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1.
基于子结构分析方法,提出了土-结构相互作用体系中数值解和解析解耦合的地震反应分析方法。此方法中,数值解是用有限元方法来模拟上部结构的非线性动力行为;而弹性结构-刚性基础-半无限大弹性地基中频域内的解析解,是通过离散时间递归滤波方法得到时域内的解来等效,且在整个体系中,利用土、结构两个子结构边界上的力和位移协调求解。本文提出的方法用有限元程序Opensees来实现,并用于一个线弹性单层框架结构的动力分析中。这种耦合的分析方法得到的结果,与土-结构相互作用单自由度体系的解析解进行了比较,验证此方法的精度、稳定性和工程实用性。 相似文献
2.
通过离散弹簧模型模拟层间隔震结构的土-结构相互作用(SSI效应),建立了层间隔震结构考虑SSI效应的简化4自由度体系(4-DOF)的结构动力方程,推导了由4自由度体系(4-DOF)向等效2自由度体系(2-DOF)的等效方程。基于等效2-DOF简化计算模型,给出了考虑SSI效应的层间隔震结构地震响应预测的计算流程,并通过一个算例对两种简化模型进行了对比验证分析。结果表明:对层间隔震结构进行考虑SSI效应的地震响应预测分析时,基于等效2-DOF的简化计算模型可替代常用的4-DOF模型,方法简单有效且精度符合要求。 相似文献
3.
膜结构风振中流固耦合效应的数值模拟研究 总被引：2，自引：1，他引：1
对膜结构风致振动中的流固耦合效应进行了数值模拟研究。采用数值模拟方法中的强耦合整体方法,引入伪实体模型,通过伪实体模型方程,流体方程与结构方程的隐式弱形式来构成整个体系的强耦和整体式方程。采用该方法对双坡型膜结构在考虑和不考虑耦合效应下的风振响应等重要参数进行了计算分析,并将计算结果与已有风洞试验结果进行对比,结果符合良好。同时计算了结构周围空气的风速矢量、压力场分布,得到了空气流体场的变化规律。结果表明采用强耦合整体方法计算所得的解具有很好的收敛性,可以较准确地预测膜结构的风致动力响应。 相似文献
4.
成层粘弹性土中桩土耦合纵向振动时域响应研究 总被引：7，自引：3，他引：7
从三维轴对称角度出发,采用粘性阻尼粘弹性连续土介质模型,考虑桩土相互作用效应,对成层土中桩土纵向耦合振动时的桩顶时域响应进行了解析研究。求解时,首先建立定解问题,然后利用拉氏变换先对底部土层进行求解得到其振动位移形式解,然后利用桩土接触界面连续条件来考虑桩土耦合作用,分析底层土中桩段的动力反应,然后利用桩段阻抗函数的传递性,进行逐层递推求解,最终得到桩顶时域和频域响应的半解析解。通过参数影响分析和与工程实测曲线的对比,讨论分析了成层土中桩土耦合振动的响应特性,验证了本文解。基于本文研究可为桩基抗震、防震设计、桩基动力检测提供新的理论支持。 相似文献
5.
阐述了人工黏弹性边界的机理及实现地震动输入的方法,采用MATLAB软件编制了等效节点荷载计算程序。通过算例分析将理论解与数值解进行对比,验证了程序的正确性。利用ABAQUS软件建立了位于典型软土场地的正放四角锥网架土-结构相互作用体系数值仿真模型,分析了考虑土-结构相互作用后对结构动力特性的影响,并且对土-结构相互作用体系进行了动力时程分析,得到了网架结构的加速度响应、相对位移和杆件内力的分布规律,并与刚性地基假定下结构的响应进行了对比和分析。结果表明,考虑土-结构相互作用后分析所得结构峰值加速度、相对位移和杆件内力等性能指标均有显著增大。不考虑土-结构相互作用可能会低估软土场地上的空间网格结构的地震响应。进行软土场地上空间网格结构工程抗震分析时应考虑土-结构相互作用对结构地震响应的影响。 相似文献
6.
