A double angle tension member $(707010$ back to back angle$)$ carrying a force of $280kN$ connects to a gusset $12mm$ thick.

$[10]$

a$.$ Determine the required number of M$20$ grade $8\mathrm{.}8$ bolts for this connection.

b$.$ Determine the total bearing resistance on the gusset.

c$.$ Determine the required number of $M20$ grade $10\mathrm{.}9$ s bolts for a wired brushed hot dip galvanized surface

Galaxy A$545$G