Literature Survey on Shear in FRC Beams - On Shear Behavior of Structural Elements Made of Steel Fiber Reinforced Concrete - page 39

3.13 Fibers In fl uence on Dowel Action

The interaction between ber contribution and the various resistant mechanisms is

always favorable for strut-bending and dowel action and unfavorable for aggregate
interlock. It involves a signi

cant reduction in the role of aggregate interlock, and
an increase in dowel action, especially in reinforced concrete beams when the
stirrup spacing is not altered even if bers are added [ 96 ].

On the other hand, the dowel resistance of reinforced concrete beams depends on
the tensile strength of the concrete and the bending resistance of tension steel [ 21 ].
The presence of

bers improved the tensile strength of the concrete in the splitting
plane along the reinforcement [ 7 ].
The stiffness of the dowel zone increases if the ber content, amount of tension

steel, or amount of tension steel, or amount of web reinforcement also increases.
The

ber reinforcement is very effective in containing the dowel crack growth due
to the crack arrester, and make failures very ductile. Beams with web reinforcement
showed similar load capacity and ductility but suffered spalling and disintegration
of the concrete cover. The rst crack and ultimate dowel strength increase almost

linearly with the exural strength of the composite and also they are very sensitive

to the distribution of

fl

ber in the dowel zone being affected by the spacing and
concrete cover of the main reinforcement and the presence of stirrups which could
lead to non-uniform ber distribution [ 21 ].

bers clearly control the cracking and displacement in the dowel
zone, and enable the beams to fully use the contribution to shear due to dowel
action [ 28 ].

In conclusion,

3.14 Hollow Core Slabs (HCS) Made with FRC

3.14.1 Introduction

The Hollow Core Slabs (HCS) are manufactured by a long-line extrusion system
which imposes restrictions on the placing of transverse reinforcement. HCS are
therefore exempt from the minimum shear reinforcement requirements found in
Design Codes [ 97 , 98 ]. This lack of transverse reinforcement leads to a number of
potential problems in the use of HCS [ 99 ]. In 1994, a study [ 100 ] suggested that the
inclusion of steel bers in HCS would be an economic solution to some of these

problems [ 101 ].