考虑SSI效应储油罐的子结构实验方法与数值模拟 总被引：1，自引：0，他引：1
提出了应用振动台子结构试验方法来研究考虑土-结构相互作用（SSI）效应储罐的抗震性能,该方法将土体简化为双自由度八参量集总参数模型进行模拟,储罐作为试验子结构应用振动台加载,两部分联机完成振动台子结构试验。该方法能完成大比例尺储罐试验,具有传统试验方法难以比拟的优势。然后,通过数值模拟分析了SSI效应对储罐动力响应的影响。分别研究了不同储液高度和不同地基刚度对储罐位移和加速度响应的影响。研究结果表明：考虑SSI效应时,罐体位移响应和加速度响应均有所减小,土质越软,效果越明显;随着储液高度的增高,位移、加速度反应呈现减小趋势。 相似文献
7.
在传统输电塔抗震分析中,通常假设输电塔固定在地面上,而不考虑土G结构相互作用(SoilG Structure Interaction,SSI)对结构的影响,从而可能导致输电塔抗震性能评估不准确.依托某 1000kV输电铁塔实际工程,对地震动激励下考虑SSI的输电塔进行综合的地震响应、倒塌破坏和倒塌易损性分析.在 ABAQUS中,通过沿桩体设置依据 API规范确定的零长度弹簧模拟土体与桩体间的相互作用,建立考虑SSI的输电塔有限元模型.基于数值模型,开展输电塔动力特性和结构动力响应分析.采用增量动力分析(Incremental Dynamic Analysis,IDA)方法,研究SSI对输电塔倒塌机理和易损性的影响.结果表明:考虑和未考虑SSI的输电塔振型相似,但自振频率相差较大;忽略SSI会低估输电塔的地震响应,同时高估输电塔的抗倒塌能力.因此考虑SSI可以提高输电塔抗震能力,进而确保输电线路的安全性. 相似文献
8.
自振特征是核电厂结构动力分析首先应考虑的因素,它也是影响核电厂反应谱特征的关键因素之一。采用常规的自振特性分析方法(如Lanczos法等)只能以核电厂上部结构为模型进行计算求其固有频率,在复杂场地条件下,这样的计算结果通常与更符合实际的土-结构相互作用(SSI)模型计算结果存在较大差异。本文以SASSI用户手册中的典型压水堆核电厂土-结构动力相互作用模型为研究对象,采用时域显式有限元法结合透射人工边界方法及相应编写的三维显式有限元程序3DSSI,计算了同一上部结构,结合多工况局部复杂场地条件的核电厂SSI体系的单脉冲响应,并通过求传递函数幅值谱方法,获得各种工况下SSI体系的自振频率。依据计算结果,分别研究了核电厂上部结构、自由场及SSI体系的自振特征及其相互联系,并通过比较研究,讨论了局部复杂场地特性对核电厂SSI体系自振特性影响等问题,进而加深了对核电厂动力特征及动力安全区性的认知。 相似文献
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10.
层状土介质中群桩及其上部结构体系对任意入射地震波的响应 总被引：2，自引：0，他引：2
本文舍弃桩基动力分析中的土介平面应变假定，采用薄层内位移纡性变化条件下的动力Ｇｒｅｅｎ函数形成桩－土－桩相互作用所需的土介质柔度矩阵，用梁单元模拟桩的运动，用振型分解方法来考虑上部结构与桩基承台间的动力相互作用，以任意地震波入射为初始运动输入，建立了层状土介质中群桩及其上部结构体系对放射地震波响应的半解析分析模型，研究了桩基及其上部结构体系对不同角度入射、ＳＨ、ＳＶ和Ｐ波的动力响应，结果表明，本文 相似文献
11.
