Building engineering ?

Discussion in 'Off-topic' started by a_springfield, Oct 25, 2020.

  1. a_springfield

    a_springfield Well-Known Member

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    Is there anyone here that has knowledge about lvls in buildings. I am trying to see what size I need for a header for a building.
     
  2. Wegahe

    Wegahe NRA Instructor

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    What distance are y0u trying to span and what is the ultimate load it will bear.
     

  3. gunsmoker

    gunsmoker Lawyer and Gun Activist

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    0CE76989-BD17-4D28-BB3E-4164AAC41BB8.jpeg

    I do all my structural engineering with Legos.
     
  4. a_springfield

    a_springfield Well-Known Member

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    16’ post to post one will have metal trusses 4’ from one post and another one with truss centered. I am building a 40x45 shed and only want 4 posts on one side. The load will be 40’ metal truss plus purlins and tim plus the occasional snow load. I have seen a 16” lvl used on a 23’ span holding up a 25’ stick built truss building, so I think it will be fine on the 16’ spans.
     
  5. Wegahe

    Wegahe NRA Instructor

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    The 16'' should be fine but will need to be triple. Glue and bolt them together. this is only a wild guess since I don't have all the numbers such as how much the truss actually weighs and what is sitting on the truss. If they are floor trusses they may need an additional LVL that would not be needed if only a roof was sitting on them.
     
  6. MWAG

    MWAG Active Member

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    you can't just say bolt 3 lvl's together because it will also depend on the thickness as well as the width...
    There is no standard lvl width or thickness... I've seen lvl's anywhere from 1 1/2" thick to 6" thick and as much as 24 in wide depending on the application
     
  7. jrm

    jrm Sledgehammer

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    No, but you also can't expect to get reliable structural engineering information on a gun forum.
     
    Rugerer likes this.
  8. Nemo

    Nemo Man of Myth and Legend

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    Unless you are shooting at structural engineers.

    Nemo
     
  9. Wegahe

    Wegahe NRA Instructor

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    Most LVLs are 1.75'' thick. Without more specific information this is the starting point. I have never in over 50 years had any experience with an LVL that was only 1.5'' thick. Two glued and screwed are required to support common TJIs used in a floor structure. However in this case with the information available using steel (which is significantly heavier that a wood TJI) you need the extra LVL to carry the estimated (read wild guess) load.
     
  10. GeorgiaHybrid

    GeorgiaHybrid Member

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    Do yourself a big favor, hire a structural engineer to do the calcs. You will be covered if anything ever happens and you will be paying for an expert opinion by a licensed professional. Not a bunch of guys on an internet forum that have a second cousin twice removed that used to be married to an engineer during the Korean war.
     
  11. Wegahe

    Wegahe NRA Instructor

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    I have been in the construction industry since 1969. I do not fall into any of the categories you describe. :mrgreen:
     
  12. Nemo

    Nemo Man of Myth and Legend

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    And you willing to let him rely on your calculations and instructions? They may be and likely are correct.

    But his-- I understood what he said and did it as he said to do, but it still fell down killing 2 adults and 4 kids at the move in celebration might give you a headache or 2.

    Getting a good structural engineer officially on it is a very good idea.

    Nemo
     
  13. a_springfield

    a_springfield Well-Known Member

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    The roof trusses are angle iron scissors on 12’ center. I spoke to a guy building carports with the same style trusses and he uses double 12” lvl for a 24’ span.
     
  14. a_springfield

    a_springfield Well-Known Member

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    I will also be adding in a header under the lvl to frame in garage doors so they will also be supported some
     
  15. 45_Fan

    45_Fan Well-Known Member

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    I think you need an engineering drawing. You call it a header but then you say it will have trusses. That’s no longer a header or header calculation, that’s a beam span question.

    Or to make a gun forum metaphor out of your question, “What size clip for the shoulder thingy that goes up?” I’m steeped in confusion by what’s asked or implied.
     
  16. Wegahe

    Wegahe NRA Instructor

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    If you want real numbers instead of a wild guess then perhaps posting actual distances, loads, weights and everything sitting on the trusses such as flooring and roofing. Since you posted 12' center instead of 12'' center how much does the roofing weigh that will span 12' from one truss to the next? I have seen people use a single 4x4 for a 12' header. Works for a while but not forever. Also what size angle iron is it? What gauge steel is it? 1''X1'' is not as heavy as 4''X4''.
     
  17. a_springfield

    a_springfield Well-Known Member

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    The building is going to be 40x 48. Trusses on 12’ centers with 2x6 on edge for prulins. I am wanting to only have 4 posts on one side so I can have 3 doors 2 10’ and one 12’ wide and centered (the posts will be in the way). The other side I will use 5 posts with the truss straight on the post. The roof is galvalume metal.

    The side that uses lvls will be posts on 16’ centers. One lvl will have a truss dead center 8’ from each post and the other 2 will have the truss sitting 4 feet from the post one way and 12 the other.
     
  18. gunsmoker

    gunsmoker Lawyer and Gun Activist

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    A picture (or drawing) is worth
    all those words, above.
    And more.
     
  19. dhaller

    dhaller Active Member

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    Offhand, you'll need to provide an engineer's letter for the truss system when you apply for the permit *anyway*, so I'd just select whichever licensed engineer has some grease in your county and have his office either review your plan and/or assist with it.

    That might pay for itself anyway since they might suggest an easier/cheaper/more efficient means of doing whatever it is you want to do? Food for thought.

    I'd just call up my county permitting office, get a list of licensed engineers from them, and make some calls.

    DH
     
  20. jrm

    jrm Sledgehammer

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    Not necessarily (depends on the jurisdiction). But surely he didn't just go get some random trusses. Trusses are engineered for a specific load and span. The LVLs should be, too. Whoever engineered the trusses ought to engineer the support for the trusses, too. And it wasn't someone on this forum.