预应力混凝土箱梁竖向预应力钢筋有效预应力检测研究

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、锚固段刚度增大系数与外露段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锚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。

Study on Tensioning Force of Vertical Finish Rolled Threaded Reinforcing Bar In Prestressed Concrete Box Girder Webs

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 tensioning 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 coefficient 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 increment 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.