Inelastic displacement ratios (IDRs) of nonlinear soil–structure interaction (SSI) systems located at sites with cohesive soils are investigated in this study. To capture the effects of inelastic cyclic behavior of the supporting soil, the Beam on Nonlinear Winkler Foundation (BNWF) model is used. The superstructure is modeled using an inelastic single-degree-of-freedom (SDOF) system model. Nonlinear SSI systems representing various combinations of unconfined compressive strengths and shear wave velocities are considered in the analysis. A set of strong ground motions recorded at sites with soft to stiff soils is used for considering the record-to-record variability of IDRs. It is observed that IDRs for nonlinear SSI systems are sensitive to the strength and the stiffness properties of both the soil and the structure. For the case of SSI systems on the top of cohesive soils, the compressive strength of the soil has a significant impact on the IDRs, which cannot be captured by considering only the shear wave velocity of the soil. Based on the results of nonlinear time-history analysis, a new equation is proposed for estimating the mean and the dispersion of IDRs of SSI systems depending on the characteristic properties of the supporting soil, dimensions of the foundation, and properties of the superstructure. A probabilistic framework is presented for the performance-based seismic design of SSI systems located at sites with cohesive soils. 相似文献
12.
为减少直接分析三维大尺度复杂土-结构动力相互作用问题的计算量,提高计算效率,本文直接从波动方程出发,提出了较常规子结构法更简单的两步简化计算过程,即第一步简化上部复杂结构体系为集中质量杆系模型,并求基础处等效输入,第二步通过等效输入求上部结构各位置的动力反应.其中第一步计算主要采用集中质量显式有限单元法结合局部透射人工... 相似文献
13.
Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover (CMP) procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interaction (SSI) in pushover analysis is ignored. In this paper the CMP procedure is modified for one-way asymmetric plan mid and high-rise buildings considering SSI. The extended CMP (ECMP) procedure is proposed in order to overcome some limitations of the CMP procedure. In this regard, 10, 15 and 20 story buildings with asymmetric plan are studied considering SSI assuming three different soil conditions. Using nonlinear response history analysis under a set of bidirectional ground motion; the exact responses of these buildings are calculated. Then the ECMP procedure is evaluated by comparing the results of this procedure with nonlinear time history results as an exact solution as well as the modal pushover analysis procedure and FEMA 356 load patterns. The results demonstrate the accuracy of the ECMP procedure. 相似文献
14.
《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
15.
Edward H. Stehmeyer III Dimitris C. Rizos 《Soil Dynamics and Earthquake Engineering》2008,28(6):468-479
This paper utilizes and expands on existing coupled BEM–FEM (finite element method) methods for the investigation of the effects of soil structure interaction (SSI) on both an un-retrofitted and seismically isolated typical bridge structure. A simple numerical model of the bridge and surrounding soil is formulated and excited by an earthquake excitation. Utilizing Newmark's β FEM solution method along with the closed form B-spline BIRF method, the structural damped period, composite damping ratio, pier relative displacement, and base shear demand are monitored. From these results, the effects of SSI on this structure are identified. Additionally, the importance of the relative rigidity between the soil-foundation system and the bridge structure is also investigated. The results of the studies indicate that the response of the complete structure system considered is affected by the inclusion of SSI effects. Furthermore, the efficiency of the isolation measures designed using fixed base conditions is decreased by considering SSI over a certain relative rigidity range that is quantified using the structure to soil-foundation natural frequency ratio. 相似文献
16.
Probabilistic analysis of soil‐structure interaction effects on the seismic performance of structures 
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下载免费PDF全文 This paper revisits the phenomenon of dynamic soil‐structure interaction (SSI) with a probabilistic approach. For this purpose, a twofold objective is pursued. First, the effect of SSI on inelastic response of the structure is studied considering the prevailing uncertainties. Second, the consequence of practicing SSI provisions of the current seismic design codes on the structural performance is investigated in a probabilistic framework. The soil‐structure system is modeled by the sub‐structure method. The uncertainty in the properties of the soil and the structure is described by random variables that are input to this model. Monte Carlo sampling analysis is employed to compute the probability distribution of the ductility demand of the structure, which is selected as the metrics for the structural performance. In each sample, a randomly generated soil‐structure system is subjected to a randomly selected and scaled ground motion. To comprehensively model the uncertainty in the ground motion, a suite of 3269 records is employed. An extensive parametric study is conducted to cover a wide range of soil‐structure systems. The results reveal the probability that SSI increases the ductility demand of structures designed based on the conventional fixed‐based assumption but built on flexible soil in reality. The results also show it is highly probable that practicing SSI provisions of modern seismic codes increase the ductility demand of the structure. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
17.
