Title:
Unified Approach for Minimum Reinforcement of Concrete Beams
Author(s):
Alessandro P. Fantilli, Bernardino Chiaia, and Andrea Gorino
Publication:
Structural Journal
Volume:
113
Issue:
5
Appears on pages(s):
1107-1116
Keywords:
bending moment; ductility index; fiber-reinforced concrete beams; lightly reinforced concrete beams; minimum reinforcement
DOI:
10.14359/51688927
Date:
9/1/2016
Abstract:
The structural behavior of lightly reinforced concrete (LRC) and fiber-reinforced concrete (FRC) beams in bending is similar and
depends on the amount of reinforcing bars and fibers, respectively. For this reason, a unified approach is introduced herein for the evaluation of the minimum reinforcement. Such approach is based on the definition of the ductility index (DI), which is a function of the difference between the ultimate bending moment and the effective cracking moment. DI is higher than zero when LRC and FRC beams show a ductile response, whereas it is negative in the case of a brittle behavior. In accordance with several experimental data, the linear dependence of DI on the amount of reinforcement can be demonstrated. Thus, a new design-by-testing procedure can be established to determine the minimum reinforcement (that is, reinforcing bars or fibers) of a concrete beam, which corresponds to DI equal to zero.