带黏弹性阻尼器钢结构振动台试验研究

Study on shaking table test of a steel structure with additional viscoelastic dampers

为研究新型合成材料黏弹性阻尼器在地震作用下的减震效果和耗能特征,将6个黏弹性阻尼器按层间柱形式安装在钢框架结构中,分别对无控结构和有控结构进行3条峰值加速度由0.1g^0.6g逐步增大的地震波作用下的振动台试验。通过对结构动力特性和结构响应的对比分析,研究黏弹性阻尼器的减震效果和耗能特征。试验结果表明:结构加速度和位移减震效果明显,剪力减震效果有限;黏弹性阻尼器频率相关性不明显,主要为剪切变形幅值相关性;随着剪切变形增加,阻尼器提供附加刚度降低,引起结构自振频率从2.81 Hz降至1.19 Hz;随着剪切变形增加,附加阻尼比先增后减,最大为18.21%;黏弹性阻尼器初始刚度对结构带来的不利影响不容忽视;黏弹性阻尼器具有良好的极限剪切变形能力,最大剪应变达到336%。

In order to investigatethe dissipation characteristics and control effect of a kind of viscoelastic( VE) damper with new elestomeric material during earthquakes,a shaking table test on a steel frame structure added with VE dampers was designed and conducted. Six dampers were installed in pairs at each story of the structure and connected to the upper and lower beam vertically. The structure with additional VE dampers and that without additional VE damper were subjected to three ground motions whose peak ground accelerations( PGAs) vary from 0. 1g to 0. 6g. The dynamic properties and structural responses of the two structures were compared. The experimental results indicate that the control effect on acceleration and displacement is remarkable,while the effect on the shear force is limited. The frequency dependence of VE damper is not obvious. The additional stiffness decreases along with the increase of damper deformation,while the additional damping ratio initially increases and then declines. The structural frequency varies from 2. 81 Hz to 1. 19 Hz,and the maximum additional damping ratio is 18. 21%. The adverse effect caused by initial stiffness of VE damper must not be ignored. The maximum deformation of VE dampers is remarkable,and the maximum shear strain in this test reaches 336%.