作　　者： ; ; ; ;

机构地区： 华南理工大学建筑学院亚热带建筑科学国家重点实验室

出　　处： 《防灾减灾工程学报》 2013年第3期329-335,共7页

摘　　要： 目前国内外对混凝土结构的抗火性能评估几乎都是针对独立构件开展的,很少考虑相邻构件之间的相互约束作用。实际火灾调查与明火试验表明,结构中构件的火灾行为与独立构件有着较明显的差别。本文开展了具有端部约束的碳纤维布加固混凝土梁的高温反应分析,揭示了轴向/转动约束刚度比、梁截面尺寸、跨度、荷载比、加固量、配筋率、保护层厚度和防火涂料厚度等参数对ISO834标准升温作用下约束加固梁的梁端弯矩的影响规律。在此基础上,给出了高温下约束加固梁的梁端弯矩实用计算方法。研究表明:①随着升温时间的增加,约束加固梁的梁端弯矩总体呈现先逐渐增大而后渐趋平缓的趋势;②防火保护(即使防火涂料厚度只有10mm)对高温下约束加固梁的梁端弯矩影响显著。 Abstract： Current provisions in codes and standards evaluate the fire behavior of reinforced concrete （RC） structure based on the isolated structural members, i.e. slabs, beams and columns, without considering the effects of end restraints on the fire behavior. However, previous fire tests and actual fire incidents have shown that the fire behavior of structural members is obviously different from that of isolated members, due to the adjoining structural member restraint. The CFS strengthened RC beams with elastic axial and rotational restraints at beam ends are selected for numerical parametric study, and the effects of some parameters （i. e., axial/rotational restraint ratio, section dimensions, length, load ratio, strengthening ratio, reinforcement ratio, thickness of concrete cover, and thickness of fire insulation） on the bending moment at the ends of the restrained RC beams exposed to ISO834 standard fire are analyzed. Based on the extensive simulation results, a practical calculation method for the bending moment at the ends of the rstrained beams subjected to fire is proposed. It can be found that： （1） the bending moment at the ends of the restrained beams increases gradually first and then changes gently; and （2） the beding moment at the ends of the restrained beams strengthened with CFS and with fire insulation is quite different from that without fire insulation, even in the case that the thickness of the fire insulation is only 10 mm.

关 键 词： 高温 碳纤维布 加固混凝土梁 端部约束 弯矩

领　　域： [建筑科学]