输电线路钢管塔微风振动及其对结构安全性的影响

输电钢管塔的微风振动, 是其部分圆截面构件在较低风速时发生的由卡门涡街引起的横风向运动。文章根据振动理论给出微风振动钢管构件的起振临界风速Vcr 和共振力的简明计算方法, 分析了共振产生的弯曲和疲劳应力对易发生微风振动的杆塔斜材和辅材结构安全性的影响。计算结果表明, 共振弯曲应力一般不会造成构件弯曲破坏, 但高频振动可能导致结构疲劳破坏, 尤其是杆端约束接近于固接的构件。

Steel Tube Transmission Tower Aeolian Vibration and Its Influences on Structural Safety

Steel tube transmission tower aeolian vibration is lateral motions of some circular tower members induced by Karman vortex under relatively low wind speed.Based on vibration theory,this paper presents concise methods for critical wind speed,Vcr,at which tube members start the aeolian vibration,and resonance force calculations,and analyzes the influences of resonant bending and fatigue stress on safety of web and auxiliary members that are subject to the aeolian vibration.Computation results show that resonant bending stresses normally do not cause member bending failure,however,high frequency vibration may cause structural fatigue failure,especially those members with end constraints close to clamped condition.