The horizontal redundant brace is being added at the midpoint of a braced bay (tension rods)of an existing guy-tower. The enginner is indicating the connection for this redundant member to be designed for a member force of +/- 12K. The angle size for the redundant is 2 1/2 x 2 1/2 x 1/4 and the gusset plate thickness is to be 3/8".
If you are sure the brace will always be in tension, then I agree with csd72...use at least 2 bolts. If there's a chance of compression, assuming the brace is longer than a few feet, you might have a buckling problem. Your angle can handle 12k up to about 6 or 7 feet if continuous. If gussetted, only about 1/2 that.
My concern is more with the gusset connection to the tower leg. I am using a 2-bolt connection. The engineer chose the angle size and assume he designed properly for both tension and compression.
