火灾后钢筋混凝土梁抗剪承载力

Shear capacity of fire-damaged reinforced concrete beams

研究火灾后钢筋混凝土梁抗剪承载力,建立了钢筋混凝土梁的非线性有限元模型,对其在火灾后的抗剪性能进行了数值模拟。有限元模型考虑了火灾作用后混凝土和钢筋的材料损伤,分析了火灾时间、剪跨比、混凝土强度、箍筋直径和箍筋间距对钢筋混凝土梁抗剪承载力和刚度的影响程度。结果表明,随着火灾时间的增加、剪跨比的增大或混凝土强度的下降,火灾后钢筋混凝土梁的抗剪承载力和刚度均明显下降。随着箍筋直径的下降或箍筋间距的增大,火灾后钢筋混凝土梁的抗剪承载力下降,而刚度变化较小。

In order to research the shear capacity of fire-damaged reinforced concrete （RC） beams, the nonlinear finite element model was developed. Considering mechanical properties de- scending of concrete and steel reinforcing bar, the parameters of fire-damaged RC beam, including fire time, shear span to depth ratios, concrete strength, stirrup diameters and stirrup spac- ing, were analyzed. Based on numerical analysis, the change of shear capacity and rigidity of fire-- damaged RC beam were i-dentified. The results showed that with fire time increase or shear span to depth ratio increase or concrete strength decrease, shear capacity and rigidity of fire-damaged RC beam declined obviously. With stirrup diameters decrease or stirrup spacing increase, shear capacity of fire-damaged RC beam declined, but rigidity of fire-damaged RC beam had little change.