After the publication of this article [1] the authors pointed out to us that a formula was incorrectly shown due to an error during typesetting as:

$$ \mathrm{Ultimate}\ \mathrm{stress}=8\mathrm{bFL}/\left({\mathrm{a}\mathrm{b}}^3\hbox{--} {\mathrm{a}}^{\prime }{\mathrm{b}}^{\prime }3\right)\uppi $$
$$ {\mathrm{Young}}^{'}\mathrm{s}\ \mathrm{modulus}={4\mathrm{FL}}^3/3\mathrm{d}\left({\mathrm{a}\mathrm{b}}^3\hbox{--} {\mathrm{a}}^{\prime }{\mathrm{b}}^{\prime }3\right)\uppi $$

It should have been shown as:

$$ \mathrm{Ultimate}\ \mathrm{stress}=8\mathrm{bFL}/\left({\mathrm{a}\mathrm{b}}^3\hbox{--} {\mathrm{a}}^{\prime }{{\mathrm{b}}^{\prime}}^3\right)\uppi $$
$$ {\mathrm{Young}}^{'}\mathrm{s}\ \mathrm{modulus}={4\mathrm{FL}}^3/3\mathrm{d}\left({\mathrm{a}\mathrm{b}}^3\hbox{--} {\mathrm{a}}^{\prime }{{\mathrm{b}}^{\prime}}^3\right)\uppi $$

BMC apologise for this error. The original article was corrected.