Comparison and analysis of the results of grillage method and single beam method to continuous box girder with variable width

The continuous box girder with variable width has been widely applied in the superstructure of modern viaducts. The stress states of the box girder with variable width are more complex compared to those of the box girder with the same width. In this study, both single beam and grillage models are established to analyze the continuous box girder with variable width. The results of models indicate that reaction forces from the grillage model are more accurate, compared with those from the single beam model. In addition, the grillage model can reflect complex spatial distribution of stress states of the superstructure and non-uniform internal forces of each web. It concludes that taking advantages of the grillage models, the grillage models are recommended to be used to accurately analyze and design the continuous box girder with variable width in the aspects of the arrangement of prestressed tendons, bearings selection and dimension of cross beams.