摘要
为进一步研究受损部分预应力混凝土(PPC)斜拉桥主梁裂缝灌浆加固后的疲劳性能,对受较大疲劳及静力损伤的PPC斜拉桥节段缩尺模型主梁进行裂缝灌浆加固,并开展疲劳及疲劳后静载试验研究。研究结果表明:在疲劳荷载作用下,灌浆裂缝未重新开裂,在疲劳加载初期(约20万次),结构体系刚度下降较快,后期下降较平缓;250万次疲劳加载后,主梁L/4、L/2和3L/4截面处的结构体系刚度分别降低12.83%、9.48%、13.62%,较原主梁第4轮疲劳加载下结构体系刚度下降幅度大,但疲劳结束时结构体系刚度仍然比原主梁第4轮疲劳加载初始结构体系刚度大;对裂缝进行灌浆处置能有效恢复PPC斜拉桥主梁的抗裂强度及结构体系刚度;随着荷载增大,灌浆裂缝逐步张开,但最大裂缝宽度对应位置发生转移,同时不断有新裂缝产生,且裂缝分布区域范围增大,环氧树脂胶的作用极大地延缓了裂缝宽度的增大,提高了主梁的抗裂性能;环氧树脂胶不仅能修复混凝土裂缝界面,同时能有效恢复钢筋与混凝土间的黏结滑移损伤;对受严重损伤的PPC斜拉桥主梁仅进行裂缝灌浆处置后,主梁仍然具有良好的抗疲劳性能,同时,其疲劳后的抗裂性能及刚度也得到较大恢复。
In order to further investigate the fatigue performance of the main beam of the damaged partially prestressed concrete(PPC)cable-stayed bridge after crack grouting reinforcement,a scaled model of the PPC cable-stayed bridge section with significant fatigue and static damage to the main beam for crack grouting reinforcement was used,and fatigue and post fatigue static load tests were carried out.The results show that under fatigue load,the grouting cracks do not crack again,and the stiffness of the structural system decreases rapidly in the initial stage of fatigue loading(within about 200000 times),and gradually in the later stage.After 2.5 million times of fatigue loading,the structural system stiffness of the main beam at L/4,L/2,and 3L/4 sections decreases by 12.83%,9.48%,and 13.62%,respectively,which is larger than that of the original main beam under the fourth round of fatigue loading.However,at the end of fatigue loading,the stiffness of the structural system is still greater than the initial structural system stiffness of the original main beam under the fourth round fatigue loading.The crack grouting treatment can effectively restore the crack resistance strength and structural system stiffness of the main beam of PPC cable-stayed bridge.With the increase of load,the grouting cracks gradually open,but the position of the maximum crack width shifts.At the same time,new cracks are constantly generated,and the range of crack distribution area increases.The effect of epoxy resin adhesive greatly delays the development of crack width and improves the crack resistance of the main beam.Epoxy resin adhesive can not only repair the crack interface of concrete,but also effectively recover the bond slip damage between steel bars and concrete.The main beam of the severely damaged PPC cable-stayed bridge still has strong fatigue resistance after crack grouting treatment,and the crack resistance and stiffness of the main beam after fatigue are greatly restored.
作者
袁晟
颜东煌
王文熙
刘昀
潘权
袁明
YUAN Sheng;YAN Donghuang;WANG Wenxi;LIU Yun;PAN Quan;YUAN Ming(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China;Testing Consulting Co.Ltd.,Changsha University of Science&Technology,Changsha 410076,China;College of Civil Engineering,Hunan University,Changsha 410082,China;Institute of Road and Bridge Enginering,Hunan Communication Engineering Polytechnic,Changsha 410132,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第3期1068-1081,共14页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51878073,52078054,52278141)
湖南省交通科技项目(201932)
湖南省自然科学基金资助项目(2021jj30730)
湖南省研究生科研创新项目(CX20200832)。
关键词
桥梁工程
混凝土斜拉桥
部分预应力
灌缝加固
疲劳性能
模型试验
bridge engineering
concrete cable-stayed bridge
partial prestress
grouting reinforcement
fatigue performance
model test
