In the present paper the experimental results referred to monotonic and cyclic tests on fibrous reinforced concrete (FRC) beams are presented and discussed. The influence of longitudinal and transverse steel bars, of type and percentages of fibers, of the shear to depth span ratios and of the cover thickness are estimated. Experimental results highlight that fibers are a very effective shear reinforcement in R.C. beams both under monotonic and cyclic actions, but under reversal cyclic actions, if shear failure is attained, the contribution due to the fibers reflects mainly in the bridging actions across the cracks and brittle failure can be partially avoided. In these cases and especially for seismic design ductile failure in flexure is more suitable and over strength in shear is required, the latter being obtained with a good combination of fibers and stirrups. Form theoretical point of view shear and flexural strength prevision was made by using a recent model developed by the authors able to take into account of the main parameters governing the flexural behavior of fibrous reinforced concrete beams. Finally, some design consideration for the use of FRC in seismic design of beams are given.
