ORIGINAL ARTICLE
Connections for composite concrete slab and LVL flooring
systems
Bruce L. Deam Æ Massimo Fragiacomo Æ
Andrew H. Buchanan
Received: 16 January 2007 / Accepted: 9 May 2007 / Published online: 5 June 2007
Ó RILEM 2007
Abstract Composite concrete slab and timber floor-
ing systems are commonly used in many parts of the
world to exploit the high strength-to-weight ratio of
timber and the good acoustic separation provided by
concrete floor slabs. This paper describes the results of
an experimental programme that investigated the
suitability of a range of connectors to transfer shear
between a concrete slab and a laminated veneer
lumber (LVL) beam. Shear tests on reduced scale
specimens were performed with the aim of comparing
the strength, stiffness, and post-peak performance of
different connectors such as round and rectangular
concrete plugs with and without screw and steel pipe
reinforcement, proprietary (SFS) screws, coach
screws with different diameters, sheet brace anchors,
and framing brackets. The rectangular concrete plug
reinforced with a coach screw was found to provide
the greatest stiffness and strength, as well as favour-
able post-peak behaviour. Such a system can be used
for cost-effective composite floor systems due to its
efficient cost-to-capacity ratio, which reduces the
number of connectors needed along the beam axis to
achieve the composite action.
Keywords Connector Á LVL Á Structural
engineering Á Timber–concrete composite beams Á
Wood
1 Introduction
Composite concrete and timber (CCT) beams repre-
sent a structural technique widely used for both
strength and stiffness upgrading of existing and new
floors. This technique consists of connecting an
existing or new timber beam to a concrete slab cast
above the timber beam, using a suitable connection
system [1]. Steel mesh is usually cast into the slab to
resist potential tensile stresses due to bending, and to
reduce the concrete crack width. CCT beams provide
many benefits compared with traditional timber
floors, including greater strength and stiffness, less
susceptibility to vibration, improved seismic and fire
resistance, better acoustic separation and thermal
mass. The lower weight than reinforced concrete
floors also imposes less load on the foundations and
B. L. Deam
Department of Civil Engineering,
University of Canterbury, Private Bag 4800,
Christchurch 8140, New Zealand
e-mail: bruce.deam@canterbury.ac.nz
M. Fragiacomo (&)
Department of Architecture and Planning, Faculty of
Architecture, University of Sassari, Palazzo del Pou Salit,
Piazza Duomo 6, 07041 Alghero, Italy
e-mail: fragiacomo@uniss.it
A. H. Buchanan
Department of Civil Engineering,
University of Canterbury, Private Bag 4800,
Christchurch 8140, New Zealand
e-mail: andy.buchanan@canterbury.ac.nz
Materials and Structures (2008) 41:495–507
DOI 10.1617/s11527-007-9261-x