烟囱悬挂内筒-转动摩擦阻尼器减震止晃研究

Seismic response control of chimney with suspended flue and rotational friction dampers

研究了利用转动摩擦阻尼器(rotational friction dampers,RFD)和悬挂排烟内筒对高耸钢筋混凝土地震响应进行被动控制。首先提出了烟囱用FRD节点的构造做法,将RFD置于内、外筒之间,在地震作用下,允许内、外筒产生适量相对位移,使RFD产生摩擦耗能。其次,对该体系的地震响应被动控制进行了理论研究,将内、外筒视为质量和弹性连续分布的梁,基于假设模态法,采用Bouc-Wen滞回模型模拟RFD,用Lagrange方程推导了受控体系的非线性运动微分方程及其空间状态方程。最后,以某275 m高烟囱为例,对比分析了两种罕遇地震作用下的5种减震方案。通过选用合理的RFD参数、位置和内筒悬挂长度,能获得满意的减震效果。

The seismic response control of a high rise reinforced concrete chimney by combining the suspended flue ducts and Rotational Friction Dampers(RFD).The detailing of the RFD joint for chimney is firstly presented.The RFD is placed between the outer and the inner shells.When a relative displacement is generated between the two cylinders under earthquake,a portion of the kinetic energy of the structure is dissipated.The seismic response of the system is then analyzed.The two cylinders are regarded as a continuous system,by using the assumed-modes method,and adopting the Bouc-Wen model of hysteresis for RFD,the state space formulation of the equation of motion of the system is derived based on Lagrange's equations.A chimney of 275 m high is then taken as an example to investigate the feasibility of the proposed control strategy.Five vibration control schemes under two strong earthquakes are compared and the results show that the vibration of outer shell can be substantially suppressed by using RFD with optimal parameters,position and suspended flue lengths.