钢筋混凝土建筑物振动特性的高度效应研究

Study on the height effect of vibration characteristics about reinforced concrete buildings

建筑物振动特性对于结构抗震设计有重要的理论价值,其中自振周期和阻尼比是2个主要的动力参数。对福州地区129栋不同高度钢筋混凝土建筑物进行振动测试,并统计建筑物的基本特征,研究了高度在21~99m范围内建筑物的自振周期和阻尼比随建筑物高度变化的规律。结果表明:建筑物自振周期随高度增加而增大,有良好的相关性,自振周期约是高度的0.018 63倍;长短轴向自振周期也随高度的增加而增大,长轴向自振周期约是高度的0.014 56倍,短轴向自振周期约是高度的0.018 46倍;随着建筑物高度的增大,阻尼比、长轴向阻尼比和短轴向阻尼比这三者在一定的范围内近似均匀分布,对高度的敏感性低,其中建筑物阻尼比的平均值为4.44%,与建筑抗震设计规范所取的定值5%是比较接近的。研究结论:可为蓬勃发展的高层钢筋混凝土建筑物的初期设计提供科学依据。

The vibration characteristics of buildings have important theoretical value for seismic design of structures, in which the natural period and damping ratio are two main dynamic parameters. A vibration test was performed in Fuzhou area of 129 reinforced concrete buildings that height is in the range of 21 - 99m and the basic feature of buildings is noted to research the relationship between the natural period, damping ratio with the height of buildings. The result shows that there is a good correlation between the natural period and height, and the natural period is about 0.01863 times of the height. Natural period in longitudinal direction is about 0. 01456 times of the height, and in transverse direction is about 0. 01846 times of the height. As the height of the building increases, the damping ratio, damping ratio in longitudinal direction and in transverse direction are approximate uniform distribution, and they have low sensitivity to building＇ s height. Moreover the average value of the damping ratio is 4.44% that is close to the code for seismic design of buildings set 5%. The conclusion can provide scientific basis for the initial design of the high rise reinforced concrete buildings.