火灾下预应力损失对新型弦支穹顶结构稳定性影响分析
Stability Analysis of Pre-stress Loss on Suspend-dome Structure Under Fire Hazard
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摘要: 为了研究奥运会羽毛球馆在火灾情况下的性能,作者基于大空间空气升温理论对温度场进行了模拟,通过预应力损失反映温度变化对索力大小的影响,并对弦支穹顶结构进行了双重非线性影响的稳定承载力分析研究.计算结果表明,结构在90min火灾后除最外圈环索以外,其余环索的预应力损失比较明显,整体稳定承载力下降约1/5,但仍具有一定的安全储备;材料高温蠕变性对结构稳定承载力的影响很小,在结构抗火分析时可以忽略.Abstract: To study the behavior of the badminton gymnasium for 2008 Olympic Games in case of fire,numerical simulation of the temperature field is performed,which is based on the model of air temperature rising for large buildings. By defining pre-stress loss in calculation program,the influences of temperature variations on cable forces is reflected. Corresponding analysis involving geometry and material nonlinearities are carried out to predict the behavior of the structure. The results shows that 90 minutes after the structure is exposed to fire,there are significant reductions in circumferential cable forces except the outmost one,and there is about one fifth decline in overall stability capacity without losing its safety. The studies indicates that thermal creep of material can hardly influence the bearing capacity,and can be neglected in anti-fire analysis.