排序方式： 共有56条查询结果，搜索用时 15 毫秒
41.
在近断层地震动下桥梁结构将发生较大反应,减隔震设计是减轻地震损伤的重要手段。提出了在桥梁双柱墩横桥向设置防屈曲支撑(BRB),在纵桥向设置铅芯橡胶支座(LRB)的双向减隔震体系。利用Midas Civil软件建立3种不同减隔震方式的桥梁结构模型:LRB仅单向,LRB双向与LRB联合BRB,运用非线性时程分析方法计算了桥墩反应(墩顶侧移角、残余位移角和曲率延性)、LRB支座变形和BRB的耗能特性等。结果表明:在近断层地震动输入下联合设置LRB和BRB的双向减隔震桥梁减震效果明显,相比其它2种方式,能有效降低墩柱的塑性变形及起到保护桥墩的作用。在横桥向,桥墩最大侧移角、残余位移角和最大曲率延性系数都显著降低。 相似文献
42.
Coupling behavior of shear deformation and end rotation of elastomeric seismic isolation bearings 
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下载免费PDF全文 This paper presents a mechanical model for predicting the behavior of elastomeric seismic isolation bearings subject to combined end rotations and shear deformation. The mechanical model consists of a series of axial springs at the top, mid‐height and bottom of the bearing to vertically reproduce asymmetric bending moment distribution in the bearings. The model can take into account end rotations of the bearing, and the overall rotational stiffness includes the effect of the variation of vertical load on the bearing and the imposed shear deformation. Static bending tests under various combinations of vertical load and shear deformation were performed to identify the mechanical characteristics of bearings. The test results indicate that bearing rotational stiffness increases with increasing vertical load but decreases with increasing shear deformation. Simulation analyses were conducted to validate the new mechanical model. The results of analyses using the new model show very good agreement with experimental observations. A series of seismic response analyses were performed to demonstrate the dynamic behavior of top‐of‐column isolated structures, a configuration where the end rotations of isolation bearings are typically expected to be larger. The results suggest that the end rotations of elastomeric bearings used in practical top‐of‐column isolated structures do not reduce the stability limit of isolation system. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
43.
A modal procedure for non-linear analysis of multistorey structures with high-damping base-isolation systems was proposed. Two different isolation devices were considered in the analysis: an high-damping laminated rubber bearing and a lead-rubber bearing. Starting from deformational properties verified by tests, the isolation systems were characterized using three different analytical models (an Elastic Viscous, a Bilinear Hysteretic and a Wen's Model) with parameters depending from maximum lateral strain. After non-linear modelling of isolation and lateral-force-resisting systems, the effects of material non-linearities were considered as pseudo-forces applied to the equivalent linear system (Pseudo-Force Method) and the formally linearized equations of motion were uncoupled by the transformation defined by the complex mode shapes. The modal responses were finally obtained with an extension of Nigam–Jennings technique to non-linear and non-classically damped systems, in conjunction with an iterative technique searching for non-linear contributions satisfying equations of motion and constitutive laws. Since the properties of the isolated structure usually change with maximun lateral strain of isolation bearings, the integration of a new set of governing equations was required for each design-displacement value. The procedure proposed was described in detail and then applied for the determination of modal and total seismic responses in some real cases. At first, a very good agreement between non-linear responses obtained with the proposed mode superposition and with a direct integration method was observed. Then a comparison of results obtained with the three different analytical models of the isolation bearings was carried out. At last, the exact modal response obtained with analytical models depending from the design displacement of the isolation bearings was compared with two different approximated solutions, evaluated using mode shapes and isolation properties, respectively, calculated under simplified hypothesis.© 1998 John Wiley & Sons, Ltd. 相似文献
44.
Satoshi Fujita Keisuke Minagawa Go Tanaka Haruo Shimosaka 《Soil Dynamics and Earthquake Engineering》2011
Recently strong seismic waves or long period seismic waves have been observed in various earthquakes that occurred in Japan. As a result improvements of existing seismic isolation systems are deemed necessary. The present study proposed an intelligent seismic isolation system encompassing air bearings and earthquake early warning (EEW) system. Such system exhibits adequate isolation performance. The air bearings are isolation device that may render infinite the superstructure natural period by floating them, and the EEW is applied for a trigger of isolation. This paper illustrates the proposed system and discusses the experimental results of a test carried out with the system. Laboratory tests carried out in the present research demonstrate the effectiveness of the proposed base isolated systems and prove its efficacy in mitigating the effects of three-dimensional seismic waves. For example, the system suppressed the horizontal response acceleration of an isolation target to 38% of input acceleration. 相似文献
45.
