Interface shear behavior between high-strength precast girders and lightweight cast-in-place slabs

The overall purpose of this study is to examine the shear-friction behavior of shear interface with transverse reinforcement between precast girder using high-strength concrete and cast-in-place slab with lightweight concrete. Eighteen push-off specimens, with testing parameters of lightweight coarse aggregate size, slab concrete type and shear reinforcement ratio, were tested in this investigation. Based on the analysis of the experiment, this study suggests that the granular size of lightweight coarse aggregate did not play a significant role in the shear strength of interface and the shear transfer strength of lightweight slab concrete specimens are greater than that of normal weight slab concrete specimens having the same concrete compressive strength, interface reinforcement ratio and interface treatment. Additional, the transfer reinforcing steel can improve shear capacity and residual resistance obviously. For both sand-lightweight and normal weight cast-in-place slab concretes, the interface shear strengths predicted by the design equations given in AASHTO LRFD 2014 and ACI 318-14 are conservative.