大跨度环形钢结构卸载方案分析与监测

ANALYSIS AND MONITORING OF UNLOADING SCHEME FOR LARGE-SPAN ANNULAR STEEL STRUCTURE

以齐河国家现代农业产业园环形钢结构工程为研究对象,分析了环形钢结构的力学特性,并进行施工模拟,通过对各支撑点同步卸载、分级循环卸载、分区分级卸载3种卸载方案进行对比,选取最优卸载方案并进行施工监测。结果表明,环形钢结构在卸载过程中,除了受到弯矩、剪力以及轴力作用,还会受到一定的扭转作用,扭转作用与结构自重、跨度以及悬挑长度成正比;通过有限元模拟分析,采用分级循环卸载方案进行卸载时结构应力、位移变化比较稳定,同时受场地条件影响较小,可以进行指导卸载;通过监测数据与有限元模拟数据对比分析,采用分级循环卸载方案卸载时计算值与监测值基本吻合,应力、位移变化平稳,可为同类工程提供技术支撑。

Taking the annular steel structure project of Qihe National Modern Agricultural Industrial Park as the research object,the mechanical characteristics of the annular steel structure were analyzed,and the construction simulation was carried out.By comparing three unloading schemes,namely,synchronous unloading at support points,hierarchical cyclic unloading and zone-based hierarchical unloading,the optimal unloading scheme was selected,and construction monitoring was conducted.Results show that the annual steel structure is subject to some torsion in addition to the bending torque,shear force and axial force.The torsion is directly proportional to the structural weight,span and cantilever length.Through the finite element simulation analysis,the hierarchical cyclic unloading scheme features relatively stable structural stress and displacement change,which is affected little by site conditions and suitable for guidance in unloading.By comparing and analyzing the monitoring data and finite element simulation data,the calculated data are essentially consistent with the monitoring data in the hierarchical cyclic unloading scheme,with steady changes in the stress and displacement,thus providing a technical support for similar projects.