采用自平衡预应力中空管的混凝土梁预应力传递长度研究  

Prestress Transmission Length in Concrete Beam with Self-Balancing Prestressed Hollow Ducts

作　　者：夏云龙 张伟 戴杰[3] XIA Yunlong;ZHANG Wei;DAI Jie(Zhejiang Institute of Digital and Intelligent Transportation Technology,Ltd.,Hangzhou 310030,China;Zhejiang Communications Investment Highway Construction Management Co.,Ltd.,Hangzhou 310020,China;School of Highway,Chang′an University,Xi′an 710064,China)

机构地区：[1]浙江数智交院科技股份有限公司,浙江杭州310030 [2]浙江交投交通建设管理有限公司,浙江杭州315000 [3]长安大学公路学院,陕西西安710064

出　　处：《桥梁建设》2023年第5期33-40,共8页Bridge Construction

基　　金：浙江省交通运输厅科研计划项目(2015Y07)。

摘　　要：针对传统短束预应力筋存在的问题,提出一种主要由中空管和穿过中空管的反力钢棒等组成的自平衡预应力中空管构造。为了解采用自平衡预应力中空管的混凝土梁的传力特性,采用有限元与试验相结合的方法分析锚垫板设置情况、混凝土强度、中空管尺寸、有效预应力对中空管预应力传递长度的影响,提出中空管预应力传递长度简化计算公式。结果表明:自平衡预应力中空管可作为有锚垫板的先张预应力钢筋传递预应力;预应力传递长度与中空管尺寸、有效预应力近似成正比,与混凝土抗拉强度近似成反比;现有国内外规范均不适用于中空管预应力传递长度的计算,所提出的简化计算公式计算的中空管预应力传递长度与实测值吻合良好;实桥应用结果显示采用自平衡预应力中空管的混凝土梁预应力传递特性和试验结果相符,预应力传递可靠。To address the transmission length issue of short prestressing tendons,this study presents a type of self-balancing prestressed hollow duct with main components of a hollow duct and the reaction steel bars passing through the hollow duct.To examine the load transfer characteristics of the concrete beam with the self-balancing prestressed hollow ducts,tests together with numerical simulation were conducted to analyze the influence of multiple factors on the prestress transmission length of the hollow duct,including the placement of anchor pads,concrete strength,duct dimension and effective prestress.On the basis of which,a simplified equation to calculate the prestress transmission length of the hollow duct is proposed.The results of the analysis demonstrate that the self-balancing prestressed hollow duct can act as pretensioned prestressing tendonds with anchor pads in prestress transmission.The prestress transmission length is approximately proportional to the dimension of hollow duct and effective prestress,while inversely proportional to the concrete tensile strength.Due to that there are no applicable equations to calculate the prestress transmission length of the hollow duct given in the Chinese and overseas specifications,a simplified equation is proposed,which generates results that agree well with the measured values.The application practice proves that the prestress transmission chacracteristics of the concrete beam with self-balancing prestressed hollow ducts are in line with the test values,with reliable prestress transmission performance.

关 键 词：预应力混凝土梁 自平衡预应力中空管 传力特性 预应力传递长度 有限元法 预应力张拉试验 简化计算方法 

分 类 号：TU378[建筑科学—结构工程] U441[建筑科学—桥梁与隧道工程]