Investigations on Interface Shear-stress Transfer Behavior of Concrete Composite Slabs with Lattice Girders.

Concrete-to-concrete interface shear-stress transfer behavior is crucial for concrete composite slabs with lattice girders. In practice, diagonal reinforcements in the lattice girders make shear reinforcement ratios with ranging from 0.05% to 0.3%. However, numerous studies have shear reinforcement ratios greater than 0.5%, and investigations on interface with low shear reinforcement ratios are still insufficient. To investigate the shear-stress transfer behavior and to propose a simplified approach to calculate shear-capacity, direct shear tests were carried out to obtain the effects of surface roughness, shear reinforcement ratio and shear reinforcement inclined angle on shear-stress behavior. The tested results showed that the concrete-to-concrete interface occurred debonding brittle failure. The ultimate shear strength was mainly provided by interface bond strength, and the residual shear strength depended on shear reinforcement and surface roughness. The bond strength of smooth surface decreased by 26.5% than that of rough surface. The inclined angle of shear reinforcement should be not greater than 90. Finite element models established in ABAQUS were validated based on the tested results, which could be used to enlarge the parameters' range. The parametric analysis was conducted, and the dominant factors affecting on the interface shear-capacity were obtained. At last, a simplified approach was developed. [ABSTRACT FROM AUTHOR]