cellular beam

[cmrdata]

There have been a lot of wonderful things said about the cellular/castellated "smart" beam in the articles. Could anyone offer your opinions about the general pro's and con's of such system when compared to traditional wide flange beams?

 

[KootK]

Pro: Efficient from a material perspective. Great if there's a global war on or some other reason for a material shortage. Also good if people are inexpensive relative to materials in your region. Maybe good from an environmental standpoint but energy expended as a result of fabrication and shipping will dampen that some.

Con: They require additional fabrication (cutting and welding). After being used in WWII, castellated beams were dead for a long time in many markets for this reason. Somehow, the Smart Beam folks have managed to overcome this, presumably using improved fabrication technologies.

Pro: You can make a floor/roof member that has the depth and material efficiency of a open webbed steel joist but is still relatively easy to paint / galvanize / fireproof. The few times that I've used cellular beams, it's been in pool buildings where the steel needed to be repainted at intervals to keep it looking fresh. It's much easier to paint a castellated beam than an open webbed steel joist.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[cmrdata]

Thank you, KootK, for your in depth discussion on the pro's and con's.
I'm also curious if it would be more tricky when it comes to overall coordination, for example:

1. In-coming beam that framed into this smart beam needs to be located in such way that the connection shear plate on the "web" of the cellular beam (assuming not an double angle connection) cannot be at where the "voids" are.

2. How well does the various sizes of the pips, ducts fit within the voids of the cellular beam. I assume you don't want to create a "custom" cellular beam with different void sizes and shapes just to fit the mechanical elements, which would be silly?

Thanks.

 

[KootK]

Both of those are pertinent issues crmdata. For my projects, the celluar beams were strictly used for infill, not supporting girders. And the mechanical agreed to adapt to the opening layout as required. We just had to give it to them early enough for them to coordinate.

It may be possible to adapt hole layout to suit mechanical. It may also be possible to omit holes to facilitate connection of supported beams. I'd check with a manufacturer before making any assumptions however. Blodgett's tome has a great section on castellated beams. If I remember correctly, there was a definite plan to how the beams are cut and reconstituted such that the fabrication remains efficient. I suspect that messing with the holes would have messed that up back in the day. The Smart Beam folks may have ways around such limitations however.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[cmrdata]

Thanks a lot, KootK.