Experimental and Analytical Investigations of a Timber–Concrete Composite Beam Using a Hardwood Interface Layer

Abstract

This paper presents a study that examined the use of a new connection system in a prefabricated timber–concrete composite (TCC) beam in which a hardwood layer was glued to the top of a timber web to reinforce a dowel-type connection. Embedment tests highlighted the mechanical advantages associated with the use of Eucalyptus sideroxylon, which had a mean density of 1,080 kg/m3. The slip modulus of the proposed connection determined from double shear tests outperformed a prefabricated connection involving dowel connectors and no hardwood layer by 75%. Full-scale testing was undertaken on six beams, with two configurations of shear connectors studied. For each beam, the load-deflection behavior, relative slip between the concrete and timber at each connector, and strain profile at the midspan were measured. A simulation model was developed from which a parametric analysis was undertaken. Composite action of 81.9% was achieved when the minimum spacing was used. Using the γ-method as a design guideline is recommended. This connection system avoided the additional labor associated with using notches or adhesive at the interface and was easily fabricated.