# D1.F.4.2 Minimum Flexural Reinforcement

The code specifies to dispose a minimum area of flexural reinforcement where tension reinforcement is required.

As a minimum bound, the condition that is given in
9.6.2.1is used. Although it is intended only for prestressed beams, it may be
used also in reinforced concrete beams and control in odd circumstances such as
where the specified cover is extremely large. The bending strength of the
section is designed to be at least 1.2 Mcr, where the cracking
moment is assumed to be applied to each axis separately as uniaxial bending. No
simultaneous biaxial moments are considered. The cracking moments about each
axis are calculated to cause the stress in the extreme tension fiber to reach
fr. In order to account for a possible varying of elastic
modulus (Ec) values, the following formula is used ignoring
the effect of the inertia product (Ixy):

${M}_{cr\left(region\right)}=\mathrm{}\frac{{\sigma}_{cr\left(region\right)}{E}_{c}{I}_{c}}{{E}_{c\left(region\right)}{c}_{\left(region\right)}}$

where_{cr(region)}
| = | |

_{c(region)}
| = | |

_{(region)}
| = | |

_{c}I_{c}
| = | |

= | ||

= |

The cracking moment is individually calculated for each axis and only considers a particular axis if there is a considerable bending moment about that axis. The sign of the acting moment is also considered.

This minimum bound is considered only when the 9.6.1.2 or 9.6.1.3 is also applied