摘要
提出一种新的预应力高强钢丝绳-聚合物砂浆面层抗弯加固RC桥梁技术(PHSW-PM加固技术),通过1根受弯加固梁的静力试验和4根受弯加固梁的疲劳试验,重点研究加固层界面状况、预应力水平及锚固方式等参数对加固试件受弯疲劳性能的影响。试验结果表明:所提加固技术可有效提高RC梁的抗弯承载力,在0.2P_(u1)～0.35P_(u1)(P_(u1)为试件SWB-S-1的极限承载力)疲劳荷载幅值下,所有加固件均能承受200万次疲劳荷载作用,未出现明显疲劳破坏特征;与采用端部锚固方式相比,采用分布式锚固方式可有效提高加固层与原构件界面的黏结性能,显著增强加固层与被加固件共同工作性能,采用分布式锚固方式加固构件在疲劳后静载试验发生弯曲破坏,钢丝绳高强特性得到充分发挥,延性也得到有效提高;采用端部锚固方式的加固构件,加固层界面黏结性能缺乏稳定性,易发生黏结锚固破坏,降低加固效果,有界面缺陷的加固件性能与对比件相当;同时预应力可有效提高加固试件的抗弯刚度和抗裂性能;基于平截面假定,提出PHSW-PM加固RC梁受弯承载力计算公式。研究成果可为既有桥梁抗弯加固提供一种高效可行的加固技术。
An innovative technique for increasing the flexural capacity of reinforced concrete(RC) bridge girders using prestressed high-strength steel wires and polymer mortar(PHSW-PM) is presented and investigated in this paper. Static test on one flexural strengthened RC beam and fatigue test on four flexural strengthened RC beams were conducted to study the fatigue behavior of retrofitted specimens. Particular emphases were taken on the influence of three parameters including interface conditions of reinforcement layer, prestress levels of high-strength steel wire, and anchorage modes, on the fatigue behavior of the strengthened RC beams. Test results indicated that the proposed PHSW-PM strengthening technique could effectively improve the flexural capacity of RC beams and all the reinforced specimens could withstand more than two million times of fatigue load in amplitude from 0.2Pu1 to 0.35Pu1 with no obvious fatigue failure characteristics. Compared to the end anchorage mode, the distribution anchorage mode could improve the bond performance of reinforcement interface, which could effectively enhance the cooperative behavior of the reinforcement layer and the RC beam. The reinforced specimen with distribution anchorage mode failed in flexural failure mode under static loading after two million times fatigue test, in which the high strength characteristics of the steel wire were fully utilized, and the strength and the ductility of the specimen had been significantly improved. The fatigue behavior of the specimen with interface defect was almost equivalent to that of the corresponding reinforced one, which shows that the bond behavior of reinforcement interface in end anchorage mode lacked stability. The reinforced specimens with end anchorage were prone to debonding failure thus reducing the reinforcement effect. Meanwhile, prestress could potentially enhance the flexural stiffness and anti-cracking performance of retrofitted specimens. Finally, based on the plane-section assumption, a formula for flexural bearing ca
作者
柳战强
黄群贤
郭子雄
何煜川
LIU Zhan-qiang;HUANG Qun-xian;GUO Zi-xiong;HE Yu-chuan(School of Civil Engineering,Huaqiao University,Xiamen 361021,Fujian,China;Key Laboratory for Structure Engineering and Disaster Prevention of Fuiian Province,Huaqiao University,Xiamen 361021,Fujian,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2018年第11期102-112,共11页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51208219
51408238)
福建省自然科学基金项目(2016J01240)
福建省科技重大项目(2015Y4007)
华侨大学研究生科研创新能力培育计划资助项目
关键词
桥梁工程
抗弯加固
疲劳试验
预应力高强钢丝绳
聚合物砂浆
bridge engineering
strengthen in moment
fatigue test
prestressed high-strength steel wire
polymer mortar
