Bolting Question

[nad1019]

I am desinging a connection to transfer moment (small amount) and have specified Turn of Nut pretension. Should I design the bolts using SC shear values, or bearing type? There is not tension on the bolt group, long slotted holes are used in the direction of force.

 

[JAE]

If you have slotted holes in the direction of the force, you should use Slip Critical Bolts which require some form of verifying the pretensioning (either turn of nut, calibrated wrench, direct tension washers, etc.)

 

[Ron]

I agree with JAE...also, don't forget that if you have moment developed in the connection, you do have tension in the bolts (from the couple created by the moment)

 

[chichuck]

I agree with JAE. One more point: see AISC 1989 spec (the one in the 9th Edition manual) Section J3.2.e. There they point out that i) you only can have long slotted holes in one of the connected parts, and ii) if the part with the long slotted holes is an outside ply (that means it is directly under a nut or bolt head, then you need plate washers or a bar with standard size holes in it directly under the head(nut).

Ron's comment about tension would be true if ned's connection were an end plate type connection, but from the description given, I don' think that is the case. Rather, I think there are angles, tees or plates connecting the beam flange to the column flange. Ned, am I correct?


Regards,


chichuck