The External Prestressing CFRP Reinforced Concrete Thin-wall Box Girder Flexural Performance Test And Research

In recent years, thin-wall box girder of concrete is good mechanical properties inbridge engineering especially in high speed railway, highway has extensively used,because it is good overall stress and big bending stiffness wrest resistant. In thelong-term operation of the project, all sorts of factors cause cracking of concretethin-wall box girder and declining bearing capacity, which affects durability ofthin-wall box girder. It is important that using effective reinforcement measures toimprove the durability of the concrete thin-wall box girder and the ultimate bearingcapacity. Combined with the strengthening technology at home and abroad and abroadand current situation of the development of the concrete and the application inthin-walled box girder. This paper adopts a kind of effective reinforcement way, whichis reinforcement technology of the external prestressing CFRP, the concrete thin-wallbox girder for strengthening experiment research and analysis, the main researchcontents and the results are as follows:1、Combined with research group developed by CFRP prestressed anchoragespecial for deficiency were improved, and through the improvement of the anchorageproceed performance test of CFRP. It is not only checks the good of anchorageperformance, but also determines limit the real CFRP tensile strength. At the sametime, according to the development of the subject puts forward a set of relativelypractical prestressed CFRP tension method and construction craft;2、This paper adopts thin-wall box girder externally prestressed concrete withCFRP reinforcement for the test, measuring and analyzing the reinforcement of thethin-wall box girder after deflection change, crack development, the strain of concreteand reinforcement strain and strain increment prestressed CFRP with the changes ofthe load. through adoption CFRP reinforcement can improve the external prestressingconcrete thin-wall box girder of ultimate bearing capacity, make existing crack widthreduced even closed, increase the stiffness of the cross section, reduce the deflection,delay new crack development and reduce the maximum crack width.3、This paper analyzes CFRP reinforced concrete of the external prestressingthin-walled box girder and the reinforcement of the box girder, the destroy formseveral possible, puts forward some about strengthening the limit of the box girder, thedeformation of the bending moment validation for analysis, calculation methods and formulas, and through the experimental test results for strengthening box girders of ultimate bearingcapacity, deflection, the largest average crack spacing, the maximum crack width and thecalculated value is analyzed, the results can be agreement.