I've run into a situation a number of times in the last few years where a WF steel beam to WF steel beam sliding connection would be nice. Basically I don't want my beam to act like a strut transfering axial forces to the beam it frames into. Does anyone know of a good detail that transfers shear without transfering axial force? I thought slotted holes might work, but there's got to be a better way out there.

Depending on your slotted hole detail you may want to avoid slotted holes all together. There is at least one collapse that I know about that was caused by a slip connection with elongated holes in the shear connection. I would find a way to place the beam on a seat and then place a Teflon bearing plate between the steel beam and the seat.

This is the failure I was referring to:

http://failures.wikispaces.com/David+L.+Lawrence+C...

Does anyone know of a connection other than a positive bearing connection that works? It would be useful to frame one beam INTO the other.

Do not use "poor mans" expansion joint, or horizontal slots as noted above. Although there were several erection and QC issues that contributed to the Pittsburg collapse, these connections are not intended to perform as horizontal movement connections. Even if attention is paid to the slot condition and erection, other issues will impacted the horizontal movement. Friction of the bolt against the bearing surface of the hole, unequal force distribution, and the vertical shear force will result in binding and bolt plowing. Lubricating these connections is not an option in RCSC.

The ideal option is to provided slide bearing seated connections. These will perform as expected.

www.FerrellEngineering.com

Thanks for the link SPE, I hadn't heard of that one.

If you are referring to a movement joint in a building, total separation by double columns is the best approach. If your sales approach is not good enough to convince the architect, slide bearings are the next best approach. But nothing that you do will prevent increased depth at that point, as it can't be done by just framing into the web.

I have used a hinged link for this purpose, but the geometry has to be accommodating.

BA

What's a hinged link?

A vertical hanger hinged top and bottom.

BA

With the teflon bearing seat solution that was provided for the Pittsburgh building, is there anything holding the beam on the bearing plate or is it just sitting there?

That was my thought too. Are any guides or retainers typically placed along the bottom flange or elsewhere?

demayeng
Typically an small angle is provided on the top flange or beam web to stablize the beam on the seat. The angle has slots in the horizontal direction to allow movement. However, this angle carrys no shear, as all of the shear load is supported by the bearing seat.

www.FerrellEngineering.com

If required for stability, slide bearings can be made with guides to prevent transverse movement, and also to prevent uplift. Best to provide requirements to the bearing company and let them come up with a proposed solution.

http://www.granor.com.au/products/structural-beari...