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truss question

Discussion in 'Residential Structural Codes' started by ICE, Jun 15, 2013.

  1. ICE

    ICE Moderator

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    The bearing point is shown on the plans as being directly beneath the vertical member and here we are offset. The trusses are approx. 35' long.

    Do you think that the offset is too much? Does it matter at all? There are three bearing points for these trusses; at each end and this one about 6' from the end.

    [​IMG]
     
  2. Frank

    Frank Registered User

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    What is the reaction at that bearing point? I would guess several hundred pounds on a 2x4--

    It needs to go back to the truss design engineer for review and suggested repair if needed
     
  3. pyrguy

    pyrguy Moderator

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    The design has moments of movement that cause the stresses to be distributed in the members of the truss so that loads can be carried. Change anything in the design, without the design engineer's written OK, can cause failure. Is the difference in the bearing point OK? It's up to the designer.
     
  4. jar546

    jar546 *****istrator

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    I hope they did not nail that truss to the top plates
     
  5. ICE

    ICE Moderator

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    The framing is passable but still hack to me. In just this picture I see nail tails, short studs and trimmers, plate splices a foot apart, shims over a header....and look at those 16s at the king to header.
     
    #5 ICE, Jun 15, 2013
    Last edited by a moderator: Jun 15, 2013
  6. Uncle Bob

    Uncle Bob Registered User

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    I agree with Frank and Pyrguy, stop everything until the design engineer makes repair requirements or tells them to tear it out. I don't like these plate connected truss' anyway; and if not installed properly the home owner is out of luck. What I'd really like is for the truss design company to have to do the inspections and sign off on it (taking responsibility for the installation). Uncle Bob
     
  7. Rider Rick

    Rider Rick Silver Member

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    Tiger,

    Not Approved install per engineering.

    It will not work the trusses will sag.

    I have seen it.
     
  8. ICE

    ICE Moderator

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    I sent them back to engineering. I will post the result when it happens.
     
  9. Daddy-0-

    Daddy-0- Moderator

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    Good call. They need to bear where designed to bear or back for engineering like Frank, Uncle Bob and others have said. Good call. That gets missed a lot. Someone should post a truss engineering sheet pic showing what the bearing point spec looks like for those who don't know.
     
  10. Rider Rick

    Rider Rick Silver Member

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    Daddy-o,

    That a great idea.

    We can also go over the truss bracing.

    Which is not per engineering most of the time out in the field.
     
  11. kyhowey

    kyhowey Silver Member

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    As a former truss designer, you can usually get by with an offset the width of the bearing. Even with a 3.5" offset, I would still ask for a new truss drawing showing the current bearing location and make sure none of the plates change. I doubt this will pass without a repair of some type. Might want to check the girder nailing pattern as well. Nails look too far apart unless it's nailed on the other side as well.
     
  12. hlfireinspector

    hlfireinspector Silver Member

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    Question from fire guy. Why are there H clips on the insulation panels? I can see light through the cracks.
     
  13. mjesse

    mjesse Registered User

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  14. Rio

    Rio Silver Member

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    It should be checked by the truss engineer and it's very, very likely the truss engineer isn't going to make them tear it out. You can see on the photo that the whole area there is beefed up and the truss engineer will probably be okay with it being the distance it is away from where it should be.

    Regarding the not liking plate connected trusses what's not to like? Through the use of pressed plate truss technology affordable large span openings have been made possible as well as a lower cost of delivery of the framing package and with the number (millions upon millions) of these roofs performing for decades with minimal problems they have been proven to perform very well indeed.
     
  15. Rider Rick

    Rider Rick Silver Member

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    Rio,

    It's when there is a fire and the fire fighter is on the roof.

    That's when roof trusses fail.
     
  16. Rio

    Rio Silver Member

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    In a fire all sorts of building systems can and do fail and unfortunately sometimes fire fighters do die as a result. What that has to do with this current issue is beyond me, especially as I specifically said 'CONSULT WITH THE TRUSS ENGINEER'.
     
  17. Rider Rick

    Rider Rick Silver Member

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    Rio,

    Through the use of pressed plate truss technology affordable large span openings have been made possible as well as a lower cost of delivery of the framing package and with the number (millions upon millions) of these roofs performing for decades with minimal problems they have been proven to perform very well indeed.

    There is a big problem with pressed plate truss technology.

    It fails in a fire.
     
  18. Rio

    Rio Silver Member

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    That's a valid criticism however I'm sure that fire fighters are well aware of the limitations and have been trained to deal with them accordingly. The same criticism could probably be made regarding engineered floor joist systems as well as engineered roof joist systems and platform framing in general.
     
  19. Rider Rick

    Rider Rick Silver Member

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    Rio,

    I think you took what I said wrong.

    I didn't mean to criticize you at all.

    I do think any kind of truss system floor or roof is not safe for the fire fighter.

    But old fashion platform framing with solid wood beams would be the safest in a fire for the fire fighter.
     
  20. Rio

    Rio Silver Member

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    Thanks Rider, I appreciate the heads up and this is an interesting discussion. I would say that as the technology of building advances, if that's the right word for it, there's pluses and minuses that come along with it. I guess the ideal home from a fire safety aspect would be a concrete one with treated furniture fully sprinklered inside and out; of course that would also be very expensive.

    As it is just the requirement for putting sprinklers in houses has cost us work as many people are on very tight budgets and as chunks of the budget get taken up by more and more requirements the ability to build gets reduced more and more. I'm sure that a roof conventionally framed under the current codes, would be more resistant to collapse than a truss framed house, how much more I'm not sure. It would also cost more and be another chunk taken out of the construction budget, pushing towards a greater inability for the house to be built or the addition to be done.
     

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