锈蚀箍筋约束混凝土的本构关系模型

Constitutive model for confined concrete with corroded stirrups

在役钢筋混凝土结构的箍筋往往发生锈蚀,对约束混凝土的应力-应变关系具有显著影响。鉴于此,综合考虑箍筋锈蚀对峰值应力和应变软化段斜率的影响,建立了锈蚀矩形箍筋约束混凝土的本构关系模型。首先揭示了箍筋锈蚀对约束混凝土应力-应变关系曲线的影响规律;然后基于36组锈蚀矩形箍筋约束混凝土棱柱体的轴压试验,建立了锈胀裂缝宽度和配箍特征值与峰值应力和应变软化的修正系数之间的关系;进而在经典的Kent-Scott-Park模型基础上,通过引入峰值应力和应变软化的修正系数来考虑箍筋锈蚀的影响,建立了锈蚀矩形箍筋约束混凝土的本构关系模型。分析结果表明,模型预测结果与试验数据吻合较好;随着锈胀裂缝宽度的增大,约束混凝土的峰值应力逐渐降低,而应变软化段的斜率逐渐增加。

Corrosion of stirrup often occurs in existing reinforced concrete structure,which significantly affects the stressstrain relationship of confined concrete. A constitutive model for confined concrete with corroded rectangular stirrups was established by taking into account the influences of corrosion of stirrup on both peak stress and slope of strain softening.The influence of corrosion of stirrup on stress-strain curve of confined concrete was explored first. Then the relationships between width of corrosion crack and characteristic value of stirrup with the modified coefficients of peak stress and strain softening were established based on the experimental data of 36 confined concrete prisms with corroded rectangular stirrups. Finally,a constitutive model for confined concrete with corroded rectangular stirrups was established based on the Kent-Scott-Park model by introducing modified coefficients of peak stress and strain softening. The analysis results show that the predicted results of the proposed model agree well with the experimental data. Moreover,the peak stress of confined concrete decreases and the slope of strain softening increases gradually with the increase of crack width.