Rabbit12
Structural
- Jul 23, 2014
- 495
I'm in a situation where I'm working with another engineer in a different country on some buildings for a client in the US. I'm working closely with this other engineer as I'm the stamping engineer. The new structures must be designed per the 2012 IBC.
This second company (who is building the structures) has a proprietary cold-formed panel system they are proposing to use for both the roof diaphragm and the shear walls. The panels are 22ga, 20" long and connect at the ends as shown in my attached sketch. At each end they are adding a 12" insulation clip. This clip serves two purposes. It provides support for batt insulation and also increase the section properties since these panels span 16' between support beams.
Per the IBC we need to design the diaphragm per AISI S310. In Section D of AISI S310 panels must be between 0.5" and 7.5" deep to use that standard to calculate diaphragm strength. It seems black and white we don't meet those requirements so I'm trying to find another option to develop/calculate diaphragm strength. One thought was to apply sheet steel to the bottom of the insulation clips. The sheet steel would span 20" but wouldn't carry any load other than self-weight. I thought it could be a viable solution, but the more I dig into the AISI standards I keep seeing things that appear to stop me. For instance, in AISI S213 Section D, the only diaphragm values provided are for wood panels. In section D1, it says diaphragms can consist of sheet steel, but the question becomes how to calculate the strength?
To muddy the waters even more, they want to use these as shear walls too. If I go to the shear wall Section C in S213 values are provided but minimum stud depth is 3.5" and we don't have a true "C" shape as there isn't any vertical return from the flanges. Seems to me we can't use the tabulated values for walls too.
For all the cold-formed experts. Am I missing something? Seems trying to use these panels is difficult at best. Is it possible to use flat steel sheet for a diaphragm? If so, are there any tabulated values for strength or a source for calculating it?
This second company (who is building the structures) has a proprietary cold-formed panel system they are proposing to use for both the roof diaphragm and the shear walls. The panels are 22ga, 20" long and connect at the ends as shown in my attached sketch. At each end they are adding a 12" insulation clip. This clip serves two purposes. It provides support for batt insulation and also increase the section properties since these panels span 16' between support beams.
Per the IBC we need to design the diaphragm per AISI S310. In Section D of AISI S310 panels must be between 0.5" and 7.5" deep to use that standard to calculate diaphragm strength. It seems black and white we don't meet those requirements so I'm trying to find another option to develop/calculate diaphragm strength. One thought was to apply sheet steel to the bottom of the insulation clips. The sheet steel would span 20" but wouldn't carry any load other than self-weight. I thought it could be a viable solution, but the more I dig into the AISI standards I keep seeing things that appear to stop me. For instance, in AISI S213 Section D, the only diaphragm values provided are for wood panels. In section D1, it says diaphragms can consist of sheet steel, but the question becomes how to calculate the strength?
To muddy the waters even more, they want to use these as shear walls too. If I go to the shear wall Section C in S213 values are provided but minimum stud depth is 3.5" and we don't have a true "C" shape as there isn't any vertical return from the flanges. Seems to me we can't use the tabulated values for walls too.
For all the cold-formed experts. Am I missing something? Seems trying to use these panels is difficult at best. Is it possible to use flat steel sheet for a diaphragm? If so, are there any tabulated values for strength or a source for calculating it?
