Design the double$-$shear bolted connection

$($Figure $2)$ of two plates $(320-20)$ using bolts of M$245\mathrm{.}8.$

$($i$.$e$.,$ How many columns do we need for this connection?$).$

$-$ The design force is equal to the design tension resistance of the member $($NtRd$).$

$-$ The grade of the steel for the plates is $$275.$

$-$ The shear plane passes through the threadless part of the bolt.$-$ There are $4$ rows of blots.