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  1. gcs3pe

    Roof deck tripping snow drift requirements, per reviewer

    Exactly, on both counts. Lu = 12" so use 20' (although I will have two beams 15' apart, so I can see how it might cause some type of drifting). I'm now trying to convince the client to live with a 15' x 15' deck and trying to convince the reviewer that if I keep the beams hovering right above...
  2. gcs3pe

    Roof deck tripping snow drift requirements, per reviewer

    I misspoke earlier - the reviewer is okay with the 15' limit for the deck area and railing. The beams, however, will be 30' wide because I cannot load the center of the building economically. Pg is 30, Pf calcs to 21, but the local code is Pf = 30 min.
  3. gcs3pe

    Roof deck tripping snow drift requirements, per reviewer

    The code is the IBC. Does that provision apply to snow loading? I always thought of that in terms of changes in use. If it does, and if the roof was be considered a single element, than I could probably keep the net increase to 5%, but breaking the roof down into beams and joists, any...
  4. gcs3pe

    Roof deck tripping snow drift requirements, per reviewer

    If I hang the deck joists flush between the beams, the finished deck elevation (and the tops of the beams) looks to be about 2' off the deck in back and 3' off the deck in front (roof slopes from back to front). The deck will have handrails all the way around it, though, but I might be able to...
  5. gcs3pe

    Roof deck tripping snow drift requirements, per reviewer

    Looking to put a 15'x20' roof deck atop an existing, older, 30'x40' building. The existing structure of the nearly flat roof does not meet today's building code. In order to leave the roof undisturbed, we planned to span the roof from side wall to side wall with small W shaped beams (the side...
  6. gcs3pe

    Unique roof rafter configuration and the analysis thereof...

    Mike - If you mean I should design trusses that meet the client's requirements - well, that would be a fine idea if this big boy wasn't already built! If you meant that I should try and turn what's already there into trusses - it'd be possible, I suppose, but the clients have plans for the...
  7. gcs3pe

    Unique roof rafter configuration and the analysis thereof...

    The IBC and IRC require 20 psf live loading for attics, but that's enough to sink the whole truss (if you can call it that). Hanging a 22' wide floor at 20/10 from the midpoint of a long set of rafters appears to overload them. Any ideas? And it must add to the wall thrust, too.
  8. gcs3pe

    Unique roof rafter configuration and the analysis thereof...

    Stop me if you've heard this before (but I'll need a picture to believe you). I'm reviewing the roof framing for a client with a 48' deep center hall colonial. The 10/12 pitch is formed with 11.88" LVL rafters at 16" on center, and they're tied at the top of the outside wall with continuous...
  9. gcs3pe

    Patchwork of holes in the web of a steel beam

    Ahhh contractors. I was brought onto a site where a 24' long W10x88 has been installed flush in a ceiling and the contractor has taken some liberties with pipe penetrations (see attached). A quick beam analysis shows no real issues with the selection of the beam - it's effectively uniformly...
  10. gcs3pe

    Fluted steel column capacity

    third pic Thanks!http://files.engineering.com/getfile.aspx?folder=e64ccf72-d4cf-40c8-aea0-ed6becf764ab&file=Column.jpg
  11. gcs3pe

    Fluted steel column capacity

    second pichttp://files.engineering.com/getfile.aspx?folder=80cb3d41-6edb-40d5-bf63-ef7c932fc5da&file=Column_base.jpg
  12. gcs3pe

    Fluted steel column capacity

    The 8'6" steel fluted column in these pictures is in service in the top floor of an old factory (1900+/-) building that was converted into condominiums in the early 1990s. It supports the roof structure of the building, but a client is hoping it's got the capacity to support one corner of a new...
  13. gcs3pe

    Welding question for built up beam

    Thanks for the lesson, guys - as always. A 20' beam with a 5k point requires impressively little welding.
  14. gcs3pe

    Welding question for built up beam

    I've got a 7.25" deep floor box into which I must shoehorn a steel beam. A W6x25 deflects too much on it's own, so I intend to build up the section with .25" x 4" plates welded to the top and bottom flanges. The fabricator says a continuous fillet weld will cause heat damage the W6. Is that...
  15. gcs3pe

    Two span floor joist

    Are we having fun yet, or what? I ignored the program's results within 10 minutes of the post. The software was, in fact, taking the bottom of the joists as laterally unsupported (Cl=.53 => Fb'=605). Modeling it as laterally supported follows AE's calcs at good by 68%. My questions tend to...
  16. gcs3pe

    Two span floor joist

    It seems like full lateral bracing across the bottom (in the form of sheetrock) reduces the bending stress to nearly that found in the spliced condition (two single spans). That's what I was missing.
  17. gcs3pe

    Two span floor joist

    I've got a 24' wide house with a bearing wall dead center down the middle. StruCalc and Code say 2x10 floor joists (#2 DFL) at 16" are way more than fine for 30/20 loading at 12' span. Why then, does adding a second, equivalent span in StruCalc fail? I'd like to run continuous 24' joists over...
  18. gcs3pe

    Rafter design with intermediate support

    I agree. I suspect the builder will put a ceiling in, but I'll make sure he does. In any case, the large thrust forces from the original model (which warranted bolts and/or straps) have now dropped down to a magnitude that can be handled by nails - so thrust drops off my radar with the new...
  19. gcs3pe

    Rafter design with intermediate support

    My bad, communication error - I know the n/s ridge board is not a support. And, as I said, the rafters are tied together at the plates with connections that can handle the thrust. So, I'll model the opposing rafter as a third support (same diagram as modeling the ridge board as a support, but...
  20. gcs3pe

    Rafter design with intermediate support

    4 - your drawing is spot on, and you'll both be happy to know the attic walls have been well thought out and the loads are safe to the foundation. Model the ridge board as a support, huh? That's simple enough. I thought it would be more complicated than that because they don't meet at 90...

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