Study Of Construction Monitoring Technology Of Through Tied Arch Bridge For Qinjiang128m Super Large Bridge

Through tied arch bridge, which combines both advantages of the both beam and arch, iswell known for its reasonable mechanical properties, big stiffness and elegant appearance.This paper mainly study the construction monitoring of Qinjiang extra-large bridge, whosemain span is steel tube concrete tied arch bridge and its span reaches128m, in the expansionof Guangxi coastal railway project. The primary contents as follows:(1) The present development situation and development trend of through tied arch bridgeis introduced briefly. The mechanical characteristics and the existing problems are elaborateillustrated and the analysis principle and construction control theory of through tied archbridge based on infinite element theory are also introduced.(2) Adaptive control method is adopt to monitor the linear of the girder and the mainparameters of this bridge are identified by means of least square method, which can pretestand the deformation of the beam, to determine the formwork erection elevation. The camberof the Qinjiang Bridge is calculated by combination of the engineering practice and relevantcalculation method and the influencing factors of camber setting method and comparativeanalysis of through tied arch bridge are also taken into account. Finally, the conclusion thatthe alignment of each construction meets design requirements is made by comparing thepractical data with the calculation result.(3) The stress of the concrete and the surface of steel tube arch rib is monitored bytemperature memory type reinforcement stress meter and JMZX-416type intelligent digitalstring type strain gauge respectively. Mature theories are used to analyze the test data andconcluded that the non-force strain caused by the shrinkage and creep of concrete structurecan be accounted for30%~40%of the total strain.(4) The local stress analysis of arch foot are made by using ANSYS entity unit toconfirm the whole stress of arch foot is reasonable. Of course, it suggested that strengthen ofthe arch foot can be appropriately along the surface of the arch foot under design andconstruction.(5) By discussing the existing determination method and test method of reasonable cableforce and analyzing the actual situation, the influence matrix method and frequency methodare selected as the basic theory to adjust and test the cable force of the Qinjiang Bridge. Theerror within5%between the final cable force and the design force justifies the rationality ofthe influence matrix method theory.