Boat Storage Building Expansion joint

[XR250]

I am designing a 182' x 72' boat storage building. The construction is 2x6 x 14' walls with 2:12 gable wood trusses spanning 36' supported on a center bearing wall. 26ga metal roofing and siding on purlins are providing the stability in conjunction with some interior shearwalls. Is is necessary to have an expansion joint in this building?

 

[KootK]

I vote no on the expansion joint. My thoughts:

1) Per the oft quoted graph below, 182' just ain't that far in steel or concrete.

2) Google tells me that the thermal coefficient of expansion for wood is about 1/4 of that for steel.

3) Steel connections are stronger than wood but, then, wood connections would allow more slip I'd think.

4) Although the framing is wood, the deck is steel. No problem

4a) I suspect that you'd be fine if you took no special measures to address this.

4b) One strategy to address this might be to use corrosion appropriate pins for deck fastening rather than welds. That way, each sheet can deform a little around its fasteners without a brittle weld failure.

4c) A second strategy might be to set up your framing such that the deck flutes run along the short dimension of the building. Sounds as though you're already planning to span your deck the the the other way.

4d) On second thought, I suspect that you might actually be using standing seam roofing here (26 ga). If so, ignore all of point four.

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.

 

[hokie66]

I agree that no expansion jointing is necessary. However, the roofing and siding will expand and contract, so the fasteners should be able to accommodate movement. This is commonly done in two ways: by fastening through the ridges rather than the valleys, or by using concealed fastener clips (standing seam roofing). Whichever you use, the cladding should not be relied on for diaphragm action, in my opinion.

 

[XR250]

@Kootk: The metal siding ribs run vertical and attach to horizontal 2x4's. The roof deck ribs do run in the short direction. It is a screw down PBR profile roof attached to purlins spaced 24" O.c. that run the long direction. The sidelaps will be screwed as well.

@Hokie66: These types of buildings are typically braced by the cladding. I have testing done by the NFBA that shows that even 29ga material would work in this situation. There is other testing that has also been done for PBR profile panels. The panels have to be screwed on the flats to give it the diaphragm.
There are other buildings on this property without expansion joints that are much longer so I do not feel too bad about not using one. Just trying to cover my butt.

Thanks for your collective advice!