钢-UHPC轻型组合梁负弯矩区接缝抗弯试验  

Experiment on the flexural performance of joint in steel-UHPC lightweight composite beams

作　　者：孔祥武 韩玉 胡美韵 晏班夫 KONG Xiangwu;HAN Yu;HU Meiyun;YAN Banfu(Guangxi Road and Bridge Engineering Group Co.,Ltd.,Nanning 530004,China;College of Civil Engineering,Hunan University,Changsha 410083,China;School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China)

机构地区：[1]广西路桥工程集团有限公司,南宁530011 [2]湖南大学土木工程学院,长沙410083 [3]广西大学土木建筑工程学院,南宁530004

出　　处：《桂林理工大学学报》2023年第3期414-423,共10页Journal of Guilin University of Technology

基　　金：湖南省科技计划项目(2020GK2026)。

摘　　要：针对传统钢板组合梁墩顶负弯矩区混凝土顶板易开裂的问题,提出了一种预制钢-UHPC轻型组合梁结构,设计了适用于该组合梁墩顶负弯矩区的横向接缝构造,通过强配筋及现浇UHPC材料的方式提高负弯矩区阶梯状T型湿接缝的抗弯、抗裂性能。以云南昌保高速公路某跨线桥为依托工程,对组合梁墩顶负弯矩区进行1∶2缩尺模型抗弯加载试验,分析了加载全过程的荷载-挠度曲线、荷载-应变曲线及截面应变分布、裂缝开展、破坏形态等,结果表明:横梁上部UHPC湿接缝的设置协同横梁构造有效提升了墩顶负弯矩区的抗裂性能;由于新旧UHPC界面钢纤维不连续,使得负弯矩区现浇UHPC与预制梁UHPC桥面板结合处成为结构受力最薄弱位置,组合梁抗弯承载力也由该处截面控制,提出了与横梁接缝结构破坏模式相对应的接缝截面塑性抗弯承载力计算方法,抗弯承载力理论计算值与试验值基本相符。Aiming at the problem that the concrete roof is easy to crack in the negative moment area of the traditional steel plate composite beam pier,a prefabricated steel-UHPC(ultra-high performance concrete)of light composite beam structure is proposed.The transverse joint structure in the negative moment area on the top of the pier improves the bending and crack resistance of the stepped T wet joint in the negative moment area by means of strong reinforcement and cast-in-place UHPC material.Taking a bridge over the Changbao Expressway in Yunnan as supporting project,a 1∶2 scale model flexural loading test was carried out.The load-deflection curve,load-strain curve,cross-section strain distribution,and destruction phenomenon of the whole loading process were studied.It shows that the establishment of UHPC wet joints with lower transverse beam can effectively reduce the cracks in the upper negative moment zone.The transverse beam and the bottom plate of steel beam can work together to resist the compression force so that the yield process of the steel beam can be delayed.The failure pattern of the test model shows that due to the discontinuity of the steel fibers between the old and new UHPC materials,the section at the joint of the cast-in-place UHPC and the precast beam in the negative bending moment area becomes the weak position of the structure,and the flexural bearing capacity of the composite beam is also controlled by this section.The calculation method of the plastic flexural capacity of the joint section corresponding to the failure mode of the beam joint structure is proposed.The analysis shows that the theoretical calculation value of the flexural capacity is basically consistent with the experimental value.

关 键 词：钢-UHPC组合梁 负弯矩区 横向接缝 抗弯承载力 加载试验 

分 类 号：U443.31[建筑科学—桥梁与隧道工程] U448.21[交通运输工程—道路与铁道工程]