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  1. Greenalleycat

    Manager Says Keep the Restraints — I Think They’re Unnecessary. Who’s Right?

    @ALphaSpace if you've allowed for the moment and the axial load and the cantilever column effective length...why are you using a 200x16 SHS that is ~2.5x the strength it needs to be? Surely you could adopt a more economic section Considering that you have a column either side + welded beam and...
  2. Greenalleycat

    Manager Says Keep the Restraints — I Think They’re Unnecessary. Who’s Right?

    Choras, it looks to me that the column is used to support the 2 flights of stairs and has beams welded off to take the load These will prevent buckling in that direction In the other direction there is no restraint therefore the design has two 'restraint beams' at each level - these are the ones...
  3. Greenalleycat

    Manager Says Keep the Restraints — I Think They’re Unnecessary. Who’s Right?

    It looks like the axial load is applied quite eccentrically to the column? Is that factored into your assessment
  4. Greenalleycat

    Steel Deck Cantilever

    The only thing that comes to mind is that this is probably appropriate for a UDL but may not be appropriate for a point load Wind uplift on a metal deck - sure Footfall at the end of a cantilever? The local effects of the point load may cause a different failure mode to govern This insight...
  5. Greenalleycat

    good reference for alterations of existing reinf. CMU walls?

    Braced frame could be channels with their webs against the block and bolted into it Doubt you'll get a (reasonble) moment frame to be stiff enough to compare to a wall Could look at building new pilasters at the ends of your openings to frame them out and create boundary elements for the wall...
  6. Greenalleycat

    good reference for alterations of existing reinf. CMU walls?

    I'm not aware of a specific reference. I don't think one is needed though: working through this rationally is what engineers are paid for I work in a high seismicity country so am familiar with the intricacies but not US specific stuff Issue 1 - providing appropriate gravity support to your new...
  7. Greenalleycat

    Paradoxical strut-and-tie tests (less = more)

    I went to an S&T presentation a few years back that showed different but very similar testing with the same results I recall that the explanation is that the narrow shape of the compressive element constrained the compression shape from fanning out and limited the transverse tension strain This...
  8. Greenalleycat

    Temporary Plate to Hold Anchor weight

    what is your question?
  9. Greenalleycat

    Strut and Tie

    Getting philosophical, all ties are diagonal if you rotate your piece of paper
  10. Greenalleycat

    Pilaster minimum reinforcement

    Interesting article, thanks for that
  11. Greenalleycat

    Raft on piles

    Are the walls underneath the slab or above it? You have to be very careful with mixing and matching raft/piles and walls/strip footings I have been dealing with a damaged house that has a basement with this system...the walls have settled far more than the piled foundations and there is now a...
  12. Greenalleycat

    Anchorage of Positive Moment Reinforcement

    No I don't agree with that. The point is to ensure that some steel is fully developed...doubling the steel and putting in shitty development length on both doesn't meet this requirement Also, I suspect that the development length required is more than 230mm? You have 12db PLUS a cog (which I'm...
  13. Greenalleycat

    Eccentric Pad Footing with Tie Bars?

    This is my guess as well, though I'm dubious of this detailing in practice That said, I've seen similar (and worse) detailing here in NZ and haven't observed issues yet...
  14. Greenalleycat

    Pilaster minimum reinforcement

    @ Your logic is inconsistent. Currently, it sounds like you're wanting to avoid designing the concrete as a column but also want to rely on it as a structural element - you can't have your cake and eat it too There are two ways that the concrete encasement can stiffen the W steel beam 1/ By...
  15. Greenalleycat

    Concrete hinge or pin

    Well that detail already shows one of the difficulties with this theoretical detail - you still have a moment capacity at the base, it's just that the lever arm has reduced to half the width of the wall at the critical point. It's not like it has zero moment capacity, it just has a lot less. And...
  16. Greenalleycat

    Pilaster minimum reinforcement

    I don't agree with the composite assumption. Composite action relies on vertical shear transfer between the steel and concrete interface...this is slick and there will be very little friction. You need welded studs or similar to be making that assumption. I would be placing 4/ 10 or 12mm bars...
  17. Greenalleycat

    Concrete hinge or pin

    Concrete hinges are basically the opposite to pins, can you be clearer what you want and why? Hinge = a designated zone for plastic deformation, any developed concrete design code can give you details on this. Basically, well-anchored reinforcement and lots of stirrups. Pin = a node with zero...
  18. Greenalleycat

    Welded together baseplate

    OK like 10kN. Not a huge load. Probably OK. Will presumably be getting torsional effects etc in the baseplate though so make sure you consider this By the time they FPBW two plates together wouldn't it just be cheaper to get it fabbed? They'll just start with a larger plate and cut a square out...
  19. Greenalleycat

    Welded together baseplate

    The answer is "it could be OK, but it depends"....Give us more to go off What is the baseplate for? How high are the loads? Why do you need to do this? Geometry? Are the plates stacked on top of each other or beside each other?
  20. Greenalleycat

    Retaining concrete reinforced block wall

    Looks like an expensive undertaking I don't really understand the geometry of this (how big is the patio now vs extended?) etc but my suggestion is using a suspended deck over piles Timber would be easiest but you could do it in concrete if you really wanted - have a few very deep / large...

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