基于拉伸刚化的钢筋混凝土等效本构关系

针对混凝土拉伸刚化影响钢筋混凝土（RC）构件开裂后刚度和挠度，建立了包含3个阶段的钢筋混凝土等效本构关系.该本构关系采用换算截面法得出各临界点的截面惯性矩和中性轴的位置，对比ACI 318和Eurocode 2规范所计算梁的挠度，结果表明:Eurocode 2规范预测的结果更接近试验值.采用非弹性梁弯曲理论对第1阶段进行分析，得出RC弹性模量；第2，3阶段考虑混凝土的拉伸刚化，采用Eurocode 2规范分析梁横截面的性质，得出RC等效本构. 

The Equivalent Constitutive Relationship for Reinforced Concrete Based on Tension-Stiffening

The tension stiffening of concrete affects the stiffness and deflection of reinforced concrete. The equivalent constitutive relationship for reinforced concrete(RC) including three stages was obtained in this paper. The moment of inertia and the distance from the neutral axis to the extreme fiber at the critical points were computed by the transformed section approach. A comparison between the deflections of beams calculated by ACI 318 and Eurocode 2 shows that the predictions by Eurocode 2 are closer to experimental observations. The non-elastic bending theory was used in the first stage, and the elastic modulus was obtained. The method of Eurocode 2 was adopted to calculate the parameters in the cross section in the second and third stages, and the equivalent stress-strain relationship was obtained.