PDF《张拉大跨径简支转连续箱梁桥收缩徐变效应_张拉》

第9卷第2期2009 年4月交通运输工程学报Journal of T raffic and Transportation Engineering Vol.

9 No.

2 Apr .

2009 收稿日期 : 2008-12 -25 基金项目 : 交通部科技攻关项目(

2003 -319-H

01 -010) 作者简介 : 周绪红(

1956 -) , 男 ,湖南南县人 , 长安大学教授 , 工学博士 , 从事钢结构和钢 -混凝土组合结构研究 . 文章编号 : 1671-1637( 2009)

02 -0039 -06 大跨径简支转连续箱梁桥收缩徐变效应 周绪红1,

2 ,乔朋2 ,狄谨2 ,吕忠达2 ,崔婷2 ( 1.兰州大学 土木工程与力学学院, 甘肃 兰州 730000;

2 .长安大学 公路学院, 陕西 西安 710064) 摘要: 利用杆系有限元模型计算了大跨径简支转连续箱梁预制和施工过程中的应力分布和线形 变化 ,研究了预应力束二次张拉对收缩徐变的作用 .以6*70 m 连续箱梁为例, 按照老化理论原 始算法、 老化理论修正算法、 JTJ

023 ―85 规范附录算法与 JTG D62 ―2004 规范附录算法, 进行了 收缩徐变效应对简支状态和连续状态下箱梁结构应力和变形影响的对比分析 .分析结果表明 : 不 同算法的收缩徐变效应对各跨跨中或支点应力影响的最大差值均在

15 %以内, 对边跨 、 次边跨 、 中 跨跨中挠度影响的最大差值分别为

36 %、79 %、

54 %,其中 JTJ

023 ―85 规范附录算法计算的挠度 最小 ,JTG D62 ―2004 规范附录算法计算的挠度最大 , 也最接近实测挠度, 因此, 收缩徐变理论的 计算分析结果可靠. 关键词: 桥梁工程;

预应力混凝土箱梁;

收缩徐变;

二次张拉 ;

结构变形 中图分类号 : U448 .

213 文献标志码: A Shrinkage and creep effects of long-span simple-supported- to-continuous box girder bridge ZHO U Xu-hong1 ,

2 , QIAO Peng2 , DI Jin2 , LU Zhong-da2 , CUI Ting2 (

1 . School of Civil Engineering and Mechanics , Lanzhou University, Lanzhou 730000, Gansu, China;

2. School of Highw ay, Chang an University, Xi an 710064, Shaanxi , China ) Abstract: The stress distributions and deformations of long-span simple-supported-to-continuous box girder bridge during different construction stages w ere calculated by bar finite element models . The influence of prestressed bar s second-time stretching on shrinkage and creep effects w as studied .Taking the

6 *70 m continuous box girder bridge as an example , according to different types of calculating methods , including the original algorithm of aging theory , the modified algorithm of aging theory , the algorithm in the annex of JTJ

023 ―85 Code and the algorithm in the annex of JTG D62 ―2004 Code , the influences of shrinkage and creep effects on the stresses and deformations of box girders during simple-supported stage and continuous stage were compared .Computational result show s that the maximum influencing discrepancies of stresses at mid spans and supporting points are w ithin

15 %, and the maximum influencing discrepancies of deflections at the mid-sections of end span , side span and midspan are separately

36 %,

79 %and

54 %.The deflection calculated by the algorithm in the annex of JTJ

023 ―85 Code is smallest , w hile that calculated by the algorithm in the annex of JTG D62 ―2004 Code is biggest and also is closest to the actual measured value. It s confirmed that the theoretic analysis of shrinkage and creep effects is reliable.

1 tab ,

8 figs ,

10 refs . Key words: bridge engineering ;

prestressed concrete box girder ;

shrinkage and creep ;