Research on Single Pier Jacking Technology for Large-Span Prestressed Concrete Continuous Beam Bridges

Abstract:

Taking the post earthquake repair project of a prestressed concrete continuous beam bridge as an example, a finite element model of the bridge was established using Midas Civil software. Three working conditions were analyzed, including single pier uplift, single pier uplift+moving load, and single pier uplift+gradient heating. The variation laws of support reaction force, upper and lower edge stress of the beam, and stress of prestressed steel bars were studied. Research has shown that when the bridge pier is lifted, the prestressed steel bars on the top plate of the main beam at the separated pier first break. When the bridge pier is lifted, the concrete on the top edge of the main beam section corresponding to the jack experiences tensile cracking and damage. When the lifting height reaches the requirement for bearing replacement, traffic restrictions must be implemented for passing vehicles when lifting at the bridge pier, and traffic should be interrupted when lifting at the bridge pier. The gradient heating has a relatively small impact on the reaction force of each support, the stress of the lower flange of the beam, and the stress of the prestressed steel bars, while the stress of the upper flange has a greater impact. However, the tensile stress and compressive stress of the upper flange of the beam at the jacking point have a certain positive impact on the jacking construction.