A self-centering dual system,which is composed of an occupancy subsystem and a damage controlling subsystem in system level,is proposed.The system can be simplified into a double-beam system that consists of a combination of a shear beam and a flexural beam according to deforming features of the two subsystems.The closed form solution of the modal shapes is presented,and the effects of the stiffness ratio α0 between the flexural beam and the shear beam,and the stiffness ratio Rf between the flexural beam and the linear rotational spring on modal shapes and modal drifts are investigated.Moreover,the effects of the two stiffness ratios,damping ratio and higher modes on the generalized interstory drift spectrum computed by modal superposition are also examined.It is concluded that,by adding a reasonable amount of damping,the self centering dual system with 1＜α0 ＜3 and 1＜Rf＜5,can not only suppress the higher modes and achieve a relatively unified distribution of interstory drift along the height but also reduce the maximum responses.Moreover,the generalized interstory drift spectrum can be treated as a tool to fulfill the direct displacement-based design of the proposed system.%提出了复合自复位结构体系,该结构体系在层次上由基本功能分区和损伤控制分区组成.根据不同分区的结构变形特征将复合自复位结构体系简化为由剪切梁和弯曲梁组成的双梁分布体系模型.求解得到复合自复位结构体系振型方程的闭合解,分析该体系在不同剪弯刚度比和弯曲梁与其底部约束刚度比下振型和振型转角的变化规律.基于振型叠加法得到体系的广义层间位移角谱,分析了剪弯刚度比和弯曲梁与其底部约束刚度比、阻尼比和高阶模态对体系广义层间位移角谱的影响.结果表明:在剪弯刚度比介于1～3的区间,弯曲梁与其底部约束刚度比介于1～5的区间,通过附加一定的阻尼,体系不仅可以抑制高阶振型的影响得到较均匀的层间位移分布而且可以降低最大响应.以广义层间位移角谱为工具,可以实现复合自复位结构体系直接基于位移的设计.
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