Steel Truss Splice

[courtnvm]

Has anyone encountered a heavy WT splice for a long span steel truss. If so, what have you seen as a typical detail.

I have considered providing a splice detail such as CJP weld the flanges and provide a plate on either side of the WT web with slip critical bolts to transfer the maximum moment and axial force. Does this sound acceptable?

Thank you,
Val

 

[unclesyd]

See thread175-164700

 

[courtnvm]

Thank you for the thread link. I am also looking to see if it would also work to CJP the flanges and bolt the webs together.

Thanks,
vAL

 

[lkjh345]

Courtnvm:

Just some thoughts.


I'm maybe missing something, but you say '..with slip critical bolts to transfer the maximum moment and axial force ..'. Is the truss loaded between panel points? If not, you should only have axial forces in a truss.



Is the WT member a chord member or a web member of the truss?

If a chord member: are you planning on having your splice at the middle of the truss span? If you can move the splice a panel or two away from the middle panel, your chord forces drop off and you might be ablt to bolt the splice together. This is certainly easier than welding. I've bolted large WT's together with flange plates each side of the flange, and web plates each side of the web. Since the bolts are in double shear, not as many are required as single shear bolts.

 

[courtnvm]

lkjh345, thanks for your input.

This truss is not my design, but from what I understand it is a long span roof truss which has WT12x65.5 top and bottom chords. The fabricator has suggested to full pen the flanges and bolt the webs.

I understand that slip critical may not need to be used, but I really don't know what the full function of the truss will be. I guess I am just assuming that I need to transfer full flexural capacity of the WT to be safe.

For clarification, I would have a total of three plates at the flange and a total of two plates at the web? I had thought of this also, but didn't know if that was widely used for chord splices.

I believe the maximum chord force is like 120 kips, which seems reasonable for a roof truss.

Well thanks for your help!!!

 

[lkjh345]

Yes, you would have 3 plates on the flange, and two plates on the web.

120 kips does not seem unreasonable, and with bolts in double shear, it will not be all that many.

FWIW, I would use at least 3 bolts (on each side of the splice) in any line of bolts. That may be conservative for what you are doing, but I'm just that way sometimes. .

 

[courtnvm]

I totally understand.

Thanks for the input.

Val

 

[dik]

I would try to avoid the CJP welds if possible... is it possible to bolt or fillet weld?

Dik