The Galloping Phenomenon And Its Control Of Bridge Structure

In the past of the twentieth century,the bridge engineering of world has experienced a high-speed development. With the 21st century coming, the bridge engineering will get into a new period of crossing ocean and connecting islands. With more and more long-span suspension Bridges and cable-stayed bridges have been constructed, the bridge structure will become more bigger,softer and lighter. So the impact of wind-induced vibration to the bridge is becoming moer and more significant,and the wind resistance stability problem of bridge structure is increasingly important. Galloping phenomenon as one important content of wind-induced vibration phenomenons also receives more attention of world bridge engineering.this paper, focusing on the bridge structure of Galloping phenomenon and its control measures, mainly includs the following aspects:(1)In the basis of relevant aerodynamics theory, the mechanism of galloping has been analyzed.By theory the key factor of appearing galloping is that lift line is negative. And the response of bridge structure to galloping and galloping vibration model has been analyzed.(2)A large of related materials about galloping of bridge and other constructures have been colleted. Respectively from aspects of the galloping phenomenon and distinguishing basis,the galloping possibly occurred on the bridge components has been introduced in detail.(3)With regard to the calculation of the galloping critical wind speed of bridge tower structure,two metheds have been introduced.And through the specific example and the wind-tunnel experiment datas,the results concluded by the two galloping critical-wind-speed calculation formulas have been compared,and which one is more accurate can be find.(4)The concept of structure control and its classification are introduced,and on the basis of that, the wind induced vibration control measures of bridge structure are summarized from the aspects of passive control, active control, hybrid control and semi-active control.(5)Respectively from the aspects of the steel mix joint part girder bridge, H suspenders and cables of cable-stayed Bridges,the galloping pneumatic control of bridge structure are analyzed.(6)The galloping stability control of bridge tower are studied. And this paper introduces a new type of towering structure vibration damper--gyro ant-vibration damper.