T形截面柱的非线性分析   总被引：6，自引：0，他引：6  

李晓莉  郭棣  吴敏哲 《世界地震工程》2005,21(3):122-125

编制了适用于任意截面的钢筋混凝土压弯构件截面的弯矩—曲率非线性分析程序。在此基础上,计算了考虑非线性变形的异形柱弯矩—曲率关系,并研究了翼缘、轴压比等因素对异形柱强度和延性的影响,可作为异形柱研究的参考依据。  相似文献   

带双腹板顶底角钢连接初始刚度研究     

王新武 《世界地震工程》2005,21(4):123-125

初始连接刚度在节点刚度分类和钢结构地震分析中占有很重要的地位,因此研究连接的初始刚度很有现实意义。主要研究带双腹板顶底角钢连接初始刚度的确定方法以及影响其性能的主要因素。  相似文献   

CALCULATING THE DYNAMIC STIFFNESS MATRIX OF 2-D FOUNDATIONS BY DISCRETE WAVE NUMBER INDIRECT BOUNDARY ELEMENT METHODS     

J. X. ZHAO  A. J. CARR  P. J. MOSS 《地震工程与结构动力学》1997,26(1):115-133

Apart from some special cases, calculating the dynamic stiffness matrix of foundations on a layered half-space, especially for embedded foundations, is computationally expensive. An efficient method for two-dimensional foundations in a horizontally layered soil media is presented in this paper. This method is based on indirect boundary element methods and uses discrete wave number solution methods for calculating Green's functions for displacements and analytical methods for the integrations over the boundary. For surface foundations, the present method applies at all frequencies. For embedded foundations or for constructing energy transmitting boundaries, because the free-field part is modelled by boundary elements and the excavated part is modelled by finite elements, the present method applies only at low frequencies for the spring coefficients (the real parts of the dynamic stiffness matrix) but applies at all frequencies for the damping coefficients (the imaginary part of the dynamic stiffness matrix) for undamped sites. The novelty of the method can be used for three-dimensional foundations. © 1997 by John Wiley & Sons, Ltd.  相似文献   

Seismic behaviour of confined masonry walls     

Miha Tomaevi   Iztok Klemenc 《地震工程与结构动力学》1997,26(10):1059-1071

The results of tests of plain and confined masonry walls with h/l ratio equal to 1·5, made at 1:5 scale, have been used to develop a rational method for modelling the seismic behaviour of confined masonry walls. A trilinear model of lateral resistance–displacement envelope curve has been proposed, where the resistance is calculated as a combination of the shear resistance of the plain masonry wall panel and dowel effect of the tie-columns’ reinforcement. Lateral stiffness, however, is modelled as a function of the initial effective stiffness and damage, occurring to the panel at characteristic limit states. Good correlation between the predicted and experimental envelopes has been obtained in the particular case studied. The method has been also verified for the case of prototype confined masonry walls with h/l ratio equal to 1·0. Good correlation between the predicted and experimental values of lateral resistance indicates the general validity of the proposed method. © 1997 John Wiley & Sons, Ltd.  相似文献   

Spring-dashpot-mass models for foundation vibrations     

John P. Wolf 《地震工程与结构动力学》1997,26(9):931-949

The foundation on deformable soil, which, in general, radiates energy, can be represented in structural dynamics as a simple spring-dashpot-mass model with frequency-independent coefficients. For the two limiting cases of a site, the homogeneous half-space and the homogeneous layer fixed at its base, the coefficients are specified in tables for varying parameters such as ratios of dimensions and Poisson's ratio. Rigid foundations on the surface and with embedment are considered for all translational and rotational motions. In a practical analysis of soil–structure interaction this dynamic model of the foundation is coupled directly to that of the structure, whereby a standard dynamics program is used. © 1997 by John Wiley & Sons, Ltd.  相似文献   

考虑尺寸效应的近海桥梁天然橡胶隔震支座力学性能老化时变规律研究          下载免费PDF全文

李艳敏  马玉宏  赵桂峰 《世界地震工程》2020,(4):169-177

目前天然橡胶支座（NRB）的性能研究大多未考虑尺寸效应,在前期开展的近海桥梁隔震支座和材料老化时变规律研究的基础上,同时考虑支座直径尺寸变化和老化作用时间的影响对NRB的性能进行研究。首先采用ABAQUS有限元软件对不同直径尺寸NRB的性能进行分析,得到了NRB性能随直径尺寸的变化规律;然后结合前期老化作用对NRB及其橡胶材料性能时变规律的影响研究成果,分析了直径尺寸及老化作用时间共同作用下,NRB性能的变化规律,并通过ABAQUS有限元分析,验证了该变化规律的准确性。结果表明:NRB的水平刚度和竖向刚度均随其直径尺寸的增大呈正比例增大趋势;NRB水平刚度比和竖向刚度比均随老化作用时间的增长呈线性增大趋势;且直径为150mm的NRB在实际环境老化60a后,其水平刚度和竖向刚度的增长幅度分别为:30.8%和16.41%,由此可见老化作用时间对NRB水平刚度的影响较显著,对其竖向刚度的影响较小。研究内容可为隔震桥梁结构中支座缩尺模型试验的相关设计提供参考,并为将实验室缩尺橡胶隔震支座的相关成果较好地应用于实际工程计算及设计中提供依据。  相似文献   

