Experimental study on notched connectors for glulam-lightweight concrete composite beams

Abstract

A new type of structural element, the timber-concrete composite beam, exhibited excellent structural performance. The notched connector is widely used in timber-concrete composite systems as a result of its considerable shear capacity and stiffness. Six groups of push-out tests were performed to investigate the shear performance of the notched connectors for the timber-concrete composite beams, with consideration to the varying concrete types, the shear length of the timber, and whether the notch was reinforced. From the test results, the notched connectors that corresponded to the shear fracture of concrete or timber had a low shear capacity and poor ductility. Notched connectors that simultaneously failed at the concrete slab (via shear force), as well as at the lag screw reinforcement point during bending presented the greatest shear capacity. This was followed by the notched connectors that exhibited diagonal-compression failure at the concrete slab. Screw fasteners in the notch were shown to improve the strength, ductility, and post-peak behavior of the notched connectors. In addition, the concrete type, the shear length of the timber, and whether the notch was reinforced were found to have no major influence on the slip modulus of the notched connectors.