预应力混凝土箱梁竖向预应力钢筋有效预应力检测研究.pdf

第38卷,第3期
公路工程
Vol 35
2013年6月
Highway Engineering
Jun.,2013
预应力混凝土箱梁竖向预应力钢筋
有效预应力检测研究
刘小燕!,王玮玮,张峰2,齐广志2
1.长沙理工大学,湖南长沙410000;2.山东大学岩土与结构工程研究中心,山东济南250061)
[摘要]在大跨度预应力混凝土桥梁中,竖向预应力不足或预应力损失过大将导致箱梁腹板产生斜裂缝,如
何检测箱梁竖向预应力钢筋的损失,寻找箱梁施工时竖向预应力筋张拉力简单实用的检测方法成为大家关注的热
点。为了能够有效的检测箱梁施工过程中的竖向预应力是否达到设计值,本文基于结构动力学理论,通过有限元
模型的大量模拟计算,建立起竖向预应力筋外露段长度、错固段刚度增大系数与外露發动力特性之间的参数关系;
通过模型试验建立了箱梁竖向预应力筋有效预应力和错固段刚度增大系数的关系,并在现场某座连续刚构桥上进
行了部分节段的检测。本文方法为高效、简便的检测竖向预应力钢筋的有效预应力提供了保障。
关键词]精轧螺纹钢;张拉力;外露段;箱梁;腹板
中图分类号]U448.213[文献标识码]A
[文章编号]1674-0610(2013)03-0184-04
Study on Tensioning Force of Vertical Finish Rolled Threaded
Reinforcing Bar In Prestressed Concrete Box Girder Webs
Lid Xiaoyan WANG Weiwei, ZHANG Feng,, QT Guangzhi
(1. Changsha University of Science and Technology, Changsha, Hunan 410000, China; 2. Shandong
University, Geotechnical and Structural Engineering Research Center, Jinan, Shandong 250061, China
L Abstract J As for the long span prestressed concrete bridge, the shortage of vertical prestressing
and the outgrow loss of prestressing can both lead to inclined cracks in webs. And how to detect the loss
of vertical prestressing in box girder and find the simple and practical detection method to detect the ten
sioning force of vertical prestressing tendon are becoming the focus of research. In order to estimate that
effectively whether the tensioning force accord with the devised number or not, the paper is based on the
theory of structural dynamics through the numerical simulation calculation with plenty of finite models
The parameter relationship, which is among the exsertion segment length, the stiffness increment coeffi
cient of the anchoring segment, and the exsertion segment dynamic characteristics of vertical prestressing
tendon, has been built. Besides, the relationship between the effective prestress and the stiffness incre
ment coefficient of the anchoring segment of vertical prestressing tendon has been built, at the same time
partial segment of a continuous rigid frame bridge has been test. This paper would provide guarantee for
the efficient and simple effective prestess detection of vertical prestressing tendon
L Key words] finishing rolling rebar; tensioning force; exsertion segment; box-girder; web
0前言
控制不严,纵向和竖向预应力损失过大;加上运营期
车辆荷载严重超载等都可能导致主拉应力过大。尽
腹板斜裂缝是预应力混凝土连纮箱梁较常见的管腹板主拉应力大小与纵向预应力筋布置方式、竖
裂缝形式,腹板斜裂缝的成因复杂多样,其开裂的根向预应力筋、温度应力、徐变应力等多方面的因素有
本原因是腹板中的主拉应力过大。如设计时对结构关,。但箱梁中的竖向预应力仍然是抵抗剪应力
构造、主拉应力等问题考虑不周;施工期对施工质量和主拉应力的重要因素,尤其是在纵向预应力不变
收稿日期]2012-08-2
[作者简介」刘小燕(1963-),女,教授,士,主要研究方向:钢筋混凝土基本理论,桥梁结构分析,大跨径桥梁试验研究