酸雨侵蚀箍筋约束混凝土本构模型研究

郑跃 郑山锁 明铭 阮升

摘   要：采用人工气候环境模拟技术模拟酸雨环境，对15组箍筋约束混凝土棱柱体试件进行加速腐蚀，进而进行轴压试验，研究了箍筋锈蚀对约束混凝土破坏形态、峰值应力、峰值应变、极限应变和应力-应变曲线形状的影响. 基于Mander模型及现有研究成果，确定了未腐蚀试件本构模型峰值应力、峰值应变、极限应变和形状系数等参数的计算公式，并通过对试验结果的回归分析，得到了考虑箍筋锈蚀率影响的形状系数和各特征点参数修正系数拟合公式，最终建立了酸雨侵蚀箍筋约束混凝土本构模型. 与试验结果对比发现，采用该模型计算得到的各试件峰值应力、峰值应变、极限应变及应力-应变曲线形状均与试验结果符合较好，表明所建立的本构模型能较为准确地反映遭受酸雨侵蚀箍筋约束混凝土力学性能，可用于该环境下RC结构剩余承载力及抗震性能评估.

关键词：约束混凝土;应力-应变曲线;酸雨侵蚀;锈蚀箍筋;轴压试验;Mander模型

中图分类号：TU365;TU317.1              文献标志码：A

文章编号：1674—2974（2021）01—0135—09

Abstract：In order to study the influence of stirrup corrosion level on the failure modes， peak stress， peak strain， ultimate strain and shape of stress-strain curve of the confined concrete，15 reinforced concrete prism specimens are subjected to acid rain erosion in the acid environment modeled by artificial climate simulation technique followed by axial compression tests. Based on the Manders model and the existing research results， the calculation formulas for the peak stress，peak strain， ultimate strain and shape factor of the uncorroded specimens are determined. The factor calculation formulas for peak stress， peak strain， ultimate strain and shape factor of corroded specimens are developed by regression analysis of test data， respectively， and then the constitutive model of confined concrete by acid rain erosion is established. By comparing the simulation results with the experimental data， it can be found that all the peak stress， peak strain， ultimate strain and stress-strain curves shape of the specimens obtained by proposed method are in good agreement with the experimental data. Thus， the constitutive mode for confined concrete established in this paper can accurately reflect the mechanical performance of RC prism specimen by acid rain erosion， indicating its adaptiveness for estimating the residual bearing capacity and the seismic performance of RC structure under the acid rain environment.

Key words：confined concrete;stress-strain curves;acid rain erosion;corroded stirrups;axial compression test;Manders model

酸雨侵蝕引起的混凝土碳化和钢筋锈蚀是导致RC结构抗震性能劣化的主要原因之一[1-3]. RC构件中配置的箍筋能约束混凝土横向变形，使其处于三向应力状态，从而提高约束区混凝土的承载能力和变形能力. 研究表明[4-9]，箍筋锈蚀会显著降低其对约束区混凝土的约束作用，使得构件承载力、延性等发生不同程度退化. 因此有必要研究酸雨侵蚀……