基于频率法的张弦结构钢拉杆施工内力监测方法研究与工程应用  

Research and Application of Internal Force Monitoring Method for Beam-String Steel Tie Rod Construction Based on Frequency Method

作　　者：周国军 刘圣 严卫荣 张宇鑫 Guojun Zhou;Sheng Liu;Weirong Yan;Yuxin Zhang(Zhejiang Jinggong Steel Building Group Co.,Ltd.,Shaoxing 312030,China;Wenzhou Airport Group Management Co.,Ltd.,Wenzhou 325024,China;School of Architectural Engineering of Shanghai Normal University,Shanghai 201418,China)

机构地区：[1]浙江精工钢结构集团有限公司,浙江绍兴312030 [2]温州机场集团管理有限公司,浙江温州325024 [3]上海师范大学建筑工程学院,上海201418

出　　处：《钢结构（中英文）》2022年第9期17-24,共8页Steel Construction（Chinese & English）

基　　金：上海市自然科学基金项目(13ZR1430500)。

摘　　要：张弦结构由上弦刚体、下弦柔性拉杆及其之间的刚性撑杆构成,柔性拉杆通常采用钢索或钢拉杆,在结构体系中为受拉构件。温州机场在天窗部位布置异形张弦结构,设计院对张弦结构钢拉杆施工成型内力提出了明确的容许范围。根据钢结构总体施工方案,张弦结构在楼面拼装阶段采用被动建立预应力技术,施加初拉力后随屋盖整体提升到设计标高。设计明确了张弦结构施工完毕状态钢拉杆内力标准值,称为成型内力标准值。以成型内力标准值为目标值,结合钢结构施工方案和钢拉杆张拉方案,采用全过程仿真模拟分析技术,试算求出钢拉杆初拉力标准值。为保证钢拉杆成型内力满足设计要求,掌握钢拉杆内力变化过程,确保结构处于安全状态,需对钢拉杆施工过程中的内力进行监测。频率法测量钢拉杆内力是基于频率与内力间相关关系由频率直接推算得出。分析该天窗张弦结构的特点可以发现,钢拉杆两端均通过销轴连接,边界条件近似于理想铰接,这种边界条件在钢拉杆振动时,对振动幅度的衰减和振动频率的干扰最小。因此,频率法适用于本工程钢拉杆内力监测。提升过程是结构受力体系转换的过程,是一个动态变化的过程,也是钢拉杆内力波动最频繁的过程,需对钢拉杆内力进行监测。考虑到应变法技术成熟、对环境变化适应能力强、操作简便、结果可靠的特点,提升过程中,采用在钢拉杆上安装应变传感器的方法来监测钢拉杆的内力。通过施工模拟、测点选择、施工准备及设备安装、现场测试以及数据采集、分析,得出如下结论:1)频率法与应变法测量的结果都在允许范围内,避免了张拉力不足或超张拉现象,验证了被动预应力施工技术的可行性;2)实测内力变化趋势与理论计算分析内力变化趋势相符,说明了实测值的有效性;3)两种测量方法差值的相对值The String structure consists of a rigid body at the top chord,a flexible tie rod at the bottom chord and a rigid strut between them,steel cable or steel tie rod is usually used as flexible tie rod,in the structural system,it is a tension member.Special shaped truss string structure is arranged at skylight of Wenzhou Airport,the design institute has put forward a clear allowable range for the internal force in the construction of tension string structure steel tie rod.According to the overall construction scheme of steel structure,passive prestressing technology was adopted in the stage of floor assembly of string structure,after the initial tension was applied,the whole roof was lifted to the design elevation.The standard value of internal force of steel tie rod at the end of construction was defined in the design,it was called the standard value of forming internal force.Taking the standard value of forming internal force as the target value,combined with steel structure construction scheme and steel tie rod tension scheme,the whole process simulation analysis technology was adopted,the standard value of initial tension of steel tie rod was tried to calculate.In order to ensure that the forming internal force of steel tie rod meets the design requirements,master the change process of internal force of steel tie rod,ensure that the structure is in a safe state,it is necessary to monitor the internal force of steel tie rod during construction.The internal force of steel tie rod measured by frequency method is directly calculated by the correlation between frequency and internal force.By analyzing the characteristics of the string structure of the skylight,it can be found that,both ends of the steel tie rod are connected by pins,the boundary conditions are approximate to ideal hinge,this kind of boundary condition is suitable for the vibration of steel tie rod,the disturbance to vibration amplitude attenuation and vibration frequency is minimum.Therefore,the frequency method is suitable for the internal force moni

关 键 词：频率法 应变法 监测 钢拉杆 内力 

分 类 号：TU758.11[建筑科学—建筑技术科学]