考虑二次受力的CFRP布加固RC梁短期挠度研究  

Study on short-term deflection of RC beams strengthened by CFRP sheet considering secondary load

作　　者：毛宇欣 黄俊豪 钱永久[2] Mao Yu-xin;Huang Jun-hao;Qian Yong-jiu(China Merchants Chongqing Communications Technology Research&Design Institute Co.Ltd,Chongqing 400067,China;Civil Engineering Department,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]中交第二公路勘察设计研究院有限公司,湖北武汉430056 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《工程抗震与加固改造》2023年第4期130-137,155,共9页Earthquake Resistant Engineering and Retrofitting

基　　金：国家自然科学基金面上项目(51778532)。

摘　　要：为研究二次受力对CFRP抗弯加固混凝土梁桥短期挠度的影响,完成了5根RC简支梁在不同持载水平下的CFRP布抗弯加固试验,基于试验结果修正了现有CFRP布加固梁短期截面刚度计算公式,继而推导了考虑二次受力的加固梁短期挠度计算方法。结果表明CFRP布加固对梁屈服后的截面刚度提升较大,可达未加固梁的1.65倍;当初始荷载由未加固梁极限荷载的10%增至90%时,加固后梁的截面刚度提升幅度由6.46%降至0.80%,二次受力对正常使用阶段RC梁加固后的刚度提升有不利影响;二次受力加固梁的极限挠度相比直接加固梁分别增加了8.95%、28.31%和59.54%,表明当破坏由CFRP应变控制时,二次受力对加固梁的延性发挥有利。In order to study the influence of secondary load on the short-term deflection of concrete beam bridges strengthened by CFRP sheets,five RC simply supported beams strengthened by CFRP sheets under different levels of preload are tested.Based on the test results,the existing calculation formula of short-term section stiffness of strengthened beams is modified,and then the calculation method of short-term deflection of strengthened beams considering secondary load is derived.The results show that the section stiffness of strengthened beams after yield increases greatly,which is 1.65 times of that of unstrengthened beams;when the initial load increases from 10%to 90%of the ultimate load of unstrengthened beam,the increase of the section stiffness of strengthened beams decreases from 6.46%to 0.80%,which means the secondary load has a negative effect on the stiffness of RC beams in service;the ultimate deflections of strengthened beams under secondary load are 8.95%,28.31%and 59.54%higher than that of directly strengthened beams,respectively,which shows that when the failure is controlled by CFRP strain,the secondary load is beneficial to the ductility of the strengthened beam.

关 键 词：桥梁工程 钢筋混凝土梁 CFRP加固 二次受力 短期挠度 分段叠加法 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]