叠层厚橡胶支座竖向压缩与拉伸力学性能研究

STUDY ON COMPRESSIVE AND TENSILE BEHAVIORS OF THICK RUBBER BEARINGS

  • 摘要: 为有效地缓解城市轨道交通上盖结构抗侧刚度不连续、竖向振动舒适度的突出问题,叠层厚橡胶支座逐渐应用于该类结构隔震/振设计。而面向上盖多层或高层结构,支座需具有较高的竖向承载力,并应准确验算其拉应力。因此,该文设计了第一、第二形状系数分别为10.3和4.0的叠层厚橡胶支座,开展了支座竖向压缩和拉伸力学性能研究。通过足尺支座试验,获得其竖向力学性能参数,结果表明:竖向设计承载力下,各橡胶层均匀凸出,没有发生整体侧向屈曲;拉伸荷载下,各橡胶层均匀拉伸变形,拉伸应力满足规范限值。随后,建立支座ABAQUS有限元模型,橡胶竖向压缩采用Yeoh本构关系,可较准确地模拟支座竖向压缩刚度;为考虑橡胶空穴拉伸损伤的本构关系,编写UHYPER用户子程序,可精确地模拟支座拉伸刚度和拉伸承载力。最后,根据试验和数值模拟结果,建立叠层厚橡胶支座竖向压缩刚度、拉伸刚度和拉伸承载力计算方法。该研究成果可为叠层厚橡胶支座在多层或高层结构的振震双控设计提供试验和理论支撑。

     

    Abstract: To effectively alleviate the main problems in urban over-track buildings, i.e., the abrupt change of lateral stiffness and discomfort caused by the vertical vibration, laminated thick rubber bearings (TRBs) are gradually used in the earthquake- and subway-induced isolation design of these buildings. Nevertheless, when it comes to multi-story or high-rise over-track buildings, a relatively large vertical loading capacity is required for TRBs, and the tensile stress needs to be examined carefully. Thus, a TRB with the first and second shape factors of 10.3 and 4.0, respectively, was designed, and the compressive and tensile behaviors of this bearing were studied. According to full-scale isolator tests, its mechanical properties in the vertical direction were obtained. The results showed that under a design compressive load each rubber layer bulged evenly and there was no overall lateral buckling. Under tensile loading, even tensile deformation could be found for all rubber layers, and its tensile stress met the code limit. Then, an ABAQUS finite element model for this TRB was built. The Yeoh constitutive relationship was used to simulate the rubber under compression, and it showed that the compressive stiffness of this TRB could be well predicted. To consider the tensile damage of bearings after cavitation into the constitutive relationship of rubber, the UHYPER subroutine was developed. Accordingly, the tensile stiffness and capacity of this isolator could be accurately predicted. Finally, based on experimental and numerical results, the calculation methods for the compressive and tensile stiffnesses and for tensile capacity were developed. The results of this study can provide an experimental and theoretical support for the earthquake- and subway-induced isolation design of TRBs in multi-story or high-rise over-track buildings.

     

/

返回文章
返回