Specification for coupler or sleeve nut for threaded rod tie

[Jc67roch]

I have specified ASTM A36, hot dip galvanized threaded rods for tiebacks on a project. The contractor is now asking me for a spec on coupler nuts and/or sleeve nuts, as he can't get the rods in sufficient length. Research online seems to indicated the correct spec is ASTM A563, Grade A coupler nuts hot dip galvanized. But I can't find a load rating on these. It appears that the spec provides a nut that will, by nature of the dimensions, thread, and material fully develop the strength of the A36 rod. Is this true? does anyone have more guidance or load rating information/links? Thanks.

 

[bridgebuster]

Couples are just big nuts. Per A 563, Grade A hex zinc coated couplers have a proof load stress of 68 ksi, up to 1 1/2", heavy hex is 75 ksi, and the proof load is the proof load stress x the tensile stree area. The Portland Bolt Company also has info on their website.