为评估隔震和非隔震支座对桥梁地震易损性的影响,以一座3跨连续混凝土箱梁桥为分析对象,首先建立采用铅芯橡胶隔震支座与非隔震型盆式橡胶支座下桥梁的数值模型,求得不同程度地震作用下墩顶与支座的最大位移响应;再定义转角延性比损伤指标,结合支座剪应变,分析桥墩和支座的地震易损性情况;最后通过宽界限法建立全桥地震易损性曲线。研究结果表明,支座是较容易发生损坏的构件,而桥梁系统比桥墩或支座更易发生破坏,同时铅芯橡胶支座的破坏概率明显低于非隔震型盆式支座,可见采用隔震支座能有效减小桥墩墩顶在地震作用下的最大位移,此时桥墩地震易损性优于采用非隔震支座的情况。 相似文献
46.
砌体结构工程抗震软件的结构隔震功能及算例分析 总被引：1，自引：0，他引：1
在砌体结构抗震软件开发过程中，为完善软件功能，添加了结构减震设计验算程序。作为首次应用性软件开发，暂只包含橡胶热隔震的设计与验算功能。本文主要介绍了软件应用时，橡胶垫隔震支座的设计过程，并通过对一个模拟的8层砌体建筑进行隔震设计与对比分析，给出了隔震设计后隔震效果的有关结论。 相似文献
47.
本研究系统地对低硬度橡胶隔震支座的材料及力学性能进行了试验研究。研究用低硬度橡胶天然及铅芯橡胶隔震支座18种规格总计近30个大直径隔震支座。研究内容涉及低硬度橡胶隔震支座的基本力学性能，温度、压力、剪切变形、老化及徐变等相关性能，压缩界限、拉伸界限、极限剪切变形等界限性能和屈曲特性，以及橡胶材料性能和隔震工程应用等方面。本文主要介绍低硬度橡胶天然及铅芯隔震支座的压缩、拉伸、剪切等界限性能和屈曲应力与剪切应变的相关特性，文中提出了基于刚度因子建立的橡胶支座的界限压缩和界限拉伸应力评价方程，同时还给出了剪切变形状态下的屈曲应力评价方法。 相似文献
48.
中国铅芯夹层橡胶隔震支座各种相关性能及长期性能研究 总被引：5，自引：1，他引：5
本文详细地研究了各种相关因素对中国铅芯橡胶隔震支座力学性能的 影响，同时还研究了中国铅芯夹层橡胶隔震支座的长期性能。研究包括竖向压力、频率、剪切变形循环次数、温度对隔震支座刚度及阻尼等力学性能的影响；隔震支座的耐久性能诸如老化及徐变对隔震器刚度、阻尼特性及极限变形能力的影响。研究还包括水平剪切（200次）及竖向低周疲劳（10万次）试验对隔震器力学性能的影响。 相似文献
49.
低硬度橡胶隔震支座基本力学性能及恢复力特性 总被引：4，自引：2，他引：4
本研究对低硬度橡胶隔震支座的材料性能（主要包括力学性能）进行了系统的试验开发及理论研究。研究用低硬度橡胶隔震支座包括天然橡胶隔震支座及铅芯橡胶隔震支座两大类18种规格总计近30个大直径隔震支座。研究内容涉及橡胶隔震支座竖向刚度、水平刚度及阻尼等基本力学性能；压缩界限，屈曲及极限剪切变形等界限性能；温度、压力、剪切变形、老化和徐变等相关性及长期特性；同时还对橡胶材料其他性能进行了系统的试验研究。本文主要介绍低硬度天然橡胶隔震支座及铅芯橡胶隔震支座的基本力学性能，如竖向、水平刚度和恢复力等特性。 相似文献
50.
低硬度橡胶隔震支座各种相关性及老化徐变特性 总被引：4，自引：1，他引：4
作者系统地对低硬度橡胶隔震支座的材料和力学性能进行了试验研究。研究使用的低硬度橡胶隔震支座分18种规格，总计近30个大直径隔震支座。研究内容涉及低硬度橡胶隔震支座的基本力学性能；温度、压力、剪切变形、老化和徐变等相关性；压缩界限，屈曲及极限剪切变形等界限性能以及橡胶材料性能和隔震工程应用等方面。本文主要介绍低硬度橡胶隔震支座的压力、剪切变形、温度对支座刚度、阻尼等力学性能的影响，同时还对隔震支座的老化及徐变特性进行了试验研究，确定低硬度橡胶使用60年后的力学性能变化率。文中同时提出了低硬度橡胶支座的温度修正方程，并提出了隔震结构地震反应分析时支座刚度和屈服荷载变化的取值范围。 相似文献