空间预应力钢桁架火灾响应及火灾后受力性能试验研究  

Experimental study on fire response and post-fire performance of spatial prestressed steel trusses

作　　者：王新堂[1] 孙宏亮[1] Yingang Du 王万祯[1] 

机构地区：[1]宁波大学,浙江宁波315211 [2]安格利亚鲁斯金大学

出　　处：《土木工程学报》2013年第8期28-37,共10页China Civil Engineering Journal

基　　金：国家自然科学基金(51078187);浙江省公益技术应用研究项目(2012C23036)

摘　　要：对一组空间预应力钢桁架结构开展了火灾行为试验研究。模型的主杆件选用奥氏体304无缝不锈钢管,张拉钢索采用7×12+IWR镀锌高强钢绞线,通过置于模型下端中心处的伸缩小立柱施加预应力。试验采用烬类燃烧火灾模型,利用荷重块模拟施加均布荷载。结构模型两端简支,另两边自由。试验测定了火灾下桁架弦杆和腹杆的温度响应及上弦节点位移。对火灾后尚未破坏的结构模型进一步开展了原位卸载及加载试验,得到测点位移及典型单元应变。结果表明,受火时预应力钢桁架模型的位移响应处于动态变化状态,且当结构模型的最大挠度超过1/100L时,也未见发生整体坍塌。受火时预应力钢桁架的主要变形特征为部分受压杆弯曲及整体结构扭曲,且受火后的结构模型产生一定的残余变形及刚度退化,这些特性与桁架自身刚度及外荷载大小等因素有关。The experimental study on fire behavior of a set of spatial prestressed The Austenite 304 seamless stainless steel tubes were used as the truss bars of the steel structure models was conducted structure models and the 7×12 ＋ IWR steel strands with higher strength were used as the prestressed cables. A short rotatable steel column which can be elongated and retracted was set at the center of the truss right below the bottom chord of the truss to exert prestress. The embers combustible fire model was used and uniform forces were applied by load blocks. The structure model was simply- supported on the shorter sides and of free boundaries at the two longer sides. The fire temperatures of the truss bars were measured with K-type thermocouples, and the typical displacements of the upper truss nodes were obtained. The unloading and loading experiments were further conducted for the structure model after exposure to fire. The results show that the displacements of the structure model under fire are variable, and the collapse of the structure does not emerge even the maximum deflection of the structure is larger than 1/100L. It is found that the deformation of the structure under fire exhibits as local bending of some truss bars and twist of the whole structure. Residual deformation and stiffness degradation exists in the structure after exposure to fire, which is related to the factors such as stiffness of the truss and the loads applied to the structure.

关 键 词：空间预应力钢桁架 不锈钢 火灾响应 模型试验 

分 类 号：TU398[建筑科学—结构工程]