超大型混凝土冷却塔基础隔震与层间隔震性能对比研究

Comparative study on the performance of base isolation and mid-story isolation of super large reinforced concrete cooling tower

为研究隔震技术对超大型冷却塔抗震性能的影响,以某混凝土冷却塔为研究对象,利用SAP2000分别建立基础隔震与层间隔震的冷却塔有限元模型,开展了结构动力特性分析和非线性时程分析,与非隔震冷却塔相比,对比分析了基础隔震与层间隔震的隔震效果。研究结果表明:基础隔震技术与层间隔震技术均能有效地延长冷却塔结构的自振周期,降低结构地震反应,第一阶自振周期延长至近3倍,整体平动模态提前至前两阶,扭转模态提前至第三阶。对比基底剪力,基础隔震的减震性能略优于层间隔震;对比相对位移,喉部以上,基础隔震与层间隔震的冷却塔减震效果基本相同,喉部以下,层间隔震的减震效果优于基础隔震;对比加速度放大系数,塔筒各位置处基础隔震的减震效果均优于层间隔震,支柱位置处,与非隔震冷却塔相比,基础隔震的加速度略有放大。研究结果可为冷却塔的减隔震分析提供参考。

In order to explore the influence of isolation technology on the seismic performance of super large cooling tower,taking a concrete cooling tower as the research object,the finite element models of cooling tower with base isolation and mid-story isolation was established using SAP2000,and the structural dynamic behavior analysis and nonlinear time-history analysis was carried out.Compared with non-isolated cooling tower,the isolation effects of base isolation and mid-story isolation was compared and analyzed.The results show that both base isolation technology and mid-story isolation technology are able to effectively prolong the natural vibration period of the cooling tower structure and reduce the seismic response.The first natural vibration period was extended to nearly three times,the overall translational mode was advanced to the first two orders,and the torsional mode was advanced to the third order.Compared with the base shear force,the damping performance of base isolation was slightly better than that of mid-story isolation.Compared with the relative displacement,the damping effect of base isolation and mid-story isolation was basically the same above the throat,and the damping effect of mid-story isolation was better than that of base isolation below the throat.Compared with the acceleration amplification factor,the damping effect of base isolation at each position of the tower was better than that of mid-story isolation,and the acceleration of base isolation at the column position was slightly amplified compared with that of non-isolated cooling tower.The research results can provide reference for vibration reduction and isolation analysis of cooling tower.