Tie bars of $12 \: mm$ diameter are to be provided in a concrete pavement slab. The working tensile stress of the tie bars is $230 \: MPa$, the average bond strength between a tie bar and concrete is $2 \: MPa$, and the joint gap between the slabs is $10 \: mm$. Ignoring the loss of bond and the tolerance factor, the design length of the tie bars (in $mm$, round off to the nearest integer) is ________