Study On Long-term Performance Of Long Span Prestressed Concrete Bridges

A series of problems of the long-term performance(stress, deflection) oflong-span prestressed girder bridge which like cracks and increasing downwarping arefound, due to factors like creep and shrinkage of concrete and prestressed relaxation.And it is common to find that normal use of a bridge is impacted because of theseproblems.Based on a real project to establish a finite element model, this paper whichusing the methods of theoretical analysis and numerical simulation studies on thecontrol of the long-term performance of long-span prestressed concrete girderBridges.1.This paper elaborates the arrangement of prestressed tendons of the traditionallong-span prestressed concrete girder bridge, and analyse the influence of thelong-term performance of bridges and the problems that traditional arrangementcauses,and presents a optimized arrangement. Then contrast the long-termperformance of two kinds of prestressed tendons arrangement.2. Study using follow-up prestressed tendons to control long-term performance oflong-span prestressed girder bridge. Compare the stress and deflection of main girderof the bridge while the steel beams (roof beam, web beam, bottom fold beam) indifferent location are tensioned to study the best location of the follow-up prestressedtendons.3. This paper elaborates the principle and methods of closure pushing. Analysethe difference of the continuous beam-continuous rigid frame bridge and continuousrigid frame bridge, and calculate the jacking force of the continuous beam-continuousrigid frame bridge based on real project. And analyse the influence of the closurepushing for this kind of bridge.