双凹摩擦摆隔震烟风道结构地震响应

传统烟风道板式滑动支座可减少道体热胀冷缩时的摩擦阻力,但抗震耗能能力不足,缺少变形后的复位能力,且会约束道体的转动而可能导致结构破坏.将摩擦摆隔震支座用于烟风道,可同时具有热滑移、隔震功能,允许道体在温度作用下自由转动.本文对烟风道采用双凹摩擦摆中间隔震的结构体系地震响应进行了研究,建立了横向地震作用下简化的三自由度地震响应分析模型,其中双凹摩擦摆采用三线性滞回模型,推导了一阶状态空间微分运动方程.该模型的分析结果与有限元实体模型分析结果非常接近.利用简化模型研究了不同场地类别、不同强度地震激励作用下双凹摩擦摆的恢复力特点及隔震效果,结果表明:与非隔震结构相比,双凹摩擦摆隔震的烟风道的道体反力、支架剪力均得到了控制.

SEISMIC RESPONSE OF ISOLATED GAS DUCT USING DCFP BEARING

The duct slide bearing plates are used to reduce the friction force as the duct expands and contracts under temperature variations, but can not be used for seismic isolation without the re-centering capability. In this paper, a double concave friction pendulum system (DCFP) with tri-linear hysteretic behavior is adopted for the gas duct both for thermal displacement and seismic isolation. The seismically isolated duct is modeled as a three-degree-of-freedom system in the transverse direction. The first order state space formulation of the equations of motion is derived, and the theoretical analysis is verified by the finite element analysis. Then the effects of the DCFP on a gas duct and its hysteretic behavior are investigated under various earthquake excitations. Comparing with a duct without the seismic isolation,the reaction force on the DCFP and the shear force on the pier are both greatly reduced.