RC框架-核心筒高层隔震结构支座拉应力控制方法研究

Research on the control methods for bearing tensile stress of seismically isolated RC frame-core tube tall buildings

合理控制隔震支座拉应力是RC框架-核心筒高层隔震结构设计的关键难点问题。采用4种拉应力控制方法对一抗震设防烈度为8度(0.3g)、高度为98.1m的基本案例进行了拉应力控制,综合考虑控制效果和上部结构材料用量对比分析了各方法的优劣。结果表明:增大结构整体刚度可较好控制拉应力,但会显著提升材料用量和工程造价;调整支座方案可一定程度降低拉应力,基本不会改变隔震设计关键指标;优化外框架与内核心筒尺寸也可较好控制拉应力且基本不会改变材料用量和工程造价;优化外框架与内核心筒尺寸,结合支座优化可获得与增大结构整体刚度相近的控制效果。在此基础上,提出了适用于该类结构的拉应力优化控制流程体系,相比于传统方法,可采用较少的额外经济投入获得更好的拉应力控制效果。相关研究成果可为RC框架-核心筒高层隔震结构的设计提供参考。

A key problem for the seismic design of seismically isolated RC frame-core tube tall buildings is to rationally control the tensile stress of isolators. Four control methods were adopted to control the tensile stress for a basic case, which was a RC frame-core tube tall buildings with a height of 98.1 m and a seismic intensity of 8 degree(0.3g). The advantages and disadvantages of four methods were compared with the considerations of control effect and material consumption of the superstructure. The results indicate that the tensile stress could be well controlled by increasing the overall structural stiffness, while the material consumption and engineering cost significantly increase. Through the adjustment of isolators, the tensile stress could reduce to a certain extent and other critical indexes will not change. The size optimizations of outer frame and inner core tube could also well control the tensile stress without changing the material consumption and engineering cost. Furthermore, in combination with the adjustment of isolators, the control effect achieved by increasing the overall structural stiffness can be obtained. Based on these, an optimization process for controlling the tensile stress is proposed for seismically isolated RC frame-core tube tall buildings. In comparison with the traditional method, a better control effect can be achieved with less economic investment. The research outcome will assist in providing a useful reference for the design of seismically isolated RC frame-core tube tall buildings.