GFRP/CFRP混杂加固混凝土梁阻裂增强机理  

Strengthening mechanism of concrete beam strengthened with externally bonded interply hybrid GFRP/CFRP

作　　者：何小兵[1,2] 郭晓博[1] 李亚[1] 申强[3] 

机构地区：[1]重庆交通大学山区桥梁与隧道工程国家重点实验室培育基地,重庆400074 [2]重庆大学工程力学系,重庆400030 [3]交通运输部公路科学研究院,北京100088

出　　处：《华中科技大学学报（自然科学版）》2014年第1期78-83,共6页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家重点基础研究发展计划资助项目(2012CB723305);重庆市自然科学基金资助项目(2008BB6344)

摘　　要：在研究GFRP/CFRP层间混杂复合材料极限拉伸性能的基础上,对外贴GFRP/CFRP混凝土加固梁的弯曲性能进行了研究,并建立裂尖闭合力阻裂模型,分析了GFRP/CFRP混杂效应机理和GFRP/CFRP加固梁的阻裂增强机理.结果表明:外贴GFRP/CFRP能显著降低加固混凝土梁裂纹尖端的应力强度因子,加固梁具有优越的抗裂性能和承载能力,开裂荷载和极限荷载较普通梁分别提高37%和172%以上;GFRP/CFRP加固梁中,裂纹在约70%梁高处停止扩展直至裂纹出齐,与阻裂机理模型分析结论一致;与单一FRP材料拉伸呈线弹性破坏性质不同,GFRP/CFRP呈现材料分级断裂性质,具有明显的屈服台阶,其加固的梁延性破坏特征明显;不同GFRP/CFRP粘贴加固方式中,U型加固方式的阻裂增强效果最佳,加固梁开裂荷载、极限荷载较I型加固方式分别提高17%和34%以上.Based on the ultimate tensile performance of interply hybrid GFRP/CFRP （glass/carbon fi-ber reinforced polymer）,the flexural behavior of strengthened concrete beams bonded externally with interply hybrid GFRP/CFRP was investigated through four-point bending test,and then the crack clo-sure model at crack tip was adopted to interpret the hybrid effect of interply hybrid GFRP/CFRP, crack-retarding and strengthening mechanism of the strengthened beam.The results show that,com-pared with the reference beam,the strengthened ones are characterized with better anti-cracking abili-ty and load capacity as the interply hybrid GFRP/CFRP can significantly decrease the stress intensity factor at their crack tips,and the cracking load and ultimate load of the strengthened beams are re-spectively improved by 37%and 172%at least;the main crack of the strengthened beam stops propa-gating at 70%of the beam depth until all cracks emerge,which is consistent with the results by the fi-nite element analysis of the strengthened beam;different from the linear elastic characteristic of FRP up to failure,the interply hybrid GFRP/CFRP possesses obvious yield plateau under tension,and the strengthened beam with interply hybrid GFRP/CFRP is of significant characteristics of ductile failure;compared with other bonding patterns studied,the crack-retarding and strengthening effect of U-type＆amp;nbsp;bonding pattern is the best when employed in the strengthened beams,of which the cracking load and ultimate load are respectively improved by 17% and 34% at least.

关 键 词：混杂材料 纤维增强复合材料 裂尖闭合力 应力强度因子 混凝土梁 有限元分析 弯曲试验 

分 类 号：TU599[建筑科学—建筑技术科学]