribution can significantly affect the strength demand and ductility reduction factor of MDOF systems.It is also found that at high levels of inelasticity,the ductility reduction factor of low-rise MDOF soil-structure systems could be significantly less than that of fixed-base structures and the reduction is less pronounced as the number of stories increases. 相似文献
18.
近断层地震动中长周期、短持时和高能量的加速度脉冲将对高层摩擦摆基础隔震结构的减震性能产生不利影响,考虑土-结构相互作用（SSI效应）后的隔震结构将产生动力耦合效应,可能进一步放大隔震结构地震响应。为此,通过一幢框架-核心筒高层摩擦摆基础隔震结构的非线性地震响应分析,考察近断层脉冲型地震动作用下框架-核心筒摩擦摆基础隔震结构的层间位移角、楼层加速度和隔震层变形等响应规律,揭示隔震体系的损伤机理。基于集总参数SR （sway-rocking）模型,分析不同场地类别与不同地震动类型对隔震体系动力响应影响规律。结果表明:高层摩擦摆基础隔震结构在近断层脉冲型地震动作用下的减震效果相比普通地震动减震效果变差,楼层剪力、层间位移角和隔震层变形等超越普通地震动作用下的1.5倍;对于Ⅲ和Ⅳ类场地类别,考虑SSI效应使隔震结构的地震响应进一步放大,弹塑性层间位移角随着土质变软增大尤为明显。 相似文献
19.
《地震工程与工程振动(英文版)》2021,20(3)
The direct finite element method is a type commonly used for nonlinear seismic soil-structure interaction(SSI) analysis. This method introduces a truncated boundary referred to as an artificial boundary meant to divide the soilstructure system into finite and infinite domains. An artificial boundary condition is used on a truncated boundary to achieve seismic input and simulate the wave radiation effect of infinite domain. When the soil layer is particularly thick, especially for a three-dimensional problem, the computational efficiency of seismic SSI analysis is very low due to the large size of the finite element model, which contains an whole thick soil layer. In this paper, an accurate and efficient scheme is developed to solve the nonlinear seismic SSI problem regarding thick soil layers. The process consists of nonlinear site response and SSI analysis. The nonlinear site response analysis is still performed for the whole thick soil layer. The artificial boundary at the bottom of the SSI analysis model is subsequently relocated upward from the bottom of the soil layer(bedrock surface) to the location nearest to the structure as possible. Finally, three types of typical sites and underground structures are adopted with seismic SSI analysis to evaluate the accuracy and efficiency of the proposed efficient analysis scheme. 相似文献
20.
基于有效的土-结相互作用有限元数值模拟方法,利用有限元软件ABAQUS对水平及竖向地震共同作用下双线盾构隧道的地震响应进行分析研究。地震动输入选取近场地震Loma、ChiChi、Mammoth和WoLong的基岩水平及竖向加速度时程记录。结果表明,不同近场地震记录对隧道结构的作用不同,隧道的地震反应与场地性质及地震动的频谱特性密切相关。对比隧道在水平及竖向地震动共同作用下的响应与单向水平地震动作用下的响应,发现隧道的最大地震附加内力及其分布均发生较大的变化,在隧道结构抗震设计中需引起重视。另外,分析中还考虑了在双向地震动共同作用下,隧道间距、土-结接触面的摩擦系数、土-结相对刚度、输入的地震记录和竖向地震动相对强度对隧道地震响应的影响等,研究结果对隧道工程的抗震设计具有一定的参考价值。 相似文献