Ordinary Concentrically Braced Frames Modification
Ordinary Concentrically Braced Frames Modification
(OP)
I am working on a project where I am using HSS tube columns and a concentrically braced frame for shear resistance. The steel horizontal braces were originally going to be steel tubes that ONLY resisted lateral loads because the architect wanted an exposed wood truss and glu-lam support beam floor system. The glu-lam beams would pass along the face of the columns where it would be supported with a seated connection and the steel horizontal braces would tie into the face of the column as usual with a diagonal tube brace and gusset connection. The reason for this is that the building will have a lot of openings and for a modern/industrial look, the architect wanted to see the steel braced frames from the outside windows looking in. After digging into the design, I started wondering if the glu-lam beam could act as the horizontal brace and resist the gravity and lateral loads. It would greatly help the economy of the project if I did not have the redundancy of the steel beam if the glu-lam could be used. I looked through the code and it does not necessarily state this is acceptable one way or another - or at least from what I have read. It gives ductility requirements and that may be my answer, but just from a thought process - it seems that these large glu-lam beams would be able to resist the axial forces from the lateral loads. Have any of you ever had this situation or come across something similar? Any input would be helpful.






RE: Ordinary Concentrically Braced Frames Modification
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Ordinary Concentrically Braced Frames Modification
RE: Ordinary Concentrically Braced Frames Modification
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Ordinary Concentrically Braced Frames Modification
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Ordinary Concentrically Braced Frames Modification
- tension only bracing?
- any weird detailing required for the thermal break?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Ordinary Concentrically Braced Frames Modification
RE: Ordinary Concentrically Braced Frames Modification
This may present an interesting opportunity. With T&C braces, you don't actually need your horizontal spandrel beams to be part of the vertical truss that forms your bracing system. As such, each of those tricky connections would only need to transfer the shear delivered at that diaphragm level. That would reduce your peak connection force by about a factor of three. It might also be a better reflection of the expected force distribution since the connection eccentricity between the braced frame and spandrel beams will introduce additional flexibility.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.