Simplified analysis method accounting for shear-lag effect of steel–concrete composite decks

• Test on shear-lag effect of composite deck is conducted.
• Simplified analysis method for arbitrary vertical traffic load is proposed.
• Simplified analysis method for axially compressive load is proposed.

Due to the influence of steel beam web, the concrete slab and steel box-beam flange would undergo significant warping in steel–concrete composite decks with wide slab. Such mechanical behavior is referred as the shear-lag effect and often calculated by adopting effective width. There arises a necessity to propose a simplified analysis method based on effective width to account for the shear-lag effect of composite decks, which would greatly assist in design analysis as it is easy to use in a general beam element model. In this paper, the static tests are carried out on a composite twin I-girder deck and a composite box-girder deck specimens. These two specimens are subjected to vertically flexural and axially compressive loads in the tests. An elaborate element model is later built and utilized to analyze the shear-lag effect of composite decks. Through elaborate element model analysis on composite decks subjected to vertically flexural and axially compressive loads, respectively, the longitudinal distribution characteristic of effective width are determined. Furthermore, the prediction formulae of effective width are proposed. Finally, based on a general beam element model, the simplified analysis method of a composite continuous I-girder deck for the design process is performed taking into consideration three load cases, which include gravity load, traffic load envelope and prestressing load.