基于纤维模型的RC结构的钢筋本构关系研究

以基于纤维模型的OpenSees软件为平台,首先,选用常用的钢筋本构(Steel01,Steel02)和混凝土本构(Mander,Hoshikuma),对PEER数据库中的两个钢筋混凝土柱的拟静力试验进行了数值建模与对比分析;再采用OpenSees软件中Reinforcing Steel钢筋本构模型,对钢筋单调拉压试验、循环加载试验、疲劳试验以及钢筋混凝土柱拟静力试验进行了模拟与对比分析.结果表明:现有的混凝土本构模型已相对成熟,并能较好地满足非线性数值模拟的精度要求,混凝土本构模型的改变对计算结果的影响不大,而钢筋本构模型的改变则会对分析结果产生较大的影响;Reinforcing Steel模型有效地提高了非线性模拟分析的精度,但也存在着对钢筋滞回曲线捏拢效应体现不足、分析结果偏于保守、计算过程较为复杂且较难收敛等缺点,尚需要对钢筋本构模型进行进一步的改进与完善.

Research on the Constitutive Models of Steel for Reinforced Concrete Structures Based on the Fiber Model

Two constitutive models for steel (Steel01 and Steel02) and two constitutive models for concrete were firstly selected to simulate two pseudo static tests for reinforced concrete columns in OpenSees based on the fiber model. Then, a constitutive model in OpenSees, i.e., Reinforcing Steel, was used to simulate the monotonic loading test, cyclic loading test, fatigue test for steel and the pseudo static test for the reinforced concrete columns. It is found that the constitutive models for concrete fibers are quite applicable for the numerical simulation and the results are not markedly affected by the change of the constitutive model for concrete fibers, while the constitutive models for steel need to be further improved because they can't perfectly meet the precision demand. Different models for steel will lead to different results. The Reinforcing Steel model can effectively improve the precision of the simulations. However, it also has some disadvantages in that it cannot clearly reflect the pinching effect of the hysteresis curves obtained from the cyclic loading tests for steel, the simulation is complex, the calculation results tend to be too conservative and are hard to converge.