斜拉桥塔-索-桥面耦合参数振动模型及响应分析

针对大跨度斜拉桥拉索与桥塔、桥面的协同振动问题，考虑拉索垂度、阻尼、倾角以及重力弦向分力的影响，引入拉索高精度抛物线形，建立了桥塔-索-桥面连续非线性精细化振动模型，推导了桥塔和桥面共同激励作用下斜拉索耦合振动方程，对比分析了2种激振模式下斜拉索的参数振动特性，并编制程序研究了桥面与拉索的频率比、桥面激励幅值、索力及阻尼对结构耦合振动特性的影响规律。结果表明：桥面与拉索频率比对系统振动的影响较大，频率比为1:2和2:1时拉索均产生强烈振动，但2:1激振模式下拉索振幅更大，达到共振时间较长；随着桥面激励幅值的增大，2:1亚谐波共振模式下的拉索振幅增长速率更快；拉索振幅随索力的增大呈非线性减小趋势；斜拉索阻尼超过2%时，继续提高自身阻尼不能有效减小其振动幅值，需要通过设置附加阻尼才能更好地抑制其振动。

Coupled Vibration Analysis of Tower-Cable-Deck of Long-Span Cable-Stayed Bridge

In order to analyze coupled vibration of tower-cable-deck under end excitation. Considering sag, angle, damping and gravity of the tangential component of cable, the high precision parabola was introduced. The refined coupled model of tower-cable-deck was established. The nonlinear vibration differential equation of tower-cable-deck under end excitation was deduced. The vibration characteristic of cable was compared with two different modes. The effect of frequency ratio of cable and deck, deck excitation amplitude, cable force, damping and angle on structure were analyzed. The results show that the frequency ratio of cable and deck have larger influence on cable vibration. The cable strongly vibrate under the frequency ratio of 2:1 and 1:2, but the amplitude of cable under 2:1 vibration mode is larger, and longer resonance time. With the increase of the deck excitation amplitude, the amplitude growth rate under 2:1 vibration mode is faster. The cable amplitude decreases with cable force increasing. When the cable damping is over 2%, the vibration amplitude of cable cannot be effectively reduced, and the vibration of the cable can be suppressed by setting additional damping.