混凝土连续箱梁支点处钢束预应力 古同 皿日 衰变研究
张 岗 。，施 颖。，宣纪明 ，刘天龙 ，
(1．长安大学公路学院，陕西西安710064；2．长安大学旧桥检测与加固技术交通行业重点实验室，
陕西西安710064；3．浙江工业大学建筑工程学院，浙江杭州310014；
4．浙江工业大学建筑规划设计研究院，浙江杭州310014)
摘 要：为研究混凝土连续梁支点处钢束在火灾下的预应力损失，选取某4跨预应力混凝土
连续箱梁进行高温衰变分析。采用ANSYS软件建立混凝土箱梁截面预应力孔道有限元模型，分
析孔道周围的温度分布，给出孔道平均温度的简化算法；分析不同火灾场景下支点截面钢束预应力
的高温衰变率，并给出支点钢束预应力衰变率的计算方法。结果表明：不同受火场景下钢柬预应力
时程衰变率趋势相同；对于腹板底部钢束，预应力衰变率在延火前期下降速度快，延火后期下降速
度慢，时间分界点约为40 min；对于腹板中上部钢柬，预应力衰变率在延火前后期内速度变化不明显。
关键词：混凝土桥；连续箱梁；有限元法；温度场；预应力损失；高温；时程衰变
中图分类号：U448．215；U441．5 文献标志码：A
Study of Prestress Decay of Steel Strands in PC Continuous
Box Beam at Support Under High Temperature
ZHANG Gang ～ ，Sill Ying。，XUAN Ji—ming ，LIU Tian—long ，。
(1． School of Highway，Chang an University，Xi an 710064，China 2． Key LaboratorY of Old Bridge Detection&
Reinforcenlent Technology of Ministry of Transport，Chang an University，Xi an 710064
， China；3．College of
Civil Engineering and Architecture，Zhejiang University of Technology，Hangzhou 310014，China；4
． Arc
hitectural Planning and Design Institute，Zhejiang University of Technology，Hangzhou 310014，China)
Abstract：To study the prestress loss of the steel strands in prestressed concrete(PC)contin—
UOUS beam at support exposed to fire，a 4-span PC continuous box beam was selected as an example
and the prestress decay of the steel strands in the beam under the high temperature was analyzed
．
The software ANSYS was used to build up the finite element model for the prestressing ducts in
the section o{the beam，the temperature distribution around the ducts was analyzed and the simpli—
fled calculation method for the average temperature of the duets was worked out． The prestress de—
cay rates of the steel strands in the section of the beam at the support under the high temperatures
of the different fire situations were analyzed as well and the calculation method for the decav rates
of the steel strands was given．The results of the analysis show that the tendencies of the time—de—
pendent prestress decay rates o the stee1 strands under the different fire situations are the same
．
For the steel strands in the bottom of the webs，the prestress decay rates decrease fast in the earlv
time of the fire duration，decrease slowly in the late time of the duration and the time boundarv
point is about 40 min．For the stee1 strands in the middle of the webs，the speeds of the decav rates

因本站资料资源较多，启用了多个文件服务器，如果浏览器下载较慢，请调用迅雷下载，特别是超过了5M以上的文件！请一定调用迅雷，有时候速度就会飞起哦，如果您的浏览器自动加载了PDF预览，文件太大又卡死，请按下载说明里的把PDF插件关闭了就可以直接下载，不会再预览了！