Investigations in twin-cell box girder bridges subjected to combined effects of bending and torsion

The main objective of this work is to study the behaviour of twin-cell box girder bridge decks when subjected to eccentric loading, thereby understanding the combined effects of bending and torsion in them. Unlike single-cell box girder bridges, there are limited works published on twin-cell box girder bridges. With the emerging use of twin-cell box girder bridges, more investigations are required in this area which will help the engineers to create better design strategies. The paper provides the details required for the development of a truss model which can be used in the design of a twin-cell box girder bridge. For this purpose, an experimental study is conducted on a scaled-down model. Considering a designer's interest the ultimate capacity of the bridge is estimated using 3D truss models which are computationally simpler. In simple cases, even hand computation will be sufficient if one uses a 2D truss model. It is found that results obtained from the experimental analysis and that from finite element models are in good agreement with the results of truss models. Moreover, among all the analysis methods compared in this study, the space truss analogy is found to be more worthy as they are less time consuming and do not require high computer capacity to analyse any structure.