Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by aquacata

  1. aquacata

    X-Brace or Diagonal Brace?

    I prefer diagonal brace since it has much less connections and reduces a lot labors. But X-Brace gives more stability and redundency. I want to know what you prefer to use in design. Please vote. Thanks!
  2. aquacata

    Steel column block-out at post-tension slab-on-grade

    The base shear is high. 70 kips at one column. I am using the L dowel from the footing to the slab, instead of the hairpin from the blockout to the slab. I like the hairpin better cause it transfers shear directly. But since the slab will be poured first, it looks to me that to have hairpin in...
  3. aquacata

    Steel column block-out at post-tension slab-on-grade

    Then you pour the footing first, leaving dowels from the footing to the slab, then pour the slab? Or you don't use the slab to take the base shear? So you have a column block-out with expansion joint around. The slab just has turn-downs sitting on the footing and there are no dowels from the...
  4. aquacata

    Steel column block-out at post-tension slab-on-grade

    Then you pour the footing first, leaving dowels from the footing to the slab, then pour the slab? Or you don't use the slab to take the base shear? So you have a column block-out with expansion joint around. The slab just has turn-downs sitting on the footing?
  5. aquacata

    Steel column block-out at post-tension slab-on-grade

    The largest block out is 30" by 30" (30" is the diagonal side, along column grid, it is 42" each way.). It is a good idea to layout the tendon around the block-out even though I don't know the tendon spacing yet. Thanks! The post-tensioned slab engineer wanted to pour the interior footing and...
  6. aquacata

    Steel column block-out at post-tension slab-on-grade

    The slab-on-grade is post-tensioned. It will be poured together with the column spread footing. Architect preferred the steel column has a regular block-out so the base plates, grout, and anchor bolts can be hided. But to do that, the tendon of the slab will need to cut/stop at the block-out...
  7. aquacata

    Composite Deck to hang 500 pound point load

    In my project, MEP wanted to hang their stuff from the composite deck (3" concrete over 3" deck) using Hilti anchors, cast-in-place and/or post installed. The deck will be drilled a hole so the anchor get into the slab concrete above 3/4" or more. The maximum point load reached 500 lbs. I am not...
  8. aquacata

    Composite Deck to hang MEP pipes/trays

    In my project, MEP wanted to hang their stuff from the composite deck (3" concrete over 3" deck) using Hilti anchors, cast-in-place and/or post installed. The deck will be drilled a hole so the anchor get into the slab concrete above 3/4" or more. The maximum point load reached 500 lbs. I am not...
  9. aquacata

    Maximum size/length of one concrete pour for elevated slab

    Actually It is the contractor who wanted to do one pour. But I am not sure if one pour for the 100'x124' size will cause cracks or not, you know, due to the shrinkage. How do you think? Thanks a lot!
  10. aquacata

    Maximum size/length of one concrete pour for elevated slab

    I have an elevated 6" thick concrete slab being supported by concrete walls at perimeter and concrete beams and columns at interior. The footprint of the slab is overall 100' x 120'. I wonder if the whole slab can be poured one time. Do I need a control joint for this size of slab? Thank you...
  11. aquacata

    zero stiffness and ill-conditioned model

    Yes that makes a lot sense. Thanks for your valuable help!
  12. aquacata

    zero stiffness and ill-conditioned model

    Thank you, slickdeals! In your way, I saw my ramp is not meshed. I will make it meshed. My ramp is straight. I assigned it as a shell since it needs to take out-of-plane gravity load. Could you please let me know to make it behave like a rigid diaphragm, what stiffness modifier need to change...
  13. aquacata

    zero stiffness and ill-conditioned model

    After I ran my ETABS building model, I got a warning message of zero stiffness at a joint. Also it specified my model is unstable and ill-conditioned. In your experience, could you tell what is the most possible reason for that? I suspect that my ramp area is not connected to its edge beams. I...
  14. aquacata

    Anchor rod minimum embedment length

    I am designing concrete spread footings of steel columns. The footing thickness is determined by the anchor rod embedment length. No moment and no uplift exist in my base plate. I wonder in this situation, what is the minimum anchor rod embedment length. Please let me know. Thanks a lot!
  15. aquacata

    Footing of corner column at property line

    DaveAtkins, I put a large eccentricity, say 70", in both directions. That is why it needs 12'x12' size footing. The footing absolutely has partial bearing. As for overturning, I used footing weight , soil weight and slab-on-grade weight over footing to counteract. If you think this is not...

Part and Inventory Search