考虑力组合效应的钢框架端板连接力学行为     

梁刚  郭宏超  刘云贺  杨迪雄 《地震工程与工程振动》2019,39(1):96-105

为研究不同力组合效应对平齐端板连接力学行为的影响,采用ABAQUS程序建立不同受力情况下连接的非线性简化有限元模型,通过与国内外典型试验结果对比分析,验证了有限元模型的可靠性。基于此通过考虑8种力组合因素的影响,分析了2种不同钢等级的梁柱节点力学行为,进一步讨论了EC3 Part 1-8规范的适用性。结果表明:简化有限元模型在弯矩-转角曲线、破坏形态、初始刚度和塑性抗力等方面与试验结果吻合良好。框架梁轴力对节点的力学行为影响显著,当轴拉力为20%的框架梁轴向塑性抗力N_pl时,高强钢节点的刚度和强度分别降低68%和52%;当轴压力为-20%N_pl时,刚度和强度分别增加89%和42%。此外节点的滞回耗能能力、破坏模式以及分类属性与梁轴力水平密切相关。对于高强钢梁柱平齐端板节点,EC3规范对框架梁轴压力的限值仍过于保守。研究结果对于提高结构的抗倒塌能力和组合力作用下的理论研究具有重要参考价值。  相似文献   

Seismic responses of postyield hardening single–degree-of-freedom systems incorporating high-strength elastic material     

Hanlin Qiang  Peng Feng  Zhe Qu 《地震工程与结构动力学》2019,48(6):611-633

It is widely accepted that ductility design improves the seismic capacity of structures worldwide. Nevertheless, inelastic deformation allows serious damage to occur in structures. Previous studies have shown that a certain level of postyield stiffness may reduce both the peak displacement and residual deformation of a structure. In recent years, several high-strength elastic materials, such as fiber-reinforced polymer (FRP) and high-strength steel bars, have been developed. Application of these materials can easily provide a structure with a much higher and more stable postyield stiffness. Many materials, members, and structures that incorporate both high-strength elastic materials and conventional materials show significant postyield hardening (PYH) behaviors. The significant postyield stiffness of PYH structures can help effectively reduce both peak and residual deformations, providing a choice when designing resilient structures. However, the findings of previous studies of structures with elastic-perfectly plastic (EPP) behavior or small postyield stiffness may not be accurate for PYH structures. The postyield stiffness of a structure must be considered an important primary structural parameter, in addition to initial stiffness, yielding strength, and ductility. In this paper, extensive time history and statistical analyses are carried out for PYH single–degree-of-freedom (SDOF) systems. The mean values and coefficients of variation of the peak displacement and residual deformation are obtained and discussed. A new R-μ_p-T-α relationship and damage index for PYH structures are proposed. A theoretical model for the calculation of residual deformation is also established. These models provide a basis for developing the appropriate seismic design and performance evaluation procedures for PYH structures.  相似文献   

EFFECT OF SLAB FLEXIBILITY ON INTERACTION BETWEEN TWO CIRCULAR FOUNDATIONS     

G.&#x;S. LIOU 《地震工程与结构动力学》1996,25(6):561-583

The paper is aimed at investigating the effect of foundation rigidity on dynamic stiffness for two circular foundations on a viscoelastic medium. To generate the dynamic stiffness, a substructure technique is employed. For the substructure of a viscoelastic medium, the solution for wave motion reported in Reference 11 is used. For the substructures of two flexible foundations, classical plate theory with the inertial force neglected is employed to find the displacement fields of the foundation plates subjected to the interaction stresses. Then, the continuity condition for all the substructures is imposed implicitly by using the variational principle; then with the help of the reciprocal theorem the dynamic stiffness for the two flexible foundations can be obtained. For the numerical study, the boundary condition at the rims of both foundation plates is assumed to be a hinge connection to superstructures. Some numerical investigations are performed and the effect of foundation rigidity on dynamic stiffness is examined. Some discussions and conclusions are also made.  相似文献   

SEQUENTIAL STIFFNESS DESIGN FOR SEISMIC DRIFT RANGES OF A SHEAR BUILDING–PILE–SOIL SYSTEM     

T. NAKAMURA  I. TAKEWAKI  Y. ASAOKA 《地震工程与结构动力学》1996,25(12):1405-1420

A shear building supported by a prescribed pile–soil system is subjected to bedrock earthquake input. A new design procedure is presented for generating a sequence of stiffness designs satisfying the constraints on interstorey drifts. The mean peak interstorey drifts of the shear building subjected to a set of spectrum-compatible ground motions at the bedrock are evaluated by a modal combination rule. Tuning of the fundamental natural period of a shear building with a fixed base with that of a shear beam ground results in a non-monotonic sequence of stiffness designs with respect to a ground stiffness parameter and previous approaches cannot be applied to such a problem. This difficulty in finding such a non-monotonic sequence is overcome by utilizing the ground stiffness parameter and the superstructure stiffness parameter alternately in multiple design phases and by developing a new multi-phase perturbation technique. Fundamental characteristics of this sequence of stiffness designs and the effect of ground stiffnesses on the design of the shear building are disclosed. It is further shown that the stiffness contour method is also useful for the design procedure such that a scattering effect in the estimates of ground stiffnesses is taken into account. The usefulness of the proposed procedure of sequential stiffness design and contour line method is demonstrated through several sequential design examples.  相似文献