Emulation Analysis Of Long Span Concrete Bridge Based On The Detection Of Effective Pretensioned Force

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.