水平向地震下双层岛式地铁车站结构的动力变形特征 总被引：1，自引：0，他引：1
根据南京地铁车站建设的实际背景,以浅埋于深厚软土场地中某个典型的两层双柱三跨的地铁车站结构为研究对象,对考虑SSI效应时地铁车站结构水平向非线性地震反应规律进行了研究。本文中主要探讨了侧向有软土层存在时地铁车站结构的水平向相对位移反应和加速度反应规律。结果表明:车站结构顶、底板之间的最大相对水平位移接近于自由场地对应点间的最大相对水平位移,而车站结构的侧向水平相对位移曲线明显区别于自由场地对应深度范围内两点间的水平相对位移曲线,采用三次多项式能很好地拟合车站接轨的水平相对位移沿侧墙高度的变化曲线,初步给出了各拟合参数用车站结构顶、底板间最低水平相对位移拟合的经验公式;同时,考虑SSI效应时,传递到车站结构基底处的峰值加速度反应明显大于自由场地对应点处的峰值加速度反应。 相似文献
18.
考虑水-饱和土场地-结构耦合时的沉管隧道地震反应分析 总被引：6，自引：0，他引：6
用理想流体介质模拟水层、流体饱和多孔介质模拟饱和土地层,在理想流体介质与流体饱和多孔介质相连接边界的连续条件基础上,结合已有的对理想流体介质、流体饱和多孔介质进行动力反应分析的显式有限元方法,开考虑地层与结构的动力相互作用,建立了进行水与场地、结构耦合动力分析的方法。利用该方法对沉管隧道的地震响应进行了研究,重点分析了水深、地质条件等因素对沉管隧道地震反应的影响,并从中得出了一些可供相关人员进行沉管隧道抗震分析时参考的结论。 相似文献
19.
考虑地基土液化影响的桩基高层建筑体系地震反应分析 总被引：5，自引：2，他引：5
本文建立了土体－结构体系地震反应分析的混合有限元法，并研究了地基土液化对地震反应的影响。本方法把土体－结构体系简化为一个完整的体系，该体系由梁（柱）单元、剪切杆单元、刚体单元、平面四边形等参单元与三角形单元、界面单元的任意组合来模拟。桩与上部结构材料视为线弹性体，土介质视为非线性材料。土的静应力－应变关系之间的非线性用邓肯一张模型来描述；土的动应力－应变关系之间的非线性和振动孔隙水压力对土的软化效 相似文献
20.
《Soil Dynamics and Earthquake Engineering》2012,32(12):1690-1702
Simulating dynamic soil–structure interaction (SSI) problems is a challenge when using a shaking table because of the semi-infinity of soil foundations. This paper develops real-time dynamic hybrid testing (RTDHT) for SSI problems in order to consider the radiation damping effect of the semi-infinite soil foundation using a shaking table. Based on the substructure concept, the superstructure is physically tested and the semi-infinite foundation is numerically simulated. Thus, the response of the entire system considering the dynamic SSI is obtained by coupling the numerical calculation of the soil and the physical test of the superstructure. A two-story shear frame on a rigid foundation was first tested to verify the developed RTDHT system, in which the top story was modeled as the physical substructure and the bottom story was the numerical substructure. The RTDHT for a two-story structure mounted on soil foundation was then carried out on a shaking table while the foundation was numerically simulated using a lumped parameter model. The dynamic responses, including acceleration and shear force, were obtained under soft and hard soil conditions. The results show that the soil–structure interaction should be reasonably taken into account in the shaking table testing for structures. 相似文献