Practical Application of Hybrid Mass Damper System for Traffic-Induced Vibration Highway Bridges

公路桥梁在移动试验车作用下的动力响应试验结果表明，主梁的响应频率随试验车速度的增加而增加。这种动力响应具有瞬态特性，即由于车辆在桥梁上行驶而引起的振幅和频率的变化。被动式TMD（调谐质量阻尼器）对这类交通振动的控制是一个难点。在本研究中，混合控制系统结合被动式和主动式的优点。将弹簧质量系统的固有频率调整为模型桥梁的第一阶固有频率。通过加速度计测量桥梁的响应，用交流伺服控制器控制质量跟随桥梁的响应，并通过模型梁的动力学试验，与TMD控制进行了对比，验证了混合控制系统的有效性。模型车的固有频率约为3Hz，调整为模型梁的第一阶固有频率。在另一种情况下，车辆的固有频率约为4Hz。梁的动态响应以r.m.s. (root均方）的位移和加速度在跨度中心和反作用力在支持。动力反力在这里审查关于环境动力效应附近的地面和建筑物从交通引起的桥梁振动。与TMD相比，混合控制系统对有效值的减小幅度更大，位移的减小幅度大于加速度和反力的减小幅度。

Experimental results of dynamic response of highway bridges under a moving test vehicle show that frequency of girder's response increases with increasing of velocity of the test vehicle. Such dynamic response has transient properties, that is, amplitude and frequency change due to traveling of vehicle on bridges. It is difficult that this kind of traffic-induced vibration is controlled by TMD (Tuned Mass Damper) of passive type. In this study, hybrid control system combining merits of passive type and active type is developed. Natural frequency of a springmass system is adjusted to the first natural frequency of a model bridge. The mass is controlled by AC servomotor to follow the response of the bridge, which is measured by a accelerometer.Dynamic tests of a model girder are carried out to show the effectiveness of the hybrid control system compared with a control by TMD.A model vehicle is made of four wheels, and moved at a constant speed by a inverter controlled AC motor. The natural frequency of the model vehicle is about 3Hz, that is adjusted to the first natural frequency of the model girder. In another case the natural frequency of the vehicle is about 4Hz. Dynamic response of the girder is estimated in terms of r.m.s. (root mean square) of a displacement and an acceleration at the span center and reaction forces at supports. Dynamic reaction forces are examined here in respect to environmental dynamic effects to nearby ground and buildings from the traffic-induced vibration of bridges. Values of r.m.s are more reduced by the hybrid control system compared with TMD.The reduced rates for the displacement are larger than those for the acceleration or the reaction forces.