Lateral Calculation and Analysis of Shear Lag Effect of Extra-wide Triple-cell Single Box Girder

摘要

The main bridge of Yunshi Hanjiang River Bridge is a prestressed concrete extradosed bridge with two pylons, a single cable plane and with span arrangement (128+238+128)m. The main girder of the bridge is the concrete continuous triple-cell single box girder of long cantilevers and variable sections, the box girder is 26.5m wide. The cantilever of girder is 5.75m wide as to reduce the self-weight of main girder. In the design, the software Dr.Bridge was used to establish the finite element model for the box girder and to carry out the global calculation of the girder lateral calculation. The software ANSYS was used as well to establish the finite element model for the segments of the main girder and to carry out the analysis of the local stress of the girder. The results of the calculation and analysis indicate that the global structure of the bridge is safe and reliable and the structure can meet the requirements for highway vehicle riding safety and comfort. No significant local stress concentration appears in the main girder, the stress amplitude values of the stay cables are within 30Mpa, and the structure can meet the requirements for durability in the process of service of the bridge. With long cantilever design greatly reduce the self-weight of main girder and saving cost, at the same time make the bridge look lighter and beautiful. The results of the analysis provide a reference for analysis on the shear lag effect and lateral calculation of the concrete continuous triple-cell single box girder of long cantilevers and variable sections.