高温效应对钢筋-混凝土动态黏结性能的影响:精细化模拟  

Effect of high temperature on the dynamic bonding performance of reinforced concrete:a refined simulation

作　　者：李潇雅 张仁波[1,2] 金浏 邓小芳[1] 杜修力 LI Xiao-ya;ZHANG Ren-bo;JIN Liu;DENG Xiao-fang;DU Xiu-li(The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Department of Civil Engineering,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]清华大学土木工程系,北京100084

出　　处：《振动工程学报》2023年第4期1062-1072,共11页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(51822801,51978022)。

摘　　要：为研究高温效应对钢筋⁃混凝土动态黏结性能的影响,建立了考虑带肋钢筋表面特征和混凝土材料非均质性的三维细观模型,与试验的破坏模式和黏结应力⁃滑移曲线进行对比,验证了细观模型的合理性。在此基础上,分析了高温下和冷却后钢筋⁃混凝土动态黏结应力⁃滑移行为的变化规律。结合数值模拟结果,建立了考虑高温效应的动态黏结强度预测公式。结果表明:细观模型能够反映变形钢筋与混凝土界面的开裂过程和黏结破坏机理;随着应变率的增加,高温下或冷却后的混凝土损伤区域逐渐减小;应变率相同时,高温下混凝土的损伤区域明显大于冷却后;随着温度的升高,高温下或冷却后试件的极限黏结强度均线性下降;相同温度环境下,应变率增加使得极限黏结强度非线性提高;预测结果与试验结果的良好吻合,说明本文提出的经验公式可以合理反映钢筋⁃混凝土动态极限黏结强度的高温效应。To study the effect of high temperature on the dynamic bonding performance of reinforcement concrete,a three-dimen⁃sional mesoscale model considering the surface characteristics of deformed reinforcement and the heterogeneity of concrete was es⁃tablished.Compared with the experimental failure pattern and bond stress-slip curve,the rationality of the mesoscale model was verified.On this basis,the variation of dynamic bond-slip behavior of reinforcement concrete at a high temperature or after cooling down was analyzed.Combined with the numerical simulation results,a dynamic bond strength prediction equation considering the high temperature effect was developed.The results show that:the mesoscopic model can reflect the cracking process and bonding failure mechanism of the interface between deformed reinforcement and concrete;with the increase of strain rate,the damaged area of concrete at high temperature or after cooling down decreases gradually.At the strain rate,the damaged area of concrete at high temperature is significantly larger than that after cooling down;with the increase of temperature,the ultimate bond strength de⁃creases linearly at a high temperature or after cooling down;at the same temperature,the increase in strain rate makes the ultimate bond strength increase nonlinearly;the good agreement between the predicted results and the experimental results indicates that the empirical formulae presented in this work can reasonably reflect the high temperature effect on the dynamic ultimate bond strength between reinforcement and concrete.

关 键 词：混凝土 动态黏结性能 变形钢筋 高温效应 精细化模拟 

分 类 号：TU528[建筑科学—建筑技术科学] TV431[水利工程—水工结构工程]