局部加高的UHPC免模板湿接缝抗弯模型试验  

Bending Model Experiment of Local Heightened UHPC with Formwork⁃free Wet Joint

作　　者：马健 熊江东 苏官林 段春雨 苗玲 李立峰[3] MA Jian;XIONG Jiangdong;SU Guanlin;DUAN Chunyu;MIAO Ling;LI Lifeng(Nujiang Meili Highway Greenway Construction Engineering Headquarters,Lushui Yunnan 673200,China;Yunnan Comprehensive Transportation Development Center,Kunming 650032,China;School of Civil Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]怒江美丽公路绿道建设工程指挥部,云南泸水673200 [2]云南省综合交通发展中心,昆明650032 [3]湖南大学土木工程学院,长沙410082

出　　处：《铁道建筑》2024年第9期68-75,共8页Railway Engineering

基　　金：国家自然科学基金(52278176,51978257);云南省交通运输厅科技创新及示范项目(MLGLLD-GCC-2023-01);中国建筑第五工程局有限公司科技研发计划(cscec5b-2020-17)。

摘　　要：为简化装配式桥梁湿接缝现场施工工艺(免模板、免焊接),简化接缝段钢筋构造并提高接缝抗裂性,本文提出一种以普通混凝土(Normal Concrete,NC)预制桥面板局部加高部分作为底模的超高性能混凝土(Ultra-High Performance Concrete,UHPC)免模板湿接缝构造形式。为了检验这种结构的力学性能,设计了7片试验梁,包括2片整体梁、1片常规接缝梁和4片免模板接缝梁,以钢纤维掺量、层间抗剪钢筋和界面配筋率为试验参数,采用四点加载的方式完成了试验梁抗弯性能试验,获得了试验梁的开裂荷载、裂缝分布、破坏模式和应力应变状态等关键试验结果。试验结果表明:接缝梁与整体梁均发生弯曲破坏,未布置层间抗剪钢筋的加高接缝梁主裂缝均位于接缝段,其余试验梁主裂缝均位于预制段;随着钢纤维含量的提高,加高接缝梁的抗裂性能也随之提升;布置了层间抗剪钢筋的加高接缝梁抗裂性能仅次于UHPC整体梁,同时具有结构简单、施工简化、造价经济等优点,说明该接缝构造形式运用于实际工程中是可行和可靠的;UHPC钢纤维含量建议取1.0%。In order to simplify the on-site construction technology of wet joints of assembled bridges(formwork-free and welding-free),simplify the reinforcement structure of joints and improve the crack resistance of joints,this paper proposes a kind of Ultra-High Performance Concrete(UHPC)formwork-free wet joint structure with the local heightened part of normal concrete(NC)precast bridge deck as the bottom formwork.In order to test the mechanical properties of this structure,seven test beams were designed,including two integral beams,one conventional joint beam and four formwork-free joint beams.The steel fiber content,inter-layer shear reinforcement and interface reinforcement ratio were used as test parameters.The four-point loading method was used to complete the flexural performance test of the test beam,and the key test results such as cracking load,crack distribution,failure mode and stress-strain state of the test beam were obtained.The test results show that both the joint beam and the integral beam have bending failure.The main cracks of the heightened joint beam without interlayer shear reinforcement are located in the joint section,and the main cracks of the other test beams are located in the precast section.With the increase of steel fiber content,the crack resistance of the heightened joint beam is also improved.The crack resistance of the heightened joint beam with interlayer shear reinforcement is second only to that of UHPC integral beam.At the same time,it has the advantages of simple structure,simplified construction and economical cost,which shows that the joint structure is feasible and reliable in practical engineering.The steel fiber content of UHPC is recommended to be 1.0%.

关 键 词：预制装配桥梁 超高性能混凝土 模型试验 预制桥面板 湿接缝 抗裂性能 

分 类 号：U448.218[建筑科学—桥梁与隧道工程]