Light Gage Diagonal Metal Bridging for Wood Joists

[StructuralEd]

Does light gage diagonal bridging for wood joists meet IBC requirements?
The 2009 IBC notes that substitute metal bridging needs to provide rigidity equal to 1"x 3" lumber. That seems a tall order considering that metal bridging literature that I've seen notes for "tension only", implying that there is little rigidity of the product itself.
Any comments would be appreciated.

 

[StructuralEd]

Also, does the joist member load direction matter to the "tension" bridging function if it is installed as X bridging?

 

[XR250]

I don't know how they allow 1x3 , 1x4 or anything but plywood or OSB.. That being said, there are plenty of houses around here that have used them and have survived pretty strong hurricanes. I guess the sheetrock is doing alot.

 

[msquared48]

Bridging has the dual functions of spreading gravity point loads to more than one joist - 2 or 3 - and preventing the rollover of the joists. This can be done by either tension or compression They are usually installed along the joist span at intervals not to exceed 8 feet.

Mike McCann
MMC Engineering

 

[XR250]

oops, I thought he was taking about wall bracing.
I don't see anyone installing joist bridging anymore

 

[StructuralEd]

Mike,

Do you know if the tension only metal bridging is accepted by the 2009 IBC?

 

[msquared48]

Excel... that does not mean that they should not be.

Structural Ed: No. But I do not know why it would not be. If Simpson has it, it should be compliant.

Mike McCann
MMC Engineering

 

[XR250]

I think the NDS only requires it on 2x12 or larger joists. Many framers claim the wood X-bridging causes squeaks. should it be there? - I don't know.
It is hard to say how effective it is anyway - especially if the floor system is designed conservatively.

 

[moltenmetal]

Local (Ontario) building code requires bridging or solid blocking between solid lumber joists at mid span beyond a certain span- no choice in the matter. Of course people are using engineered joists now mostly, but I would imagine they use blocking rather than bridging with those when (if) it is required. X bridging CAN cause squeaks, but the biggest culprit for squeaks is typically poor connection between the subfloor and the joists, which PL400 solves very effectively but of course framers hate it because it's messy- they will skip this step if you're not there watching. As to whether or not metal X bridging is an acceptable alternative, I don't know- never seen it.

 

[XR250]

funny, everyone in my neck of the woods uses subfloor adhesive, but nobody installs bridging

 

[StructuralEd]

Excel,

So does the IBC.