Literature Survey on Shear in FRC Beams - On Shear Behavior of Structural Elements Made of Steel Fiber Reinforced Concrete - page 18

bers
equal to 0.64 % had similar or even better postcracking behavior than beams with
minimum amount of transverse reinforcement [ 27 ].

Experimental tests showed that beams made with FRC with a volume of

3.3.4 Effect of Fibers on Shear Cracking

Fibers are very effecting containing the dowel crack growth by means of the crack
arrester controlling the propagation and widening of the dowel crack [ 6 , 7 , 16 , 19 ,
21 , 22 , 28 32 ]. The aggregate interlock increases due to the reduction of crack

spacing and widths providing a better durability of the structure [ 6 , 19 ].
Structural elements made with high concrete compressive strength had smaller
crack widths due to denser concrete matrix, better bond to the

-

bers and also due to
the load transfer across the cracks [ 4 ]. The stabilization of the action of the bers

takes place at ULS with values close to a crack width of 1.2 - 1.4 mm [ 33 ].

3.3.5 Effect of Fibers on Yielding of Longitudinal Bars

Fibers increase the load level at which the longitudinal reinforcement yields [ 4 ];
therefore, the load bearing capacity of tensile members and bending beams increase
with the presence of bers [ 24 ].

3.3.6 Effect of Fibers on Cracking Distribution

Increased ber volumes allow the development of multiple cracking, distributed

and complex in the shear span [ 4 , 5 , 11 , 32 , 34

40 ] avoiding or delaying the
localization of a major shear-critical crack responsible of a brittle collapse [ 3 , 9 , 11 ,
17 ]. The multiple cracking produces a redistribution of stresses [ 31 , 41 ] giving
visible warning prior the collapse of the structure [ 11 , 32 ].
Steel

-

bers became effective after formation of shear crack and resist the

principal tensile stressed until the complete pullout or yielding of bers occurs at

one critical crack [ 41 ]. After the occurrence of the bers start working,

carry the entire applied load and tend to avoid the localization of microcracks in
macrocracks. Consequently, the post-cracking strength increases and a considerable
ductility can be achieved due to the ability of the

rst crack,

bers to bridge and carry the

stresses crossing the crack faces [ 18 , 20 ].