Study On The Reinforcement Mechanism Of Hollow Slab Bridge Based On Method Of Discarding Beam And Adding Rib

With the sharp increase of the number heavy vehicles in China, manybridges have been damaged; which are to be repaired, reinforced andtransformed so as to improve the bearing capacity and service life of the bridge.Aimed at pre-stressed concrete hollow slab bridges, a novel reinforcementmethod－discarding beam and adding rib has been proposed recently. To makethis reinforcement method to be used widely in engineering projects, it isessential to study on the reinforcement mechanism of discard beam with addingrib.This paper takes reinforcement of hollow slab bridges for example. Typicalfinite element models of the discard beam with add girder web was establishedby the finite element analysis software－ANSYS. According to the typical finiteelement models, the effect of concrete’s shrinkage, creep and addingprestressing on method of discarding beam with adding rib is analyzed, and thereinforcement mechanism of discard beam with add girder web is discussed.By analyzing the influence of new-old concrete’s shrinkage and creepdifference on the stress, it is found that bring compressive stress to the hollow beam compressive stress and tensile stress to the new rib, the influence value ofstress would gradually increase with time. This shows that the difference ofnew-old concrete’s shrinkage and creep is benefit for old beams; however, it isadverse for new ribs. Surface of the stress influence variation rules of maingirder and joint by concrete shrinkage and creep is slightly affected bytransverse connection, but remarkably affected by linear of new tendons more.Through analyzing the changes of stress and deflection of old beams and newribs during grandly adding prestressing bar, it confirms that adding prestressinggreatly changes the stress of old beams and new ribs, and improvement of thebearing capacity of bridge is obvious. The study also shows that the change oflateral tie anchor position has less impact on stress and deflection of main girder.Under the influence of the shrinkage and creep, the shear stress of joint surfaceand tensile stress of vertical joint surface is very low.The results can not only give reference to the analysis of this kind of bridgestrengthening engineering, but provide evidence to the other bridges repairment.