基于节段预制拼装施工阶段的PK箱梁剪力滞效应研究  

Research on Shear Lag Effect of PK Box Girder Based on Precast Segment Assembling Construction Stage

作　　者：赵健 ZHAO Jian(China Railway Construction Bridge Engineering Bureau Group Co.Ltd.,Tianjin 300300,China)

机构地区：[1]中国铁建大桥工程局集团有限公司,天津300300

出　　处：《铁道建筑技术》2022年第1期17-21,共5页Railway Construction Technology

基　　金：天津市科技开发项目(19YDL ZSF00030)。

摘　　要：为探究混凝土PK箱梁在节段预制拼装施工阶段的剪力滞效应,以石首长江公路大桥为工程背景,采用空间结构计算理论以及现场实测方法对模型计算结果进行验证,研究PK箱梁在自重作用,预应力张拉、提升与滑移不同阶段的剪力滞效应的变化规律,为类似工程提供理论支撑。研究结果表明:考虑空间预应力的PK箱梁结构模型计算结果与实测结果吻合较好,误差在6%~7%之间;自重作用时应力较小,但剪力滞效应最大,提升与滑移阶段的剪力滞效应相对较小,且沿箱梁截面呈非线性走势;张拉横向预应力越大,剪力滞系数曲线沿横桥向越趋于平缓,预应力对剪力滞的影响效果明显;预应力张拉量相等时,吊点与滑靴位置的改变是影响剪力滞效应的主要因素。建议在设计节段预制拼装施工方案时,对预应力张拉方法以及吊点与滑靴位置的设置予以充分考虑,控制箱梁剪力滞效应,保障施工阶段结构的安全性。To investigate the shear lag effect of concrete PK box girder in the prefabricated construction stage of the section,this paper takes the Shishou Yangtze River Highway Bridge as the engineering background,and uses the space structure calculation theory and the field measurement method to verify the calculation results,and study the change law of the shear lag effect of the PK box girder under its self-weight,prestressed tension,lifting and slipping at different stages,so as to provide theoretical support for similar projects.The research shows that the calculation results of the PK box girder structure model considering spatial prestress are in good agreement with the measured results,the error is between 6%and 7%;the stress is small when the self-weight is applied,but the shear lag effect is maximum,the shear lag effect in the lifting and slipping stages is relatively small,and the section along the box girder is nonlinear;the greater the transverse prestressing force,the more the shear lag curve becomes gentler along the transverse bridge,the effect of prestress on shear lag is obvious;when the prestressed tension is equal,the change of the position of the lifting point and the shoe is the main factor affecting the shear lag effect.It is recommended that when designing the prefabricated assembly construction plan of the segments,the prestressed tensioning method and the setting of the lifting point and the position of the sliding shoe should be fully considered to control the shear lag effect of the box girder,so as to ensure the safety of the structure during the construction phase.

关 键 词：桥梁工程 剪力滞效应 空间结构计算理论 PK箱梁 节段预制拼装 

分 类 号：U441[建筑科学—桥梁与隧道工程] U445.466[交通运输工程—道路与铁道工程]