索力监测对保障索杆张力结构施工张拉阶段预张力的有效建立或服役期中的结构安全具有重要意义.以一个新型索杆张力结构——乐清市体育场月牙形索桁张力罩棚结构为例,结合该结构的特点制定了索力监测方案,将FBG和EM两种索力测量方法应用于该结构的索力监测并建立了能够长期运作的实时索力监测系统,介绍了利用这两种方法测量索力的关键步骤.通过分析该索力监测系统在施工张拉阶段的监测结果发现,FBG和EM传感器能够准确地反映结构施工张拉阶段的预张力变化,体育场结构有效地建立了设计预张力,上、下径向索及内环索的预张力偏差均在8%以内.
Cable pretension monitoring is of great significance to ensure the effective establishment of pretension.in the construction pretensioning stage and structure safety in service period of cable-bar tensile structures. Taking a new-type cable-bar tensile structure, a crescent-shaped cable-truss tensile canopy structure of Yueqing Stadium as an example, the cable force monitoring scheme was made up based on the characteristics of the structure. The FBG and EM methods were applied to monitor cable forces and a longterm real-time monitoring system was set up. The key steps of measuring cable forces by the two methods were also clarified. Through analyzing the monitoring results of the system in the construction pretensio- ning stage, the FBG and EM sensors could accurately reflect the structural pretension change during this period. The design pretension of stadium structure was effectively established. The pretension deviations of upper and lower radial cables as well as inner ring cables were controlled within 8%.