FRP ledge angle 1

[WWTEng]

I have very little experience using FRP so I am looking for some input here from folks who have worked with this material. Please see the attached sketch. The FRP angle is proposed (by the architect) to support the curtain wall and its preferred over steel because for better thermal results.

• The little bit of research I have done indicates that FRP angle can't be used in flexure. I am not sure if that applies to this condition.
• Second question: Are their grades of FRP similar to aluminum and if so what the most common grade/type.

 

[msquared48]

This detail scares the cr&* out of me considering having to deal with the brick veneer lateral support too.

Thermal breaks are great for energy savings, but at the expense of the structure is always a concern to me.



Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[WWTEng]

M2: Are you referring to some ties from the veneer that may end up @ the angle? Because the angle is not carrying any brick, only the curtain wall.

 

[Ron]

Not a snowball's chance in hell that I'd do that. FRP is great stuff in the right application. This is not one of those. FRP is susceptible to creep (exacerbated if exposed to thermal cycling) and this one could be under multiple modes of stress at the same time. Wouldn't do it.

 

[msquared48]

Agree with Ron here...

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[bookowski]

You can use FRP plate shims behind the angle for a thermal break.

 

[WWTEng]

Book, I was thinking the same. Thermal break won't be as good as the arch would probably like but structure comes first.

 

[bookowski]

Check out this modernsteel article - they have some details that are almost like your condition:

http://www.modernsteel.com/Uploads/Issues/January_2010/012010_Jan10_ThermalBridging_Web.pdf

 

[rd78]

I can't speak to the thermal break issue, but a comment about the use of FRP here in general ...

First of all there are no real "grades" of FRP. As a matter of fact, while processes and profiles may be similar from vendor to vendor they are not automatically interchangeable. It is much like getting anchors from Powers or Hilti - kinda similar but each has their own characteristics. One more elaboration... FRP encompasses much more than the plates and profiles referred to here. These other items are manufactured far differently and have wide ranging strengths and properties. This detail is referring specifically to pultrusions.

I don't know the clearances involved or the design requirements, but be aware that FRP has as much as 3x the thermal expansion of steel.

In the Modern Steel article there is a detail of a bent plate of FRP. You could fabricate such a critter, but not bend it like steel.

All the best.