跨度120m三角锥体空间钢结构施工卸载监测技术研究

大跨钢结构卸载阶段是拆除支撑体系、结构成形内力重分布的过程，是施工的关键步骤。以大同美术馆钢结构屋盖施工卸载为例，介绍了一种能够保障施工卸载安全的监测技术。首先通过数值模拟，分析对比了同步卸载与不同步卸载两种方案，并考虑了温度作用对钢结构的影响，确定了卸载方案及监测方案，进而对卸载阶段结构的应力、变形及温度进行实时监测，确保施工卸载阶段的安全。监测结果表明，大跨钢结构应力受温度影响较大，考虑温度影响的计算值更趋近于实测值，故温度影响不能忽视。结构卸载后应力与变形需要一段时间才能趋于稳定，因此监测周期建议延长。卸载完成后大部分应力监测值小于或接近计算值，卸载过程中应力变化明显，卸载后应力趋于稳定，保证了卸载过程结构屋盖的安全。

Research on construction unloading monitoring technology of120m triangular pyramidal space steel structure

The unloading stage of large span steel structures involves the dismantling of supporting system and the redistribution of internal forces, which is a key step of the whole construction process. Taking the construction unloading of Datong steel roof as an example, the monitoring technology of unloading to guarantee the construction safety was introduced. The monitoring system was installed before unloading, and the stress, deformation and temperature were real-timely monitored during the unloading stage of structures to ensure the construction safety. The monitoring results indicates that the stress of long-span steel structures is greatly affected by temperature, so the temperature effect should be considered in the calculation, whose result is close to the measured value. After unloading, the stress and deformation of the structure take a period of time to stabilize, so the monitoring period should be extended. After the unloading stage, most of the monitored stress values are less than or close to the calculated values. The stress changes obviously during unloading process and tends to be stable after unloading, which ensures the safety and stability of the structural roof.