锈蚀钢筋混凝土梁动态抗弯性能细观数值研究  

Meso numerical study on dynamic anti-bending performance of corroded RC beam

作　　者：张仁波[1,2] 杨鸿申 金浏 邓小芳[1] 杜修力 ZHANG Renbo;YANG Hongshen;JIN Liu;DENG Xiaofang;DU Xiuli(The Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China;School of Civil Enginerring,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]清华大学土木水利学院,北京100084

出　　处：《振动与冲击》2023年第9期77-85,共9页Journal of Vibration and Shock

基　　金：国家重点研发计划(2019YFC1511003);国家自然科学基金(51822801)。

摘　　要：为研究锈蚀对钢筋混凝土(reinforced concrete,RC)梁动态力学性能的影响,考虑钢筋锈蚀和应变率效应及混凝土内部结构的非均质性,建立锈蚀钢筋混凝土梁两阶段三维细观尺度数值模型。钢筋的非均匀锈蚀膨胀以施加非均匀径向位移的方式模拟,并以保护层开裂“最终状态”作为之后混凝土梁动载模拟的“初始输入条件”,获得锈蚀后的动态力学行为。在验证了数值模型合理性的基础上,分析了钢筋锈蚀引起的保护层锈胀开裂行为及不同应变率下构件力学性能的变化。结果表明:钢筋锈蚀使混凝土梁产生了明显的纵向裂缝,梁的承载力随钢筋锈蚀率增加而降低;高应变率下,混凝土梁发生冲切破坏,梁的承载力显著提高;锈蚀混凝土梁承载力损失与锈蚀后梁频率降低系数(反映刚度损失)近似呈线性规律,且低应变率下的承载力对频率变化更加敏感。最后,基于模拟结果回归分析,发展建立了考虑锈蚀及应变率耦合影响的混凝土梁动态抗弯承载力预测公式。Here,to study effects of corrosion on dynamic mechanical properties of reinforced concrete(RC)beam,a two-stage 3D meso scale numerical model of corroded RC beam was established considering effects of corrosion of reinforcement,strain rate and heterogeneity of concrete internal structures.The non-uniform corrosion expansion of reinforcement was simulated by applying non-uniform radial displacement,and the“final state”of protective layer cracking was taken as the“initial input condition”of the subsequent dynamic load simulation of concrete beam to obtain its dynamic mechanical behavior after corrosion.After verifying the rationality of the numerical model,corrosion cracking behavior of protective layer caused by rebar corrosion and variation of mechanical properties of members under different strain rates were analyzed.The results showed that rebar corrosion causes obvious longitudinal cracks in concrete beam,and load-bearing capacity of concrete beam decreases with increase in corrosion rate of steel bars;under high strain rates,concrete beam has punching-shear failure,and its load-bearing capacity is significantly improved;load-bearing capacity loss of corroded concrete beam is approximately linear with frequency reduction coefficient(reflecting stiffness loss)of corroded beam,and load-bearing capacity under low strain rates is more sensitive to frequency changes.Finally,based on regression analysis of simulation results,a formula to predict dynamic flexural capacity of RC beam considering coupling effects of corrosion and strain rate was developed.

关 键 词：钢筋混凝土(RC)梁 钢筋锈蚀 抗弯承载力 动态荷载 细观模拟 

分 类 号：TH375.1[机械工程—机械制造及自动化]