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在试验基础上,引入损伤力学中的Loland模型进行盐冻混凝土的单轴抗压分析,并将模型下降段修正为非线性关系表达式。依据试验数据,对《混凝土结构设计规范》(GB50010—2002)建议的混凝土应力-应变表达式中的参数进行回归,结合修正Loland模型,得到与冻融循环次数和水灰比相关的混凝土盐冻损伤本构模型。编制Fortran程序,应用所提出的本构模型对盐蚀、持续荷载和冻融循环共同作用下的钢筋混凝土梁进行截面非线性全过程分析。研究结果表明:多因素复合作用下,随冻融循环次数与水灰比的增加,混凝土初始损伤不断增大,峰值应力降低,对应应变加大,但延性无明显变化;盐冻条件下,随着持续荷载增大,梁的极限承载力降低。
Based on the experiment, the Loland model in damage mechanics is introduced to analyze the uniaxial compression of salt-frozen concrete and the correction of the descending section of the model to a non-linear expression. Based on the experimental data, the parameters in the concrete stress-strain formula proposed in “Code for Design of Concrete Structures” (GB50010-2002) are regressed, and the modified Loland model is used to obtain the concrete salt frost which is related to the number of freeze-thaw cycles and the water-cement ratio Damage constitutive model The Fortran program is compiled and the nonlinear model of the proposed model is used to analyze the nonlinear cross-section of the RC beams under the combined effect of salt-corrosion, continuous loading and freeze-thaw cycles. The results showed that with the increase of the number of freeze-thaw cycles and the water-cement ratio, the initial damage of concrete increased, the peak stress decreased and the corresponding strain increased, but the ductility did not change obviously. Under the conditions of salt-freezing, As the sustained load increases, the ultimate bearing capacity of the beam decreases.