Investigation on Flexural Performance of Orthotropic Steel–ECC Composite Bridge Decks

Engineered cementitious composites (ECCs) have become a viable substitute for conventional concrete in orthotropic steel–concrete composite bridge decks (CBDs) because of their favorable tensile properties, which enhance crack resistance and overall durability of CBDs. This research investigated the flexural performance of steel–ECC CBDs under sagging and hogging moments through testing, theoretical calculations, and numerical simulations. Specifically, the effects of shear connection degree and shear connector type were examined. The experimental findings demonstrated that decreasing the shear connection degree increased the relative slippage and separation at the steel–ECC interface and resulted in a reduced yield load and yield deflection for steel–ECC CBDs. Moreover, rubber-sleeved studs proved to be more effective in reducing both crack quantity and crack width than conventional studs and bolts. The conventional theoretical calculation can well predict flexural capacity for steel–ECC CBDs under sagging moments. However, when calculating the flexural capacity for steel–ECC CBDs under hogging moments, it is necessary to introduce a reduction coefficient to account for U-rib’s buckling.