摘要
自应力钢管陶粒混凝土不仅具有轻质、高强的特点,并可弥补轻集料混凝土因弹性模量较小而导致钢管约束不足的缺陷。本文通过对4组12根受火后的钢管自应力陶粒混凝土短柱及9根未受火钢管混凝土短柱受力性能的对比试验,分析了不同参数的钢管自应力陶粒混凝土短柱火灾后轴压承载力和破坏形态。重点讨论了试件的自应力大小(膨胀剂掺量)、含钢率及受火条件等因素对钢管自应力陶粒混凝土短柱火灾后轴压承载力及相关力学性能的影响。结果表明,自应力大小对钢管陶粒混凝土短柱火灾后轴压承载力的影响与试件含钢率有关,且初始自应力对含钢率相对较低试件的火灾后轴压性能的改善效果更加显著;试件含钢率越高,轴压力作用下的火灾后钢管自应力陶粒混凝土短柱的延性则越好。膨胀剂掺量为51 kg/m3(P2型)的试件,无论受火温度为700℃还是900℃,其火灾后的线弹性刚度受试件含钢率影响的规律基本一致。
Self stress ceramsite concrete filled steel tubular short columns（SSCC-STSC） not only has the advantages of lighter weight and higher strength, but also overcomes the defect of inadequate restraint of the steel tube to the core concrete, in which the smaller elastic modulus of the commonly used light-weight aggregate concrete can be improved by the self stress produced in core concrete of the composite columns. However, study of post-fire performance of SSCC-STSC after exposure to fire has yet to be explored. In this study, a comparative study of axial compressive mechanical behavior of twelve unprotected SSCC-STSC after exposure to fire and nine of the composite columns not subjected to fire were put forward through experimental investigation, and the post-fire axialcompressive bearing capacity and failure form of the specimens with different parameters were discussed. Effects of the factors such as self stress （ adding amount of expansive agent）, steel proportion and fire condition on the strength and the other related property of SSCC-STSC were especially discussed. The results show that effect of value of self stress on axial compressive bearing capacity of the SSCC-STSC after exposure to fire is related to steel proportion of the specimen, and the initial self stress is more effective in improving the axial compressive performance of the SSCC-STSC with lower steel proportion. However, the ductility of the specimen after exposure to fire is better for higher steel proportion. For specimens with 51 kg/m3 expansive agent mixing, effect of steel ratio on linear elastic stiffness of the specimens is nearly the same for the fire temperature 700°C or 900°C.
出处
《自然灾害学报》
CSCD
北大核心
2014年第1期210-220,共11页
Journal of Natural Disasters
基金
国家自然科学基金面上项目(51278254)
浙江省公益技术应用研究项目(2012C23036)
关键词
自应力
轻骨料
钢管混凝土柱承载力
火灾后
轴压力学性能
self stress
lightweight aggregate
bearing capacity of concrete filled steel tubular column
post-fire
axial compressive mechanical behavior
