半刚性连接钢框架结构附加有效阻尼比

Additional Effective Damping Ratio of Semi-Rigidly Connected Steel Frame

目的研究半刚性连接钢框架参数对结构附加有效阻尼比的影响,为半刚性组合钢框架的抗震设计提供依据.方法从半刚性连接钢框架的特点出发,结合结构附加有效阻尼比的思想,推导了半刚性连接钢框架的附加有效阻尼比计算公式,基于该计算公式,通过参数分析研究了半刚性连接钢框架结构的3个重要参数对结构附加有效阻尼比的影响.结果连接转动刚度增大,附加有效阻尼比增大,且影响较大;结构附加有效阻尼比随着节点抗弯承载力增大而减小,但是呈现非线性变化,随抗弯承载力增大,附加有效阻尼比的变化幅度逐渐减弱;结构变形幅度增大,附加有效阻尼比逐步增大,且基本呈现线性变化.基于参数分析结果,半刚性连接钢框架结构附加有效阻尼比可取0.005.结论根据附加有效阻尼比修正设计反应谱,可以确定地震作用并进行半刚性连接钢框架结构的抗震计算.

In order to design the semi-rigidly connected steel frame in seismic area, the damping ratio must be acquired. Based on the characteristic of the semi-rigidly connected steel frame and principle of additional effective damping ratio, the calculation method of the additional effective damping ratio of semi-rigidly connected steel frame was derived. The influences of three important parameters of semi-rigidly connected steel frame on the damping ratio have been analyzed. These parameters are the rotational stiffness, the moment capacity, and the rotation of the joint. The results presented that the rotational stiffness had a vital importance on the damping ratio, with the increases of the stiffness, the damping ratio increases too. For the moment capacity, as it increases, the damping ratio decreases. The relation between the story drift and the additional effective damping ratio is almost linear, with the story drift increasing, the damping ratio increases. Based on the results of the parameters analysis, the additional effective damping ratio of semi-rigidly connected steel frame can be 0. 005. The design spectrum is modified accommodating the effective damping ratio, so the seismic load of semi-rigidly connected steel frame can be determined.