节段预制UHPC桥梁接缝抗剪性能试验研究  

Experimental Study on the Shear Behavior of Joints in Precast Segmental UHPC Bridges

作　　者：郑凡 江建 李有志 ZHENG Fan;JIANG Jian;LI Youzhi(College of Civil Engineering,Hunan University,Changsha,Hunan 410082,China;Shenzhen Tagen(Group)Co.,Ltd.,Shenzhen,Guangzhou 518019,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]深圳市天健(集团)股份有限公司,广东深圳518019

出　　处：《公路工程》2022年第6期1-9,41,共10页Highway Engineering

基　　金：国家自然科学基金项目(51978257)。

摘　　要：节段预制UHPC桥梁目前缺乏相应设计标准和规范指南,成为学者广泛关注的问题。为更好地推广预制UHPC桥梁应用,对接缝受力性能展开研究,以正应力水平、键齿数目和接缝类型为主要研究参数,设计并完成11个UHPC接缝试件的直剪加载试验,获得了键齿的破坏形态、裂缝分布特征和荷载-位移曲线等。基于试验结果确定了胶层黏结贡献和摩擦系数,并根据摩尔应力圆建立了UHPC接缝直剪强度计算公式。结果表明:平胶接缝试件的破坏模式表现为黏结面的脱离,UHPC未出现明显损伤;键齿胶接缝试件破坏前胶层已经开裂,破坏时裂缝主要集中于键齿根部,胶接缝抗剪强度由键齿抗剪、未开裂胶层黏结和接缝面摩擦提供;干接缝试件的破坏区域分散,试件表面混凝土剥离严重;提高正应力水平和键齿数目可以有效提高接缝的抗剪强度;单键齿胶接缝比单键齿干接缝试件承载力高出约10.3%,三键齿胶接缝比三键齿干接缝试件承载力高出约7.4%;提出的UHPC胶接缝计算公式与试验结果平均比值为0.99,标准偏差0.03。Precast segmental UHPC bridges(PSUBs)have become a common concern due to the lack of corresponding design guidelines and specification.In order to promote the application of UHPC bridges,the aim of this research is to investigate the shear behavior of the joints in PSUBs.Confining stress,the number of shear keys,and joint types were the main test parameters considered in this study.In total,11 UHPC joint specimen were tested,and the failure mode,crack distribution,and load-displacement curves were obtained.The contribution of epoxy layer and the friction coefficients were obtained from experimental results.Basedon Mohr s circle,the calculation method for ultimate shear strength of UHPC joints were developed.The test results show that the failure mode of epoxy joints was the spalling of epoxy layer,and there was no damage on surfaces of UHPC joints.Prior to failure of keyed joints,the epoxy layer cracked and mainly distributed at the root of shear keys.Dry joint specimens shown a wider damage of failure and a serious spalling of concrete.The shear capacity can be effectively increased with the increasement of confining stress and the number of shear keys.The shear capacity of the single-keyed epoxy joint specimen was 10.3%higher than single-keyed dry one,and the shear capacity of the three-keyed epoxy joint specimen was 7.4%higher than three-keyed dry one.The proposed calculation method was also found to have a good agreement with the test results,with an average ratio of 0.99 and a standard deviation of 0.03.

关 键 词：桥梁工程 超高性能混凝土 胶接缝 干接缝 直剪强度 

分 类 号：U441[建筑科学—桥梁与隧道工程]