隔震结构高宽比及支座竖向力分析

Study on Height-Width Ratio of Isolated Structure and Vertical Force of Bearing

采用基于一阶振型的简化设计方法,推导出竖向地震、水平地震、重力荷载下支座竖向力计算公式,得出边支座拉应力和压应力的控制荷载组合,并讨论了支座竖向力、结构周期、场地类别、设防烈度、支座布置对隔震结构高宽比限值的影响。结果表明:(1)减少宽度方向的支座排数,可以降低罕遇地震下隔震结构支座拉应力;(2)重力荷载下支座压应力小于某界限点压应力时,高宽比限值由罕遇地震下拉应力控制;大于界限点压应力时,高宽比限值由罕遇地震下压应力控制,该界限点与特征周期以及上部结构特性相关;(3)隔震结构周期变长,高宽比限值会相应提高,合理选择隔震层刚度,可以将隔震技术用于高宽比较大的建筑。

Using the simplified design method based on the first order vibration mode, the calculation formula of the vertical force of the bearing under vertical earthquake, horizontal earthquake and gravity load is derived, and the control load combination of the tensile stress and compressive stress of the side bearing is obtained. The influence of vertical force of the bearing, structural period, site type, design intensity, and bearing layout on the height width ratio limit value of the isolation structure is discussed. The results show that:(1) reducing the number of bearing rows in the width direction can reduce the bearing tensile stress of isolated structures under rare earthquakes;(2) When the compressive stress of the bearing under gravity load is less than the compressive stress of a certain boundary point, the height width ratio limit value is controlled by the pull-down stress of rare earthquake;when it is greater than the boundary point compressive stress, the height width ratio limit is controlled by the compressive stress of rare earthquake, and the boundary point is related to characteristic period;(3) As the period of isolated structure becomes longer, the limit value of height width ratio will be increased accordingly. If the stiffness of isolation layer is selected reasonably, the isolation technology can be used for buildings with large height width ratio.