广播电视发射塔桅杆段风致疲劳寿命研究

Study on Wind-induced Fatigue Kife of Mast Section of Ningxia Radio and Television Transmission Tower

高耸结构主要承受变化的风荷载,发生疲劳破坏对结构性能的影响较大,而对于塔架结构来说,风荷载是否被定义为疲劳荷载一直存在争议。针对这一问题,本文以宁夏广播电视发射塔工程为例,对桅杆段进行风致疲劳损伤及疲劳寿命研究。工程设计时对整体结构及桅杆段分别进行了风洞试验,通过雨流计数法得到风荷载作用下桅杆段构件的应力幅值的概率密度分布,采用时域法分析其风致疲劳寿命。结果表明,桅杆段构件最大应力幅值均小于疲劳截止限,无需计算疲劳寿命;连接法兰螺栓的疲劳寿命在500年以上,满足钢结构设计标准的疲劳要求。

Tall structures are mainly subjected to varying wind loads,and fatigue failure has a great impact on structural performance,and for tower structures,whether wind loads are defined as fatigue loads has been controversial.In order to solve this problem,this paper takes the Ningxia Radio and Television Transmission Tower Project as an example to study the wind fatigue damage and fatigue life of the mast section.During the engineering design,the wind tunnel test was carried out on the overall structure and the mast section,and the probability density distribution of the stress amplitude of the mast section members under wind load was obtained by the rainflow counting method,and the wind-induced fatigue life was analyzed by the time domain method.The results show that the maximum stress amplitude of the mast segment members is less than the fatigue cut-off limit,and there is no need to calculate the fatigue life.The fatigue life of the connecting flange bolt is more than 500 years,which meets the fatigue requirements of the steel structure design standard.