Shear Tests on Notch Connections for Timber-Concrete Composite Floor Beams Using Low Strength Lightweight Concrete

Abstract

Notch connections are commonly used in timber concrete composite (TCC) members because of the simple geometry of the solution making execution easy and the high strength and stiffness resulting from the mechanical interlock between the timber and concrete. However, the use of low strength lightweight concrete in TCC applications is limited in the literature. Therefore, in this work, shear tests were conducted on notch shear connections between glulam timber and low strength lightweight concrete, in which the effects of notch dimension and adding a screw in the notch have been analyzed. From the obtained force-slip curves, strength, stiffness, and the ductility of the shear connection have been assessed. The tested connections' strength and stiffnesses are compared with the analytical approaches given in TCC Technical Specification CEN/TS 19103. The results show that the use of low strength lightweight concrete, even with a low modulus of elasticity, provides a stiff solution. The observed failure mode agrees with the EN 1995-1-1 requirement; however, an overestimation is observed for the load predictions. For the specimens with screws, an improvement in strength capacity, stiffness and deformation capacity was noticed.