高阻尼混凝土框架的动力特性与抗震试验

在混凝土中加入高阻尼掺料,从而有效地提高钢筋混凝土结构自身的阻尼比,这是从材料角度出发的一种新的结构振动控制方法。本文利用聚合物的高阻尼特性和材料的表面改性技术,在普通钢筋混凝土柱中掺加一定数量的苯丙乳液和改性的硅粉,制作了3组单层两榀混凝土框架;然后对其进行了试验研究,测定了框架结构的阻尼比和频率等动力特性;并且研究和比较了不同地震动下高阻尼混凝土框架的相对位移和绝对加速度反应。试验结果表明:改性硅粉和苯丙乳液的加入均可以提高混凝土框架结构破坏前后的阻尼比,分别提高52.4%、82.3%和27.5%、42.5%;改性硅粉可以有效地提高混凝土框架结构破坏前后的刚度,分别提高5%和15%~50%;虽然苯丙乳液的加入降低了混凝土框架结构的初始刚度,大约降低17%,但却提高了混凝土框架结构破坏后的残余刚度,提高大约10%~20%。改性硅粉和苯丙乳液的加入对于混凝土框架结构地震反应的减振控制起到了很好的作用。

Experiments on dynamic properties of concrete frame models with high damping ratios

It is a new problem of vibration control that the fundamental damping ratio of traditional reinforced concrete structures may be increased by the incorporation of damping admixtures.Surface modification and polymers are effective on developing the damping ability of cement-based materials.In this paper,three groups of 1/4 models of high damping concrete frames with treated silica fume and styrene-acrylic were tested on the shaking table.Dynamic parameters such as damping ratio and frequency were analyzed,and the responses of relative displacement and absolute acceleration were compared.The experiments show that the damping ratios of plain concrete frame are increased respectively by 52.4% and 82.3%,when treated silica fume and styrene-acrylic emulsion are mixed in,and after the frames are destroyed,the damping ratio of concrete frame with treated silica fume and styrene-acrylic emulsion is increased respectively by 27.5% and 42.5% as compared with the plain concrete frame.Treated silica fume may effectively increase the stiffness of plain concrete frame before and after the destruction,although the styrene-acrylic emulsion decreases the initial stiffness of plain concrete frame,residual stiffness of plain concrete frame with styrene-acrylic emulsion is increased after damage.Also treated silica fume and styrene-acrylic emulsion play a major role in developing the seismic resistance.