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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。
At present, almost all the evaluations of fire resistance of concrete structures at home and abroad are aimed at independent components, and few consider the mutual restraint effect between adjacent components. The actual fire investigation and open flame test show that there is a clear difference between the fire behaviors of the components in the structure and the independent components. In this paper, the high temperature response analysis of CFRP-reinforced concrete beams with end restraint was carried out. The axial / rotational restraint stiffness ratio, beam cross-sectional dimension, span, load ratio, reinforcement, reinforcement ratio, Thickness and other parameters on the beam bending moment of the beam strengthened by ISO834 under constant temperature. On this basis, the practical calculation method of beam end bending moment of beam with strengthened beam under high temperature is given. The results show that: (1) With the increase of heating time, the bending moment of beams with restraint reinforcement tends to increase firstly and then gradually tends to be gentle; (2) fire protection (even if the thickness of fireproof coating is only 10mm) Beam end moment significantly affected.