Connection Design
Connection Design
(OP)
I have s a situation where I have a pipe column (2-3 kips) bearing on the top chord of an open web truss. There is no guarantee that it will be able to hit a panel point, so I have to provide reinforcing between the panel points.
The detail I came up with needs three roof penetrations per pipe column to do this, and I do not like it. Does anyone have a detail they have used that is simple and uses fewer roof penetrations to install?
I can post the details I have sketched when I get to work if needed.
The detail I came up with needs three roof penetrations per pipe column to do this, and I do not like it. Does anyone have a detail they have used that is simple and uses fewer roof penetrations to install?
I can post the details I have sketched when I get to work if needed.






RE: Connection Design
RE: Connection Design
With metal deck over the joist, how did you connect to the side of the joist without welding or bolting to the top and bottom flanges of the joist, or did you?
The joist is existing and this is a retrofit, so I am worried about compromising the capacity of the joists by welding or bolting to the flanges. Currently, I am trying to literally sandwich the flanges between two angles and three bearing plates, shimming and grouting as needed.
Mike McCann
MMC Engineering
RE: Connection Design
I would love to bolt or weld to eliminate the two end plates, but I can't see how right now.
Mike McCann
MMC Engineering
RE: Connection Design
Mike McCann
MMC Engineering
RE: Connection Design
For the bottom connection, try using a beefy 8" long angle spanning to either side of the joist (perpendicular to chords) these can take the bolts easily and then can be welded/bolted back to back for a (4) bolt configuration to keep them from walking, and tack them to the chord if you want.
RE: Connection Design
RE: Connection Design
RE: Connection Design
Thanks for the channel suggestion. I'll look into that.
Placement of the transverse 8" deep angles could be interfered with by the chord member of the truss though, particularly at the 8" depth plus the depth of the angles. I am trying to make this connection as adaptable as possible to any field condition, but I know that is a longshot. Have to try though...
I am supporting a steel equipment platform (600#)and about 900# of equipment in a high seismic zone, so I am concerned with developing some moment capacity at the diaphragm level too. Not much, just some.
I guess the vertical reaction is only 650# or so per post considering some additional platform live load.
Mike McCann
MMC Engineering
RE: Connection Design
Where you end up hitting between the panel points we will add the web members discussed above. I would not try to develop any type of moment at the base of the column. If necessary develop the moment in the steel above the roof.