The Effect of Bedding Layer on the Strength of Shear Connection in Full-Depth Precast Deck

Shear connection in a steel-concrete composite bridge with a full-depth precast deck is characterized by the material properties of the non-shrink mortar, which is the filler in the pockets for the shear connectors, and the existence of a bedding layer between the precast deck and the steel girder. As a consequence, the behavior of the shear connection is very different from that of the more widely used cast-in-place concrete deck. Experiments on push test specimens with several parameters varied, such as the cross-sectional area of the stud connectors, the compressive strength of the mortar, and the thickness of the bedding layer, were performed to evaluate the ultimate strength of the shear connection in the precast deck. The test results have shown that the effect of the compressive strength of the mortar on the ultimate strength of the shear connection is insignificant within the limit of these tests. The ultimate strength of the shear connection decreases considerably with an increase of the bedding layer thickness. An empirical equation for the ultimate strength of the shear connection considering the effect of the bedding layer thickness is presented in this paper. Based on the results, recommendations for the design of the stud shear connection in a full depth precast deck are suggested.