考虑箍筋与CFRP布相互作用的CFRP布加固RC梁受剪承载力细观研究  

Meso-scale study on shear bearing capacity of CFRP sheets strengthened RC beams considering interaction between stirrups and CFRP sheets

作　　者：金浏[1] 张江兴 李冬[1] 杜修力[1] JIN Liu;ZHANG Jiangxing;LI Dong;DU Xiuli(Key laboratory of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市减灾与防灾防护教育部重点实验室,北京100124

出　　处：《建筑结构学报》2024年第3期208-219,共12页Journal of Building Structures

基　　金：国家自然科学基金项目(51978022);北京市自然科学基金项目(JQ22025);北京市科技新星计划(20220484047)。

摘　　要：为揭示CFRP布加固RC梁剪切破坏机理,采用同时考虑混凝土材料细观非均质性、钢筋与混凝土相互作用、CFRP布与混凝土相互作用的数值模拟方法,建立CFRP布加固RC梁三维细观数值分析模型。分析了箍筋、CFRP布及其相互作用对梁剪切破坏的影响,建立了CFRP布加固RC梁截面名义抗剪强度修正计算式。研究表明:梁受剪承载力随配箍率(0%、0.2%、0.5%、0.8%)和配纤率(0%、0.066 8%、0.133 6%、0.267 2%)增大均有不同程度提高,但提高幅度随配箍率和配纤率增加而减小;箍筋应变和CFRP布应变均与主斜裂缝位置紧密相关,越靠近主斜裂缝位置的应变越大,且峰值应变随配箍率和配纤率增加而减小,当配纤率由0.066 8%增至0.267 2%时,CFRP布应变降低了45.9%,当配箍率由0.2%增至0.8%时,CFRP布应变减小了30.6%;箍筋和CFRP布之间存在不利相互作用,其对梁的剪切贡献不能简单叠加;建立的考虑配箍率、配纤率及其相互作用影响的CFRP布加固RC梁截面名义抗剪强度修正计算式计算值与试验值的误差小于20%,较为准确合理,可用于预测CFRP布加固RC梁的受剪承载力。In order to reveal the shear failure mechanism of CFRP sheets strengthened reinforced concrete(RC)beams,a three-dimensional(3D)meso-scale simulation method was adopted,which simultaneously considered the meso-heterogeneity of concrete materials,the interaction between reinforcement and concrete,and the interaction between CFRP sheets and concrete.A 3D meso-scale numerical analysis model of CFRP sheets strengthened RC beams was established.The influence of stirrups,CFRP sheets and the interaction between them on the shear failure behavior of RC beams were emphatically analyzed,and a modified formula of shear strength of CFRP sheets strengthened RC beams was established.The results show that the shear bearing capacity of beams increases with the increase of stirrup ratio and fiber ratio,however the increase range decreases with the increase of stirrup ratio and fiber ratio.Both the stirrup strains and CFRP strains are closely related to the position of the main oblique crack,the closer to the main oblique crack,the greater the strains are,and the peak strain decreases with the increase of stirrup ratio and fiber ratio;when the CFRP fiber ratio increases from 0.0668%to 0.2672%,the strain of CFRP decreases by 45.9%,and when the stirrup ratio increases from 0.2%to 0.8%,the strain of CFRP decreases by 30.6%.There is an adverse interaction between stirrups and CFRP sheets,and their contributions to the shear bearing capacity of the beam cannot be simply superimposed.The error between the experimental value and the prediction of the modified calculation formula of shear bearing capacity of CFRP sheets strengthened RC beams considering the influence of the stirrup ratio,fiber ratio and their interaction is less than 20%,indicating that the formula is accurate and reasonable,and can be used to predict and calculate the shear bearing capacity of RC beams strengthened with CFRP sheets.

关 键 词：钢筋混凝土梁 配箍率 CFRP配纤率 细观分析 剪切性能 

分 类 号：TU375.1[建筑科学—结构工程] TU311.41