下击暴流作用下输电塔-线体系倒塌破坏研究

STUDY ON THE COLLAPSE FAILURE OF TRANSMISSION TOWER-LINE SYSTEM UNDER DOWNBURST

下击暴流在近地面形成的短时破坏性强风会对建筑结构造成较大威胁,尤其是输电塔-线体系等风敏感结构。依托实际工程,该文建立了输电塔-线体系有限元模型,采用确定性-随机性混合模型生成下击暴流风场,基于Tian-Ma-Qu本构模型模拟了该结构在下击暴流作用下的连续倒塌过程。结果表明,下击暴流下输电塔表现为在极短时间内的局部大变形,该区域大量斜材和少量主材相继屈曲是导致输电塔发生整体倒塌的主要原因。该输电塔的薄弱部位是第六节间,在抗下击暴流设计中应重点关注。

The short-term destructive strong wind formed by the downburst near the ground will pose a greater threat to building structures,especially to wind-sensitive structures such as transmission tower-line systems.Based on practical engineering,a new finite element model for the transmission tower-line system is established.The deterministic-stochastic hybrid model is used to simulate the generation of the downburst wind field.Based on the Tian-Ma-Qu material model,the progressive collapse process of the structure under the downburst is conducted.The research results demonstrate that:the transmission tower under the downburst performs its significant local deformation in a short time,the buckling of many diagonal members and several main members is the governing reason for the entire collapse of the tower.The segment 6 of the tower is considered the weakest position,to which should be particularly paid attention in the design of the structural resistance to downburst.