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  1. driftLimiter

    retrofitting new opening into an existing CMU exterior bearing/shear wall?

    I think you have this backwards a bit. Your procedure from 12.2.3 seems fine but.... OMF's are normally governed by drift but they will be compatible with the deflection of the CMU shear walls. The challenge will be to get the OMF's to resist any meaning full load because the shear walls are not...
  2. driftLimiter

    Can a R/C moment frame ever go pass 1% interstory drift without collapsing (NLTHA)

    Its hard man its the most sophisticated analysis technique we have. And you are the one reporting issues with it so you tell me how hard it is.
  3. driftLimiter

    Distributing or not to distribute concentrated live load per ASCE 7

    I always just think about a point load on the rafter of 200#. If the rafter cant support that then something feels wrong. I have only ever invoked the 2.5' sq area in a very specialized floor case.
  4. driftLimiter

    Can a R/C moment frame ever go pass 1% interstory drift without collapsing (NLTHA)

    Sounds like it comes down to the hinge hysteretic settings and p-delta. The moment-curvature settings for the hinges need to be well thought out and be determined based on good seismic detailing practices. NLTHA is a finicky beast and if your not extremely confident in your settings and good at...
  5. driftLimiter

    Seismic and Wind on connected building

    When you say wind controlled I assume you mean that the base shear due to wind is greater than the seismic base shear. That does not alleviate the need for seismic detailing. You must ensure seismic detailing is performed at least to the level required based on seismic design category, and...
  6. driftLimiter

    retrofitting new opening into an existing CMU exterior bearing/shear wall?

    You could use a dual system or a horizontal combination system. I don't see special masonry walls combined with omfs in the dual systems section of Table 12.2-1
  7. driftLimiter

    retrofitting new opening into an existing CMU exterior bearing/shear wall?

    I can't really think of a specific reference document that covers your case. You have to use your judgement, and for lateral I feel you are on the right track. You cant expect a moment frame to take any load away from the existing CMU walls because of relative stiffness. So you are left with...
  8. driftLimiter

    Valid Pin Boundary Condition?

    I find it very insightful human909 not pedantic at all :D
  9. driftLimiter

    Valid Pin Boundary Condition?

    where is human909? Im curious to see what they would say to OP. @duckhawk, remember that stiffness 'attracts' load. But also that ultimate limit states can aid our design process. Sure the connection exhibits some moment stiffness as others have indicated, but as you keep increasing that...
  10. driftLimiter

    ASCE 7 wind load for round irrigation tank

    In this equation its the 'projected' area. Meaning you project the surface area to a single plan. My read is that there are no windward and leeward components to account for when using it. Your second question is more interesting. You could treat it like wall that is open to atmosphere and compare.
  11. driftLimiter

    Odd Vertical Bracing

    If resisting seismic loading in SDC D or above, I think this would be difficult using prescriptive design per AISC. Do the beams in your diagram represent floor levels ? The type and ductility of this frame needs to be addressed if SDC D or above. That is a pretty significant hurdle.
  12. driftLimiter

    How to attach concrete buttress wall to toe side face of CMU retaining wall?

    Sketch please. and Loading information if applicable.
  13. driftLimiter

    Ultimate vs. Allowable Passive Pressure - which to use with a safety factor

    1802.1 just says that allowable pressures shall be used with allowable stress design load combos. Though I haven't yet had a geotech provide ultimate values, there is precedent for using them for foundation at least in ASCE7-22 12.13.5. Granted this section is in reference to seismic loading...
  14. driftLimiter

    Steel Vierendeel Truss End Connections

    Also your model has slip at one end and I would be looking to detail it that way or investigate the consequences of locking it in. I like the idea of a simple shear tab on the top chord and potentially another shear tab at the bottom chord perhaps with slotted holes.
  15. driftLimiter

    Best practice for connecting existing trusses and rafters to a proposed I-beam header.

    Looks like one of the property brothers designed this.
  16. driftLimiter

    Aluminum Design - Unbraced unequal leg angles in bending

    They have examples for unsymmetrical sections in flexure also 'open unsymmetrical shapes in flexure'. This should work for your unequal angle leg.
  17. driftLimiter

    Steel Cranked Beam End Supports

    I worry about this until I see the lateral support deflection. Get it small enough and I stop worrying about it.
  18. driftLimiter

    Deciding the lateral force resisting system.

    The slab needs to serve the role of drag strut collector. Some assessment of the tension and compression capacity of the slab as a strut/tie needs to be performed. There are different approaches used, some add supplemental reinforcement while others use the slab distributed reinforcement over a...
  19. driftLimiter

    ASCE 7-16 15.4-6 - Approx. Seismic Period Follow Up

    It is odd that you are saying gravity loads cause lateral deflections. The only reasons I can think of that that would happen are if you have a lot of P-delta or If your lateral system supports dead load (thrust typically from non-vertical gravity load resisting elements). First I think you...
  20. driftLimiter

    Bolt Hole Bearing Concerns Under Purely Axial Eccentric Load in Timber Connections

    Free body diagram. Can you use two plates on the sides of the wood beam instead so that the bolts are in shear only?

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