摘要
为了更好地研究大气环境中的混凝土结构在冻融作用下的耐久性能,采用气冻气融的试验方法,对足尺(150mm×300mm×2700mm)钢筋混凝土梁在不同冻融循环次数作用后的抗弯承载力进行了研究,分析了冻融对钢筋混凝土梁在静荷载作用下的裂缝发展规律、开裂荷载、极限荷载、跨中挠度以及混凝土截面应变的影响。研究结果表明:经过冻融循环作用后的钢筋混凝土梁在静荷载作用下,其裂缝发展规律与未冻融梁基本一致;随着冻融循环次数的增加,开裂荷载、极限荷载以及跨中挠度逐渐降低,冻融循环150次时,开裂荷载下降为未冻融时的60%,极限荷载下降为未冻融时的86.7%,跨中挠度下降为未冻融时的79%;混凝土截面应变符合平截面假定,且随着冻融循环次数增加,混凝土受压区高度有所增加。
In order to better study the durability of concrete structures in the atmosphere under freezing and thawing,the test method of air-freezing and air-thawing was used to study flexural bearing capacities of the full-scale (150mm×300mm×2700mm)reinforced concrete beams in different freeze-thaw cycles.The effects of freezing and thawing on the crack development law,cracking load,ultimate load,mid-span deflection and concrete cross-section strain of reinforced concrete beams under static load were analyzed.The study results show that tile crack development law of reinforced concrete beams subjected to freeze-thaw cycles is basically the same as that of beams without freeze-thaw cycles.With the increase of freeze-thaw cycles,the cracking load,ultimate load and mid-span deflection gradually reduce.When the freeze-thaw cycle time is 150,the cracking load decreases to 60% at the time of non-freeze-thaw cycle,and the ultimate load decreases to 86.7% at the time of non-freeze-thaw cycle,and the mid-span deflection decreases to 79% at the time of non-freeze-thaw cycle.The concrete cross-section strain conforms to the fiat section assumption,and as the number of freeze-thaw cycles increases,the concrete compression zone height increases.
作者
关虓
牛荻涛
李强
肖前慧
Guan Xiao;Niu Ditao;Li Qiang;Xiao Qianhui(School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China;School of Civil Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China)
出处
《建筑结构》
CSCD
北大核心
2018年第22期62-66,共5页
Building Structure
基金
国家自然科学基金(51278403)
教育部长江学者和创新团队发展计划(IRT13089)
关键词
气冻气融
开裂荷载
极限荷载
跨中挠度
截面应变
air-freezing and air-thawing
crack load
ultimate load
mid-span deflection
cross-section strain
