【作者】 徐嵩基；

【导师】 宋一凡；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2007， 硕士

【摘要】 预应力混凝土连续箱梁是大、中跨径桥梁最主要的结构型式之一,其中预应力筋的有效预应力值是一个不确定的参数,控制着预应力混凝土结构裂缝的形成、开展及挠度的大小、甚至是构件的承载力。实际预应力损失增大后的桥梁评价已成为一个十分复杂的技术难题,目前国内还没有切实有效的检测和评价方法,在一些方面的研究甚至还是空白。作为西部交通建设科技项目“大、中跨径混凝土桥梁预应力检测技术研究”中子课题“预应力筋有效预应力检测技术研究”的一重要部分,本文在对预应力混凝土连续箱梁引起预应力损失各种因素分析的基础上,提出了单根钢束纵向有效预应力的沿程分布模式、钢束分类原则及相应的模拟方法；给出了同一截面钢束间有效预应力的预测模型,分别研究了对称布置及非对称布置的长、短钢束有效预应力值的预测计算公式；提出了一套完整的预应力混凝土连续箱梁桥有效预应力的分析评价方法,并以一座预应力混凝土变截面连续箱梁桥实体工程为依托,按39根钢束、11个控制截面,并分别按规范理论计算的表层钢束有效预应力值折减10%、20%、30%、40%作为4种工况,对依托工程进行有效预应力仿真分析和正常使用阶段的结构抗裂验算。本文提出了一种对预应力混凝土连续箱梁桥有效预应力分析评价的方法,实现了混凝土连续箱梁桥有效预应力的评估,为预应力混凝土桥梁缺损状况的综合评价及制订检测技术指南奠定了基础。更多还原

【Abstract】 Prestressed concrete continuous box-girder bridges are the one of main structure pattern of large-span and moderate-span bridges. The effective prestressing force value of the prestressing force tendons is an uncertain parameter.To the concrete structure of prestressing force, it controls the forming, development of the crack, the size of deflection, and even the bearing capacity of the component. The bridge evaluation after the increasing of the reality loss of prestress has become a very complicated technique difficulties. At present, there are no effective measuring and evaluation method in china, and even the research in some aspects is still a blank.The article discusses an important part of "the research on effective prestressing force detection technology of prestressing force tendons", which is the sub-research of the constructive science and technology item of the westward traffic-"the research on prestressing force detection technology on large-span and moderate-span concrete bridges". Basing on the analysis of all kinds of factors causing prestressed losing to prestressed concrete continuous box-girder bridges, the thesis puts forward distribution pattern along single-root steel tendons of longitudinal effective prestressing force, classification criteria of steel tendons test and corresponding simulation method. The predictive model of the effective prestressing force among steel tendons of the same cross-section is presented. It studies the calculate formulae for prediction, about the effective prestressing force value of long and short steel tendons which arrange symmetrically and unsymmetrically. The artical appraise an intact anlysis and evaluation method of the effective prestressing force on prestressed concrete continuous box-girder bridges. It is on the real engineering of a prestressed concrete continuous box girder bridge with variable cross section. Complying with 39 steel tendons,11 control section and 4 working conditions,simulation analysis of and crack resisting calculation in the stage of using are presented.The 4 working conditions are put forward after discounting 10%,20%,30% and 40% from the effective prestressing force value of steel tendons in surface layer according to the gauge theories.In this paper, one kind of anlysis method to appraise about effective prestressing force of prestressed concrete continuous box-girder bridges is provided. It has realized the evaluation of the effective prestressing force of concrete continuous box-girder bridges. It also has established the foundation for the comprehensive evalution of the defective prestressed concrete bridges and the formulation of detection technology guide.更多还原