膜下索穹顶太阳辐射非均匀温度效应研究

RESEARCH ON SOLAR RADIATION NON-UNIFORM TEMPERATURE EFFECT ON CABLE DOME UNDER MEMBRANE

索穹顶结构常采用膜屋面,高透光膜屋面可使太阳辐射透过膜材作用在下部结构上,且降低了结构周围的对流换热作用,可能形成"温箱效应",使膜下索穹顶结构产生显著的非均匀温度效应。基于内蒙古伊旗全民健身中心索穹顶,分别考虑ETFE、PTFE两种膜材,对其进行膜下索穹顶结构太阳辐射非均匀温度场和温度效应分析。结果表明:膜下索穹顶结构存在显著的太阳辐射非均匀温度场和温度效应,膜材的太阳辐射透射系数是主要影响因素之一。升温导致索穹顶结构预应力损失严重,考虑太阳辐射非均匀升温工况比考虑极端气温均匀升温工况的膜下索穹顶预应力损失更为明显,在设计中应予以考虑。

The membrane roof structure are often used in the cable dome. Due to high solar transmittance of membrane materials,most of solar radiation can pass through the membrane and irradiate on the steel structures below the membrane. Based on the cable dome of the national fitness center in Ejin Horo Banner of the Inner Mongolia,taking account of ETFE and PTFE membranes,the solar radiation non-uniform temperature field and temperature effect were analyzed. As a result,the solar radiation could induce a significant non-uniform temperature field and thermal effect around the cable dome. The temperature increment of the cable dome caused a significant prestressing loss. The solar transmittance of membrane roof was the main factor affecting the non-uniform temperature field and thermal effect of the cable dome below.