Beam End to Beam End Connection 1

[22west]

I need to place an I beam, simply supported on the ends, across a 12 foot span.
Due to the geometry around the entrance to the room where the beam is to be installed, I can only bring in lengths of the I beam that are 6 feet or less.

I plan to butt two 6 foot lengths together, connecting them in the middle of the span.

What is a typical or recommended connection at this 'end to end' joint?
Should the connection plates be on the webs only? The flanges only? or Both?

I cannot seem to find a connection similar to this load case anywhere except for a column-end to column-end connection (where the connection plates are on the flanges only)

Note that, since this beam must be easily removed form the area from time to time, the connection must be a bolted connection.

 

[SperlingPE]

Connecting at mid-span where the moment is highest for a simple support beam?

If the beam is highly stressed, the beam needs to be put back together as if it was never two pieces.
1. Full pen butt weld it together.
2. Use plates on the flanges and web. Size plates and welds to resist moment and shear.
3. Depending on the required load, bolted connection may work.

 

[DaveAtkins]

This definitely calls for a moment connection. One of my professors said (and I have never forgotten this), that in order to create a moment connection, you must "grab the flanges."
My point--the flanges must be spliced, as well as the web. This can be accomplished with a plate at each flange, and one at the web, or with an end plate moment connection.

DaveAtkins

 

[COEngineeer]

12 feet seems short to me. Are you sure you cannot bring it in trough a window? There has to be a window in the room right?

 

[HouseBoy]

What kind of clearance around the splice area do you have? It's true that yo need to "grab the flanges" but with steel, that can be done in a number of ways. It may be possible (if you have enough clearance at the bottom of the beam) to use an end plate moment connection. This is similar to what you would see for a pre-engineered metal building. The ends of the beam pieces are welded to end plates (they would look almost like base plates) and there would be bolts above and below the flanges. If the bending is simple, you would likely be able to have the end plates flush with the top of the beam, have two bolts just under the top flange (since this flange would be in compression) and at the bottom flange you would have a pair of bolts above the bottom flange and a pair below the bottom flange. the bottom bolts would be proportioned to take the tension force. It is possibel to proportion these to fit on one side of the flange but if so, the bolts are not as efficient.
Of course all of this should be sized by an experienced structural engineer but the technique is relatively common, especially in the pre-eng metal building industry.

 

[22west]

I think I see what you mean houseguy, I have attached a sketch to this link :



I think that is probably the best way to do it, actually I believe I have seen this before...I am going to go with this.

Thanks to all for your most-informative help.

 

[HouseBoy]

That is exactly right.
Again, There are (I think) standard AISC proceedures for the design of this connection. I'm not sure about the latest edition but I think in the older (green) book. Maybe not but it's worth a look.

 

[rholder98]

Another idea is instead of using (2) 6 ft pieces, use one 6 ft piece and (2) 3 ft pieces. You've got two splice locations, but they are in lower moment regions, so the stresses would be less. I don't know if it helps, but it's a thought.

 

[sdz]

Actually, if you have to ask the question you don't know enough to design it. It's not just having a detail that works in concept, you have to size end plates and bolts for the loads.

If you use fully tensioned bolts they can't be re-used if you they are removed.

 

[22west]

I'm not designing it.
Its conceptual.